Source file src/reflect/all_test.go

     1  // Copyright 2009 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  package reflect_test
     6  
     7  import (
     8  	"bytes"
     9  	"encoding/base64"
    10  	"flag"
    11  	"fmt"
    12  	"go/token"
    13  	"io"
    14  	"math"
    15  	"math/rand"
    16  	"os"
    17  	. "reflect"
    18  	"reflect/internal/example1"
    19  	"reflect/internal/example2"
    20  	"runtime"
    21  	"sort"
    22  	"strconv"
    23  	"strings"
    24  	"sync"
    25  	"sync/atomic"
    26  	"testing"
    27  	"time"
    28  	"unsafe"
    29  )
    30  
    31  var sink interface{}
    32  
    33  func TestBool(t *testing.T) {
    34  	v := ValueOf(true)
    35  	if v.Bool() != true {
    36  		t.Fatal("ValueOf(true).Bool() = false")
    37  	}
    38  }
    39  
    40  type integer int
    41  type T struct {
    42  	a int
    43  	b float64
    44  	c string
    45  	d *int
    46  }
    47  
    48  type pair struct {
    49  	i interface{}
    50  	s string
    51  }
    52  
    53  func assert(t *testing.T, s, want string) {
    54  	if s != want {
    55  		t.Errorf("have %#q want %#q", s, want)
    56  	}
    57  }
    58  
    59  var typeTests = []pair{
    60  	{struct{ x int }{}, "int"},
    61  	{struct{ x int8 }{}, "int8"},
    62  	{struct{ x int16 }{}, "int16"},
    63  	{struct{ x int32 }{}, "int32"},
    64  	{struct{ x int64 }{}, "int64"},
    65  	{struct{ x uint }{}, "uint"},
    66  	{struct{ x uint8 }{}, "uint8"},
    67  	{struct{ x uint16 }{}, "uint16"},
    68  	{struct{ x uint32 }{}, "uint32"},
    69  	{struct{ x uint64 }{}, "uint64"},
    70  	{struct{ x float32 }{}, "float32"},
    71  	{struct{ x float64 }{}, "float64"},
    72  	{struct{ x int8 }{}, "int8"},
    73  	{struct{ x (**int8) }{}, "**int8"},
    74  	{struct{ x (**integer) }{}, "**reflect_test.integer"},
    75  	{struct{ x ([32]int32) }{}, "[32]int32"},
    76  	{struct{ x ([]int8) }{}, "[]int8"},
    77  	{struct{ x (map[string]int32) }{}, "map[string]int32"},
    78  	{struct{ x (chan<- string) }{}, "chan<- string"},
    79  	{struct{ x (chan<- chan string) }{}, "chan<- chan string"},
    80  	{struct{ x (chan<- <-chan string) }{}, "chan<- <-chan string"},
    81  	{struct{ x (<-chan <-chan string) }{}, "<-chan <-chan string"},
    82  	{struct{ x (chan (<-chan string)) }{}, "chan (<-chan string)"},
    83  	{struct {
    84  		x struct {
    85  			c chan *int32
    86  			d float32
    87  		}
    88  	}{},
    89  		"struct { c chan *int32; d float32 }",
    90  	},
    91  	{struct{ x (func(a int8, b int32)) }{}, "func(int8, int32)"},
    92  	{struct {
    93  		x struct {
    94  			c func(chan *integer, *int8)
    95  		}
    96  	}{},
    97  		"struct { c func(chan *reflect_test.integer, *int8) }",
    98  	},
    99  	{struct {
   100  		x struct {
   101  			a int8
   102  			b int32
   103  		}
   104  	}{},
   105  		"struct { a int8; b int32 }",
   106  	},
   107  	{struct {
   108  		x struct {
   109  			a int8
   110  			b int8
   111  			c int32
   112  		}
   113  	}{},
   114  		"struct { a int8; b int8; c int32 }",
   115  	},
   116  	{struct {
   117  		x struct {
   118  			a int8
   119  			b int8
   120  			c int8
   121  			d int32
   122  		}
   123  	}{},
   124  		"struct { a int8; b int8; c int8; d int32 }",
   125  	},
   126  	{struct {
   127  		x struct {
   128  			a int8
   129  			b int8
   130  			c int8
   131  			d int8
   132  			e int32
   133  		}
   134  	}{},
   135  		"struct { a int8; b int8; c int8; d int8; e int32 }",
   136  	},
   137  	{struct {
   138  		x struct {
   139  			a int8
   140  			b int8
   141  			c int8
   142  			d int8
   143  			e int8
   144  			f int32
   145  		}
   146  	}{},
   147  		"struct { a int8; b int8; c int8; d int8; e int8; f int32 }",
   148  	},
   149  	{struct {
   150  		x struct {
   151  			a int8 `reflect:"hi there"`
   152  		}
   153  	}{},
   154  		`struct { a int8 "reflect:\"hi there\"" }`,
   155  	},
   156  	{struct {
   157  		x struct {
   158  			a int8 `reflect:"hi \x00there\t\n\"\\"`
   159  		}
   160  	}{},
   161  		`struct { a int8 "reflect:\"hi \\x00there\\t\\n\\\"\\\\\"" }`,
   162  	},
   163  	{struct {
   164  		x struct {
   165  			f func(args ...int)
   166  		}
   167  	}{},
   168  		"struct { f func(...int) }",
   169  	},
   170  	{struct {
   171  		x (interface {
   172  			a(func(func(int) int) func(func(int)) int)
   173  			b()
   174  		})
   175  	}{},
   176  		"interface { reflect_test.a(func(func(int) int) func(func(int)) int); reflect_test.b() }",
   177  	},
   178  	{struct {
   179  		x struct {
   180  			int32
   181  			int64
   182  		}
   183  	}{},
   184  		"struct { int32; int64 }",
   185  	},
   186  }
   187  
   188  var valueTests = []pair{
   189  	{new(int), "132"},
   190  	{new(int8), "8"},
   191  	{new(int16), "16"},
   192  	{new(int32), "32"},
   193  	{new(int64), "64"},
   194  	{new(uint), "132"},
   195  	{new(uint8), "8"},
   196  	{new(uint16), "16"},
   197  	{new(uint32), "32"},
   198  	{new(uint64), "64"},
   199  	{new(float32), "256.25"},
   200  	{new(float64), "512.125"},
   201  	{new(complex64), "532.125+10i"},
   202  	{new(complex128), "564.25+1i"},
   203  	{new(string), "stringy cheese"},
   204  	{new(bool), "true"},
   205  	{new(*int8), "*int8(0)"},
   206  	{new(**int8), "**int8(0)"},
   207  	{new([5]int32), "[5]int32{0, 0, 0, 0, 0}"},
   208  	{new(**integer), "**reflect_test.integer(0)"},
   209  	{new(map[string]int32), "map[string]int32{<can't iterate on maps>}"},
   210  	{new(chan<- string), "chan<- string"},
   211  	{new(func(a int8, b int32)), "func(int8, int32)(0)"},
   212  	{new(struct {
   213  		c chan *int32
   214  		d float32
   215  	}),
   216  		"struct { c chan *int32; d float32 }{chan *int32, 0}",
   217  	},
   218  	{new(struct{ c func(chan *integer, *int8) }),
   219  		"struct { c func(chan *reflect_test.integer, *int8) }{func(chan *reflect_test.integer, *int8)(0)}",
   220  	},
   221  	{new(struct {
   222  		a int8
   223  		b int32
   224  	}),
   225  		"struct { a int8; b int32 }{0, 0}",
   226  	},
   227  	{new(struct {
   228  		a int8
   229  		b int8
   230  		c int32
   231  	}),
   232  		"struct { a int8; b int8; c int32 }{0, 0, 0}",
   233  	},
   234  }
   235  
   236  func testType(t *testing.T, i int, typ Type, want string) {
   237  	s := typ.String()
   238  	if s != want {
   239  		t.Errorf("#%d: have %#q, want %#q", i, s, want)
   240  	}
   241  }
   242  
   243  func TestTypes(t *testing.T) {
   244  	for i, tt := range typeTests {
   245  		testType(t, i, ValueOf(tt.i).Field(0).Type(), tt.s)
   246  	}
   247  }
   248  
   249  func TestSet(t *testing.T) {
   250  	for i, tt := range valueTests {
   251  		v := ValueOf(tt.i)
   252  		v = v.Elem()
   253  		switch v.Kind() {
   254  		case Int:
   255  			v.SetInt(132)
   256  		case Int8:
   257  			v.SetInt(8)
   258  		case Int16:
   259  			v.SetInt(16)
   260  		case Int32:
   261  			v.SetInt(32)
   262  		case Int64:
   263  			v.SetInt(64)
   264  		case Uint:
   265  			v.SetUint(132)
   266  		case Uint8:
   267  			v.SetUint(8)
   268  		case Uint16:
   269  			v.SetUint(16)
   270  		case Uint32:
   271  			v.SetUint(32)
   272  		case Uint64:
   273  			v.SetUint(64)
   274  		case Float32:
   275  			v.SetFloat(256.25)
   276  		case Float64:
   277  			v.SetFloat(512.125)
   278  		case Complex64:
   279  			v.SetComplex(532.125 + 10i)
   280  		case Complex128:
   281  			v.SetComplex(564.25 + 1i)
   282  		case String:
   283  			v.SetString("stringy cheese")
   284  		case Bool:
   285  			v.SetBool(true)
   286  		}
   287  		s := valueToString(v)
   288  		if s != tt.s {
   289  			t.Errorf("#%d: have %#q, want %#q", i, s, tt.s)
   290  		}
   291  	}
   292  }
   293  
   294  func TestSetValue(t *testing.T) {
   295  	for i, tt := range valueTests {
   296  		v := ValueOf(tt.i).Elem()
   297  		switch v.Kind() {
   298  		case Int:
   299  			v.Set(ValueOf(int(132)))
   300  		case Int8:
   301  			v.Set(ValueOf(int8(8)))
   302  		case Int16:
   303  			v.Set(ValueOf(int16(16)))
   304  		case Int32:
   305  			v.Set(ValueOf(int32(32)))
   306  		case Int64:
   307  			v.Set(ValueOf(int64(64)))
   308  		case Uint:
   309  			v.Set(ValueOf(uint(132)))
   310  		case Uint8:
   311  			v.Set(ValueOf(uint8(8)))
   312  		case Uint16:
   313  			v.Set(ValueOf(uint16(16)))
   314  		case Uint32:
   315  			v.Set(ValueOf(uint32(32)))
   316  		case Uint64:
   317  			v.Set(ValueOf(uint64(64)))
   318  		case Float32:
   319  			v.Set(ValueOf(float32(256.25)))
   320  		case Float64:
   321  			v.Set(ValueOf(512.125))
   322  		case Complex64:
   323  			v.Set(ValueOf(complex64(532.125 + 10i)))
   324  		case Complex128:
   325  			v.Set(ValueOf(complex128(564.25 + 1i)))
   326  		case String:
   327  			v.Set(ValueOf("stringy cheese"))
   328  		case Bool:
   329  			v.Set(ValueOf(true))
   330  		}
   331  		s := valueToString(v)
   332  		if s != tt.s {
   333  			t.Errorf("#%d: have %#q, want %#q", i, s, tt.s)
   334  		}
   335  	}
   336  }
   337  
   338  func TestCanSetField(t *testing.T) {
   339  	type embed struct{ x, X int }
   340  	type Embed struct{ x, X int }
   341  	type S1 struct {
   342  		embed
   343  		x, X int
   344  	}
   345  	type S2 struct {
   346  		*embed
   347  		x, X int
   348  	}
   349  	type S3 struct {
   350  		Embed
   351  		x, X int
   352  	}
   353  	type S4 struct {
   354  		*Embed
   355  		x, X int
   356  	}
   357  
   358  	type testCase struct {
   359  		// -1 means Addr().Elem() of current value
   360  		index  []int
   361  		canSet bool
   362  	}
   363  	tests := []struct {
   364  		val   Value
   365  		cases []testCase
   366  	}{{
   367  		val: ValueOf(&S1{}),
   368  		cases: []testCase{
   369  			{[]int{0}, false},
   370  			{[]int{0, -1}, false},
   371  			{[]int{0, 0}, false},
   372  			{[]int{0, 0, -1}, false},
   373  			{[]int{0, -1, 0}, false},
   374  			{[]int{0, -1, 0, -1}, false},
   375  			{[]int{0, 1}, true},
   376  			{[]int{0, 1, -1}, true},
   377  			{[]int{0, -1, 1}, true},
   378  			{[]int{0, -1, 1, -1}, true},
   379  			{[]int{1}, false},
   380  			{[]int{1, -1}, false},
   381  			{[]int{2}, true},
   382  			{[]int{2, -1}, true},
   383  		},
   384  	}, {
   385  		val: ValueOf(&S2{embed: &embed{}}),
   386  		cases: []testCase{
   387  			{[]int{0}, false},
   388  			{[]int{0, -1}, false},
   389  			{[]int{0, 0}, false},
   390  			{[]int{0, 0, -1}, false},
   391  			{[]int{0, -1, 0}, false},
   392  			{[]int{0, -1, 0, -1}, false},
   393  			{[]int{0, 1}, true},
   394  			{[]int{0, 1, -1}, true},
   395  			{[]int{0, -1, 1}, true},
   396  			{[]int{0, -1, 1, -1}, true},
   397  			{[]int{1}, false},
   398  			{[]int{2}, true},
   399  		},
   400  	}, {
   401  		val: ValueOf(&S3{}),
   402  		cases: []testCase{
   403  			{[]int{0}, true},
   404  			{[]int{0, -1}, true},
   405  			{[]int{0, 0}, false},
   406  			{[]int{0, 0, -1}, false},
   407  			{[]int{0, -1, 0}, false},
   408  			{[]int{0, -1, 0, -1}, false},
   409  			{[]int{0, 1}, true},
   410  			{[]int{0, 1, -1}, true},
   411  			{[]int{0, -1, 1}, true},
   412  			{[]int{0, -1, 1, -1}, true},
   413  			{[]int{1}, false},
   414  			{[]int{2}, true},
   415  		},
   416  	}, {
   417  		val: ValueOf(&S4{Embed: &Embed{}}),
   418  		cases: []testCase{
   419  			{[]int{0}, true},
   420  			{[]int{0, -1}, true},
   421  			{[]int{0, 0}, false},
   422  			{[]int{0, 0, -1}, false},
   423  			{[]int{0, -1, 0}, false},
   424  			{[]int{0, -1, 0, -1}, false},
   425  			{[]int{0, 1}, true},
   426  			{[]int{0, 1, -1}, true},
   427  			{[]int{0, -1, 1}, true},
   428  			{[]int{0, -1, 1, -1}, true},
   429  			{[]int{1}, false},
   430  			{[]int{2}, true},
   431  		},
   432  	}}
   433  
   434  	for _, tt := range tests {
   435  		t.Run(tt.val.Type().Name(), func(t *testing.T) {
   436  			for _, tc := range tt.cases {
   437  				f := tt.val
   438  				for _, i := range tc.index {
   439  					if f.Kind() == Ptr {
   440  						f = f.Elem()
   441  					}
   442  					if i == -1 {
   443  						f = f.Addr().Elem()
   444  					} else {
   445  						f = f.Field(i)
   446  					}
   447  				}
   448  				if got := f.CanSet(); got != tc.canSet {
   449  					t.Errorf("CanSet() = %v, want %v", got, tc.canSet)
   450  				}
   451  			}
   452  		})
   453  	}
   454  }
   455  
   456  var _i = 7
   457  
   458  var valueToStringTests = []pair{
   459  	{123, "123"},
   460  	{123.5, "123.5"},
   461  	{byte(123), "123"},
   462  	{"abc", "abc"},
   463  	{T{123, 456.75, "hello", &_i}, "reflect_test.T{123, 456.75, hello, *int(&7)}"},
   464  	{new(chan *T), "*chan *reflect_test.T(&chan *reflect_test.T)"},
   465  	{[10]int{1, 2, 3, 4, 5, 6, 7, 8, 9, 10}, "[10]int{1, 2, 3, 4, 5, 6, 7, 8, 9, 10}"},
   466  	{&[10]int{1, 2, 3, 4, 5, 6, 7, 8, 9, 10}, "*[10]int(&[10]int{1, 2, 3, 4, 5, 6, 7, 8, 9, 10})"},
   467  	{[]int{1, 2, 3, 4, 5, 6, 7, 8, 9, 10}, "[]int{1, 2, 3, 4, 5, 6, 7, 8, 9, 10}"},
   468  	{&[]int{1, 2, 3, 4, 5, 6, 7, 8, 9, 10}, "*[]int(&[]int{1, 2, 3, 4, 5, 6, 7, 8, 9, 10})"},
   469  }
   470  
   471  func TestValueToString(t *testing.T) {
   472  	for i, test := range valueToStringTests {
   473  		s := valueToString(ValueOf(test.i))
   474  		if s != test.s {
   475  			t.Errorf("#%d: have %#q, want %#q", i, s, test.s)
   476  		}
   477  	}
   478  }
   479  
   480  func TestArrayElemSet(t *testing.T) {
   481  	v := ValueOf(&[10]int{1, 2, 3, 4, 5, 6, 7, 8, 9, 10}).Elem()
   482  	v.Index(4).SetInt(123)
   483  	s := valueToString(v)
   484  	const want = "[10]int{1, 2, 3, 4, 123, 6, 7, 8, 9, 10}"
   485  	if s != want {
   486  		t.Errorf("[10]int: have %#q want %#q", s, want)
   487  	}
   488  
   489  	v = ValueOf([]int{1, 2, 3, 4, 5, 6, 7, 8, 9, 10})
   490  	v.Index(4).SetInt(123)
   491  	s = valueToString(v)
   492  	const want1 = "[]int{1, 2, 3, 4, 123, 6, 7, 8, 9, 10}"
   493  	if s != want1 {
   494  		t.Errorf("[]int: have %#q want %#q", s, want1)
   495  	}
   496  }
   497  
   498  func TestPtrPointTo(t *testing.T) {
   499  	var ip *int32
   500  	var i int32 = 1234
   501  	vip := ValueOf(&ip)
   502  	vi := ValueOf(&i).Elem()
   503  	vip.Elem().Set(vi.Addr())
   504  	if *ip != 1234 {
   505  		t.Errorf("got %d, want 1234", *ip)
   506  	}
   507  
   508  	ip = nil
   509  	vp := ValueOf(&ip).Elem()
   510  	vp.Set(Zero(vp.Type()))
   511  	if ip != nil {
   512  		t.Errorf("got non-nil (%p), want nil", ip)
   513  	}
   514  }
   515  
   516  func TestPtrSetNil(t *testing.T) {
   517  	var i int32 = 1234
   518  	ip := &i
   519  	vip := ValueOf(&ip)
   520  	vip.Elem().Set(Zero(vip.Elem().Type()))
   521  	if ip != nil {
   522  		t.Errorf("got non-nil (%d), want nil", *ip)
   523  	}
   524  }
   525  
   526  func TestMapSetNil(t *testing.T) {
   527  	m := make(map[string]int)
   528  	vm := ValueOf(&m)
   529  	vm.Elem().Set(Zero(vm.Elem().Type()))
   530  	if m != nil {
   531  		t.Errorf("got non-nil (%p), want nil", m)
   532  	}
   533  }
   534  
   535  func TestAll(t *testing.T) {
   536  	testType(t, 1, TypeOf((int8)(0)), "int8")
   537  	testType(t, 2, TypeOf((*int8)(nil)).Elem(), "int8")
   538  
   539  	typ := TypeOf((*struct {
   540  		c chan *int32
   541  		d float32
   542  	})(nil))
   543  	testType(t, 3, typ, "*struct { c chan *int32; d float32 }")
   544  	etyp := typ.Elem()
   545  	testType(t, 4, etyp, "struct { c chan *int32; d float32 }")
   546  	styp := etyp
   547  	f := styp.Field(0)
   548  	testType(t, 5, f.Type, "chan *int32")
   549  
   550  	f, present := styp.FieldByName("d")
   551  	if !present {
   552  		t.Errorf("FieldByName says present field is absent")
   553  	}
   554  	testType(t, 6, f.Type, "float32")
   555  
   556  	f, present = styp.FieldByName("absent")
   557  	if present {
   558  		t.Errorf("FieldByName says absent field is present")
   559  	}
   560  
   561  	typ = TypeOf([32]int32{})
   562  	testType(t, 7, typ, "[32]int32")
   563  	testType(t, 8, typ.Elem(), "int32")
   564  
   565  	typ = TypeOf((map[string]*int32)(nil))
   566  	testType(t, 9, typ, "map[string]*int32")
   567  	mtyp := typ
   568  	testType(t, 10, mtyp.Key(), "string")
   569  	testType(t, 11, mtyp.Elem(), "*int32")
   570  
   571  	typ = TypeOf((chan<- string)(nil))
   572  	testType(t, 12, typ, "chan<- string")
   573  	testType(t, 13, typ.Elem(), "string")
   574  
   575  	// make sure tag strings are not part of element type
   576  	typ = TypeOf(struct {
   577  		d []uint32 `reflect:"TAG"`
   578  	}{}).Field(0).Type
   579  	testType(t, 14, typ, "[]uint32")
   580  }
   581  
   582  func TestInterfaceGet(t *testing.T) {
   583  	var inter struct {
   584  		E interface{}
   585  	}
   586  	inter.E = 123.456
   587  	v1 := ValueOf(&inter)
   588  	v2 := v1.Elem().Field(0)
   589  	assert(t, v2.Type().String(), "interface {}")
   590  	i2 := v2.Interface()
   591  	v3 := ValueOf(i2)
   592  	assert(t, v3.Type().String(), "float64")
   593  }
   594  
   595  func TestInterfaceValue(t *testing.T) {
   596  	var inter struct {
   597  		E interface{}
   598  	}
   599  	inter.E = 123.456
   600  	v1 := ValueOf(&inter)
   601  	v2 := v1.Elem().Field(0)
   602  	assert(t, v2.Type().String(), "interface {}")
   603  	v3 := v2.Elem()
   604  	assert(t, v3.Type().String(), "float64")
   605  
   606  	i3 := v2.Interface()
   607  	if _, ok := i3.(float64); !ok {
   608  		t.Error("v2.Interface() did not return float64, got ", TypeOf(i3))
   609  	}
   610  }
   611  
   612  func TestFunctionValue(t *testing.T) {
   613  	var x interface{} = func() {}
   614  	v := ValueOf(x)
   615  	if fmt.Sprint(v.Interface()) != fmt.Sprint(x) {
   616  		t.Fatalf("TestFunction returned wrong pointer")
   617  	}
   618  	assert(t, v.Type().String(), "func()")
   619  }
   620  
   621  var appendTests = []struct {
   622  	orig, extra []int
   623  }{
   624  	{make([]int, 2, 4), []int{22}},
   625  	{make([]int, 2, 4), []int{22, 33, 44}},
   626  }
   627  
   628  func sameInts(x, y []int) bool {
   629  	if len(x) != len(y) {
   630  		return false
   631  	}
   632  	for i, xx := range x {
   633  		if xx != y[i] {
   634  			return false
   635  		}
   636  	}
   637  	return true
   638  }
   639  
   640  func TestAppend(t *testing.T) {
   641  	for i, test := range appendTests {
   642  		origLen, extraLen := len(test.orig), len(test.extra)
   643  		want := append(test.orig, test.extra...)
   644  		// Convert extra from []int to []Value.
   645  		e0 := make([]Value, len(test.extra))
   646  		for j, e := range test.extra {
   647  			e0[j] = ValueOf(e)
   648  		}
   649  		// Convert extra from []int to *SliceValue.
   650  		e1 := ValueOf(test.extra)
   651  		// Test Append.
   652  		a0 := ValueOf(test.orig)
   653  		have0 := Append(a0, e0...).Interface().([]int)
   654  		if !sameInts(have0, want) {
   655  			t.Errorf("Append #%d: have %v, want %v (%p %p)", i, have0, want, test.orig, have0)
   656  		}
   657  		// Check that the orig and extra slices were not modified.
   658  		if len(test.orig) != origLen {
   659  			t.Errorf("Append #%d origLen: have %v, want %v", i, len(test.orig), origLen)
   660  		}
   661  		if len(test.extra) != extraLen {
   662  			t.Errorf("Append #%d extraLen: have %v, want %v", i, len(test.extra), extraLen)
   663  		}
   664  		// Test AppendSlice.
   665  		a1 := ValueOf(test.orig)
   666  		have1 := AppendSlice(a1, e1).Interface().([]int)
   667  		if !sameInts(have1, want) {
   668  			t.Errorf("AppendSlice #%d: have %v, want %v", i, have1, want)
   669  		}
   670  		// Check that the orig and extra slices were not modified.
   671  		if len(test.orig) != origLen {
   672  			t.Errorf("AppendSlice #%d origLen: have %v, want %v", i, len(test.orig), origLen)
   673  		}
   674  		if len(test.extra) != extraLen {
   675  			t.Errorf("AppendSlice #%d extraLen: have %v, want %v", i, len(test.extra), extraLen)
   676  		}
   677  	}
   678  }
   679  
   680  func TestCopy(t *testing.T) {
   681  	a := []int{1, 2, 3, 4, 10, 9, 8, 7}
   682  	b := []int{11, 22, 33, 44, 1010, 99, 88, 77, 66, 55, 44}
   683  	c := []int{11, 22, 33, 44, 1010, 99, 88, 77, 66, 55, 44}
   684  	for i := 0; i < len(b); i++ {
   685  		if b[i] != c[i] {
   686  			t.Fatalf("b != c before test")
   687  		}
   688  	}
   689  	a1 := a
   690  	b1 := b
   691  	aa := ValueOf(&a1).Elem()
   692  	ab := ValueOf(&b1).Elem()
   693  	for tocopy := 1; tocopy <= 7; tocopy++ {
   694  		aa.SetLen(tocopy)
   695  		Copy(ab, aa)
   696  		aa.SetLen(8)
   697  		for i := 0; i < tocopy; i++ {
   698  			if a[i] != b[i] {
   699  				t.Errorf("(i) tocopy=%d a[%d]=%d, b[%d]=%d",
   700  					tocopy, i, a[i], i, b[i])
   701  			}
   702  		}
   703  		for i := tocopy; i < len(b); i++ {
   704  			if b[i] != c[i] {
   705  				if i < len(a) {
   706  					t.Errorf("(ii) tocopy=%d a[%d]=%d, b[%d]=%d, c[%d]=%d",
   707  						tocopy, i, a[i], i, b[i], i, c[i])
   708  				} else {
   709  					t.Errorf("(iii) tocopy=%d b[%d]=%d, c[%d]=%d",
   710  						tocopy, i, b[i], i, c[i])
   711  				}
   712  			} else {
   713  				t.Logf("tocopy=%d elem %d is okay\n", tocopy, i)
   714  			}
   715  		}
   716  	}
   717  }
   718  
   719  func TestCopyString(t *testing.T) {
   720  	t.Run("Slice", func(t *testing.T) {
   721  		s := bytes.Repeat([]byte{'_'}, 8)
   722  		val := ValueOf(s)
   723  
   724  		n := Copy(val, ValueOf(""))
   725  		if expecting := []byte("________"); n != 0 || !bytes.Equal(s, expecting) {
   726  			t.Errorf("got n = %d, s = %s, expecting n = 0, s = %s", n, s, expecting)
   727  		}
   728  
   729  		n = Copy(val, ValueOf("hello"))
   730  		if expecting := []byte("hello___"); n != 5 || !bytes.Equal(s, expecting) {
   731  			t.Errorf("got n = %d, s = %s, expecting n = 5, s = %s", n, s, expecting)
   732  		}
   733  
   734  		n = Copy(val, ValueOf("helloworld"))
   735  		if expecting := []byte("hellowor"); n != 8 || !bytes.Equal(s, expecting) {
   736  			t.Errorf("got n = %d, s = %s, expecting n = 8, s = %s", n, s, expecting)
   737  		}
   738  	})
   739  	t.Run("Array", func(t *testing.T) {
   740  		s := [...]byte{'_', '_', '_', '_', '_', '_', '_', '_'}
   741  		val := ValueOf(&s).Elem()
   742  
   743  		n := Copy(val, ValueOf(""))
   744  		if expecting := []byte("________"); n != 0 || !bytes.Equal(s[:], expecting) {
   745  			t.Errorf("got n = %d, s = %s, expecting n = 0, s = %s", n, s[:], expecting)
   746  		}
   747  
   748  		n = Copy(val, ValueOf("hello"))
   749  		if expecting := []byte("hello___"); n != 5 || !bytes.Equal(s[:], expecting) {
   750  			t.Errorf("got n = %d, s = %s, expecting n = 5, s = %s", n, s[:], expecting)
   751  		}
   752  
   753  		n = Copy(val, ValueOf("helloworld"))
   754  		if expecting := []byte("hellowor"); n != 8 || !bytes.Equal(s[:], expecting) {
   755  			t.Errorf("got n = %d, s = %s, expecting n = 8, s = %s", n, s[:], expecting)
   756  		}
   757  	})
   758  }
   759  
   760  func TestCopyArray(t *testing.T) {
   761  	a := [8]int{1, 2, 3, 4, 10, 9, 8, 7}
   762  	b := [11]int{11, 22, 33, 44, 1010, 99, 88, 77, 66, 55, 44}
   763  	c := b
   764  	aa := ValueOf(&a).Elem()
   765  	ab := ValueOf(&b).Elem()
   766  	Copy(ab, aa)
   767  	for i := 0; i < len(a); i++ {
   768  		if a[i] != b[i] {
   769  			t.Errorf("(i) a[%d]=%d, b[%d]=%d", i, a[i], i, b[i])
   770  		}
   771  	}
   772  	for i := len(a); i < len(b); i++ {
   773  		if b[i] != c[i] {
   774  			t.Errorf("(ii) b[%d]=%d, c[%d]=%d", i, b[i], i, c[i])
   775  		} else {
   776  			t.Logf("elem %d is okay\n", i)
   777  		}
   778  	}
   779  }
   780  
   781  func TestBigUnnamedStruct(t *testing.T) {
   782  	b := struct{ a, b, c, d int64 }{1, 2, 3, 4}
   783  	v := ValueOf(b)
   784  	b1 := v.Interface().(struct {
   785  		a, b, c, d int64
   786  	})
   787  	if b1.a != b.a || b1.b != b.b || b1.c != b.c || b1.d != b.d {
   788  		t.Errorf("ValueOf(%v).Interface().(*Big) = %v", b, b1)
   789  	}
   790  }
   791  
   792  type big struct {
   793  	a, b, c, d, e int64
   794  }
   795  
   796  func TestBigStruct(t *testing.T) {
   797  	b := big{1, 2, 3, 4, 5}
   798  	v := ValueOf(b)
   799  	b1 := v.Interface().(big)
   800  	if b1.a != b.a || b1.b != b.b || b1.c != b.c || b1.d != b.d || b1.e != b.e {
   801  		t.Errorf("ValueOf(%v).Interface().(big) = %v", b, b1)
   802  	}
   803  }
   804  
   805  type Basic struct {
   806  	x int
   807  	y float32
   808  }
   809  
   810  type NotBasic Basic
   811  
   812  type DeepEqualTest struct {
   813  	a, b interface{}
   814  	eq   bool
   815  }
   816  
   817  // Simple functions for DeepEqual tests.
   818  var (
   819  	fn1 func()             // nil.
   820  	fn2 func()             // nil.
   821  	fn3 = func() { fn1() } // Not nil.
   822  )
   823  
   824  type self struct{}
   825  
   826  type Loop *Loop
   827  type Loopy interface{}
   828  
   829  var loop1, loop2 Loop
   830  var loopy1, loopy2 Loopy
   831  var cycleMap1, cycleMap2, cycleMap3 map[string]interface{}
   832  
   833  type structWithSelfPtr struct {
   834  	p *structWithSelfPtr
   835  	s string
   836  }
   837  
   838  func init() {
   839  	loop1 = &loop2
   840  	loop2 = &loop1
   841  
   842  	loopy1 = &loopy2
   843  	loopy2 = &loopy1
   844  
   845  	cycleMap1 = map[string]interface{}{}
   846  	cycleMap1["cycle"] = cycleMap1
   847  	cycleMap2 = map[string]interface{}{}
   848  	cycleMap2["cycle"] = cycleMap2
   849  	cycleMap3 = map[string]interface{}{}
   850  	cycleMap3["different"] = cycleMap3
   851  }
   852  
   853  var deepEqualTests = []DeepEqualTest{
   854  	// Equalities
   855  	{nil, nil, true},
   856  	{1, 1, true},
   857  	{int32(1), int32(1), true},
   858  	{0.5, 0.5, true},
   859  	{float32(0.5), float32(0.5), true},
   860  	{"hello", "hello", true},
   861  	{make([]int, 10), make([]int, 10), true},
   862  	{&[3]int{1, 2, 3}, &[3]int{1, 2, 3}, true},
   863  	{Basic{1, 0.5}, Basic{1, 0.5}, true},
   864  	{error(nil), error(nil), true},
   865  	{map[int]string{1: "one", 2: "two"}, map[int]string{2: "two", 1: "one"}, true},
   866  	{fn1, fn2, true},
   867  
   868  	// Inequalities
   869  	{1, 2, false},
   870  	{int32(1), int32(2), false},
   871  	{0.5, 0.6, false},
   872  	{float32(0.5), float32(0.6), false},
   873  	{"hello", "hey", false},
   874  	{make([]int, 10), make([]int, 11), false},
   875  	{&[3]int{1, 2, 3}, &[3]int{1, 2, 4}, false},
   876  	{Basic{1, 0.5}, Basic{1, 0.6}, false},
   877  	{Basic{1, 0}, Basic{2, 0}, false},
   878  	{map[int]string{1: "one", 3: "two"}, map[int]string{2: "two", 1: "one"}, false},
   879  	{map[int]string{1: "one", 2: "txo"}, map[int]string{2: "two", 1: "one"}, false},
   880  	{map[int]string{1: "one"}, map[int]string{2: "two", 1: "one"}, false},
   881  	{map[int]string{2: "two", 1: "one"}, map[int]string{1: "one"}, false},
   882  	{nil, 1, false},
   883  	{1, nil, false},
   884  	{fn1, fn3, false},
   885  	{fn3, fn3, false},
   886  	{[][]int{{1}}, [][]int{{2}}, false},
   887  	{math.NaN(), math.NaN(), false},
   888  	{&[1]float64{math.NaN()}, &[1]float64{math.NaN()}, false},
   889  	{&[1]float64{math.NaN()}, self{}, true},
   890  	{[]float64{math.NaN()}, []float64{math.NaN()}, false},
   891  	{[]float64{math.NaN()}, self{}, true},
   892  	{map[float64]float64{math.NaN(): 1}, map[float64]float64{1: 2}, false},
   893  	{map[float64]float64{math.NaN(): 1}, self{}, true},
   894  	{&structWithSelfPtr{p: &structWithSelfPtr{s: "a"}}, &structWithSelfPtr{p: &structWithSelfPtr{s: "b"}}, false},
   895  
   896  	// Nil vs empty: not the same.
   897  	{[]int{}, []int(nil), false},
   898  	{[]int{}, []int{}, true},
   899  	{[]int(nil), []int(nil), true},
   900  	{map[int]int{}, map[int]int(nil), false},
   901  	{map[int]int{}, map[int]int{}, true},
   902  	{map[int]int(nil), map[int]int(nil), true},
   903  
   904  	// Mismatched types
   905  	{1, 1.0, false},
   906  	{int32(1), int64(1), false},
   907  	{0.5, "hello", false},
   908  	{[]int{1, 2, 3}, [3]int{1, 2, 3}, false},
   909  	{&[3]interface{}{1, 2, 4}, &[3]interface{}{1, 2, "s"}, false},
   910  	{Basic{1, 0.5}, NotBasic{1, 0.5}, false},
   911  	{map[uint]string{1: "one", 2: "two"}, map[int]string{2: "two", 1: "one"}, false},
   912  
   913  	// Possible loops.
   914  	{&loop1, &loop1, true},
   915  	{&loop1, &loop2, true},
   916  	{&loopy1, &loopy1, true},
   917  	{&loopy1, &loopy2, true},
   918  	{&cycleMap1, &cycleMap2, true},
   919  	{&cycleMap1, &cycleMap3, false},
   920  }
   921  
   922  func TestDeepEqual(t *testing.T) {
   923  	for _, test := range deepEqualTests {
   924  		if test.b == (self{}) {
   925  			test.b = test.a
   926  		}
   927  		if r := DeepEqual(test.a, test.b); r != test.eq {
   928  			t.Errorf("DeepEqual(%#v, %#v) = %v, want %v", test.a, test.b, r, test.eq)
   929  		}
   930  	}
   931  }
   932  
   933  func TestTypeOf(t *testing.T) {
   934  	// Special case for nil
   935  	if typ := TypeOf(nil); typ != nil {
   936  		t.Errorf("expected nil type for nil value; got %v", typ)
   937  	}
   938  	for _, test := range deepEqualTests {
   939  		v := ValueOf(test.a)
   940  		if !v.IsValid() {
   941  			continue
   942  		}
   943  		typ := TypeOf(test.a)
   944  		if typ != v.Type() {
   945  			t.Errorf("TypeOf(%v) = %v, but ValueOf(%v).Type() = %v", test.a, typ, test.a, v.Type())
   946  		}
   947  	}
   948  }
   949  
   950  type Recursive struct {
   951  	x int
   952  	r *Recursive
   953  }
   954  
   955  func TestDeepEqualRecursiveStruct(t *testing.T) {
   956  	a, b := new(Recursive), new(Recursive)
   957  	*a = Recursive{12, a}
   958  	*b = Recursive{12, b}
   959  	if !DeepEqual(a, b) {
   960  		t.Error("DeepEqual(recursive same) = false, want true")
   961  	}
   962  }
   963  
   964  type _Complex struct {
   965  	a int
   966  	b [3]*_Complex
   967  	c *string
   968  	d map[float64]float64
   969  }
   970  
   971  func TestDeepEqualComplexStruct(t *testing.T) {
   972  	m := make(map[float64]float64)
   973  	stra, strb := "hello", "hello"
   974  	a, b := new(_Complex), new(_Complex)
   975  	*a = _Complex{5, [3]*_Complex{a, b, a}, &stra, m}
   976  	*b = _Complex{5, [3]*_Complex{b, a, a}, &strb, m}
   977  	if !DeepEqual(a, b) {
   978  		t.Error("DeepEqual(complex same) = false, want true")
   979  	}
   980  }
   981  
   982  func TestDeepEqualComplexStructInequality(t *testing.T) {
   983  	m := make(map[float64]float64)
   984  	stra, strb := "hello", "helloo" // Difference is here
   985  	a, b := new(_Complex), new(_Complex)
   986  	*a = _Complex{5, [3]*_Complex{a, b, a}, &stra, m}
   987  	*b = _Complex{5, [3]*_Complex{b, a, a}, &strb, m}
   988  	if DeepEqual(a, b) {
   989  		t.Error("DeepEqual(complex different) = true, want false")
   990  	}
   991  }
   992  
   993  type UnexpT struct {
   994  	m map[int]int
   995  }
   996  
   997  func TestDeepEqualUnexportedMap(t *testing.T) {
   998  	// Check that DeepEqual can look at unexported fields.
   999  	x1 := UnexpT{map[int]int{1: 2}}
  1000  	x2 := UnexpT{map[int]int{1: 2}}
  1001  	if !DeepEqual(&x1, &x2) {
  1002  		t.Error("DeepEqual(x1, x2) = false, want true")
  1003  	}
  1004  
  1005  	y1 := UnexpT{map[int]int{2: 3}}
  1006  	if DeepEqual(&x1, &y1) {
  1007  		t.Error("DeepEqual(x1, y1) = true, want false")
  1008  	}
  1009  }
  1010  
  1011  func check2ndField(x interface{}, offs uintptr, t *testing.T) {
  1012  	s := ValueOf(x)
  1013  	f := s.Type().Field(1)
  1014  	if f.Offset != offs {
  1015  		t.Error("mismatched offsets in structure alignment:", f.Offset, offs)
  1016  	}
  1017  }
  1018  
  1019  // Check that structure alignment & offsets viewed through reflect agree with those
  1020  // from the compiler itself.
  1021  func TestAlignment(t *testing.T) {
  1022  	type T1inner struct {
  1023  		a int
  1024  	}
  1025  	type T1 struct {
  1026  		T1inner
  1027  		f int
  1028  	}
  1029  	type T2inner struct {
  1030  		a, b int
  1031  	}
  1032  	type T2 struct {
  1033  		T2inner
  1034  		f int
  1035  	}
  1036  
  1037  	x := T1{T1inner{2}, 17}
  1038  	check2ndField(x, uintptr(unsafe.Pointer(&x.f))-uintptr(unsafe.Pointer(&x)), t)
  1039  
  1040  	x1 := T2{T2inner{2, 3}, 17}
  1041  	check2ndField(x1, uintptr(unsafe.Pointer(&x1.f))-uintptr(unsafe.Pointer(&x1)), t)
  1042  }
  1043  
  1044  func Nil(a interface{}, t *testing.T) {
  1045  	n := ValueOf(a).Field(0)
  1046  	if !n.IsNil() {
  1047  		t.Errorf("%v should be nil", a)
  1048  	}
  1049  }
  1050  
  1051  func NotNil(a interface{}, t *testing.T) {
  1052  	n := ValueOf(a).Field(0)
  1053  	if n.IsNil() {
  1054  		t.Errorf("value of type %v should not be nil", ValueOf(a).Type().String())
  1055  	}
  1056  }
  1057  
  1058  func TestIsNil(t *testing.T) {
  1059  	// These implement IsNil.
  1060  	// Wrap in extra struct to hide interface type.
  1061  	doNil := []interface{}{
  1062  		struct{ x *int }{},
  1063  		struct{ x interface{} }{},
  1064  		struct{ x map[string]int }{},
  1065  		struct{ x func() bool }{},
  1066  		struct{ x chan int }{},
  1067  		struct{ x []string }{},
  1068  		struct{ x unsafe.Pointer }{},
  1069  	}
  1070  	for _, ts := range doNil {
  1071  		ty := TypeOf(ts).Field(0).Type
  1072  		v := Zero(ty)
  1073  		v.IsNil() // panics if not okay to call
  1074  	}
  1075  
  1076  	// Check the implementations
  1077  	var pi struct {
  1078  		x *int
  1079  	}
  1080  	Nil(pi, t)
  1081  	pi.x = new(int)
  1082  	NotNil(pi, t)
  1083  
  1084  	var si struct {
  1085  		x []int
  1086  	}
  1087  	Nil(si, t)
  1088  	si.x = make([]int, 10)
  1089  	NotNil(si, t)
  1090  
  1091  	var ci struct {
  1092  		x chan int
  1093  	}
  1094  	Nil(ci, t)
  1095  	ci.x = make(chan int)
  1096  	NotNil(ci, t)
  1097  
  1098  	var mi struct {
  1099  		x map[int]int
  1100  	}
  1101  	Nil(mi, t)
  1102  	mi.x = make(map[int]int)
  1103  	NotNil(mi, t)
  1104  
  1105  	var ii struct {
  1106  		x interface{}
  1107  	}
  1108  	Nil(ii, t)
  1109  	ii.x = 2
  1110  	NotNil(ii, t)
  1111  
  1112  	var fi struct {
  1113  		x func(t *testing.T)
  1114  	}
  1115  	Nil(fi, t)
  1116  	fi.x = TestIsNil
  1117  	NotNil(fi, t)
  1118  }
  1119  
  1120  func TestIsZero(t *testing.T) {
  1121  	for i, tt := range []struct {
  1122  		x    interface{}
  1123  		want bool
  1124  	}{
  1125  		// Booleans
  1126  		{true, false},
  1127  		{false, true},
  1128  		// Numeric types
  1129  		{int(0), true},
  1130  		{int(1), false},
  1131  		{int8(0), true},
  1132  		{int8(1), false},
  1133  		{int16(0), true},
  1134  		{int16(1), false},
  1135  		{int32(0), true},
  1136  		{int32(1), false},
  1137  		{int64(0), true},
  1138  		{int64(1), false},
  1139  		{uint(0), true},
  1140  		{uint(1), false},
  1141  		{uint8(0), true},
  1142  		{uint8(1), false},
  1143  		{uint16(0), true},
  1144  		{uint16(1), false},
  1145  		{uint32(0), true},
  1146  		{uint32(1), false},
  1147  		{uint64(0), true},
  1148  		{uint64(1), false},
  1149  		{float32(0), true},
  1150  		{float32(1.2), false},
  1151  		{float64(0), true},
  1152  		{float64(1.2), false},
  1153  		{math.Copysign(0, -1), false},
  1154  		{complex64(0), true},
  1155  		{complex64(1.2), false},
  1156  		{complex128(0), true},
  1157  		{complex128(1.2), false},
  1158  		{complex(math.Copysign(0, -1), 0), false},
  1159  		{complex(0, math.Copysign(0, -1)), false},
  1160  		{complex(math.Copysign(0, -1), math.Copysign(0, -1)), false},
  1161  		{uintptr(0), true},
  1162  		{uintptr(128), false},
  1163  		// Array
  1164  		{Zero(TypeOf([5]string{})).Interface(), true},
  1165  		{[5]string{"", "", "", "", ""}, true},
  1166  		{[5]string{}, true},
  1167  		{[5]string{"", "", "", "a", ""}, false},
  1168  		// Chan
  1169  		{(chan string)(nil), true},
  1170  		{make(chan string), false},
  1171  		{time.After(1), false},
  1172  		// Func
  1173  		{(func())(nil), true},
  1174  		{New, false},
  1175  		// Interface
  1176  		{New(TypeOf(new(error)).Elem()).Elem(), true},
  1177  		{(io.Reader)(strings.NewReader("")), false},
  1178  		// Map
  1179  		{(map[string]string)(nil), true},
  1180  		{map[string]string{}, false},
  1181  		{make(map[string]string), false},
  1182  		// Ptr
  1183  		{(*func())(nil), true},
  1184  		{(*int)(nil), true},
  1185  		{new(int), false},
  1186  		// Slice
  1187  		{[]string{}, false},
  1188  		{([]string)(nil), true},
  1189  		{make([]string, 0), false},
  1190  		// Strings
  1191  		{"", true},
  1192  		{"not-zero", false},
  1193  		// Structs
  1194  		{T{}, true},
  1195  		{T{123, 456.75, "hello", &_i}, false},
  1196  		// UnsafePointer
  1197  		{(unsafe.Pointer)(nil), true},
  1198  		{(unsafe.Pointer)(new(int)), false},
  1199  	} {
  1200  		var x Value
  1201  		if v, ok := tt.x.(Value); ok {
  1202  			x = v
  1203  		} else {
  1204  			x = ValueOf(tt.x)
  1205  		}
  1206  
  1207  		b := x.IsZero()
  1208  		if b != tt.want {
  1209  			t.Errorf("%d: IsZero((%s)(%+v)) = %t, want %t", i, x.Kind(), tt.x, b, tt.want)
  1210  		}
  1211  
  1212  		if !Zero(TypeOf(tt.x)).IsZero() {
  1213  			t.Errorf("%d: IsZero(Zero(TypeOf((%s)(%+v)))) is false", i, x.Kind(), tt.x)
  1214  		}
  1215  	}
  1216  
  1217  	func() {
  1218  		defer func() {
  1219  			if r := recover(); r == nil {
  1220  				t.Error("should panic for invalid value")
  1221  			}
  1222  		}()
  1223  		(Value{}).IsZero()
  1224  	}()
  1225  }
  1226  
  1227  func TestInterfaceExtraction(t *testing.T) {
  1228  	var s struct {
  1229  		W io.Writer
  1230  	}
  1231  
  1232  	s.W = os.Stdout
  1233  	v := Indirect(ValueOf(&s)).Field(0).Interface()
  1234  	if v != s.W.(interface{}) {
  1235  		t.Error("Interface() on interface: ", v, s.W)
  1236  	}
  1237  }
  1238  
  1239  func TestNilPtrValueSub(t *testing.T) {
  1240  	var pi *int
  1241  	if pv := ValueOf(pi); pv.Elem().IsValid() {
  1242  		t.Error("ValueOf((*int)(nil)).Elem().IsValid()")
  1243  	}
  1244  }
  1245  
  1246  func TestMap(t *testing.T) {
  1247  	m := map[string]int{"a": 1, "b": 2}
  1248  	mv := ValueOf(m)
  1249  	if n := mv.Len(); n != len(m) {
  1250  		t.Errorf("Len = %d, want %d", n, len(m))
  1251  	}
  1252  	keys := mv.MapKeys()
  1253  	newmap := MakeMap(mv.Type())
  1254  	for k, v := range m {
  1255  		// Check that returned Keys match keys in range.
  1256  		// These aren't required to be in the same order.
  1257  		seen := false
  1258  		for _, kv := range keys {
  1259  			if kv.String() == k {
  1260  				seen = true
  1261  				break
  1262  			}
  1263  		}
  1264  		if !seen {
  1265  			t.Errorf("Missing key %q", k)
  1266  		}
  1267  
  1268  		// Check that value lookup is correct.
  1269  		vv := mv.MapIndex(ValueOf(k))
  1270  		if vi := vv.Int(); vi != int64(v) {
  1271  			t.Errorf("Key %q: have value %d, want %d", k, vi, v)
  1272  		}
  1273  
  1274  		// Copy into new map.
  1275  		newmap.SetMapIndex(ValueOf(k), ValueOf(v))
  1276  	}
  1277  	vv := mv.MapIndex(ValueOf("not-present"))
  1278  	if vv.IsValid() {
  1279  		t.Errorf("Invalid key: got non-nil value %s", valueToString(vv))
  1280  	}
  1281  
  1282  	newm := newmap.Interface().(map[string]int)
  1283  	if len(newm) != len(m) {
  1284  		t.Errorf("length after copy: newm=%d, m=%d", len(newm), len(m))
  1285  	}
  1286  
  1287  	for k, v := range newm {
  1288  		mv, ok := m[k]
  1289  		if mv != v {
  1290  			t.Errorf("newm[%q] = %d, but m[%q] = %d, %v", k, v, k, mv, ok)
  1291  		}
  1292  	}
  1293  
  1294  	newmap.SetMapIndex(ValueOf("a"), Value{})
  1295  	v, ok := newm["a"]
  1296  	if ok {
  1297  		t.Errorf("newm[\"a\"] = %d after delete", v)
  1298  	}
  1299  
  1300  	mv = ValueOf(&m).Elem()
  1301  	mv.Set(Zero(mv.Type()))
  1302  	if m != nil {
  1303  		t.Errorf("mv.Set(nil) failed")
  1304  	}
  1305  }
  1306  
  1307  func TestNilMap(t *testing.T) {
  1308  	var m map[string]int
  1309  	mv := ValueOf(m)
  1310  	keys := mv.MapKeys()
  1311  	if len(keys) != 0 {
  1312  		t.Errorf(">0 keys for nil map: %v", keys)
  1313  	}
  1314  
  1315  	// Check that value for missing key is zero.
  1316  	x := mv.MapIndex(ValueOf("hello"))
  1317  	if x.Kind() != Invalid {
  1318  		t.Errorf("m.MapIndex(\"hello\") for nil map = %v, want Invalid Value", x)
  1319  	}
  1320  
  1321  	// Check big value too.
  1322  	var mbig map[string][10 << 20]byte
  1323  	x = ValueOf(mbig).MapIndex(ValueOf("hello"))
  1324  	if x.Kind() != Invalid {
  1325  		t.Errorf("mbig.MapIndex(\"hello\") for nil map = %v, want Invalid Value", x)
  1326  	}
  1327  
  1328  	// Test that deletes from a nil map succeed.
  1329  	mv.SetMapIndex(ValueOf("hi"), Value{})
  1330  }
  1331  
  1332  func TestChan(t *testing.T) {
  1333  	for loop := 0; loop < 2; loop++ {
  1334  		var c chan int
  1335  		var cv Value
  1336  
  1337  		// check both ways to allocate channels
  1338  		switch loop {
  1339  		case 1:
  1340  			c = make(chan int, 1)
  1341  			cv = ValueOf(c)
  1342  		case 0:
  1343  			cv = MakeChan(TypeOf(c), 1)
  1344  			c = cv.Interface().(chan int)
  1345  		}
  1346  
  1347  		// Send
  1348  		cv.Send(ValueOf(2))
  1349  		if i := <-c; i != 2 {
  1350  			t.Errorf("reflect Send 2, native recv %d", i)
  1351  		}
  1352  
  1353  		// Recv
  1354  		c <- 3
  1355  		if i, ok := cv.Recv(); i.Int() != 3 || !ok {
  1356  			t.Errorf("native send 3, reflect Recv %d, %t", i.Int(), ok)
  1357  		}
  1358  
  1359  		// TryRecv fail
  1360  		val, ok := cv.TryRecv()
  1361  		if val.IsValid() || ok {
  1362  			t.Errorf("TryRecv on empty chan: %s, %t", valueToString(val), ok)
  1363  		}
  1364  
  1365  		// TryRecv success
  1366  		c <- 4
  1367  		val, ok = cv.TryRecv()
  1368  		if !val.IsValid() {
  1369  			t.Errorf("TryRecv on ready chan got nil")
  1370  		} else if i := val.Int(); i != 4 || !ok {
  1371  			t.Errorf("native send 4, TryRecv %d, %t", i, ok)
  1372  		}
  1373  
  1374  		// TrySend fail
  1375  		c <- 100
  1376  		ok = cv.TrySend(ValueOf(5))
  1377  		i := <-c
  1378  		if ok {
  1379  			t.Errorf("TrySend on full chan succeeded: value %d", i)
  1380  		}
  1381  
  1382  		// TrySend success
  1383  		ok = cv.TrySend(ValueOf(6))
  1384  		if !ok {
  1385  			t.Errorf("TrySend on empty chan failed")
  1386  			select {
  1387  			case x := <-c:
  1388  				t.Errorf("TrySend failed but it did send %d", x)
  1389  			default:
  1390  			}
  1391  		} else {
  1392  			if i = <-c; i != 6 {
  1393  				t.Errorf("TrySend 6, recv %d", i)
  1394  			}
  1395  		}
  1396  
  1397  		// Close
  1398  		c <- 123
  1399  		cv.Close()
  1400  		if i, ok := cv.Recv(); i.Int() != 123 || !ok {
  1401  			t.Errorf("send 123 then close; Recv %d, %t", i.Int(), ok)
  1402  		}
  1403  		if i, ok := cv.Recv(); i.Int() != 0 || ok {
  1404  			t.Errorf("after close Recv %d, %t", i.Int(), ok)
  1405  		}
  1406  	}
  1407  
  1408  	// check creation of unbuffered channel
  1409  	var c chan int
  1410  	cv := MakeChan(TypeOf(c), 0)
  1411  	c = cv.Interface().(chan int)
  1412  	if cv.TrySend(ValueOf(7)) {
  1413  		t.Errorf("TrySend on sync chan succeeded")
  1414  	}
  1415  	if v, ok := cv.TryRecv(); v.IsValid() || ok {
  1416  		t.Errorf("TryRecv on sync chan succeeded: isvalid=%v ok=%v", v.IsValid(), ok)
  1417  	}
  1418  
  1419  	// len/cap
  1420  	cv = MakeChan(TypeOf(c), 10)
  1421  	c = cv.Interface().(chan int)
  1422  	for i := 0; i < 3; i++ {
  1423  		c <- i
  1424  	}
  1425  	if l, m := cv.Len(), cv.Cap(); l != len(c) || m != cap(c) {
  1426  		t.Errorf("Len/Cap = %d/%d want %d/%d", l, m, len(c), cap(c))
  1427  	}
  1428  }
  1429  
  1430  // caseInfo describes a single case in a select test.
  1431  type caseInfo struct {
  1432  	desc      string
  1433  	canSelect bool
  1434  	recv      Value
  1435  	closed    bool
  1436  	helper    func()
  1437  	panic     bool
  1438  }
  1439  
  1440  var allselect = flag.Bool("allselect", false, "exhaustive select test")
  1441  
  1442  func TestSelect(t *testing.T) {
  1443  	selectWatch.once.Do(func() { go selectWatcher() })
  1444  
  1445  	var x exhaustive
  1446  	nch := 0
  1447  	newop := func(n int, cap int) (ch, val Value) {
  1448  		nch++
  1449  		if nch%101%2 == 1 {
  1450  			c := make(chan int, cap)
  1451  			ch = ValueOf(c)
  1452  			val = ValueOf(n)
  1453  		} else {
  1454  			c := make(chan string, cap)
  1455  			ch = ValueOf(c)
  1456  			val = ValueOf(fmt.Sprint(n))
  1457  		}
  1458  		return
  1459  	}
  1460  
  1461  	for n := 0; x.Next(); n++ {
  1462  		if testing.Short() && n >= 1000 {
  1463  			break
  1464  		}
  1465  		if n >= 100000 && !*allselect {
  1466  			break
  1467  		}
  1468  		if n%100000 == 0 && testing.Verbose() {
  1469  			println("TestSelect", n)
  1470  		}
  1471  		var cases []SelectCase
  1472  		var info []caseInfo
  1473  
  1474  		// Ready send.
  1475  		if x.Maybe() {
  1476  			ch, val := newop(len(cases), 1)
  1477  			cases = append(cases, SelectCase{
  1478  				Dir:  SelectSend,
  1479  				Chan: ch,
  1480  				Send: val,
  1481  			})
  1482  			info = append(info, caseInfo{desc: "ready send", canSelect: true})
  1483  		}
  1484  
  1485  		// Ready recv.
  1486  		if x.Maybe() {
  1487  			ch, val := newop(len(cases), 1)
  1488  			ch.Send(val)
  1489  			cases = append(cases, SelectCase{
  1490  				Dir:  SelectRecv,
  1491  				Chan: ch,
  1492  			})
  1493  			info = append(info, caseInfo{desc: "ready recv", canSelect: true, recv: val})
  1494  		}
  1495  
  1496  		// Blocking send.
  1497  		if x.Maybe() {
  1498  			ch, val := newop(len(cases), 0)
  1499  			cases = append(cases, SelectCase{
  1500  				Dir:  SelectSend,
  1501  				Chan: ch,
  1502  				Send: val,
  1503  			})
  1504  			// Let it execute?
  1505  			if x.Maybe() {
  1506  				f := func() { ch.Recv() }
  1507  				info = append(info, caseInfo{desc: "blocking send", helper: f})
  1508  			} else {
  1509  				info = append(info, caseInfo{desc: "blocking send"})
  1510  			}
  1511  		}
  1512  
  1513  		// Blocking recv.
  1514  		if x.Maybe() {
  1515  			ch, val := newop(len(cases), 0)
  1516  			cases = append(cases, SelectCase{
  1517  				Dir:  SelectRecv,
  1518  				Chan: ch,
  1519  			})
  1520  			// Let it execute?
  1521  			if x.Maybe() {
  1522  				f := func() { ch.Send(val) }
  1523  				info = append(info, caseInfo{desc: "blocking recv", recv: val, helper: f})
  1524  			} else {
  1525  				info = append(info, caseInfo{desc: "blocking recv"})
  1526  			}
  1527  		}
  1528  
  1529  		// Zero Chan send.
  1530  		if x.Maybe() {
  1531  			// Maybe include value to send.
  1532  			var val Value
  1533  			if x.Maybe() {
  1534  				val = ValueOf(100)
  1535  			}
  1536  			cases = append(cases, SelectCase{
  1537  				Dir:  SelectSend,
  1538  				Send: val,
  1539  			})
  1540  			info = append(info, caseInfo{desc: "zero Chan send"})
  1541  		}
  1542  
  1543  		// Zero Chan receive.
  1544  		if x.Maybe() {
  1545  			cases = append(cases, SelectCase{
  1546  				Dir: SelectRecv,
  1547  			})
  1548  			info = append(info, caseInfo{desc: "zero Chan recv"})
  1549  		}
  1550  
  1551  		// nil Chan send.
  1552  		if x.Maybe() {
  1553  			cases = append(cases, SelectCase{
  1554  				Dir:  SelectSend,
  1555  				Chan: ValueOf((chan int)(nil)),
  1556  				Send: ValueOf(101),
  1557  			})
  1558  			info = append(info, caseInfo{desc: "nil Chan send"})
  1559  		}
  1560  
  1561  		// nil Chan recv.
  1562  		if x.Maybe() {
  1563  			cases = append(cases, SelectCase{
  1564  				Dir:  SelectRecv,
  1565  				Chan: ValueOf((chan int)(nil)),
  1566  			})
  1567  			info = append(info, caseInfo{desc: "nil Chan recv"})
  1568  		}
  1569  
  1570  		// closed Chan send.
  1571  		if x.Maybe() {
  1572  			ch := make(chan int)
  1573  			close(ch)
  1574  			cases = append(cases, SelectCase{
  1575  				Dir:  SelectSend,
  1576  				Chan: ValueOf(ch),
  1577  				Send: ValueOf(101),
  1578  			})
  1579  			info = append(info, caseInfo{desc: "closed Chan send", canSelect: true, panic: true})
  1580  		}
  1581  
  1582  		// closed Chan recv.
  1583  		if x.Maybe() {
  1584  			ch, val := newop(len(cases), 0)
  1585  			ch.Close()
  1586  			val = Zero(val.Type())
  1587  			cases = append(cases, SelectCase{
  1588  				Dir:  SelectRecv,
  1589  				Chan: ch,
  1590  			})
  1591  			info = append(info, caseInfo{desc: "closed Chan recv", canSelect: true, closed: true, recv: val})
  1592  		}
  1593  
  1594  		var helper func() // goroutine to help the select complete
  1595  
  1596  		// Add default? Must be last case here, but will permute.
  1597  		// Add the default if the select would otherwise
  1598  		// block forever, and maybe add it anyway.
  1599  		numCanSelect := 0
  1600  		canProceed := false
  1601  		canBlock := true
  1602  		canPanic := false
  1603  		helpers := []int{}
  1604  		for i, c := range info {
  1605  			if c.canSelect {
  1606  				canProceed = true
  1607  				canBlock = false
  1608  				numCanSelect++
  1609  				if c.panic {
  1610  					canPanic = true
  1611  				}
  1612  			} else if c.helper != nil {
  1613  				canProceed = true
  1614  				helpers = append(helpers, i)
  1615  			}
  1616  		}
  1617  		if !canProceed || x.Maybe() {
  1618  			cases = append(cases, SelectCase{
  1619  				Dir: SelectDefault,
  1620  			})
  1621  			info = append(info, caseInfo{desc: "default", canSelect: canBlock})
  1622  			numCanSelect++
  1623  		} else if canBlock {
  1624  			// Select needs to communicate with another goroutine.
  1625  			cas := &info[helpers[x.Choose(len(helpers))]]
  1626  			helper = cas.helper
  1627  			cas.canSelect = true
  1628  			numCanSelect++
  1629  		}
  1630  
  1631  		// Permute cases and case info.
  1632  		// Doing too much here makes the exhaustive loop
  1633  		// too exhausting, so just do two swaps.
  1634  		for loop := 0; loop < 2; loop++ {
  1635  			i := x.Choose(len(cases))
  1636  			j := x.Choose(len(cases))
  1637  			cases[i], cases[j] = cases[j], cases[i]
  1638  			info[i], info[j] = info[j], info[i]
  1639  		}
  1640  
  1641  		if helper != nil {
  1642  			// We wait before kicking off a goroutine to satisfy a blocked select.
  1643  			// The pause needs to be big enough to let the select block before
  1644  			// we run the helper, but if we lose that race once in a while it's okay: the
  1645  			// select will just proceed immediately. Not a big deal.
  1646  			// For short tests we can grow [sic] the timeout a bit without fear of taking too long
  1647  			pause := 10 * time.Microsecond
  1648  			if testing.Short() {
  1649  				pause = 100 * time.Microsecond
  1650  			}
  1651  			time.AfterFunc(pause, helper)
  1652  		}
  1653  
  1654  		// Run select.
  1655  		i, recv, recvOK, panicErr := runSelect(cases, info)
  1656  		if panicErr != nil && !canPanic {
  1657  			t.Fatalf("%s\npanicked unexpectedly: %v", fmtSelect(info), panicErr)
  1658  		}
  1659  		if panicErr == nil && canPanic && numCanSelect == 1 {
  1660  			t.Fatalf("%s\nselected #%d incorrectly (should panic)", fmtSelect(info), i)
  1661  		}
  1662  		if panicErr != nil {
  1663  			continue
  1664  		}
  1665  
  1666  		cas := info[i]
  1667  		if !cas.canSelect {
  1668  			recvStr := ""
  1669  			if recv.IsValid() {
  1670  				recvStr = fmt.Sprintf(", received %v, %v", recv.Interface(), recvOK)
  1671  			}
  1672  			t.Fatalf("%s\nselected #%d incorrectly%s", fmtSelect(info), i, recvStr)
  1673  			continue
  1674  		}
  1675  		if cas.panic {
  1676  			t.Fatalf("%s\nselected #%d incorrectly (case should panic)", fmtSelect(info), i)
  1677  			continue
  1678  		}
  1679  
  1680  		if cases[i].Dir == SelectRecv {
  1681  			if !recv.IsValid() {
  1682  				t.Fatalf("%s\nselected #%d but got %v, %v, want %v, %v", fmtSelect(info), i, recv, recvOK, cas.recv.Interface(), !cas.closed)
  1683  			}
  1684  			if !cas.recv.IsValid() {
  1685  				t.Fatalf("%s\nselected #%d but internal error: missing recv value", fmtSelect(info), i)
  1686  			}
  1687  			if recv.Interface() != cas.recv.Interface() || recvOK != !cas.closed {
  1688  				if recv.Interface() == cas.recv.Interface() && recvOK == !cas.closed {
  1689  					t.Fatalf("%s\nselected #%d, got %#v, %v, and DeepEqual is broken on %T", fmtSelect(info), i, recv.Interface(), recvOK, recv.Interface())
  1690  				}
  1691  				t.Fatalf("%s\nselected #%d but got %#v, %v, want %#v, %v", fmtSelect(info), i, recv.Interface(), recvOK, cas.recv.Interface(), !cas.closed)
  1692  			}
  1693  		} else {
  1694  			if recv.IsValid() || recvOK {
  1695  				t.Fatalf("%s\nselected #%d but got %v, %v, want %v, %v", fmtSelect(info), i, recv, recvOK, Value{}, false)
  1696  			}
  1697  		}
  1698  	}
  1699  }
  1700  
  1701  func TestSelectMaxCases(t *testing.T) {
  1702  	var sCases []SelectCase
  1703  	channel := make(chan int)
  1704  	close(channel)
  1705  	for i := 0; i < 65536; i++ {
  1706  		sCases = append(sCases, SelectCase{
  1707  			Dir:  SelectRecv,
  1708  			Chan: ValueOf(channel),
  1709  		})
  1710  	}
  1711  	// Should not panic
  1712  	_, _, _ = Select(sCases)
  1713  	sCases = append(sCases, SelectCase{
  1714  		Dir:  SelectRecv,
  1715  		Chan: ValueOf(channel),
  1716  	})
  1717  	defer func() {
  1718  		if err := recover(); err != nil {
  1719  			if err.(string) != "reflect.Select: too many cases (max 65536)" {
  1720  				t.Fatalf("unexpected error from select call with greater than max supported cases")
  1721  			}
  1722  		} else {
  1723  			t.Fatalf("expected select call to panic with greater than max supported cases")
  1724  		}
  1725  	}()
  1726  	// Should panic
  1727  	_, _, _ = Select(sCases)
  1728  }
  1729  
  1730  func TestSelectNop(t *testing.T) {
  1731  	// "select { default: }" should always return the default case.
  1732  	chosen, _, _ := Select([]SelectCase{{Dir: SelectDefault}})
  1733  	if chosen != 0 {
  1734  		t.Fatalf("expected Select to return 0, but got %#v", chosen)
  1735  	}
  1736  }
  1737  
  1738  func BenchmarkSelect(b *testing.B) {
  1739  	channel := make(chan int)
  1740  	close(channel)
  1741  	var cases []SelectCase
  1742  	for i := 0; i < 8; i++ {
  1743  		cases = append(cases, SelectCase{
  1744  			Dir:  SelectRecv,
  1745  			Chan: ValueOf(channel),
  1746  		})
  1747  	}
  1748  	for _, numCases := range []int{1, 4, 8} {
  1749  		b.Run(strconv.Itoa(numCases), func(b *testing.B) {
  1750  			b.ReportAllocs()
  1751  			for i := 0; i < b.N; i++ {
  1752  				_, _, _ = Select(cases[:numCases])
  1753  			}
  1754  		})
  1755  	}
  1756  }
  1757  
  1758  // selectWatch and the selectWatcher are a watchdog mechanism for running Select.
  1759  // If the selectWatcher notices that the select has been blocked for >1 second, it prints
  1760  // an error describing the select and panics the entire test binary.
  1761  var selectWatch struct {
  1762  	sync.Mutex
  1763  	once sync.Once
  1764  	now  time.Time
  1765  	info []caseInfo
  1766  }
  1767  
  1768  func selectWatcher() {
  1769  	for {
  1770  		time.Sleep(1 * time.Second)
  1771  		selectWatch.Lock()
  1772  		if selectWatch.info != nil && time.Since(selectWatch.now) > 10*time.Second {
  1773  			fmt.Fprintf(os.Stderr, "TestSelect:\n%s blocked indefinitely\n", fmtSelect(selectWatch.info))
  1774  			panic("select stuck")
  1775  		}
  1776  		selectWatch.Unlock()
  1777  	}
  1778  }
  1779  
  1780  // runSelect runs a single select test.
  1781  // It returns the values returned by Select but also returns
  1782  // a panic value if the Select panics.
  1783  func runSelect(cases []SelectCase, info []caseInfo) (chosen int, recv Value, recvOK bool, panicErr interface{}) {
  1784  	defer func() {
  1785  		panicErr = recover()
  1786  
  1787  		selectWatch.Lock()
  1788  		selectWatch.info = nil
  1789  		selectWatch.Unlock()
  1790  	}()
  1791  
  1792  	selectWatch.Lock()
  1793  	selectWatch.now = time.Now()
  1794  	selectWatch.info = info
  1795  	selectWatch.Unlock()
  1796  
  1797  	chosen, recv, recvOK = Select(cases)
  1798  	return
  1799  }
  1800  
  1801  // fmtSelect formats the information about a single select test.
  1802  func fmtSelect(info []caseInfo) string {
  1803  	var buf bytes.Buffer
  1804  	fmt.Fprintf(&buf, "\nselect {\n")
  1805  	for i, cas := range info {
  1806  		fmt.Fprintf(&buf, "%d: %s", i, cas.desc)
  1807  		if cas.recv.IsValid() {
  1808  			fmt.Fprintf(&buf, " val=%#v", cas.recv.Interface())
  1809  		}
  1810  		if cas.canSelect {
  1811  			fmt.Fprintf(&buf, " canselect")
  1812  		}
  1813  		if cas.panic {
  1814  			fmt.Fprintf(&buf, " panic")
  1815  		}
  1816  		fmt.Fprintf(&buf, "\n")
  1817  	}
  1818  	fmt.Fprintf(&buf, "}")
  1819  	return buf.String()
  1820  }
  1821  
  1822  type two [2]uintptr
  1823  
  1824  // Difficult test for function call because of
  1825  // implicit padding between arguments.
  1826  func dummy(b byte, c int, d byte, e two, f byte, g float32, h byte) (i byte, j int, k byte, l two, m byte, n float32, o byte) {
  1827  	return b, c, d, e, f, g, h
  1828  }
  1829  
  1830  func TestFunc(t *testing.T) {
  1831  	ret := ValueOf(dummy).Call([]Value{
  1832  		ValueOf(byte(10)),
  1833  		ValueOf(20),
  1834  		ValueOf(byte(30)),
  1835  		ValueOf(two{40, 50}),
  1836  		ValueOf(byte(60)),
  1837  		ValueOf(float32(70)),
  1838  		ValueOf(byte(80)),
  1839  	})
  1840  	if len(ret) != 7 {
  1841  		t.Fatalf("Call returned %d values, want 7", len(ret))
  1842  	}
  1843  
  1844  	i := byte(ret[0].Uint())
  1845  	j := int(ret[1].Int())
  1846  	k := byte(ret[2].Uint())
  1847  	l := ret[3].Interface().(two)
  1848  	m := byte(ret[4].Uint())
  1849  	n := float32(ret[5].Float())
  1850  	o := byte(ret[6].Uint())
  1851  
  1852  	if i != 10 || j != 20 || k != 30 || l != (two{40, 50}) || m != 60 || n != 70 || o != 80 {
  1853  		t.Errorf("Call returned %d, %d, %d, %v, %d, %g, %d; want 10, 20, 30, [40, 50], 60, 70, 80", i, j, k, l, m, n, o)
  1854  	}
  1855  
  1856  	for i, v := range ret {
  1857  		if v.CanAddr() {
  1858  			t.Errorf("result %d is addressable", i)
  1859  		}
  1860  	}
  1861  }
  1862  
  1863  func TestCallConvert(t *testing.T) {
  1864  	v := ValueOf(new(io.ReadWriter)).Elem()
  1865  	f := ValueOf(func(r io.Reader) io.Reader { return r })
  1866  	out := f.Call([]Value{v})
  1867  	if len(out) != 1 || out[0].Type() != TypeOf(new(io.Reader)).Elem() || !out[0].IsNil() {
  1868  		t.Errorf("expected [nil], got %v", out)
  1869  	}
  1870  }
  1871  
  1872  type emptyStruct struct{}
  1873  
  1874  type nonEmptyStruct struct {
  1875  	member int
  1876  }
  1877  
  1878  func returnEmpty() emptyStruct {
  1879  	return emptyStruct{}
  1880  }
  1881  
  1882  func takesEmpty(e emptyStruct) {
  1883  }
  1884  
  1885  func returnNonEmpty(i int) nonEmptyStruct {
  1886  	return nonEmptyStruct{member: i}
  1887  }
  1888  
  1889  func takesNonEmpty(n nonEmptyStruct) int {
  1890  	return n.member
  1891  }
  1892  
  1893  func TestCallWithStruct(t *testing.T) {
  1894  	r := ValueOf(returnEmpty).Call(nil)
  1895  	if len(r) != 1 || r[0].Type() != TypeOf(emptyStruct{}) {
  1896  		t.Errorf("returning empty struct returned %#v instead", r)
  1897  	}
  1898  	r = ValueOf(takesEmpty).Call([]Value{ValueOf(emptyStruct{})})
  1899  	if len(r) != 0 {
  1900  		t.Errorf("takesEmpty returned values: %#v", r)
  1901  	}
  1902  	r = ValueOf(returnNonEmpty).Call([]Value{ValueOf(42)})
  1903  	if len(r) != 1 || r[0].Type() != TypeOf(nonEmptyStruct{}) || r[0].Field(0).Int() != 42 {
  1904  		t.Errorf("returnNonEmpty returned %#v", r)
  1905  	}
  1906  	r = ValueOf(takesNonEmpty).Call([]Value{ValueOf(nonEmptyStruct{member: 42})})
  1907  	if len(r) != 1 || r[0].Type() != TypeOf(1) || r[0].Int() != 42 {
  1908  		t.Errorf("takesNonEmpty returned %#v", r)
  1909  	}
  1910  }
  1911  
  1912  func TestCallReturnsEmpty(t *testing.T) {
  1913  	// Issue 21717: past-the-end pointer write in Call with
  1914  	// nonzero-sized frame and zero-sized return value.
  1915  	runtime.GC()
  1916  	var finalized uint32
  1917  	f := func() (emptyStruct, *[2]int64) {
  1918  		i := new([2]int64) // big enough to not be tinyalloc'd, so finalizer always runs when i dies
  1919  		runtime.SetFinalizer(i, func(*[2]int64) { atomic.StoreUint32(&finalized, 1) })
  1920  		return emptyStruct{}, i
  1921  	}
  1922  	v := ValueOf(f).Call(nil)[0] // out[0] should not alias out[1]'s memory, so the finalizer should run.
  1923  	timeout := time.After(5 * time.Second)
  1924  	for atomic.LoadUint32(&finalized) == 0 {
  1925  		select {
  1926  		case <-timeout:
  1927  			t.Fatal("finalizer did not run")
  1928  		default:
  1929  		}
  1930  		runtime.Gosched()
  1931  		runtime.GC()
  1932  	}
  1933  	runtime.KeepAlive(v)
  1934  }
  1935  
  1936  func BenchmarkCall(b *testing.B) {
  1937  	fv := ValueOf(func(a, b string) {})
  1938  	b.ReportAllocs()
  1939  	b.RunParallel(func(pb *testing.PB) {
  1940  		args := []Value{ValueOf("a"), ValueOf("b")}
  1941  		for pb.Next() {
  1942  			fv.Call(args)
  1943  		}
  1944  	})
  1945  }
  1946  
  1947  type myint int64
  1948  
  1949  func (i *myint) inc() {
  1950  	*i = *i + 1
  1951  }
  1952  
  1953  func BenchmarkCallMethod(b *testing.B) {
  1954  	b.ReportAllocs()
  1955  	z := new(myint)
  1956  
  1957  	v := ValueOf(z.inc)
  1958  	for i := 0; i < b.N; i++ {
  1959  		v.Call(nil)
  1960  	}
  1961  }
  1962  
  1963  func BenchmarkCallArgCopy(b *testing.B) {
  1964  	byteArray := func(n int) Value {
  1965  		return Zero(ArrayOf(n, TypeOf(byte(0))))
  1966  	}
  1967  	sizes := [...]struct {
  1968  		fv  Value
  1969  		arg Value
  1970  	}{
  1971  		{ValueOf(func(a [128]byte) {}), byteArray(128)},
  1972  		{ValueOf(func(a [256]byte) {}), byteArray(256)},
  1973  		{ValueOf(func(a [1024]byte) {}), byteArray(1024)},
  1974  		{ValueOf(func(a [4096]byte) {}), byteArray(4096)},
  1975  		{ValueOf(func(a [65536]byte) {}), byteArray(65536)},
  1976  	}
  1977  	for _, size := range sizes {
  1978  		bench := func(b *testing.B) {
  1979  			args := []Value{size.arg}
  1980  			b.SetBytes(int64(size.arg.Len()))
  1981  			b.ResetTimer()
  1982  			b.RunParallel(func(pb *testing.PB) {
  1983  				for pb.Next() {
  1984  					size.fv.Call(args)
  1985  				}
  1986  			})
  1987  		}
  1988  		name := fmt.Sprintf("size=%v", size.arg.Len())
  1989  		b.Run(name, bench)
  1990  	}
  1991  }
  1992  
  1993  func TestMakeFunc(t *testing.T) {
  1994  	f := dummy
  1995  	fv := MakeFunc(TypeOf(f), func(in []Value) []Value { return in })
  1996  	ValueOf(&f).Elem().Set(fv)
  1997  
  1998  	// Call g with small arguments so that there is
  1999  	// something predictable (and different from the
  2000  	// correct results) in those positions on the stack.
  2001  	g := dummy
  2002  	g(1, 2, 3, two{4, 5}, 6, 7, 8)
  2003  
  2004  	// Call constructed function f.
  2005  	i, j, k, l, m, n, o := f(10, 20, 30, two{40, 50}, 60, 70, 80)
  2006  	if i != 10 || j != 20 || k != 30 || l != (two{40, 50}) || m != 60 || n != 70 || o != 80 {
  2007  		t.Errorf("Call returned %d, %d, %d, %v, %d, %g, %d; want 10, 20, 30, [40, 50], 60, 70, 80", i, j, k, l, m, n, o)
  2008  	}
  2009  }
  2010  
  2011  func TestMakeFuncInterface(t *testing.T) {
  2012  	fn := func(i int) int { return i }
  2013  	incr := func(in []Value) []Value {
  2014  		return []Value{ValueOf(int(in[0].Int() + 1))}
  2015  	}
  2016  	fv := MakeFunc(TypeOf(fn), incr)
  2017  	ValueOf(&fn).Elem().Set(fv)
  2018  	if r := fn(2); r != 3 {
  2019  		t.Errorf("Call returned %d, want 3", r)
  2020  	}
  2021  	if r := fv.Call([]Value{ValueOf(14)})[0].Int(); r != 15 {
  2022  		t.Errorf("Call returned %d, want 15", r)
  2023  	}
  2024  	if r := fv.Interface().(func(int) int)(26); r != 27 {
  2025  		t.Errorf("Call returned %d, want 27", r)
  2026  	}
  2027  }
  2028  
  2029  func TestMakeFuncVariadic(t *testing.T) {
  2030  	// Test that variadic arguments are packed into a slice and passed as last arg
  2031  	fn := func(_ int, is ...int) []int { return nil }
  2032  	fv := MakeFunc(TypeOf(fn), func(in []Value) []Value { return in[1:2] })
  2033  	ValueOf(&fn).Elem().Set(fv)
  2034  
  2035  	r := fn(1, 2, 3)
  2036  	if r[0] != 2 || r[1] != 3 {
  2037  		t.Errorf("Call returned [%v, %v]; want 2, 3", r[0], r[1])
  2038  	}
  2039  
  2040  	r = fn(1, []int{2, 3}...)
  2041  	if r[0] != 2 || r[1] != 3 {
  2042  		t.Errorf("Call returned [%v, %v]; want 2, 3", r[0], r[1])
  2043  	}
  2044  
  2045  	r = fv.Call([]Value{ValueOf(1), ValueOf(2), ValueOf(3)})[0].Interface().([]int)
  2046  	if r[0] != 2 || r[1] != 3 {
  2047  		t.Errorf("Call returned [%v, %v]; want 2, 3", r[0], r[1])
  2048  	}
  2049  
  2050  	r = fv.CallSlice([]Value{ValueOf(1), ValueOf([]int{2, 3})})[0].Interface().([]int)
  2051  	if r[0] != 2 || r[1] != 3 {
  2052  		t.Errorf("Call returned [%v, %v]; want 2, 3", r[0], r[1])
  2053  	}
  2054  
  2055  	f := fv.Interface().(func(int, ...int) []int)
  2056  
  2057  	r = f(1, 2, 3)
  2058  	if r[0] != 2 || r[1] != 3 {
  2059  		t.Errorf("Call returned [%v, %v]; want 2, 3", r[0], r[1])
  2060  	}
  2061  	r = f(1, []int{2, 3}...)
  2062  	if r[0] != 2 || r[1] != 3 {
  2063  		t.Errorf("Call returned [%v, %v]; want 2, 3", r[0], r[1])
  2064  	}
  2065  }
  2066  
  2067  // Dummy type that implements io.WriteCloser
  2068  type WC struct {
  2069  }
  2070  
  2071  func (w *WC) Write(p []byte) (n int, err error) {
  2072  	return 0, nil
  2073  }
  2074  func (w *WC) Close() error {
  2075  	return nil
  2076  }
  2077  
  2078  func TestMakeFuncValidReturnAssignments(t *testing.T) {
  2079  	// reflect.Values returned from the wrapped function should be assignment-converted
  2080  	// to the types returned by the result of MakeFunc.
  2081  
  2082  	// Concrete types should be promotable to interfaces they implement.
  2083  	var f func() error
  2084  	f = MakeFunc(TypeOf(f), func([]Value) []Value {
  2085  		return []Value{ValueOf(io.EOF)}
  2086  	}).Interface().(func() error)
  2087  	f()
  2088  
  2089  	// Super-interfaces should be promotable to simpler interfaces.
  2090  	var g func() io.Writer
  2091  	g = MakeFunc(TypeOf(g), func([]Value) []Value {
  2092  		var w io.WriteCloser = &WC{}
  2093  		return []Value{ValueOf(&w).Elem()}
  2094  	}).Interface().(func() io.Writer)
  2095  	g()
  2096  
  2097  	// Channels should be promotable to directional channels.
  2098  	var h func() <-chan int
  2099  	h = MakeFunc(TypeOf(h), func([]Value) []Value {
  2100  		return []Value{ValueOf(make(chan int))}
  2101  	}).Interface().(func() <-chan int)
  2102  	h()
  2103  
  2104  	// Unnamed types should be promotable to named types.
  2105  	type T struct{ a, b, c int }
  2106  	var i func() T
  2107  	i = MakeFunc(TypeOf(i), func([]Value) []Value {
  2108  		return []Value{ValueOf(struct{ a, b, c int }{a: 1, b: 2, c: 3})}
  2109  	}).Interface().(func() T)
  2110  	i()
  2111  }
  2112  
  2113  func TestMakeFuncInvalidReturnAssignments(t *testing.T) {
  2114  	// Type doesn't implement the required interface.
  2115  	shouldPanic("", func() {
  2116  		var f func() error
  2117  		f = MakeFunc(TypeOf(f), func([]Value) []Value {
  2118  			return []Value{ValueOf(int(7))}
  2119  		}).Interface().(func() error)
  2120  		f()
  2121  	})
  2122  	// Assigning to an interface with additional methods.
  2123  	shouldPanic("", func() {
  2124  		var f func() io.ReadWriteCloser
  2125  		f = MakeFunc(TypeOf(f), func([]Value) []Value {
  2126  			var w io.WriteCloser = &WC{}
  2127  			return []Value{ValueOf(&w).Elem()}
  2128  		}).Interface().(func() io.ReadWriteCloser)
  2129  		f()
  2130  	})
  2131  	// Directional channels can't be assigned to bidirectional ones.
  2132  	shouldPanic("", func() {
  2133  		var f func() chan int
  2134  		f = MakeFunc(TypeOf(f), func([]Value) []Value {
  2135  			var c <-chan int = make(chan int)
  2136  			return []Value{ValueOf(c)}
  2137  		}).Interface().(func() chan int)
  2138  		f()
  2139  	})
  2140  	// Two named types which are otherwise identical.
  2141  	shouldPanic("", func() {
  2142  		type T struct{ a, b, c int }
  2143  		type U struct{ a, b, c int }
  2144  		var f func() T
  2145  		f = MakeFunc(TypeOf(f), func([]Value) []Value {
  2146  			return []Value{ValueOf(U{a: 1, b: 2, c: 3})}
  2147  		}).Interface().(func() T)
  2148  		f()
  2149  	})
  2150  }
  2151  
  2152  type Point struct {
  2153  	x, y int
  2154  }
  2155  
  2156  // This will be index 0.
  2157  func (p Point) AnotherMethod(scale int) int {
  2158  	return -1
  2159  }
  2160  
  2161  // This will be index 1.
  2162  func (p Point) Dist(scale int) int {
  2163  	//println("Point.Dist", p.x, p.y, scale)
  2164  	return p.x*p.x*scale + p.y*p.y*scale
  2165  }
  2166  
  2167  // This will be index 2.
  2168  func (p Point) GCMethod(k int) int {
  2169  	runtime.GC()
  2170  	return k + p.x
  2171  }
  2172  
  2173  // This will be index 3.
  2174  func (p Point) NoArgs() {
  2175  	// Exercise no-argument/no-result paths.
  2176  }
  2177  
  2178  // This will be index 4.
  2179  func (p Point) TotalDist(points ...Point) int {
  2180  	tot := 0
  2181  	for _, q := range points {
  2182  		dx := q.x - p.x
  2183  		dy := q.y - p.y
  2184  		tot += dx*dx + dy*dy // Should call Sqrt, but it's just a test.
  2185  
  2186  	}
  2187  	return tot
  2188  }
  2189  
  2190  // This will be index 5.
  2191  func (p *Point) Int64Method(x int64) int64 {
  2192  	return x
  2193  }
  2194  
  2195  // This will be index 6.
  2196  func (p *Point) Int32Method(x int32) int32 {
  2197  	return x
  2198  }
  2199  
  2200  func TestMethod(t *testing.T) {
  2201  	// Non-curried method of type.
  2202  	p := Point{3, 4}
  2203  	i := TypeOf(p).Method(1).Func.Call([]Value{ValueOf(p), ValueOf(10)})[0].Int()
  2204  	if i != 250 {
  2205  		t.Errorf("Type Method returned %d; want 250", i)
  2206  	}
  2207  
  2208  	m, ok := TypeOf(p).MethodByName("Dist")
  2209  	if !ok {
  2210  		t.Fatalf("method by name failed")
  2211  	}
  2212  	i = m.Func.Call([]Value{ValueOf(p), ValueOf(11)})[0].Int()
  2213  	if i != 275 {
  2214  		t.Errorf("Type MethodByName returned %d; want 275", i)
  2215  	}
  2216  
  2217  	m, ok = TypeOf(p).MethodByName("NoArgs")
  2218  	if !ok {
  2219  		t.Fatalf("method by name failed")
  2220  	}
  2221  	n := len(m.Func.Call([]Value{ValueOf(p)}))
  2222  	if n != 0 {
  2223  		t.Errorf("NoArgs returned %d values; want 0", n)
  2224  	}
  2225  
  2226  	i = TypeOf(&p).Method(1).Func.Call([]Value{ValueOf(&p), ValueOf(12)})[0].Int()
  2227  	if i != 300 {
  2228  		t.Errorf("Pointer Type Method returned %d; want 300", i)
  2229  	}
  2230  
  2231  	m, ok = TypeOf(&p).MethodByName("Dist")
  2232  	if !ok {
  2233  		t.Fatalf("ptr method by name failed")
  2234  	}
  2235  	i = m.Func.Call([]Value{ValueOf(&p), ValueOf(13)})[0].Int()
  2236  	if i != 325 {
  2237  		t.Errorf("Pointer Type MethodByName returned %d; want 325", i)
  2238  	}
  2239  
  2240  	m, ok = TypeOf(&p).MethodByName("NoArgs")
  2241  	if !ok {
  2242  		t.Fatalf("method by name failed")
  2243  	}
  2244  	n = len(m.Func.Call([]Value{ValueOf(&p)}))
  2245  	if n != 0 {
  2246  		t.Errorf("NoArgs returned %d values; want 0", n)
  2247  	}
  2248  
  2249  	// Curried method of value.
  2250  	tfunc := TypeOf((func(int) int)(nil))
  2251  	v := ValueOf(p).Method(1)
  2252  	if tt := v.Type(); tt != tfunc {
  2253  		t.Errorf("Value Method Type is %s; want %s", tt, tfunc)
  2254  	}
  2255  	i = v.Call([]Value{ValueOf(14)})[0].Int()
  2256  	if i != 350 {
  2257  		t.Errorf("Value Method returned %d; want 350", i)
  2258  	}
  2259  	v = ValueOf(p).MethodByName("Dist")
  2260  	if tt := v.Type(); tt != tfunc {
  2261  		t.Errorf("Value MethodByName Type is %s; want %s", tt, tfunc)
  2262  	}
  2263  	i = v.Call([]Value{ValueOf(15)})[0].Int()
  2264  	if i != 375 {
  2265  		t.Errorf("Value MethodByName returned %d; want 375", i)
  2266  	}
  2267  	v = ValueOf(p).MethodByName("NoArgs")
  2268  	v.Call(nil)
  2269  
  2270  	// Curried method of pointer.
  2271  	v = ValueOf(&p).Method(1)
  2272  	if tt := v.Type(); tt != tfunc {
  2273  		t.Errorf("Pointer Value Method Type is %s; want %s", tt, tfunc)
  2274  	}
  2275  	i = v.Call([]Value{ValueOf(16)})[0].Int()
  2276  	if i != 400 {
  2277  		t.Errorf("Pointer Value Method returned %d; want 400", i)
  2278  	}
  2279  	v = ValueOf(&p).MethodByName("Dist")
  2280  	if tt := v.Type(); tt != tfunc {
  2281  		t.Errorf("Pointer Value MethodByName Type is %s; want %s", tt, tfunc)
  2282  	}
  2283  	i = v.Call([]Value{ValueOf(17)})[0].Int()
  2284  	if i != 425 {
  2285  		t.Errorf("Pointer Value MethodByName returned %d; want 425", i)
  2286  	}
  2287  	v = ValueOf(&p).MethodByName("NoArgs")
  2288  	v.Call(nil)
  2289  
  2290  	// Curried method of interface value.
  2291  	// Have to wrap interface value in a struct to get at it.
  2292  	// Passing it to ValueOf directly would
  2293  	// access the underlying Point, not the interface.
  2294  	var x interface {
  2295  		Dist(int) int
  2296  	} = p
  2297  	pv := ValueOf(&x).Elem()
  2298  	v = pv.Method(0)
  2299  	if tt := v.Type(); tt != tfunc {
  2300  		t.Errorf("Interface Method Type is %s; want %s", tt, tfunc)
  2301  	}
  2302  	i = v.Call([]Value{ValueOf(18)})[0].Int()
  2303  	if i != 450 {
  2304  		t.Errorf("Interface Method returned %d; want 450", i)
  2305  	}
  2306  	v = pv.MethodByName("Dist")
  2307  	if tt := v.Type(); tt != tfunc {
  2308  		t.Errorf("Interface MethodByName Type is %s; want %s", tt, tfunc)
  2309  	}
  2310  	i = v.Call([]Value{ValueOf(19)})[0].Int()
  2311  	if i != 475 {
  2312  		t.Errorf("Interface MethodByName returned %d; want 475", i)
  2313  	}
  2314  }
  2315  
  2316  func TestMethodValue(t *testing.T) {
  2317  	p := Point{3, 4}
  2318  	var i int64
  2319  
  2320  	// Curried method of value.
  2321  	tfunc := TypeOf((func(int) int)(nil))
  2322  	v := ValueOf(p).Method(1)
  2323  	if tt := v.Type(); tt != tfunc {
  2324  		t.Errorf("Value Method Type is %s; want %s", tt, tfunc)
  2325  	}
  2326  	i = ValueOf(v.Interface()).Call([]Value{ValueOf(10)})[0].Int()
  2327  	if i != 250 {
  2328  		t.Errorf("Value Method returned %d; want 250", i)
  2329  	}
  2330  	v = ValueOf(p).MethodByName("Dist")
  2331  	if tt := v.Type(); tt != tfunc {
  2332  		t.Errorf("Value MethodByName Type is %s; want %s", tt, tfunc)
  2333  	}
  2334  	i = ValueOf(v.Interface()).Call([]Value{ValueOf(11)})[0].Int()
  2335  	if i != 275 {
  2336  		t.Errorf("Value MethodByName returned %d; want 275", i)
  2337  	}
  2338  	v = ValueOf(p).MethodByName("NoArgs")
  2339  	ValueOf(v.Interface()).Call(nil)
  2340  	v.Interface().(func())()
  2341  
  2342  	// Curried method of pointer.
  2343  	v = ValueOf(&p).Method(1)
  2344  	if tt := v.Type(); tt != tfunc {
  2345  		t.Errorf("Pointer Value Method Type is %s; want %s", tt, tfunc)
  2346  	}
  2347  	i = ValueOf(v.Interface()).Call([]Value{ValueOf(12)})[0].Int()
  2348  	if i != 300 {
  2349  		t.Errorf("Pointer Value Method returned %d; want 300", i)
  2350  	}
  2351  	v = ValueOf(&p).MethodByName("Dist")
  2352  	if tt := v.Type(); tt != tfunc {
  2353  		t.Errorf("Pointer Value MethodByName Type is %s; want %s", tt, tfunc)
  2354  	}
  2355  	i = ValueOf(v.Interface()).Call([]Value{ValueOf(13)})[0].Int()
  2356  	if i != 325 {
  2357  		t.Errorf("Pointer Value MethodByName returned %d; want 325", i)
  2358  	}
  2359  	v = ValueOf(&p).MethodByName("NoArgs")
  2360  	ValueOf(v.Interface()).Call(nil)
  2361  	v.Interface().(func())()
  2362  
  2363  	// Curried method of pointer to pointer.
  2364  	pp := &p
  2365  	v = ValueOf(&pp).Elem().Method(1)
  2366  	if tt := v.Type(); tt != tfunc {
  2367  		t.Errorf("Pointer Pointer Value Method Type is %s; want %s", tt, tfunc)
  2368  	}
  2369  	i = ValueOf(v.Interface()).Call([]Value{ValueOf(14)})[0].Int()
  2370  	if i != 350 {
  2371  		t.Errorf("Pointer Pointer Value Method returned %d; want 350", i)
  2372  	}
  2373  	v = ValueOf(&pp).Elem().MethodByName("Dist")
  2374  	if tt := v.Type(); tt != tfunc {
  2375  		t.Errorf("Pointer Pointer Value MethodByName Type is %s; want %s", tt, tfunc)
  2376  	}
  2377  	i = ValueOf(v.Interface()).Call([]Value{ValueOf(15)})[0].Int()
  2378  	if i != 375 {
  2379  		t.Errorf("Pointer Pointer Value MethodByName returned %d; want 375", i)
  2380  	}
  2381  
  2382  	// Curried method of interface value.
  2383  	// Have to wrap interface value in a struct to get at it.
  2384  	// Passing it to ValueOf directly would
  2385  	// access the underlying Point, not the interface.
  2386  	var s = struct {
  2387  		X interface {
  2388  			Dist(int) int
  2389  		}
  2390  	}{p}
  2391  	pv := ValueOf(s).Field(0)
  2392  	v = pv.Method(0)
  2393  	if tt := v.Type(); tt != tfunc {
  2394  		t.Errorf("Interface Method Type is %s; want %s", tt, tfunc)
  2395  	}
  2396  	i = ValueOf(v.Interface()).Call([]Value{ValueOf(16)})[0].Int()
  2397  	if i != 400 {
  2398  		t.Errorf("Interface Method returned %d; want 400", i)
  2399  	}
  2400  	v = pv.MethodByName("Dist")
  2401  	if tt := v.Type(); tt != tfunc {
  2402  		t.Errorf("Interface MethodByName Type is %s; want %s", tt, tfunc)
  2403  	}
  2404  	i = ValueOf(v.Interface()).Call([]Value{ValueOf(17)})[0].Int()
  2405  	if i != 425 {
  2406  		t.Errorf("Interface MethodByName returned %d; want 425", i)
  2407  	}
  2408  
  2409  	// For issue #33628: method args are not stored at the right offset
  2410  	// on amd64p32.
  2411  	m64 := ValueOf(&p).MethodByName("Int64Method").Interface().(func(int64) int64)
  2412  	if x := m64(123); x != 123 {
  2413  		t.Errorf("Int64Method returned %d; want 123", x)
  2414  	}
  2415  	m32 := ValueOf(&p).MethodByName("Int32Method").Interface().(func(int32) int32)
  2416  	if x := m32(456); x != 456 {
  2417  		t.Errorf("Int32Method returned %d; want 456", x)
  2418  	}
  2419  }
  2420  
  2421  func TestVariadicMethodValue(t *testing.T) {
  2422  	p := Point{3, 4}
  2423  	points := []Point{{20, 21}, {22, 23}, {24, 25}}
  2424  	want := int64(p.TotalDist(points[0], points[1], points[2]))
  2425  
  2426  	// Variadic method of type.
  2427  	tfunc := TypeOf((func(Point, ...Point) int)(nil))
  2428  	if tt := TypeOf(p).Method(4).Type; tt != tfunc {
  2429  		t.Errorf("Variadic Method Type from TypeOf is %s; want %s", tt, tfunc)
  2430  	}
  2431  
  2432  	// Curried method of value.
  2433  	tfunc = TypeOf((func(...Point) int)(nil))
  2434  	v := ValueOf(p).Method(4)
  2435  	if tt := v.Type(); tt != tfunc {
  2436  		t.Errorf("Variadic Method Type is %s; want %s", tt, tfunc)
  2437  	}
  2438  	i := ValueOf(v.Interface()).Call([]Value{ValueOf(points[0]), ValueOf(points[1]), ValueOf(points[2])})[0].Int()
  2439  	if i != want {
  2440  		t.Errorf("Variadic Method returned %d; want %d", i, want)
  2441  	}
  2442  	i = ValueOf(v.Interface()).CallSlice([]Value{ValueOf(points)})[0].Int()
  2443  	if i != want {
  2444  		t.Errorf("Variadic Method CallSlice returned %d; want %d", i, want)
  2445  	}
  2446  
  2447  	f := v.Interface().(func(...Point) int)
  2448  	i = int64(f(points[0], points[1], points[2]))
  2449  	if i != want {
  2450  		t.Errorf("Variadic Method Interface returned %d; want %d", i, want)
  2451  	}
  2452  	i = int64(f(points...))
  2453  	if i != want {
  2454  		t.Errorf("Variadic Method Interface Slice returned %d; want %d", i, want)
  2455  	}
  2456  }
  2457  
  2458  type DirectIfaceT struct {
  2459  	p *int
  2460  }
  2461  
  2462  func (d DirectIfaceT) M() int { return *d.p }
  2463  
  2464  func TestDirectIfaceMethod(t *testing.T) {
  2465  	x := 42
  2466  	v := DirectIfaceT{&x}
  2467  	typ := TypeOf(v)
  2468  	m, ok := typ.MethodByName("M")
  2469  	if !ok {
  2470  		t.Fatalf("cannot find method M")
  2471  	}
  2472  	in := []Value{ValueOf(v)}
  2473  	out := m.Func.Call(in)
  2474  	if got := out[0].Int(); got != 42 {
  2475  		t.Errorf("Call with value receiver got %d, want 42", got)
  2476  	}
  2477  
  2478  	pv := &v
  2479  	typ = TypeOf(pv)
  2480  	m, ok = typ.MethodByName("M")
  2481  	if !ok {
  2482  		t.Fatalf("cannot find method M")
  2483  	}
  2484  	in = []Value{ValueOf(pv)}
  2485  	out = m.Func.Call(in)
  2486  	if got := out[0].Int(); got != 42 {
  2487  		t.Errorf("Call with pointer receiver got %d, want 42", got)
  2488  	}
  2489  }
  2490  
  2491  // Reflect version of $GOROOT/test/method5.go
  2492  
  2493  // Concrete types implementing M method.
  2494  // Smaller than a word, word-sized, larger than a word.
  2495  // Value and pointer receivers.
  2496  
  2497  type Tinter interface {
  2498  	M(int, byte) (byte, int)
  2499  }
  2500  
  2501  type Tsmallv byte
  2502  
  2503  func (v Tsmallv) M(x int, b byte) (byte, int) { return b, x + int(v) }
  2504  
  2505  type Tsmallp byte
  2506  
  2507  func (p *Tsmallp) M(x int, b byte) (byte, int) { return b, x + int(*p) }
  2508  
  2509  type Twordv uintptr
  2510  
  2511  func (v Twordv) M(x int, b byte) (byte, int) { return b, x + int(v) }
  2512  
  2513  type Twordp uintptr
  2514  
  2515  func (p *Twordp) M(x int, b byte) (byte, int) { return b, x + int(*p) }
  2516  
  2517  type Tbigv [2]uintptr
  2518  
  2519  func (v Tbigv) M(x int, b byte) (byte, int) { return b, x + int(v[0]) + int(v[1]) }
  2520  
  2521  type Tbigp [2]uintptr
  2522  
  2523  func (p *Tbigp) M(x int, b byte) (byte, int) { return b, x + int(p[0]) + int(p[1]) }
  2524  
  2525  type tinter interface {
  2526  	m(int, byte) (byte, int)
  2527  }
  2528  
  2529  // Embedding via pointer.
  2530  
  2531  type Tm1 struct {
  2532  	Tm2
  2533  }
  2534  
  2535  type Tm2 struct {
  2536  	*Tm3
  2537  }
  2538  
  2539  type Tm3 struct {
  2540  	*Tm4
  2541  }
  2542  
  2543  type Tm4 struct {
  2544  }
  2545  
  2546  func (t4 Tm4) M(x int, b byte) (byte, int) { return b, x + 40 }
  2547  
  2548  func TestMethod5(t *testing.T) {
  2549  	CheckF := func(name string, f func(int, byte) (byte, int), inc int) {
  2550  		b, x := f(1000, 99)
  2551  		if b != 99 || x != 1000+inc {
  2552  			t.Errorf("%s(1000, 99) = %v, %v, want 99, %v", name, b, x, 1000+inc)
  2553  		}
  2554  	}
  2555  
  2556  	CheckV := func(name string, i Value, inc int) {
  2557  		bx := i.Method(0).Call([]Value{ValueOf(1000), ValueOf(byte(99))})
  2558  		b := bx[0].Interface()
  2559  		x := bx[1].Interface()
  2560  		if b != byte(99) || x != 1000+inc {
  2561  			t.Errorf("direct %s.M(1000, 99) = %v, %v, want 99, %v", name, b, x, 1000+inc)
  2562  		}
  2563  
  2564  		CheckF(name+".M", i.Method(0).Interface().(func(int, byte) (byte, int)), inc)
  2565  	}
  2566  
  2567  	var TinterType = TypeOf(new(Tinter)).Elem()
  2568  
  2569  	CheckI := func(name string, i interface{}, inc int) {
  2570  		v := ValueOf(i)
  2571  		CheckV(name, v, inc)
  2572  		CheckV("(i="+name+")", v.Convert(TinterType), inc)
  2573  	}
  2574  
  2575  	sv := Tsmallv(1)
  2576  	CheckI("sv", sv, 1)
  2577  	CheckI("&sv", &sv, 1)
  2578  
  2579  	sp := Tsmallp(2)
  2580  	CheckI("&sp", &sp, 2)
  2581  
  2582  	wv := Twordv(3)
  2583  	CheckI("wv", wv, 3)
  2584  	CheckI("&wv", &wv, 3)
  2585  
  2586  	wp := Twordp(4)
  2587  	CheckI("&wp", &wp, 4)
  2588  
  2589  	bv := Tbigv([2]uintptr{5, 6})
  2590  	CheckI("bv", bv, 11)
  2591  	CheckI("&bv", &bv, 11)
  2592  
  2593  	bp := Tbigp([2]uintptr{7, 8})
  2594  	CheckI("&bp", &bp, 15)
  2595  
  2596  	t4 := Tm4{}
  2597  	t3 := Tm3{&t4}
  2598  	t2 := Tm2{&t3}
  2599  	t1 := Tm1{t2}
  2600  	CheckI("t4", t4, 40)
  2601  	CheckI("&t4", &t4, 40)
  2602  	CheckI("t3", t3, 40)
  2603  	CheckI("&t3", &t3, 40)
  2604  	CheckI("t2", t2, 40)
  2605  	CheckI("&t2", &t2, 40)
  2606  	CheckI("t1", t1, 40)
  2607  	CheckI("&t1", &t1, 40)
  2608  
  2609  	var tnil Tinter
  2610  	vnil := ValueOf(&tnil).Elem()
  2611  	shouldPanic("Method", func() { vnil.Method(0) })
  2612  }
  2613  
  2614  func TestInterfaceSet(t *testing.T) {
  2615  	p := &Point{3, 4}
  2616  
  2617  	var s struct {
  2618  		I interface{}
  2619  		P interface {
  2620  			Dist(int) int
  2621  		}
  2622  	}
  2623  	sv := ValueOf(&s).Elem()
  2624  	sv.Field(0).Set(ValueOf(p))
  2625  	if q := s.I.(*Point); q != p {
  2626  		t.Errorf("i: have %p want %p", q, p)
  2627  	}
  2628  
  2629  	pv := sv.Field(1)
  2630  	pv.Set(ValueOf(p))
  2631  	if q := s.P.(*Point); q != p {
  2632  		t.Errorf("i: have %p want %p", q, p)
  2633  	}
  2634  
  2635  	i := pv.Method(0).Call([]Value{ValueOf(10)})[0].Int()
  2636  	if i != 250 {
  2637  		t.Errorf("Interface Method returned %d; want 250", i)
  2638  	}
  2639  }
  2640  
  2641  type T1 struct {
  2642  	a string
  2643  	int
  2644  }
  2645  
  2646  func TestAnonymousFields(t *testing.T) {
  2647  	var field StructField
  2648  	var ok bool
  2649  	var t1 T1
  2650  	type1 := TypeOf(t1)
  2651  	if field, ok = type1.FieldByName("int"); !ok {
  2652  		t.Fatal("no field 'int'")
  2653  	}
  2654  	if field.Index[0] != 1 {
  2655  		t.Error("field index should be 1; is", field.Index)
  2656  	}
  2657  }
  2658  
  2659  type FTest struct {
  2660  	s     interface{}
  2661  	name  string
  2662  	index []int
  2663  	value int
  2664  }
  2665  
  2666  type D1 struct {
  2667  	d int
  2668  }
  2669  type D2 struct {
  2670  	d int
  2671  }
  2672  
  2673  type S0 struct {
  2674  	A, B, C int
  2675  	D1
  2676  	D2
  2677  }
  2678  
  2679  type S1 struct {
  2680  	B int
  2681  	S0
  2682  }
  2683  
  2684  type S2 struct {
  2685  	A int
  2686  	*S1
  2687  }
  2688  
  2689  type S1x struct {
  2690  	S1
  2691  }
  2692  
  2693  type S1y struct {
  2694  	S1
  2695  }
  2696  
  2697  type S3 struct {
  2698  	S1x
  2699  	S2
  2700  	D, E int
  2701  	*S1y
  2702  }
  2703  
  2704  type S4 struct {
  2705  	*S4
  2706  	A int
  2707  }
  2708  
  2709  // The X in S6 and S7 annihilate, but they also block the X in S8.S9.
  2710  type S5 struct {
  2711  	S6
  2712  	S7
  2713  	S8
  2714  }
  2715  
  2716  type S6 struct {
  2717  	X int
  2718  }
  2719  
  2720  type S7 S6
  2721  
  2722  type S8 struct {
  2723  	S9
  2724  }
  2725  
  2726  type S9 struct {
  2727  	X int
  2728  	Y int
  2729  }
  2730  
  2731  // The X in S11.S6 and S12.S6 annihilate, but they also block the X in S13.S8.S9.
  2732  type S10 struct {
  2733  	S11
  2734  	S12
  2735  	S13
  2736  }
  2737  
  2738  type S11 struct {
  2739  	S6
  2740  }
  2741  
  2742  type S12 struct {
  2743  	S6
  2744  }
  2745  
  2746  type S13 struct {
  2747  	S8
  2748  }
  2749  
  2750  // The X in S15.S11.S1 and S16.S11.S1 annihilate.
  2751  type S14 struct {
  2752  	S15
  2753  	S16
  2754  }
  2755  
  2756  type S15 struct {
  2757  	S11
  2758  }
  2759  
  2760  type S16 struct {
  2761  	S11
  2762  }
  2763  
  2764  var fieldTests = []FTest{
  2765  	{struct{}{}, "", nil, 0},
  2766  	{struct{}{}, "Foo", nil, 0},
  2767  	{S0{A: 'a'}, "A", []int{0}, 'a'},
  2768  	{S0{}, "D", nil, 0},
  2769  	{S1{S0: S0{A: 'a'}}, "A", []int{1, 0}, 'a'},
  2770  	{S1{B: 'b'}, "B", []int{0}, 'b'},
  2771  	{S1{}, "S0", []int{1}, 0},
  2772  	{S1{S0: S0{C: 'c'}}, "C", []int{1, 2}, 'c'},
  2773  	{S2{A: 'a'}, "A", []int{0}, 'a'},
  2774  	{S2{}, "S1", []int{1}, 0},
  2775  	{S2{S1: &S1{B: 'b'}}, "B", []int{1, 0}, 'b'},
  2776  	{S2{S1: &S1{S0: S0{C: 'c'}}}, "C", []int{1, 1, 2}, 'c'},
  2777  	{S2{}, "D", nil, 0},
  2778  	{S3{}, "S1", nil, 0},
  2779  	{S3{S2: S2{A: 'a'}}, "A", []int{1, 0}, 'a'},
  2780  	{S3{}, "B", nil, 0},
  2781  	{S3{D: 'd'}, "D", []int{2}, 0},
  2782  	{S3{E: 'e'}, "E", []int{3}, 'e'},
  2783  	{S4{A: 'a'}, "A", []int{1}, 'a'},
  2784  	{S4{}, "B", nil, 0},
  2785  	{S5{}, "X", nil, 0},
  2786  	{S5{}, "Y", []int{2, 0, 1}, 0},
  2787  	{S10{}, "X", nil, 0},
  2788  	{S10{}, "Y", []int{2, 0, 0, 1}, 0},
  2789  	{S14{}, "X", nil, 0},
  2790  }
  2791  
  2792  func TestFieldByIndex(t *testing.T) {
  2793  	for _, test := range fieldTests {
  2794  		s := TypeOf(test.s)
  2795  		f := s.FieldByIndex(test.index)
  2796  		if f.Name != "" {
  2797  			if test.index != nil {
  2798  				if f.Name != test.name {
  2799  					t.Errorf("%s.%s found; want %s", s.Name(), f.Name, test.name)
  2800  				}
  2801  			} else {
  2802  				t.Errorf("%s.%s found", s.Name(), f.Name)
  2803  			}
  2804  		} else if len(test.index) > 0 {
  2805  			t.Errorf("%s.%s not found", s.Name(), test.name)
  2806  		}
  2807  
  2808  		if test.value != 0 {
  2809  			v := ValueOf(test.s).FieldByIndex(test.index)
  2810  			if v.IsValid() {
  2811  				if x, ok := v.Interface().(int); ok {
  2812  					if x != test.value {
  2813  						t.Errorf("%s%v is %d; want %d", s.Name(), test.index, x, test.value)
  2814  					}
  2815  				} else {
  2816  					t.Errorf("%s%v value not an int", s.Name(), test.index)
  2817  				}
  2818  			} else {
  2819  				t.Errorf("%s%v value not found", s.Name(), test.index)
  2820  			}
  2821  		}
  2822  	}
  2823  }
  2824  
  2825  func TestFieldByName(t *testing.T) {
  2826  	for _, test := range fieldTests {
  2827  		s := TypeOf(test.s)
  2828  		f, found := s.FieldByName(test.name)
  2829  		if found {
  2830  			if test.index != nil {
  2831  				// Verify field depth and index.
  2832  				if len(f.Index) != len(test.index) {
  2833  					t.Errorf("%s.%s depth %d; want %d: %v vs %v", s.Name(), test.name, len(f.Index), len(test.index), f.Index, test.index)
  2834  				} else {
  2835  					for i, x := range f.Index {
  2836  						if x != test.index[i] {
  2837  							t.Errorf("%s.%s.Index[%d] is %d; want %d", s.Name(), test.name, i, x, test.index[i])
  2838  						}
  2839  					}
  2840  				}
  2841  			} else {
  2842  				t.Errorf("%s.%s found", s.Name(), f.Name)
  2843  			}
  2844  		} else if len(test.index) > 0 {
  2845  			t.Errorf("%s.%s not found", s.Name(), test.name)
  2846  		}
  2847  
  2848  		if test.value != 0 {
  2849  			v := ValueOf(test.s).FieldByName(test.name)
  2850  			if v.IsValid() {
  2851  				if x, ok := v.Interface().(int); ok {
  2852  					if x != test.value {
  2853  						t.Errorf("%s.%s is %d; want %d", s.Name(), test.name, x, test.value)
  2854  					}
  2855  				} else {
  2856  					t.Errorf("%s.%s value not an int", s.Name(), test.name)
  2857  				}
  2858  			} else {
  2859  				t.Errorf("%s.%s value not found", s.Name(), test.name)
  2860  			}
  2861  		}
  2862  	}
  2863  }
  2864  
  2865  func TestImportPath(t *testing.T) {
  2866  	tests := []struct {
  2867  		t    Type
  2868  		path string
  2869  	}{
  2870  		{TypeOf(&base64.Encoding{}).Elem(), "encoding/base64"},
  2871  		{TypeOf(int(0)), ""},
  2872  		{TypeOf(int8(0)), ""},
  2873  		{TypeOf(int16(0)), ""},
  2874  		{TypeOf(int32(0)), ""},
  2875  		{TypeOf(int64(0)), ""},
  2876  		{TypeOf(uint(0)), ""},
  2877  		{TypeOf(uint8(0)), ""},
  2878  		{TypeOf(uint16(0)), ""},
  2879  		{TypeOf(uint32(0)), ""},
  2880  		{TypeOf(uint64(0)), ""},
  2881  		{TypeOf(uintptr(0)), ""},
  2882  		{TypeOf(float32(0)), ""},
  2883  		{TypeOf(float64(0)), ""},
  2884  		{TypeOf(complex64(0)), ""},
  2885  		{TypeOf(complex128(0)), ""},
  2886  		{TypeOf(byte(0)), ""},
  2887  		{TypeOf(rune(0)), ""},
  2888  		{TypeOf([]byte(nil)), ""},
  2889  		{TypeOf([]rune(nil)), ""},
  2890  		{TypeOf(string("")), ""},
  2891  		{TypeOf((*interface{})(nil)).Elem(), ""},
  2892  		{TypeOf((*byte)(nil)), ""},
  2893  		{TypeOf((*rune)(nil)), ""},
  2894  		{TypeOf((*int64)(nil)), ""},
  2895  		{TypeOf(map[string]int{}), ""},
  2896  		{TypeOf((*error)(nil)).Elem(), ""},
  2897  		{TypeOf((*Point)(nil)), ""},
  2898  		{TypeOf((*Point)(nil)).Elem(), "reflect_test"},
  2899  	}
  2900  	for _, test := range tests {
  2901  		if path := test.t.PkgPath(); path != test.path {
  2902  			t.Errorf("%v.PkgPath() = %q, want %q", test.t, path, test.path)
  2903  		}
  2904  	}
  2905  }
  2906  
  2907  func TestFieldPkgPath(t *testing.T) {
  2908  	type x int
  2909  	typ := TypeOf(struct {
  2910  		Exported   string
  2911  		unexported string
  2912  		OtherPkgFields
  2913  		int // issue 21702
  2914  		*x  // issue 21122
  2915  	}{})
  2916  
  2917  	type pkgpathTest struct {
  2918  		index    []int
  2919  		pkgPath  string
  2920  		embedded bool
  2921  		exported bool
  2922  	}
  2923  
  2924  	checkPkgPath := func(name string, s []pkgpathTest) {
  2925  		for _, test := range s {
  2926  			f := typ.FieldByIndex(test.index)
  2927  			if got, want := f.PkgPath, test.pkgPath; got != want {
  2928  				t.Errorf("%s: Field(%d).PkgPath = %q, want %q", name, test.index, got, want)
  2929  			}
  2930  			if got, want := f.Anonymous, test.embedded; got != want {
  2931  				t.Errorf("%s: Field(%d).Anonymous = %v, want %v", name, test.index, got, want)
  2932  			}
  2933  			if got, want := f.IsExported(), test.exported; got != want {
  2934  				t.Errorf("%s: Field(%d).IsExported = %v, want %v", name, test.index, got, want)
  2935  			}
  2936  		}
  2937  	}
  2938  
  2939  	checkPkgPath("testStruct", []pkgpathTest{
  2940  		{[]int{0}, "", false, true},              // Exported
  2941  		{[]int{1}, "reflect_test", false, false}, // unexported
  2942  		{[]int{2}, "", true, true},               // OtherPkgFields
  2943  		{[]int{2, 0}, "", false, true},           // OtherExported
  2944  		{[]int{2, 1}, "reflect", false, false},   // otherUnexported
  2945  		{[]int{3}, "reflect_test", true, false},  // int
  2946  		{[]int{4}, "reflect_test", true, false},  // *x
  2947  	})
  2948  
  2949  	type localOtherPkgFields OtherPkgFields
  2950  	typ = TypeOf(localOtherPkgFields{})
  2951  	checkPkgPath("localOtherPkgFields", []pkgpathTest{
  2952  		{[]int{0}, "", false, true},         // OtherExported
  2953  		{[]int{1}, "reflect", false, false}, // otherUnexported
  2954  	})
  2955  }
  2956  
  2957  func TestMethodPkgPath(t *testing.T) {
  2958  	type I interface {
  2959  		x()
  2960  		X()
  2961  	}
  2962  	typ := TypeOf((*interface {
  2963  		I
  2964  		y()
  2965  		Y()
  2966  	})(nil)).Elem()
  2967  
  2968  	tests := []struct {
  2969  		name     string
  2970  		pkgPath  string
  2971  		exported bool
  2972  	}{
  2973  		{"X", "", true},
  2974  		{"Y", "", true},
  2975  		{"x", "reflect_test", false},
  2976  		{"y", "reflect_test", false},
  2977  	}
  2978  
  2979  	for _, test := range tests {
  2980  		m, _ := typ.MethodByName(test.name)
  2981  		if got, want := m.PkgPath, test.pkgPath; got != want {
  2982  			t.Errorf("MethodByName(%q).PkgPath = %q, want %q", test.name, got, want)
  2983  		}
  2984  		if got, want := m.IsExported(), test.exported; got != want {
  2985  			t.Errorf("MethodByName(%q).IsExported = %v, want %v", test.name, got, want)
  2986  		}
  2987  	}
  2988  }
  2989  
  2990  func TestVariadicType(t *testing.T) {
  2991  	// Test example from Type documentation.
  2992  	var f func(x int, y ...float64)
  2993  	typ := TypeOf(f)
  2994  	if typ.NumIn() == 2 && typ.In(0) == TypeOf(int(0)) {
  2995  		sl := typ.In(1)
  2996  		if sl.Kind() == Slice {
  2997  			if sl.Elem() == TypeOf(0.0) {
  2998  				// ok
  2999  				return
  3000  			}
  3001  		}
  3002  	}
  3003  
  3004  	// Failed
  3005  	t.Errorf("want NumIn() = 2, In(0) = int, In(1) = []float64")
  3006  	s := fmt.Sprintf("have NumIn() = %d", typ.NumIn())
  3007  	for i := 0; i < typ.NumIn(); i++ {
  3008  		s += fmt.Sprintf(", In(%d) = %s", i, typ.In(i))
  3009  	}
  3010  	t.Error(s)
  3011  }
  3012  
  3013  type inner struct {
  3014  	x int
  3015  }
  3016  
  3017  type outer struct {
  3018  	y int
  3019  	inner
  3020  }
  3021  
  3022  func (*inner) M() {}
  3023  func (*outer) M() {}
  3024  
  3025  func TestNestedMethods(t *testing.T) {
  3026  	typ := TypeOf((*outer)(nil))
  3027  	if typ.NumMethod() != 1 || typ.Method(0).Func.Pointer() != ValueOf((*outer).M).Pointer() {
  3028  		t.Errorf("Wrong method table for outer: (M=%p)", (*outer).M)
  3029  		for i := 0; i < typ.NumMethod(); i++ {
  3030  			m := typ.Method(i)
  3031  			t.Errorf("\t%d: %s %#x\n", i, m.Name, m.Func.Pointer())
  3032  		}
  3033  	}
  3034  }
  3035  
  3036  type unexp struct{}
  3037  
  3038  func (*unexp) f() (int32, int8) { return 7, 7 }
  3039  func (*unexp) g() (int64, int8) { return 8, 8 }
  3040  
  3041  type unexpI interface {
  3042  	f() (int32, int8)
  3043  }
  3044  
  3045  var unexpi unexpI = new(unexp)
  3046  
  3047  func TestUnexportedMethods(t *testing.T) {
  3048  	typ := TypeOf(unexpi)
  3049  
  3050  	if got := typ.NumMethod(); got != 0 {
  3051  		t.Errorf("NumMethod=%d, want 0 satisfied methods", got)
  3052  	}
  3053  }
  3054  
  3055  type InnerInt struct {
  3056  	X int
  3057  }
  3058  
  3059  type OuterInt struct {
  3060  	Y int
  3061  	InnerInt
  3062  }
  3063  
  3064  func (i *InnerInt) M() int {
  3065  	return i.X
  3066  }
  3067  
  3068  func TestEmbeddedMethods(t *testing.T) {
  3069  	typ := TypeOf((*OuterInt)(nil))
  3070  	if typ.NumMethod() != 1 || typ.Method(0).Func.Pointer() != ValueOf((*OuterInt).M).Pointer() {
  3071  		t.Errorf("Wrong method table for OuterInt: (m=%p)", (*OuterInt).M)
  3072  		for i := 0; i < typ.NumMethod(); i++ {
  3073  			m := typ.Method(i)
  3074  			t.Errorf("\t%d: %s %#x\n", i, m.Name, m.Func.Pointer())
  3075  		}
  3076  	}
  3077  
  3078  	i := &InnerInt{3}
  3079  	if v := ValueOf(i).Method(0).Call(nil)[0].Int(); v != 3 {
  3080  		t.Errorf("i.M() = %d, want 3", v)
  3081  	}
  3082  
  3083  	o := &OuterInt{1, InnerInt{2}}
  3084  	if v := ValueOf(o).Method(0).Call(nil)[0].Int(); v != 2 {
  3085  		t.Errorf("i.M() = %d, want 2", v)
  3086  	}
  3087  
  3088  	f := (*OuterInt).M
  3089  	if v := f(o); v != 2 {
  3090  		t.Errorf("f(o) = %d, want 2", v)
  3091  	}
  3092  }
  3093  
  3094  type FuncDDD func(...interface{}) error
  3095  
  3096  func (f FuncDDD) M() {}
  3097  
  3098  func TestNumMethodOnDDD(t *testing.T) {
  3099  	rv := ValueOf((FuncDDD)(nil))
  3100  	if n := rv.NumMethod(); n != 1 {
  3101  		t.Fatalf("NumMethod()=%d, want 1", n)
  3102  	}
  3103  }
  3104  
  3105  func TestPtrTo(t *testing.T) {
  3106  	// This block of code means that the ptrToThis field of the
  3107  	// reflect data for *unsafe.Pointer is non zero, see
  3108  	// https://golang.org/issue/19003
  3109  	var x unsafe.Pointer
  3110  	var y = &x
  3111  	var z = &y
  3112  
  3113  	var i int
  3114  
  3115  	typ := TypeOf(z)
  3116  	for i = 0; i < 100; i++ {
  3117  		typ = PtrTo(typ)
  3118  	}
  3119  	for i = 0; i < 100; i++ {
  3120  		typ = typ.Elem()
  3121  	}
  3122  	if typ != TypeOf(z) {
  3123  		t.Errorf("after 100 PtrTo and Elem, have %s, want %s", typ, TypeOf(z))
  3124  	}
  3125  }
  3126  
  3127  func TestPtrToGC(t *testing.T) {
  3128  	type T *uintptr
  3129  	tt := TypeOf(T(nil))
  3130  	pt := PtrTo(tt)
  3131  	const n = 100
  3132  	var x []interface{}
  3133  	for i := 0; i < n; i++ {
  3134  		v := New(pt)
  3135  		p := new(*uintptr)
  3136  		*p = new(uintptr)
  3137  		**p = uintptr(i)
  3138  		v.Elem().Set(ValueOf(p).Convert(pt))
  3139  		x = append(x, v.Interface())
  3140  	}
  3141  	runtime.GC()
  3142  
  3143  	for i, xi := range x {
  3144  		k := ValueOf(xi).Elem().Elem().Elem().Interface().(uintptr)
  3145  		if k != uintptr(i) {
  3146  			t.Errorf("lost x[%d] = %d, want %d", i, k, i)
  3147  		}
  3148  	}
  3149  }
  3150  
  3151  func BenchmarkPtrTo(b *testing.B) {
  3152  	// Construct a type with a zero ptrToThis.
  3153  	type T struct{ int }
  3154  	t := SliceOf(TypeOf(T{}))
  3155  	ptrToThis := ValueOf(t).Elem().FieldByName("ptrToThis")
  3156  	if !ptrToThis.IsValid() {
  3157  		b.Fatalf("%v has no ptrToThis field; was it removed from rtype?", t)
  3158  	}
  3159  	if ptrToThis.Int() != 0 {
  3160  		b.Fatalf("%v.ptrToThis unexpectedly nonzero", t)
  3161  	}
  3162  	b.ResetTimer()
  3163  
  3164  	// Now benchmark calling PtrTo on it: we'll have to hit the ptrMap cache on
  3165  	// every call.
  3166  	b.RunParallel(func(pb *testing.PB) {
  3167  		for pb.Next() {
  3168  			PtrTo(t)
  3169  		}
  3170  	})
  3171  }
  3172  
  3173  func TestAddr(t *testing.T) {
  3174  	var p struct {
  3175  		X, Y int
  3176  	}
  3177  
  3178  	v := ValueOf(&p)
  3179  	v = v.Elem()
  3180  	v = v.Addr()
  3181  	v = v.Elem()
  3182  	v = v.Field(0)
  3183  	v.SetInt(2)
  3184  	if p.X != 2 {
  3185  		t.Errorf("Addr.Elem.Set failed to set value")
  3186  	}
  3187  
  3188  	// Again but take address of the ValueOf value.
  3189  	// Exercises generation of PtrTypes not present in the binary.
  3190  	q := &p
  3191  	v = ValueOf(&q).Elem()
  3192  	v = v.Addr()
  3193  	v = v.Elem()
  3194  	v = v.Elem()
  3195  	v = v.Addr()
  3196  	v = v.Elem()
  3197  	v = v.Field(0)
  3198  	v.SetInt(3)
  3199  	if p.X != 3 {
  3200  		t.Errorf("Addr.Elem.Set failed to set value")
  3201  	}
  3202  
  3203  	// Starting without pointer we should get changed value
  3204  	// in interface.
  3205  	qq := p
  3206  	v = ValueOf(&qq).Elem()
  3207  	v0 := v
  3208  	v = v.Addr()
  3209  	v = v.Elem()
  3210  	v = v.Field(0)
  3211  	v.SetInt(4)
  3212  	if p.X != 3 { // should be unchanged from last time
  3213  		t.Errorf("somehow value Set changed original p")
  3214  	}
  3215  	p = v0.Interface().(struct {
  3216  		X, Y int
  3217  	})
  3218  	if p.X != 4 {
  3219  		t.Errorf("Addr.Elem.Set valued to set value in top value")
  3220  	}
  3221  
  3222  	// Verify that taking the address of a type gives us a pointer
  3223  	// which we can convert back using the usual interface
  3224  	// notation.
  3225  	var s struct {
  3226  		B *bool
  3227  	}
  3228  	ps := ValueOf(&s).Elem().Field(0).Addr().Interface()
  3229  	*(ps.(**bool)) = new(bool)
  3230  	if s.B == nil {
  3231  		t.Errorf("Addr.Interface direct assignment failed")
  3232  	}
  3233  }
  3234  
  3235  func noAlloc(t *testing.T, n int, f func(int)) {
  3236  	if testing.Short() {
  3237  		t.Skip("skipping malloc count in short mode")
  3238  	}
  3239  	if runtime.GOMAXPROCS(0) > 1 {
  3240  		t.Skip("skipping; GOMAXPROCS>1")
  3241  	}
  3242  	i := -1
  3243  	allocs := testing.AllocsPerRun(n, func() {
  3244  		f(i)
  3245  		i++
  3246  	})
  3247  	if allocs > 0 {
  3248  		t.Errorf("%d iterations: got %v mallocs, want 0", n, allocs)
  3249  	}
  3250  }
  3251  
  3252  func TestAllocations(t *testing.T) {
  3253  	noAlloc(t, 100, func(j int) {
  3254  		var i interface{}
  3255  		var v Value
  3256  
  3257  		// We can uncomment this when compiler escape analysis
  3258  		// is good enough to see that the integer assigned to i
  3259  		// does not escape and therefore need not be allocated.
  3260  		//
  3261  		// i = 42 + j
  3262  		// v = ValueOf(i)
  3263  		// if int(v.Int()) != 42+j {
  3264  		// 	panic("wrong int")
  3265  		// }
  3266  
  3267  		i = func(j int) int { return j }
  3268  		v = ValueOf(i)
  3269  		if v.Interface().(func(int) int)(j) != j {
  3270  			panic("wrong result")
  3271  		}
  3272  	})
  3273  }
  3274  
  3275  func TestSmallNegativeInt(t *testing.T) {
  3276  	i := int16(-1)
  3277  	v := ValueOf(i)
  3278  	if v.Int() != -1 {
  3279  		t.Errorf("int16(-1).Int() returned %v", v.Int())
  3280  	}
  3281  }
  3282  
  3283  func TestIndex(t *testing.T) {
  3284  	xs := []byte{1, 2, 3, 4, 5, 6, 7, 8}
  3285  	v := ValueOf(xs).Index(3).Interface().(byte)
  3286  	if v != xs[3] {
  3287  		t.Errorf("xs.Index(3) = %v; expected %v", v, xs[3])
  3288  	}
  3289  	xa := [8]byte{10, 20, 30, 40, 50, 60, 70, 80}
  3290  	v = ValueOf(xa).Index(2).Interface().(byte)
  3291  	if v != xa[2] {
  3292  		t.Errorf("xa.Index(2) = %v; expected %v", v, xa[2])
  3293  	}
  3294  	s := "0123456789"
  3295  	v = ValueOf(s).Index(3).Interface().(byte)
  3296  	if v != s[3] {
  3297  		t.Errorf("s.Index(3) = %v; expected %v", v, s[3])
  3298  	}
  3299  }
  3300  
  3301  func TestSlice(t *testing.T) {
  3302  	xs := []int{1, 2, 3, 4, 5, 6, 7, 8}
  3303  	v := ValueOf(xs).Slice(3, 5).Interface().([]int)
  3304  	if len(v) != 2 {
  3305  		t.Errorf("len(xs.Slice(3, 5)) = %d", len(v))
  3306  	}
  3307  	if cap(v) != 5 {
  3308  		t.Errorf("cap(xs.Slice(3, 5)) = %d", cap(v))
  3309  	}
  3310  	if !DeepEqual(v[0:5], xs[3:]) {
  3311  		t.Errorf("xs.Slice(3, 5)[0:5] = %v", v[0:5])
  3312  	}
  3313  	xa := [8]int{10, 20, 30, 40, 50, 60, 70, 80}
  3314  	v = ValueOf(&xa).Elem().Slice(2, 5).Interface().([]int)
  3315  	if len(v) != 3 {
  3316  		t.Errorf("len(xa.Slice(2, 5)) = %d", len(v))
  3317  	}
  3318  	if cap(v) != 6 {
  3319  		t.Errorf("cap(xa.Slice(2, 5)) = %d", cap(v))
  3320  	}
  3321  	if !DeepEqual(v[0:6], xa[2:]) {
  3322  		t.Errorf("xs.Slice(2, 5)[0:6] = %v", v[0:6])
  3323  	}
  3324  	s := "0123456789"
  3325  	vs := ValueOf(s).Slice(3, 5).Interface().(string)
  3326  	if vs != s[3:5] {
  3327  		t.Errorf("s.Slice(3, 5) = %q; expected %q", vs, s[3:5])
  3328  	}
  3329  
  3330  	rv := ValueOf(&xs).Elem()
  3331  	rv = rv.Slice(3, 4)
  3332  	ptr2 := rv.Pointer()
  3333  	rv = rv.Slice(5, 5)
  3334  	ptr3 := rv.Pointer()
  3335  	if ptr3 != ptr2 {
  3336  		t.Errorf("xs.Slice(3,4).Slice3(5,5).Pointer() = %#x, want %#x", ptr3, ptr2)
  3337  	}
  3338  }
  3339  
  3340  func TestSlice3(t *testing.T) {
  3341  	xs := []int{1, 2, 3, 4, 5, 6, 7, 8}
  3342  	v := ValueOf(xs).Slice3(3, 5, 7).Interface().([]int)
  3343  	if len(v) != 2 {
  3344  		t.Errorf("len(xs.Slice3(3, 5, 7)) = %d", len(v))
  3345  	}
  3346  	if cap(v) != 4 {
  3347  		t.Errorf("cap(xs.Slice3(3, 5, 7)) = %d", cap(v))
  3348  	}
  3349  	if !DeepEqual(v[0:4], xs[3:7:7]) {
  3350  		t.Errorf("xs.Slice3(3, 5, 7)[0:4] = %v", v[0:4])
  3351  	}
  3352  	rv := ValueOf(&xs).Elem()
  3353  	shouldPanic("Slice3", func() { rv.Slice3(1, 2, 1) })
  3354  	shouldPanic("Slice3", func() { rv.Slice3(1, 1, 11) })
  3355  	shouldPanic("Slice3", func() { rv.Slice3(2, 2, 1) })
  3356  
  3357  	xa := [8]int{10, 20, 30, 40, 50, 60, 70, 80}
  3358  	v = ValueOf(&xa).Elem().Slice3(2, 5, 6).Interface().([]int)
  3359  	if len(v) != 3 {
  3360  		t.Errorf("len(xa.Slice(2, 5, 6)) = %d", len(v))
  3361  	}
  3362  	if cap(v) != 4 {
  3363  		t.Errorf("cap(xa.Slice(2, 5, 6)) = %d", cap(v))
  3364  	}
  3365  	if !DeepEqual(v[0:4], xa[2:6:6]) {
  3366  		t.Errorf("xs.Slice(2, 5, 6)[0:4] = %v", v[0:4])
  3367  	}
  3368  	rv = ValueOf(&xa).Elem()
  3369  	shouldPanic("Slice3", func() { rv.Slice3(1, 2, 1) })
  3370  	shouldPanic("Slice3", func() { rv.Slice3(1, 1, 11) })
  3371  	shouldPanic("Slice3", func() { rv.Slice3(2, 2, 1) })
  3372  
  3373  	s := "hello world"
  3374  	rv = ValueOf(&s).Elem()
  3375  	shouldPanic("Slice3", func() { rv.Slice3(1, 2, 3) })
  3376  
  3377  	rv = ValueOf(&xs).Elem()
  3378  	rv = rv.Slice3(3, 5, 7)
  3379  	ptr2 := rv.Pointer()
  3380  	rv = rv.Slice3(4, 4, 4)
  3381  	ptr3 := rv.Pointer()
  3382  	if ptr3 != ptr2 {
  3383  		t.Errorf("xs.Slice3(3,5,7).Slice3(4,4,4).Pointer() = %#x, want %#x", ptr3, ptr2)
  3384  	}
  3385  }
  3386  
  3387  func TestSetLenCap(t *testing.T) {
  3388  	xs := []int{1, 2, 3, 4, 5, 6, 7, 8}
  3389  	xa := [8]int{10, 20, 30, 40, 50, 60, 70, 80}
  3390  
  3391  	vs := ValueOf(&xs).Elem()
  3392  	shouldPanic("SetLen", func() { vs.SetLen(10) })
  3393  	shouldPanic("SetCap", func() { vs.SetCap(10) })
  3394  	shouldPanic("SetLen", func() { vs.SetLen(-1) })
  3395  	shouldPanic("SetCap", func() { vs.SetCap(-1) })
  3396  	shouldPanic("SetCap", func() { vs.SetCap(6) }) // smaller than len
  3397  	vs.SetLen(5)
  3398  	if len(xs) != 5 || cap(xs) != 8 {
  3399  		t.Errorf("after SetLen(5), len, cap = %d, %d, want 5, 8", len(xs), cap(xs))
  3400  	}
  3401  	vs.SetCap(6)
  3402  	if len(xs) != 5 || cap(xs) != 6 {
  3403  		t.Errorf("after SetCap(6), len, cap = %d, %d, want 5, 6", len(xs), cap(xs))
  3404  	}
  3405  	vs.SetCap(5)
  3406  	if len(xs) != 5 || cap(xs) != 5 {
  3407  		t.Errorf("after SetCap(5), len, cap = %d, %d, want 5, 5", len(xs), cap(xs))
  3408  	}
  3409  	shouldPanic("SetCap", func() { vs.SetCap(4) }) // smaller than len
  3410  	shouldPanic("SetLen", func() { vs.SetLen(6) }) // bigger than cap
  3411  
  3412  	va := ValueOf(&xa).Elem()
  3413  	shouldPanic("SetLen", func() { va.SetLen(8) })
  3414  	shouldPanic("SetCap", func() { va.SetCap(8) })
  3415  }
  3416  
  3417  func TestVariadic(t *testing.T) {
  3418  	var b bytes.Buffer
  3419  	V := ValueOf
  3420  
  3421  	b.Reset()
  3422  	V(fmt.Fprintf).Call([]Value{V(&b), V("%s, %d world"), V("hello"), V(42)})
  3423  	if b.String() != "hello, 42 world" {
  3424  		t.Errorf("after Fprintf Call: %q != %q", b.String(), "hello 42 world")
  3425  	}
  3426  
  3427  	b.Reset()
  3428  	V(fmt.Fprintf).CallSlice([]Value{V(&b), V("%s, %d world"), V([]interface{}{"hello", 42})})
  3429  	if b.String() != "hello, 42 world" {
  3430  		t.Errorf("after Fprintf CallSlice: %q != %q", b.String(), "hello 42 world")
  3431  	}
  3432  }
  3433  
  3434  func TestFuncArg(t *testing.T) {
  3435  	f1 := func(i int, f func(int) int) int { return f(i) }
  3436  	f2 := func(i int) int { return i + 1 }
  3437  	r := ValueOf(f1).Call([]Value{ValueOf(100), ValueOf(f2)})
  3438  	if r[0].Int() != 101 {
  3439  		t.Errorf("function returned %d, want 101", r[0].Int())
  3440  	}
  3441  }
  3442  
  3443  func TestStructArg(t *testing.T) {
  3444  	type padded struct {
  3445  		B string
  3446  		C int32
  3447  	}
  3448  	var (
  3449  		gotA  padded
  3450  		gotB  uint32
  3451  		wantA = padded{"3", 4}
  3452  		wantB = uint32(5)
  3453  	)
  3454  	f := func(a padded, b uint32) {
  3455  		gotA, gotB = a, b
  3456  	}
  3457  	ValueOf(f).Call([]Value{ValueOf(wantA), ValueOf(wantB)})
  3458  	if gotA != wantA || gotB != wantB {
  3459  		t.Errorf("function called with (%v, %v), want (%v, %v)", gotA, gotB, wantA, wantB)
  3460  	}
  3461  }
  3462  
  3463  var tagGetTests = []struct {
  3464  	Tag   StructTag
  3465  	Key   string
  3466  	Value string
  3467  }{
  3468  	{`protobuf:"PB(1,2)"`, `protobuf`, `PB(1,2)`},
  3469  	{`protobuf:"PB(1,2)"`, `foo`, ``},
  3470  	{`protobuf:"PB(1,2)"`, `rotobuf`, ``},
  3471  	{`protobuf:"PB(1,2)" json:"name"`, `json`, `name`},
  3472  	{`protobuf:"PB(1,2)" json:"name"`, `protobuf`, `PB(1,2)`},
  3473  	{`k0:"values contain spaces" k1:"and\ttabs"`, "k0", "values contain spaces"},
  3474  	{`k0:"values contain spaces" k1:"and\ttabs"`, "k1", "and\ttabs"},
  3475  }
  3476  
  3477  func TestTagGet(t *testing.T) {
  3478  	for _, tt := range tagGetTests {
  3479  		if v := tt.Tag.Get(tt.Key); v != tt.Value {
  3480  			t.Errorf("StructTag(%#q).Get(%#q) = %#q, want %#q", tt.Tag, tt.Key, v, tt.Value)
  3481  		}
  3482  	}
  3483  }
  3484  
  3485  func TestBytes(t *testing.T) {
  3486  	type B []byte
  3487  	x := B{1, 2, 3, 4}
  3488  	y := ValueOf(x).Bytes()
  3489  	if !bytes.Equal(x, y) {
  3490  		t.Fatalf("ValueOf(%v).Bytes() = %v", x, y)
  3491  	}
  3492  	if &x[0] != &y[0] {
  3493  		t.Errorf("ValueOf(%p).Bytes() = %p", &x[0], &y[0])
  3494  	}
  3495  }
  3496  
  3497  func TestSetBytes(t *testing.T) {
  3498  	type B []byte
  3499  	var x B
  3500  	y := []byte{1, 2, 3, 4}
  3501  	ValueOf(&x).Elem().SetBytes(y)
  3502  	if !bytes.Equal(x, y) {
  3503  		t.Fatalf("ValueOf(%v).Bytes() = %v", x, y)
  3504  	}
  3505  	if &x[0] != &y[0] {
  3506  		t.Errorf("ValueOf(%p).Bytes() = %p", &x[0], &y[0])
  3507  	}
  3508  }
  3509  
  3510  type Private struct {
  3511  	x int
  3512  	y **int
  3513  	Z int
  3514  }
  3515  
  3516  func (p *Private) m() {
  3517  }
  3518  
  3519  type private struct {
  3520  	Z int
  3521  	z int
  3522  	S string
  3523  	A [1]Private
  3524  	T []Private
  3525  }
  3526  
  3527  func (p *private) P() {
  3528  }
  3529  
  3530  type Public struct {
  3531  	X int
  3532  	Y **int
  3533  	private
  3534  }
  3535  
  3536  func (p *Public) M() {
  3537  }
  3538  
  3539  func TestUnexported(t *testing.T) {
  3540  	var pub Public
  3541  	pub.S = "S"
  3542  	pub.T = pub.A[:]
  3543  	v := ValueOf(&pub)
  3544  	isValid(v.Elem().Field(0))
  3545  	isValid(v.Elem().Field(1))
  3546  	isValid(v.Elem().Field(2))
  3547  	isValid(v.Elem().FieldByName("X"))
  3548  	isValid(v.Elem().FieldByName("Y"))
  3549  	isValid(v.Elem().FieldByName("Z"))
  3550  	isValid(v.Type().Method(0).Func)
  3551  	m, _ := v.Type().MethodByName("M")
  3552  	isValid(m.Func)
  3553  	m, _ = v.Type().MethodByName("P")
  3554  	isValid(m.Func)
  3555  	isNonNil(v.Elem().Field(0).Interface())
  3556  	isNonNil(v.Elem().Field(1).Interface())
  3557  	isNonNil(v.Elem().Field(2).Field(2).Index(0))
  3558  	isNonNil(v.Elem().FieldByName("X").Interface())
  3559  	isNonNil(v.Elem().FieldByName("Y").Interface())
  3560  	isNonNil(v.Elem().FieldByName("Z").Interface())
  3561  	isNonNil(v.Elem().FieldByName("S").Index(0).Interface())
  3562  	isNonNil(v.Type().Method(0).Func.Interface())
  3563  	m, _ = v.Type().MethodByName("P")
  3564  	isNonNil(m.Func.Interface())
  3565  
  3566  	var priv Private
  3567  	v = ValueOf(&priv)
  3568  	isValid(v.Elem().Field(0))
  3569  	isValid(v.Elem().Field(1))
  3570  	isValid(v.Elem().FieldByName("x"))
  3571  	isValid(v.Elem().FieldByName("y"))
  3572  	shouldPanic("Interface", func() { v.Elem().Field(0).Interface() })
  3573  	shouldPanic("Interface", func() { v.Elem().Field(1).Interface() })
  3574  	shouldPanic("Interface", func() { v.Elem().FieldByName("x").Interface() })
  3575  	shouldPanic("Interface", func() { v.Elem().FieldByName("y").Interface() })
  3576  	shouldPanic("Method", func() { v.Type().Method(0) })
  3577  }
  3578  
  3579  func TestSetPanic(t *testing.T) {
  3580  	ok := func(f func()) { f() }
  3581  	bad := func(f func()) { shouldPanic("Set", f) }
  3582  	clear := func(v Value) { v.Set(Zero(v.Type())) }
  3583  
  3584  	type t0 struct {
  3585  		W int
  3586  	}
  3587  
  3588  	type t1 struct {
  3589  		Y int
  3590  		t0
  3591  	}
  3592  
  3593  	type T2 struct {
  3594  		Z       int
  3595  		namedT0 t0
  3596  	}
  3597  
  3598  	type T struct {
  3599  		X int
  3600  		t1
  3601  		T2
  3602  		NamedT1 t1
  3603  		NamedT2 T2
  3604  		namedT1 t1
  3605  		namedT2 T2
  3606  	}
  3607  
  3608  	// not addressable
  3609  	v := ValueOf(T{})
  3610  	bad(func() { clear(v.Field(0)) })                   // .X
  3611  	bad(func() { clear(v.Field(1)) })                   // .t1
  3612  	bad(func() { clear(v.Field(1).Field(0)) })          // .t1.Y
  3613  	bad(func() { clear(v.Field(1).Field(1)) })          // .t1.t0
  3614  	bad(func() { clear(v.Field(1).Field(1).Field(0)) }) // .t1.t0.W
  3615  	bad(func() { clear(v.Field(2)) })                   // .T2
  3616  	bad(func() { clear(v.Field(2).Field(0)) })          // .T2.Z
  3617  	bad(func() { clear(v.Field(2).Field(1)) })          // .T2.namedT0
  3618  	bad(func() { clear(v.Field(2).Field(1).Field(0)) }) // .T2.namedT0.W
  3619  	bad(func() { clear(v.Field(3)) })                   // .NamedT1
  3620  	bad(func() { clear(v.Field(3).Field(0)) })          // .NamedT1.Y
  3621  	bad(func() { clear(v.Field(3).Field(1)) })          // .NamedT1.t0
  3622  	bad(func() { clear(v.Field(3).Field(1).Field(0)) }) // .NamedT1.t0.W
  3623  	bad(func() { clear(v.Field(4)) })                   // .NamedT2
  3624  	bad(func() { clear(v.Field(4).Field(0)) })          // .NamedT2.Z
  3625  	bad(func() { clear(v.Field(4).Field(1)) })          // .NamedT2.namedT0
  3626  	bad(func() { clear(v.Field(4).Field(1).Field(0)) }) // .NamedT2.namedT0.W
  3627  	bad(func() { clear(v.Field(5)) })                   // .namedT1
  3628  	bad(func() { clear(v.Field(5).Field(0)) })          // .namedT1.Y
  3629  	bad(func() { clear(v.Field(5).Field(1)) })          // .namedT1.t0
  3630  	bad(func() { clear(v.Field(5).Field(1).Field(0)) }) // .namedT1.t0.W
  3631  	bad(func() { clear(v.Field(6)) })                   // .namedT2
  3632  	bad(func() { clear(v.Field(6).Field(0)) })          // .namedT2.Z
  3633  	bad(func() { clear(v.Field(6).Field(1)) })          // .namedT2.namedT0
  3634  	bad(func() { clear(v.Field(6).Field(1).Field(0)) }) // .namedT2.namedT0.W
  3635  
  3636  	// addressable
  3637  	v = ValueOf(&T{}).Elem()
  3638  	ok(func() { clear(v.Field(0)) })                    // .X
  3639  	bad(func() { clear(v.Field(1)) })                   // .t1
  3640  	ok(func() { clear(v.Field(1).Field(0)) })           // .t1.Y
  3641  	bad(func() { clear(v.Field(1).Field(1)) })          // .t1.t0
  3642  	ok(func() { clear(v.Field(1).Field(1).Field(0)) })  // .t1.t0.W
  3643  	ok(func() { clear(v.Field(2)) })                    // .T2
  3644  	ok(func() { clear(v.Field(2).Field(0)) })           // .T2.Z
  3645  	bad(func() { clear(v.Field(2).Field(1)) })          // .T2.namedT0
  3646  	bad(func() { clear(v.Field(2).Field(1).Field(0)) }) // .T2.namedT0.W
  3647  	ok(func() { clear(v.Field(3)) })                    // .NamedT1
  3648  	ok(func() { clear(v.Field(3).Field(0)) })           // .NamedT1.Y
  3649  	bad(func() { clear(v.Field(3).Field(1)) })          // .NamedT1.t0
  3650  	ok(func() { clear(v.Field(3).Field(1).Field(0)) })  // .NamedT1.t0.W
  3651  	ok(func() { clear(v.Field(4)) })                    // .NamedT2
  3652  	ok(func() { clear(v.Field(4).Field(0)) })           // .NamedT2.Z
  3653  	bad(func() { clear(v.Field(4).Field(1)) })          // .NamedT2.namedT0
  3654  	bad(func() { clear(v.Field(4).Field(1).Field(0)) }) // .NamedT2.namedT0.W
  3655  	bad(func() { clear(v.Field(5)) })                   // .namedT1
  3656  	bad(func() { clear(v.Field(5).Field(0)) })          // .namedT1.Y
  3657  	bad(func() { clear(v.Field(5).Field(1)) })          // .namedT1.t0
  3658  	bad(func() { clear(v.Field(5).Field(1).Field(0)) }) // .namedT1.t0.W
  3659  	bad(func() { clear(v.Field(6)) })                   // .namedT2
  3660  	bad(func() { clear(v.Field(6).Field(0)) })          // .namedT2.Z
  3661  	bad(func() { clear(v.Field(6).Field(1)) })          // .namedT2.namedT0
  3662  	bad(func() { clear(v.Field(6).Field(1).Field(0)) }) // .namedT2.namedT0.W
  3663  }
  3664  
  3665  type timp int
  3666  
  3667  func (t timp) W() {}
  3668  func (t timp) Y() {}
  3669  func (t timp) w() {}
  3670  func (t timp) y() {}
  3671  
  3672  func TestCallPanic(t *testing.T) {
  3673  	type t0 interface {
  3674  		W()
  3675  		w()
  3676  	}
  3677  	type T1 interface {
  3678  		Y()
  3679  		y()
  3680  	}
  3681  	type T2 struct {
  3682  		T1
  3683  		t0
  3684  	}
  3685  	type T struct {
  3686  		t0 // 0
  3687  		T1 // 1
  3688  
  3689  		NamedT0 t0 // 2
  3690  		NamedT1 T1 // 3
  3691  		NamedT2 T2 // 4
  3692  
  3693  		namedT0 t0 // 5
  3694  		namedT1 T1 // 6
  3695  		namedT2 T2 // 7
  3696  	}
  3697  	ok := func(f func()) { f() }
  3698  	badCall := func(f func()) { shouldPanic("Call", f) }
  3699  	badMethod := func(f func()) { shouldPanic("Method", f) }
  3700  	call := func(v Value) { v.Call(nil) }
  3701  
  3702  	i := timp(0)
  3703  	v := ValueOf(T{i, i, i, i, T2{i, i}, i, i, T2{i, i}})
  3704  	badCall(func() { call(v.Field(0).Method(0)) })          // .t0.W
  3705  	badCall(func() { call(v.Field(0).Elem().Method(0)) })   // .t0.W
  3706  	badCall(func() { call(v.Field(0).Method(1)) })          // .t0.w
  3707  	badMethod(func() { call(v.Field(0).Elem().Method(2)) }) // .t0.w
  3708  	ok(func() { call(v.Field(1).Method(0)) })               // .T1.Y
  3709  	ok(func() { call(v.Field(1).Elem().Method(0)) })        // .T1.Y
  3710  	badCall(func() { call(v.Field(1).Method(1)) })          // .T1.y
  3711  	badMethod(func() { call(v.Field(1).Elem().Method(2)) }) // .T1.y
  3712  
  3713  	ok(func() { call(v.Field(2).Method(0)) })               // .NamedT0.W
  3714  	ok(func() { call(v.Field(2).Elem().Method(0)) })        // .NamedT0.W
  3715  	badCall(func() { call(v.Field(2).Method(1)) })          // .NamedT0.w
  3716  	badMethod(func() { call(v.Field(2).Elem().Method(2)) }) // .NamedT0.w
  3717  
  3718  	ok(func() { call(v.Field(3).Method(0)) })               // .NamedT1.Y
  3719  	ok(func() { call(v.Field(3).Elem().Method(0)) })        // .NamedT1.Y
  3720  	badCall(func() { call(v.Field(3).Method(1)) })          // .NamedT1.y
  3721  	badMethod(func() { call(v.Field(3).Elem().Method(3)) }) // .NamedT1.y
  3722  
  3723  	ok(func() { call(v.Field(4).Field(0).Method(0)) })             // .NamedT2.T1.Y
  3724  	ok(func() { call(v.Field(4).Field(0).Elem().Method(0)) })      // .NamedT2.T1.W
  3725  	badCall(func() { call(v.Field(4).Field(1).Method(0)) })        // .NamedT2.t0.W
  3726  	badCall(func() { call(v.Field(4).Field(1).Elem().Method(0)) }) // .NamedT2.t0.W
  3727  
  3728  	badCall(func() { call(v.Field(5).Method(0)) })          // .namedT0.W
  3729  	badCall(func() { call(v.Field(5).Elem().Method(0)) })   // .namedT0.W
  3730  	badCall(func() { call(v.Field(5).Method(1)) })          // .namedT0.w
  3731  	badMethod(func() { call(v.Field(5).Elem().Method(2)) }) // .namedT0.w
  3732  
  3733  	badCall(func() { call(v.Field(6).Method(0)) })        // .namedT1.Y
  3734  	badCall(func() { call(v.Field(6).Elem().Method(0)) }) // .namedT1.Y
  3735  	badCall(func() { call(v.Field(6).Method(0)) })        // .namedT1.y
  3736  	badCall(func() { call(v.Field(6).Elem().Method(0)) }) // .namedT1.y
  3737  
  3738  	badCall(func() { call(v.Field(7).Field(0).Method(0)) })        // .namedT2.T1.Y
  3739  	badCall(func() { call(v.Field(7).Field(0).Elem().Method(0)) }) // .namedT2.T1.W
  3740  	badCall(func() { call(v.Field(7).Field(1).Method(0)) })        // .namedT2.t0.W
  3741  	badCall(func() { call(v.Field(7).Field(1).Elem().Method(0)) }) // .namedT2.t0.W
  3742  }
  3743  
  3744  func shouldPanic(expect string, f func()) {
  3745  	defer func() {
  3746  		r := recover()
  3747  		if r == nil {
  3748  			panic("did not panic")
  3749  		}
  3750  		if expect != "" {
  3751  			var s string
  3752  			switch r := r.(type) {
  3753  			case string:
  3754  				s = r
  3755  			case *ValueError:
  3756  				s = r.Error()
  3757  			default:
  3758  				panic(fmt.Sprintf("panicked with unexpected type %T", r))
  3759  			}
  3760  			if !strings.HasPrefix(s, "reflect") {
  3761  				panic(`panic string does not start with "reflect": ` + s)
  3762  			}
  3763  			if !strings.Contains(s, expect) {
  3764  				panic(`panic string does not contain "` + expect + `": ` + s)
  3765  			}
  3766  		}
  3767  	}()
  3768  	f()
  3769  }
  3770  
  3771  func isNonNil(x interface{}) {
  3772  	if x == nil {
  3773  		panic("nil interface")
  3774  	}
  3775  }
  3776  
  3777  func isValid(v Value) {
  3778  	if !v.IsValid() {
  3779  		panic("zero Value")
  3780  	}
  3781  }
  3782  
  3783  func TestAlias(t *testing.T) {
  3784  	x := string("hello")
  3785  	v := ValueOf(&x).Elem()
  3786  	oldvalue := v.Interface()
  3787  	v.SetString("world")
  3788  	newvalue := v.Interface()
  3789  
  3790  	if oldvalue != "hello" || newvalue != "world" {
  3791  		t.Errorf("aliasing: old=%q new=%q, want hello, world", oldvalue, newvalue)
  3792  	}
  3793  }
  3794  
  3795  var V = ValueOf
  3796  
  3797  func EmptyInterfaceV(x interface{}) Value {
  3798  	return ValueOf(&x).Elem()
  3799  }
  3800  
  3801  func ReaderV(x io.Reader) Value {
  3802  	return ValueOf(&x).Elem()
  3803  }
  3804  
  3805  func ReadWriterV(x io.ReadWriter) Value {
  3806  	return ValueOf(&x).Elem()
  3807  }
  3808  
  3809  type Empty struct{}
  3810  type MyStruct struct {
  3811  	x int `some:"tag"`
  3812  }
  3813  type MyStruct1 struct {
  3814  	x struct {
  3815  		int `some:"bar"`
  3816  	}
  3817  }
  3818  type MyStruct2 struct {
  3819  	x struct {
  3820  		int `some:"foo"`
  3821  	}
  3822  }
  3823  type MyString string
  3824  type MyBytes []byte
  3825  type MyBytesArrayPtr0 *[0]byte
  3826  type MyBytesArrayPtr *[4]byte
  3827  type MyBytesArray0 [0]byte
  3828  type MyBytesArray [4]byte
  3829  type MyRunes []int32
  3830  type MyFunc func()
  3831  type MyByte byte
  3832  
  3833  type IntChan chan int
  3834  type IntChanRecv <-chan int
  3835  type IntChanSend chan<- int
  3836  type BytesChan chan []byte
  3837  type BytesChanRecv <-chan []byte
  3838  type BytesChanSend chan<- []byte
  3839  
  3840  var convertTests = []struct {
  3841  	in  Value
  3842  	out Value
  3843  }{
  3844  	// numbers
  3845  	/*
  3846  		Edit .+1,/\*\//-1>cat >/tmp/x.go && go run /tmp/x.go
  3847  
  3848  		package main
  3849  
  3850  		import "fmt"
  3851  
  3852  		var numbers = []string{
  3853  			"int8", "uint8", "int16", "uint16",
  3854  			"int32", "uint32", "int64", "uint64",
  3855  			"int", "uint", "uintptr",
  3856  			"float32", "float64",
  3857  		}
  3858  
  3859  		func main() {
  3860  			// all pairs but in an unusual order,
  3861  			// to emit all the int8, uint8 cases
  3862  			// before n grows too big.
  3863  			n := 1
  3864  			for i, f := range numbers {
  3865  				for _, g := range numbers[i:] {
  3866  					fmt.Printf("\t{V(%s(%d)), V(%s(%d))},\n", f, n, g, n)
  3867  					n++
  3868  					if f != g {
  3869  						fmt.Printf("\t{V(%s(%d)), V(%s(%d))},\n", g, n, f, n)
  3870  						n++
  3871  					}
  3872  				}
  3873  			}
  3874  		}
  3875  	*/
  3876  	{V(int8(1)), V(int8(1))},
  3877  	{V(int8(2)), V(uint8(2))},
  3878  	{V(uint8(3)), V(int8(3))},
  3879  	{V(int8(4)), V(int16(4))},
  3880  	{V(int16(5)), V(int8(5))},
  3881  	{V(int8(6)), V(uint16(6))},
  3882  	{V(uint16(7)), V(int8(7))},
  3883  	{V(int8(8)), V(int32(8))},
  3884  	{V(int32(9)), V(int8(9))},
  3885  	{V(int8(10)), V(uint32(10))},
  3886  	{V(uint32(11)), V(int8(11))},
  3887  	{V(int8(12)), V(int64(12))},
  3888  	{V(int64(13)), V(int8(13))},
  3889  	{V(int8(14)), V(uint64(14))},
  3890  	{V(uint64(15)), V(int8(15))},
  3891  	{V(int8(16)), V(int(16))},
  3892  	{V(int(17)), V(int8(17))},
  3893  	{V(int8(18)), V(uint(18))},
  3894  	{V(uint(19)), V(int8(19))},
  3895  	{V(int8(20)), V(uintptr(20))},
  3896  	{V(uintptr(21)), V(int8(21))},
  3897  	{V(int8(22)), V(float32(22))},
  3898  	{V(float32(23)), V(int8(23))},
  3899  	{V(int8(24)), V(float64(24))},
  3900  	{V(float64(25)), V(int8(25))},
  3901  	{V(uint8(26)), V(uint8(26))},
  3902  	{V(uint8(27)), V(int16(27))},
  3903  	{V(int16(28)), V(uint8(28))},
  3904  	{V(uint8(29)), V(uint16(29))},
  3905  	{V(uint16(30)), V(uint8(30))},
  3906  	{V(uint8(31)), V(int32(31))},
  3907  	{V(int32(32)), V(uint8(32))},
  3908  	{V(uint8(33)), V(uint32(33))},
  3909  	{V(uint32(34)), V(uint8(34))},
  3910  	{V(uint8(35)), V(int64(35))},
  3911  	{V(int64(36)), V(uint8(36))},
  3912  	{V(uint8(37)), V(uint64(37))},
  3913  	{V(uint64(38)), V(uint8(38))},
  3914  	{V(uint8(39)), V(int(39))},
  3915  	{V(int(40)), V(uint8(40))},
  3916  	{V(uint8(41)), V(uint(41))},
  3917  	{V(uint(42)), V(uint8(42))},
  3918  	{V(uint8(43)), V(uintptr(43))},
  3919  	{V(uintptr(44)), V(uint8(44))},
  3920  	{V(uint8(45)), V(float32(45))},
  3921  	{V(float32(46)), V(uint8(46))},
  3922  	{V(uint8(47)), V(float64(47))},
  3923  	{V(float64(48)), V(uint8(48))},
  3924  	{V(int16(49)), V(int16(49))},
  3925  	{V(int16(50)), V(uint16(50))},
  3926  	{V(uint16(51)), V(int16(51))},
  3927  	{V(int16(52)), V(int32(52))},
  3928  	{V(int32(53)), V(int16(53))},
  3929  	{V(int16(54)), V(uint32(54))},
  3930  	{V(uint32(55)), V(int16(55))},
  3931  	{V(int16(56)), V(int64(56))},
  3932  	{V(int64(57)), V(int16(57))},
  3933  	{V(int16(58)), V(uint64(58))},
  3934  	{V(uint64(59)), V(int16(59))},
  3935  	{V(int16(60)), V(int(60))},
  3936  	{V(int(61)), V(int16(61))},
  3937  	{V(int16(62)), V(uint(62))},
  3938  	{V(uint(63)), V(int16(63))},
  3939  	{V(int16(64)), V(uintptr(64))},
  3940  	{V(uintptr(65)), V(int16(65))},
  3941  	{V(int16(66)), V(float32(66))},
  3942  	{V(float32(67)), V(int16(67))},
  3943  	{V(int16(68)), V(float64(68))},
  3944  	{V(float64(69)), V(int16(69))},
  3945  	{V(uint16(70)), V(uint16(70))},
  3946  	{V(uint16(71)), V(int32(71))},
  3947  	{V(int32(72)), V(uint16(72))},
  3948  	{V(uint16(73)), V(uint32(73))},
  3949  	{V(uint32(74)), V(uint16(74))},
  3950  	{V(uint16(75)), V(int64(75))},
  3951  	{V(int64(76)), V(uint16(76))},
  3952  	{V(uint16(77)), V(uint64(77))},
  3953  	{V(uint64(78)), V(uint16(78))},
  3954  	{V(uint16(79)), V(int(79))},
  3955  	{V(int(80)), V(uint16(80))},
  3956  	{V(uint16(81)), V(uint(81))},
  3957  	{V(uint(82)), V(uint16(82))},
  3958  	{V(uint16(83)), V(uintptr(83))},
  3959  	{V(uintptr(84)), V(uint16(84))},
  3960  	{V(uint16(85)), V(float32(85))},
  3961  	{V(float32(86)), V(uint16(86))},
  3962  	{V(uint16(87)), V(float64(87))},
  3963  	{V(float64(88)), V(uint16(88))},
  3964  	{V(int32(89)), V(int32(89))},
  3965  	{V(int32(90)), V(uint32(90))},
  3966  	{V(uint32(91)), V(int32(91))},
  3967  	{V(int32(92)), V(int64(92))},
  3968  	{V(int64(93)), V(int32(93))},
  3969  	{V(int32(94)), V(uint64(94))},
  3970  	{V(uint64(95)), V(int32(95))},
  3971  	{V(int32(96)), V(int(96))},
  3972  	{V(int(97)), V(int32(97))},
  3973  	{V(int32(98)), V(uint(98))},
  3974  	{V(uint(99)), V(int32(99))},
  3975  	{V(int32(100)), V(uintptr(100))},
  3976  	{V(uintptr(101)), V(int32(101))},
  3977  	{V(int32(102)), V(float32(102))},
  3978  	{V(float32(103)), V(int32(103))},
  3979  	{V(int32(104)), V(float64(104))},
  3980  	{V(float64(105)), V(int32(105))},
  3981  	{V(uint32(106)), V(uint32(106))},
  3982  	{V(uint32(107)), V(int64(107))},
  3983  	{V(int64(108)), V(uint32(108))},
  3984  	{V(uint32(109)), V(uint64(109))},
  3985  	{V(uint64(110)), V(uint32(110))},
  3986  	{V(uint32(111)), V(int(111))},
  3987  	{V(int(112)), V(uint32(112))},
  3988  	{V(uint32(113)), V(uint(113))},
  3989  	{V(uint(114)), V(uint32(114))},
  3990  	{V(uint32(115)), V(uintptr(115))},
  3991  	{V(uintptr(116)), V(uint32(116))},
  3992  	{V(uint32(117)), V(float32(117))},
  3993  	{V(float32(118)), V(uint32(118))},
  3994  	{V(uint32(119)), V(float64(119))},
  3995  	{V(float64(120)), V(uint32(120))},
  3996  	{V(int64(121)), V(int64(121))},
  3997  	{V(int64(122)), V(uint64(122))},
  3998  	{V(uint64(123)), V(int64(123))},
  3999  	{V(int64(124)), V(int(124))},
  4000  	{V(int(125)), V(int64(125))},
  4001  	{V(int64(126)), V(uint(126))},
  4002  	{V(uint(127)), V(int64(127))},
  4003  	{V(int64(128)), V(uintptr(128))},
  4004  	{V(uintptr(129)), V(int64(129))},
  4005  	{V(int64(130)), V(float32(130))},
  4006  	{V(float32(131)), V(int64(131))},
  4007  	{V(int64(132)), V(float64(132))},
  4008  	{V(float64(133)), V(int64(133))},
  4009  	{V(uint64(134)), V(uint64(134))},
  4010  	{V(uint64(135)), V(int(135))},
  4011  	{V(int(136)), V(uint64(136))},
  4012  	{V(uint64(137)), V(uint(137))},
  4013  	{V(uint(138)), V(uint64(138))},
  4014  	{V(uint64(139)), V(uintptr(139))},
  4015  	{V(uintptr(140)), V(uint64(140))},
  4016  	{V(uint64(141)), V(float32(141))},
  4017  	{V(float32(142)), V(uint64(142))},
  4018  	{V(uint64(143)), V(float64(143))},
  4019  	{V(float64(144)), V(uint64(144))},
  4020  	{V(int(145)), V(int(145))},
  4021  	{V(int(146)), V(uint(146))},
  4022  	{V(uint(147)), V(int(147))},
  4023  	{V(int(148)), V(uintptr(148))},
  4024  	{V(uintptr(149)), V(int(149))},
  4025  	{V(int(150)), V(float32(150))},
  4026  	{V(float32(151)), V(int(151))},
  4027  	{V(int(152)), V(float64(152))},
  4028  	{V(float64(153)), V(int(153))},
  4029  	{V(uint(154)), V(uint(154))},
  4030  	{V(uint(155)), V(uintptr(155))},
  4031  	{V(uintptr(156)), V(uint(156))},
  4032  	{V(uint(157)), V(float32(157))},
  4033  	{V(float32(158)), V(uint(158))},
  4034  	{V(uint(159)), V(float64(159))},
  4035  	{V(float64(160)), V(uint(160))},
  4036  	{V(uintptr(161)), V(uintptr(161))},
  4037  	{V(uintptr(162)), V(float32(162))},
  4038  	{V(float32(163)), V(uintptr(163))},
  4039  	{V(uintptr(164)), V(float64(164))},
  4040  	{V(float64(165)), V(uintptr(165))},
  4041  	{V(float32(166)), V(float32(166))},
  4042  	{V(float32(167)), V(float64(167))},
  4043  	{V(float64(168)), V(float32(168))},
  4044  	{V(float64(169)), V(float64(169))},
  4045  
  4046  	// truncation
  4047  	{V(float64(1.5)), V(int(1))},
  4048  
  4049  	// complex
  4050  	{V(complex64(1i)), V(complex64(1i))},
  4051  	{V(complex64(2i)), V(complex128(2i))},
  4052  	{V(complex128(3i)), V(complex64(3i))},
  4053  	{V(complex128(4i)), V(complex128(4i))},
  4054  
  4055  	// string
  4056  	{V(string("hello")), V(string("hello"))},
  4057  	{V(string("bytes1")), V([]byte("bytes1"))},
  4058  	{V([]byte("bytes2")), V(string("bytes2"))},
  4059  	{V([]byte("bytes3")), V([]byte("bytes3"))},
  4060  	{V(string("runes♝")), V([]rune("runes♝"))},
  4061  	{V([]rune("runes♕")), V(string("runes♕"))},
  4062  	{V([]rune("runes🙈🙉🙊")), V([]rune("runes🙈🙉🙊"))},
  4063  	{V(int('a')), V(string("a"))},
  4064  	{V(int8('a')), V(string("a"))},
  4065  	{V(int16('a')), V(string("a"))},
  4066  	{V(int32('a')), V(string("a"))},
  4067  	{V(int64('a')), V(string("a"))},
  4068  	{V(uint('a')), V(string("a"))},
  4069  	{V(uint8('a')), V(string("a"))},
  4070  	{V(uint16('a')), V(string("a"))},
  4071  	{V(uint32('a')), V(string("a"))},
  4072  	{V(uint64('a')), V(string("a"))},
  4073  	{V(uintptr('a')), V(string("a"))},
  4074  	{V(int(-1)), V(string("\uFFFD"))},
  4075  	{V(int8(-2)), V(string("\uFFFD"))},
  4076  	{V(int16(-3)), V(string("\uFFFD"))},
  4077  	{V(int32(-4)), V(string("\uFFFD"))},
  4078  	{V(int64(-5)), V(string("\uFFFD"))},
  4079  	{V(int64(-1 << 32)), V(string("\uFFFD"))},
  4080  	{V(int64(1 << 32)), V(string("\uFFFD"))},
  4081  	{V(uint(0x110001)), V(string("\uFFFD"))},
  4082  	{V(uint32(0x110002)), V(string("\uFFFD"))},
  4083  	{V(uint64(0x110003)), V(string("\uFFFD"))},
  4084  	{V(uint64(1 << 32)), V(string("\uFFFD"))},
  4085  	{V(uintptr(0x110004)), V(string("\uFFFD"))},
  4086  
  4087  	// named string
  4088  	{V(MyString("hello")), V(string("hello"))},
  4089  	{V(string("hello")), V(MyString("hello"))},
  4090  	{V(string("hello")), V(string("hello"))},
  4091  	{V(MyString("hello")), V(MyString("hello"))},
  4092  	{V(MyString("bytes1")), V([]byte("bytes1"))},
  4093  	{V([]byte("bytes2")), V(MyString("bytes2"))},
  4094  	{V([]byte("bytes3")), V([]byte("bytes3"))},
  4095  	{V(MyString("runes♝")), V([]rune("runes♝"))},
  4096  	{V([]rune("runes♕")), V(MyString("runes♕"))},
  4097  	{V([]rune("runes🙈🙉🙊")), V([]rune("runes🙈🙉🙊"))},
  4098  	{V([]rune("runes🙈🙉🙊")), V(MyRunes("runes🙈🙉🙊"))},
  4099  	{V(MyRunes("runes🙈🙉🙊")), V([]rune("runes🙈🙉🙊"))},
  4100  	{V(int('a')), V(MyString("a"))},
  4101  	{V(int8('a')), V(MyString("a"))},
  4102  	{V(int16('a')), V(MyString("a"))},
  4103  	{V(int32('a')), V(MyString("a"))},
  4104  	{V(int64('a')), V(MyString("a"))},
  4105  	{V(uint('a')), V(MyString("a"))},
  4106  	{V(uint8('a')), V(MyString("a"))},
  4107  	{V(uint16('a')), V(MyString("a"))},
  4108  	{V(uint32('a')), V(MyString("a"))},
  4109  	{V(uint64('a')), V(MyString("a"))},
  4110  	{V(uintptr('a')), V(MyString("a"))},
  4111  	{V(int(-1)), V(MyString("\uFFFD"))},
  4112  	{V(int8(-2)), V(MyString("\uFFFD"))},
  4113  	{V(int16(-3)), V(MyString("\uFFFD"))},
  4114  	{V(int32(-4)), V(MyString("\uFFFD"))},
  4115  	{V(int64(-5)), V(MyString("\uFFFD"))},
  4116  	{V(uint(0x110001)), V(MyString("\uFFFD"))},
  4117  	{V(uint32(0x110002)), V(MyString("\uFFFD"))},
  4118  	{V(uint64(0x110003)), V(MyString("\uFFFD"))},
  4119  	{V(uintptr(0x110004)), V(MyString("\uFFFD"))},
  4120  
  4121  	// named []byte
  4122  	{V(string("bytes1")), V(MyBytes("bytes1"))},
  4123  	{V(MyBytes("bytes2")), V(string("bytes2"))},
  4124  	{V(MyBytes("bytes3")), V(MyBytes("bytes3"))},
  4125  	{V(MyString("bytes1")), V(MyBytes("bytes1"))},
  4126  	{V(MyBytes("bytes2")), V(MyString("bytes2"))},
  4127  
  4128  	// named []rune
  4129  	{V(string("runes♝")), V(MyRunes("runes♝"))},
  4130  	{V(MyRunes("runes♕")), V(string("runes♕"))},
  4131  	{V(MyRunes("runes🙈🙉🙊")), V(MyRunes("runes🙈🙉🙊"))},
  4132  	{V(MyString("runes♝")), V(MyRunes("runes♝"))},
  4133  	{V(MyRunes("runes♕")), V(MyString("runes♕"))},
  4134  
  4135  	// slice to array pointer
  4136  	{V([]byte(nil)), V((*[0]byte)(nil))},
  4137  	{V([]byte{}), V(new([0]byte))},
  4138  	{V([]byte{7}), V(&[1]byte{7})},
  4139  	{V(MyBytes([]byte(nil))), V((*[0]byte)(nil))},
  4140  	{V(MyBytes([]byte{})), V(new([0]byte))},
  4141  	{V(MyBytes([]byte{9})), V(&[1]byte{9})},
  4142  	{V([]byte(nil)), V(MyBytesArrayPtr0(nil))},
  4143  	{V([]byte{}), V(MyBytesArrayPtr0(new([0]byte)))},
  4144  	{V([]byte{1, 2, 3, 4}), V(MyBytesArrayPtr(&[4]byte{1, 2, 3, 4}))},
  4145  	{V(MyBytes([]byte{})), V(MyBytesArrayPtr0(new([0]byte)))},
  4146  	{V(MyBytes([]byte{5, 6, 7, 8})), V(MyBytesArrayPtr(&[4]byte{5, 6, 7, 8}))},
  4147  
  4148  	{V([]byte(nil)), V((*MyBytesArray0)(nil))},
  4149  	{V([]byte{}), V((*MyBytesArray0)(new([0]byte)))},
  4150  	{V([]byte{1, 2, 3, 4}), V(&MyBytesArray{1, 2, 3, 4})},
  4151  	{V(MyBytes([]byte(nil))), V((*MyBytesArray0)(nil))},
  4152  	{V(MyBytes([]byte{})), V((*MyBytesArray0)(new([0]byte)))},
  4153  	{V(MyBytes([]byte{5, 6, 7, 8})), V(&MyBytesArray{5, 6, 7, 8})},
  4154  	{V(new([0]byte)), V(new(MyBytesArray0))},
  4155  	{V(new(MyBytesArray0)), V(new([0]byte))},
  4156  	{V(MyBytesArrayPtr0(nil)), V((*[0]byte)(nil))},
  4157  	{V((*[0]byte)(nil)), V(MyBytesArrayPtr0(nil))},
  4158  
  4159  	// named types and equal underlying types
  4160  	{V(new(int)), V(new(integer))},
  4161  	{V(new(integer)), V(new(int))},
  4162  	{V(Empty{}), V(struct{}{})},
  4163  	{V(new(Empty)), V(new(struct{}))},
  4164  	{V(struct{}{}), V(Empty{})},
  4165  	{V(new(struct{})), V(new(Empty))},
  4166  	{V(Empty{}), V(Empty{})},
  4167  	{V(MyBytes{}), V([]byte{})},
  4168  	{V([]byte{}), V(MyBytes{})},
  4169  	{V((func())(nil)), V(MyFunc(nil))},
  4170  	{V((MyFunc)(nil)), V((func())(nil))},
  4171  
  4172  	// structs with different tags
  4173  	{V(struct {
  4174  		x int `some:"foo"`
  4175  	}{}), V(struct {
  4176  		x int `some:"bar"`
  4177  	}{})},
  4178  
  4179  	{V(struct {
  4180  		x int `some:"bar"`
  4181  	}{}), V(struct {
  4182  		x int `some:"foo"`
  4183  	}{})},
  4184  
  4185  	{V(MyStruct{}), V(struct {
  4186  		x int `some:"foo"`
  4187  	}{})},
  4188  
  4189  	{V(struct {
  4190  		x int `some:"foo"`
  4191  	}{}), V(MyStruct{})},
  4192  
  4193  	{V(MyStruct{}), V(struct {
  4194  		x int `some:"bar"`
  4195  	}{})},
  4196  
  4197  	{V(struct {
  4198  		x int `some:"bar"`
  4199  	}{}), V(MyStruct{})},
  4200  
  4201  	{V(MyStruct1{}), V(MyStruct2{})},
  4202  	{V(MyStruct2{}), V(MyStruct1{})},
  4203  
  4204  	// can convert *byte and *MyByte
  4205  	{V((*byte)(nil)), V((*MyByte)(nil))},
  4206  	{V((*MyByte)(nil)), V((*byte)(nil))},
  4207  
  4208  	// cannot convert mismatched array sizes
  4209  	{V([2]byte{}), V([2]byte{})},
  4210  	{V([3]byte{}), V([3]byte{})},
  4211  
  4212  	// cannot convert other instances
  4213  	{V((**byte)(nil)), V((**byte)(nil))},
  4214  	{V((**MyByte)(nil)), V((**MyByte)(nil))},
  4215  	{V((chan byte)(nil)), V((chan byte)(nil))},
  4216  	{V((chan MyByte)(nil)), V((chan MyByte)(nil))},
  4217  	{V(([]byte)(nil)), V(([]byte)(nil))},
  4218  	{V(([]MyByte)(nil)), V(([]MyByte)(nil))},
  4219  	{V((map[int]byte)(nil)), V((map[int]byte)(nil))},
  4220  	{V((map[int]MyByte)(nil)), V((map[int]MyByte)(nil))},
  4221  	{V((map[byte]int)(nil)), V((map[byte]int)(nil))},
  4222  	{V((map[MyByte]int)(nil)), V((map[MyByte]int)(nil))},
  4223  	{V([2]byte{}), V([2]byte{})},
  4224  	{V([2]MyByte{}), V([2]MyByte{})},
  4225  
  4226  	// other
  4227  	{V((***int)(nil)), V((***int)(nil))},
  4228  	{V((***byte)(nil)), V((***byte)(nil))},
  4229  	{V((***int32)(nil)), V((***int32)(nil))},
  4230  	{V((***int64)(nil)), V((***int64)(nil))},
  4231  	{V((chan byte)(nil)), V((chan byte)(nil))},
  4232  	{V((chan MyByte)(nil)), V((chan MyByte)(nil))},
  4233  	{V((map[int]bool)(nil)), V((map[int]bool)(nil))},
  4234  	{V((map[int]byte)(nil)), V((map[int]byte)(nil))},
  4235  	{V((map[uint]bool)(nil)), V((map[uint]bool)(nil))},
  4236  	{V([]uint(nil)), V([]uint(nil))},
  4237  	{V([]int(nil)), V([]int(nil))},
  4238  	{V(new(interface{})), V(new(interface{}))},
  4239  	{V(new(io.Reader)), V(new(io.Reader))},
  4240  	{V(new(io.Writer)), V(new(io.Writer))},
  4241  
  4242  	// channels
  4243  	{V(IntChan(nil)), V((chan<- int)(nil))},
  4244  	{V(IntChan(nil)), V((<-chan int)(nil))},
  4245  	{V((chan int)(nil)), V(IntChanRecv(nil))},
  4246  	{V((chan int)(nil)), V(IntChanSend(nil))},
  4247  	{V(IntChanRecv(nil)), V((<-chan int)(nil))},
  4248  	{V((<-chan int)(nil)), V(IntChanRecv(nil))},
  4249  	{V(IntChanSend(nil)), V((chan<- int)(nil))},
  4250  	{V((chan<- int)(nil)), V(IntChanSend(nil))},
  4251  	{V(IntChan(nil)), V((chan int)(nil))},
  4252  	{V((chan int)(nil)), V(IntChan(nil))},
  4253  	{V((chan int)(nil)), V((<-chan int)(nil))},
  4254  	{V((chan int)(nil)), V((chan<- int)(nil))},
  4255  	{V(BytesChan(nil)), V((chan<- []byte)(nil))},
  4256  	{V(BytesChan(nil)), V((<-chan []byte)(nil))},
  4257  	{V((chan []byte)(nil)), V(BytesChanRecv(nil))},
  4258  	{V((chan []byte)(nil)), V(BytesChanSend(nil))},
  4259  	{V(BytesChanRecv(nil)), V((<-chan []byte)(nil))},
  4260  	{V((<-chan []byte)(nil)), V(BytesChanRecv(nil))},
  4261  	{V(BytesChanSend(nil)), V((chan<- []byte)(nil))},
  4262  	{V((chan<- []byte)(nil)), V(BytesChanSend(nil))},
  4263  	{V(BytesChan(nil)), V((chan []byte)(nil))},
  4264  	{V((chan []byte)(nil)), V(BytesChan(nil))},
  4265  	{V((chan []byte)(nil)), V((<-chan []byte)(nil))},
  4266  	{V((chan []byte)(nil)), V((chan<- []byte)(nil))},
  4267  
  4268  	// cannot convert other instances (channels)
  4269  	{V(IntChan(nil)), V(IntChan(nil))},
  4270  	{V(IntChanRecv(nil)), V(IntChanRecv(nil))},
  4271  	{V(IntChanSend(nil)), V(IntChanSend(nil))},
  4272  	{V(BytesChan(nil)), V(BytesChan(nil))},
  4273  	{V(BytesChanRecv(nil)), V(BytesChanRecv(nil))},
  4274  	{V(BytesChanSend(nil)), V(BytesChanSend(nil))},
  4275  
  4276  	// interfaces
  4277  	{V(int(1)), EmptyInterfaceV(int(1))},
  4278  	{V(string("hello")), EmptyInterfaceV(string("hello"))},
  4279  	{V(new(bytes.Buffer)), ReaderV(new(bytes.Buffer))},
  4280  	{ReadWriterV(new(bytes.Buffer)), ReaderV(new(bytes.Buffer))},
  4281  	{V(new(bytes.Buffer)), ReadWriterV(new(bytes.Buffer))},
  4282  }
  4283  
  4284  func TestConvert(t *testing.T) {
  4285  	canConvert := map[[2]Type]bool{}
  4286  	all := map[Type]bool{}
  4287  
  4288  	for _, tt := range convertTests {
  4289  		t1 := tt.in.Type()
  4290  		if !t1.ConvertibleTo(t1) {
  4291  			t.Errorf("(%s).ConvertibleTo(%s) = false, want true", t1, t1)
  4292  			continue
  4293  		}
  4294  
  4295  		t2 := tt.out.Type()
  4296  		if !t1.ConvertibleTo(t2) {
  4297  			t.Errorf("(%s).ConvertibleTo(%s) = false, want true", t1, t2)
  4298  			continue
  4299  		}
  4300  
  4301  		all[t1] = true
  4302  		all[t2] = true
  4303  		canConvert[[2]Type{t1, t2}] = true
  4304  
  4305  		// vout1 represents the in value converted to the in type.
  4306  		v1 := tt.in
  4307  		if !v1.CanConvert(t1) {
  4308  			t.Errorf("ValueOf(%T(%[1]v)).CanConvert(%s) = false, want true", tt.in.Interface(), t1)
  4309  		}
  4310  		vout1 := v1.Convert(t1)
  4311  		out1 := vout1.Interface()
  4312  		if vout1.Type() != tt.in.Type() || !DeepEqual(out1, tt.in.Interface()) {
  4313  			t.Errorf("ValueOf(%T(%[1]v)).Convert(%s) = %T(%[3]v), want %T(%[4]v)", tt.in.Interface(), t1, out1, tt.in.Interface())
  4314  		}
  4315  
  4316  		// vout2 represents the in value converted to the out type.
  4317  		if !v1.CanConvert(t2) {
  4318  			t.Errorf("ValueOf(%T(%[1]v)).CanConvert(%s) = false, want true", tt.in.Interface(), t2)
  4319  		}
  4320  		vout2 := v1.Convert(t2)
  4321  		out2 := vout2.Interface()
  4322  		if vout2.Type() != tt.out.Type() || !DeepEqual(out2, tt.out.Interface()) {
  4323  			t.Errorf("ValueOf(%T(%[1]v)).Convert(%s) = %T(%[3]v), want %T(%[4]v)", tt.in.Interface(), t2, out2, tt.out.Interface())
  4324  		}
  4325  		if got, want := vout2.Kind(), vout2.Type().Kind(); got != want {
  4326  			t.Errorf("ValueOf(%T(%[1]v)).Convert(%s) has internal kind %v want %v", tt.in.Interface(), t1, got, want)
  4327  		}
  4328  
  4329  		// vout3 represents a new value of the out type, set to vout2.  This makes
  4330  		// sure the converted value vout2 is really usable as a regular value.
  4331  		vout3 := New(t2).Elem()
  4332  		vout3.Set(vout2)
  4333  		out3 := vout3.Interface()
  4334  		if vout3.Type() != tt.out.Type() || !DeepEqual(out3, tt.out.Interface()) {
  4335  			t.Errorf("Set(ValueOf(%T(%[1]v)).Convert(%s)) = %T(%[3]v), want %T(%[4]v)", tt.in.Interface(), t2, out3, tt.out.Interface())
  4336  		}
  4337  
  4338  		if IsRO(v1) {
  4339  			t.Errorf("table entry %v is RO, should not be", v1)
  4340  		}
  4341  		if IsRO(vout1) {
  4342  			t.Errorf("self-conversion output %v is RO, should not be", vout1)
  4343  		}
  4344  		if IsRO(vout2) {
  4345  			t.Errorf("conversion output %v is RO, should not be", vout2)
  4346  		}
  4347  		if IsRO(vout3) {
  4348  			t.Errorf("set(conversion output) %v is RO, should not be", vout3)
  4349  		}
  4350  		if !IsRO(MakeRO(v1).Convert(t1)) {
  4351  			t.Errorf("RO self-conversion output %v is not RO, should be", v1)
  4352  		}
  4353  		if !IsRO(MakeRO(v1).Convert(t2)) {
  4354  			t.Errorf("RO conversion output %v is not RO, should be", v1)
  4355  		}
  4356  	}
  4357  
  4358  	// Assume that of all the types we saw during the tests,
  4359  	// if there wasn't an explicit entry for a conversion between
  4360  	// a pair of types, then it's not to be allowed. This checks for
  4361  	// things like 'int64' converting to '*int'.
  4362  	for t1 := range all {
  4363  		for t2 := range all {
  4364  			expectOK := t1 == t2 || canConvert[[2]Type{t1, t2}] || t2.Kind() == Interface && t2.NumMethod() == 0
  4365  			if ok := t1.ConvertibleTo(t2); ok != expectOK {
  4366  				t.Errorf("(%s).ConvertibleTo(%s) = %v, want %v", t1, t2, ok, expectOK)
  4367  			}
  4368  		}
  4369  	}
  4370  }
  4371  
  4372  func TestConvertPanic(t *testing.T) {
  4373  	s := make([]byte, 4)
  4374  	p := new([8]byte)
  4375  	v := ValueOf(s)
  4376  	pt := TypeOf(p)
  4377  	if !v.Type().ConvertibleTo(pt) {
  4378  		t.Errorf("[]byte should be convertible to *[8]byte")
  4379  	}
  4380  	if v.CanConvert(pt) {
  4381  		t.Errorf("slice with length 4 should not be convertible to *[8]byte")
  4382  	}
  4383  	shouldPanic("reflect: cannot convert slice with length 4 to pointer to array with length 8", func() {
  4384  		_ = v.Convert(pt)
  4385  	})
  4386  }
  4387  
  4388  var gFloat32 float32
  4389  
  4390  func TestConvertNaNs(t *testing.T) {
  4391  	const snan uint32 = 0x7f800001
  4392  	type myFloat32 float32
  4393  	x := V(myFloat32(math.Float32frombits(snan)))
  4394  	y := x.Convert(TypeOf(float32(0)))
  4395  	z := y.Interface().(float32)
  4396  	if got := math.Float32bits(z); got != snan {
  4397  		t.Errorf("signaling nan conversion got %x, want %x", got, snan)
  4398  	}
  4399  }
  4400  
  4401  type ComparableStruct struct {
  4402  	X int
  4403  }
  4404  
  4405  type NonComparableStruct struct {
  4406  	X int
  4407  	Y map[string]int
  4408  }
  4409  
  4410  var comparableTests = []struct {
  4411  	typ Type
  4412  	ok  bool
  4413  }{
  4414  	{TypeOf(1), true},
  4415  	{TypeOf("hello"), true},
  4416  	{TypeOf(new(byte)), true},
  4417  	{TypeOf((func())(nil)), false},
  4418  	{TypeOf([]byte{}), false},
  4419  	{TypeOf(map[string]int{}), false},
  4420  	{TypeOf(make(chan int)), true},
  4421  	{TypeOf(1.5), true},
  4422  	{TypeOf(false), true},
  4423  	{TypeOf(1i), true},
  4424  	{TypeOf(ComparableStruct{}), true},
  4425  	{TypeOf(NonComparableStruct{}), false},
  4426  	{TypeOf([10]map[string]int{}), false},
  4427  	{TypeOf([10]string{}), true},
  4428  	{TypeOf(new(interface{})).Elem(), true},
  4429  }
  4430  
  4431  func TestComparable(t *testing.T) {
  4432  	for _, tt := range comparableTests {
  4433  		if ok := tt.typ.Comparable(); ok != tt.ok {
  4434  			t.Errorf("TypeOf(%v).Comparable() = %v, want %v", tt.typ, ok, tt.ok)
  4435  		}
  4436  	}
  4437  }
  4438  
  4439  func TestOverflow(t *testing.T) {
  4440  	if ovf := V(float64(0)).OverflowFloat(1e300); ovf {
  4441  		t.Errorf("%v wrongly overflows float64", 1e300)
  4442  	}
  4443  
  4444  	maxFloat32 := float64((1<<24 - 1) << (127 - 23))
  4445  	if ovf := V(float32(0)).OverflowFloat(maxFloat32); ovf {
  4446  		t.Errorf("%v wrongly overflows float32", maxFloat32)
  4447  	}
  4448  	ovfFloat32 := float64((1<<24-1)<<(127-23) + 1<<(127-52))
  4449  	if ovf := V(float32(0)).OverflowFloat(ovfFloat32); !ovf {
  4450  		t.Errorf("%v should overflow float32", ovfFloat32)
  4451  	}
  4452  	if ovf := V(float32(0)).OverflowFloat(-ovfFloat32); !ovf {
  4453  		t.Errorf("%v should overflow float32", -ovfFloat32)
  4454  	}
  4455  
  4456  	maxInt32 := int64(0x7fffffff)
  4457  	if ovf := V(int32(0)).OverflowInt(maxInt32); ovf {
  4458  		t.Errorf("%v wrongly overflows int32", maxInt32)
  4459  	}
  4460  	if ovf := V(int32(0)).OverflowInt(-1 << 31); ovf {
  4461  		t.Errorf("%v wrongly overflows int32", -int64(1)<<31)
  4462  	}
  4463  	ovfInt32 := int64(1 << 31)
  4464  	if ovf := V(int32(0)).OverflowInt(ovfInt32); !ovf {
  4465  		t.Errorf("%v should overflow int32", ovfInt32)
  4466  	}
  4467  
  4468  	maxUint32 := uint64(0xffffffff)
  4469  	if ovf := V(uint32(0)).OverflowUint(maxUint32); ovf {
  4470  		t.Errorf("%v wrongly overflows uint32", maxUint32)
  4471  	}
  4472  	ovfUint32 := uint64(1 << 32)
  4473  	if ovf := V(uint32(0)).OverflowUint(ovfUint32); !ovf {
  4474  		t.Errorf("%v should overflow uint32", ovfUint32)
  4475  	}
  4476  }
  4477  
  4478  func checkSameType(t *testing.T, x Type, y interface{}) {
  4479  	if x != TypeOf(y) || TypeOf(Zero(x).Interface()) != TypeOf(y) {
  4480  		t.Errorf("did not find preexisting type for %s (vs %s)", TypeOf(x), TypeOf(y))
  4481  	}
  4482  }
  4483  
  4484  func TestArrayOf(t *testing.T) {
  4485  	// check construction and use of type not in binary
  4486  	tests := []struct {
  4487  		n          int
  4488  		value      func(i int) interface{}
  4489  		comparable bool
  4490  		want       string
  4491  	}{
  4492  		{
  4493  			n:          0,
  4494  			value:      func(i int) interface{} { type Tint int; return Tint(i) },
  4495  			comparable: true,
  4496  			want:       "[]",
  4497  		},
  4498  		{
  4499  			n:          10,
  4500  			value:      func(i int) interface{} { type Tint int; return Tint(i) },
  4501  			comparable: true,
  4502  			want:       "[0 1 2 3 4 5 6 7 8 9]",
  4503  		},
  4504  		{
  4505  			n:          10,
  4506  			value:      func(i int) interface{} { type Tfloat float64; return Tfloat(i) },
  4507  			comparable: true,
  4508  			want:       "[0 1 2 3 4 5 6 7 8 9]",
  4509  		},
  4510  		{
  4511  			n:          10,
  4512  			value:      func(i int) interface{} { type Tstring string; return Tstring(strconv.Itoa(i)) },
  4513  			comparable: true,
  4514  			want:       "[0 1 2 3 4 5 6 7 8 9]",
  4515  		},
  4516  		{
  4517  			n:          10,
  4518  			value:      func(i int) interface{} { type Tstruct struct{ V int }; return Tstruct{i} },
  4519  			comparable: true,
  4520  			want:       "[{0} {1} {2} {3} {4} {5} {6} {7} {8} {9}]",
  4521  		},
  4522  		{
  4523  			n:          10,
  4524  			value:      func(i int) interface{} { type Tint int; return []Tint{Tint(i)} },
  4525  			comparable: false,
  4526  			want:       "[[0] [1] [2] [3] [4] [5] [6] [7] [8] [9]]",
  4527  		},
  4528  		{
  4529  			n:          10,
  4530  			value:      func(i int) interface{} { type Tint int; return [1]Tint{Tint(i)} },
  4531  			comparable: true,
  4532  			want:       "[[0] [1] [2] [3] [4] [5] [6] [7] [8] [9]]",
  4533  		},
  4534  		{
  4535  			n:          10,
  4536  			value:      func(i int) interface{} { type Tstruct struct{ V [1]int }; return Tstruct{[1]int{i}} },
  4537  			comparable: true,
  4538  			want:       "[{[0]} {[1]} {[2]} {[3]} {[4]} {[5]} {[6]} {[7]} {[8]} {[9]}]",
  4539  		},
  4540  		{
  4541  			n:          10,
  4542  			value:      func(i int) interface{} { type Tstruct struct{ V []int }; return Tstruct{[]int{i}} },
  4543  			comparable: false,
  4544  			want:       "[{[0]} {[1]} {[2]} {[3]} {[4]} {[5]} {[6]} {[7]} {[8]} {[9]}]",
  4545  		},
  4546  		{
  4547  			n:          10,
  4548  			value:      func(i int) interface{} { type TstructUV struct{ U, V int }; return TstructUV{i, i} },
  4549  			comparable: true,
  4550  			want:       "[{0 0} {1 1} {2 2} {3 3} {4 4} {5 5} {6 6} {7 7} {8 8} {9 9}]",
  4551  		},
  4552  		{
  4553  			n: 10,
  4554  			value: func(i int) interface{} {
  4555  				type TstructUV struct {
  4556  					U int
  4557  					V float64
  4558  				}
  4559  				return TstructUV{i, float64(i)}
  4560  			},
  4561  			comparable: true,
  4562  			want:       "[{0 0} {1 1} {2 2} {3 3} {4 4} {5 5} {6 6} {7 7} {8 8} {9 9}]",
  4563  		},
  4564  	}
  4565  
  4566  	for _, table := range tests {
  4567  		at := ArrayOf(table.n, TypeOf(table.value(0)))
  4568  		v := New(at).Elem()
  4569  		vok := New(at).Elem()
  4570  		vnot := New(at).Elem()
  4571  		for i := 0; i < v.Len(); i++ {
  4572  			v.Index(i).Set(ValueOf(table.value(i)))
  4573  			vok.Index(i).Set(ValueOf(table.value(i)))
  4574  			j := i
  4575  			if i+1 == v.Len() {
  4576  				j = i + 1
  4577  			}
  4578  			vnot.Index(i).Set(ValueOf(table.value(j))) // make it differ only by last element
  4579  		}
  4580  		s := fmt.Sprint(v.Interface())
  4581  		if s != table.want {
  4582  			t.Errorf("constructed array = %s, want %s", s, table.want)
  4583  		}
  4584  
  4585  		if table.comparable != at.Comparable() {
  4586  			t.Errorf("constructed array (%#v) is comparable=%v, want=%v", v.Interface(), at.Comparable(), table.comparable)
  4587  		}
  4588  		if table.comparable {
  4589  			if table.n > 0 {
  4590  				if DeepEqual(vnot.Interface(), v.Interface()) {
  4591  					t.Errorf(
  4592  						"arrays (%#v) compare ok (but should not)",
  4593  						v.Interface(),
  4594  					)
  4595  				}
  4596  			}
  4597  			if !DeepEqual(vok.Interface(), v.Interface()) {
  4598  				t.Errorf(
  4599  					"arrays (%#v) compare NOT-ok (but should)",
  4600  					v.Interface(),
  4601  				)
  4602  			}
  4603  		}
  4604  	}
  4605  
  4606  	// check that type already in binary is found
  4607  	type T int
  4608  	checkSameType(t, ArrayOf(5, TypeOf(T(1))), [5]T{})
  4609  }
  4610  
  4611  func TestArrayOfGC(t *testing.T) {
  4612  	type T *uintptr
  4613  	tt := TypeOf(T(nil))
  4614  	const n = 100
  4615  	var x []interface{}
  4616  	for i := 0; i < n; i++ {
  4617  		v := New(ArrayOf(n, tt)).Elem()
  4618  		for j := 0; j < v.Len(); j++ {
  4619  			p := new(uintptr)
  4620  			*p = uintptr(i*n + j)
  4621  			v.Index(j).Set(ValueOf(p).Convert(tt))
  4622  		}
  4623  		x = append(x, v.Interface())
  4624  	}
  4625  	runtime.GC()
  4626  
  4627  	for i, xi := range x {
  4628  		v := ValueOf(xi)
  4629  		for j := 0; j < v.Len(); j++ {
  4630  			k := v.Index(j).Elem().Interface()
  4631  			if k != uintptr(i*n+j) {
  4632  				t.Errorf("lost x[%d][%d] = %d, want %d", i, j, k, i*n+j)
  4633  			}
  4634  		}
  4635  	}
  4636  }
  4637  
  4638  func TestArrayOfAlg(t *testing.T) {
  4639  	at := ArrayOf(6, TypeOf(byte(0)))
  4640  	v1 := New(at).Elem()
  4641  	v2 := New(at).Elem()
  4642  	if v1.Interface() != v1.Interface() {
  4643  		t.Errorf("constructed array %v not equal to itself", v1.Interface())
  4644  	}
  4645  	v1.Index(5).Set(ValueOf(byte(1)))
  4646  	if i1, i2 := v1.Interface(), v2.Interface(); i1 == i2 {
  4647  		t.Errorf("constructed arrays %v and %v should not be equal", i1, i2)
  4648  	}
  4649  
  4650  	at = ArrayOf(6, TypeOf([]int(nil)))
  4651  	v1 = New(at).Elem()
  4652  	shouldPanic("", func() { _ = v1.Interface() == v1.Interface() })
  4653  }
  4654  
  4655  func TestArrayOfGenericAlg(t *testing.T) {
  4656  	at1 := ArrayOf(5, TypeOf(string("")))
  4657  	at := ArrayOf(6, at1)
  4658  	v1 := New(at).Elem()
  4659  	v2 := New(at).Elem()
  4660  	if v1.Interface() != v1.Interface() {
  4661  		t.Errorf("constructed array %v not equal to itself", v1.Interface())
  4662  	}
  4663  
  4664  	v1.Index(0).Index(0).Set(ValueOf("abc"))
  4665  	v2.Index(0).Index(0).Set(ValueOf("efg"))
  4666  	if i1, i2 := v1.Interface(), v2.Interface(); i1 == i2 {
  4667  		t.Errorf("constructed arrays %v and %v should not be equal", i1, i2)
  4668  	}
  4669  
  4670  	v1.Index(0).Index(0).Set(ValueOf("abc"))
  4671  	v2.Index(0).Index(0).Set(ValueOf((v1.Index(0).Index(0).String() + " ")[:3]))
  4672  	if i1, i2 := v1.Interface(), v2.Interface(); i1 != i2 {
  4673  		t.Errorf("constructed arrays %v and %v should be equal", i1, i2)
  4674  	}
  4675  
  4676  	// Test hash
  4677  	m := MakeMap(MapOf(at, TypeOf(int(0))))
  4678  	m.SetMapIndex(v1, ValueOf(1))
  4679  	if i1, i2 := v1.Interface(), v2.Interface(); !m.MapIndex(v2).IsValid() {
  4680  		t.Errorf("constructed arrays %v and %v have different hashes", i1, i2)
  4681  	}
  4682  }
  4683  
  4684  func TestArrayOfDirectIface(t *testing.T) {
  4685  	{
  4686  		type T [1]*byte
  4687  		i1 := Zero(TypeOf(T{})).Interface()
  4688  		v1 := ValueOf(&i1).Elem()
  4689  		p1 := v1.InterfaceData()[1]
  4690  
  4691  		i2 := Zero(ArrayOf(1, PtrTo(TypeOf(int8(0))))).Interface()
  4692  		v2 := ValueOf(&i2).Elem()
  4693  		p2 := v2.InterfaceData()[1]
  4694  
  4695  		if p1 != 0 {
  4696  			t.Errorf("got p1=%v. want=%v", p1, nil)
  4697  		}
  4698  
  4699  		if p2 != 0 {
  4700  			t.Errorf("got p2=%v. want=%v", p2, nil)
  4701  		}
  4702  	}
  4703  	{
  4704  		type T [0]*byte
  4705  		i1 := Zero(TypeOf(T{})).Interface()
  4706  		v1 := ValueOf(&i1).Elem()
  4707  		p1 := v1.InterfaceData()[1]
  4708  
  4709  		i2 := Zero(ArrayOf(0, PtrTo(TypeOf(int8(0))))).Interface()
  4710  		v2 := ValueOf(&i2).Elem()
  4711  		p2 := v2.InterfaceData()[1]
  4712  
  4713  		if p1 == 0 {
  4714  			t.Errorf("got p1=%v. want=not-%v", p1, nil)
  4715  		}
  4716  
  4717  		if p2 == 0 {
  4718  			t.Errorf("got p2=%v. want=not-%v", p2, nil)
  4719  		}
  4720  	}
  4721  }
  4722  
  4723  // Ensure passing in negative lengths panics.
  4724  // See https://golang.org/issue/43603
  4725  func TestArrayOfPanicOnNegativeLength(t *testing.T) {
  4726  	shouldPanic("reflect: negative length passed to ArrayOf", func() {
  4727  		ArrayOf(-1, TypeOf(byte(0)))
  4728  	})
  4729  }
  4730  
  4731  func TestSliceOf(t *testing.T) {
  4732  	// check construction and use of type not in binary
  4733  	type T int
  4734  	st := SliceOf(TypeOf(T(1)))
  4735  	if got, want := st.String(), "[]reflect_test.T"; got != want {
  4736  		t.Errorf("SliceOf(T(1)).String()=%q, want %q", got, want)
  4737  	}
  4738  	v := MakeSlice(st, 10, 10)
  4739  	runtime.GC()
  4740  	for i := 0; i < v.Len(); i++ {
  4741  		v.Index(i).Set(ValueOf(T(i)))
  4742  		runtime.GC()
  4743  	}
  4744  	s := fmt.Sprint(v.Interface())
  4745  	want := "[0 1 2 3 4 5 6 7 8 9]"
  4746  	if s != want {
  4747  		t.Errorf("constructed slice = %s, want %s", s, want)
  4748  	}
  4749  
  4750  	// check that type already in binary is found
  4751  	type T1 int
  4752  	checkSameType(t, SliceOf(TypeOf(T1(1))), []T1{})
  4753  }
  4754  
  4755  func TestSliceOverflow(t *testing.T) {
  4756  	// check that MakeSlice panics when size of slice overflows uint
  4757  	const S = 1e6
  4758  	s := uint(S)
  4759  	l := (1<<(unsafe.Sizeof((*byte)(nil))*8)-1)/s + 1
  4760  	if l*s >= s {
  4761  		t.Fatal("slice size does not overflow")
  4762  	}
  4763  	var x [S]byte
  4764  	st := SliceOf(TypeOf(x))
  4765  	defer func() {
  4766  		err := recover()
  4767  		if err == nil {
  4768  			t.Fatal("slice overflow does not panic")
  4769  		}
  4770  	}()
  4771  	MakeSlice(st, int(l), int(l))
  4772  }
  4773  
  4774  func TestSliceOfGC(t *testing.T) {
  4775  	type T *uintptr
  4776  	tt := TypeOf(T(nil))
  4777  	st := SliceOf(tt)
  4778  	const n = 100
  4779  	var x []interface{}
  4780  	for i := 0; i < n; i++ {
  4781  		v := MakeSlice(st, n, n)
  4782  		for j := 0; j < v.Len(); j++ {
  4783  			p := new(uintptr)
  4784  			*p = uintptr(i*n + j)
  4785  			v.Index(j).Set(ValueOf(p).Convert(tt))
  4786  		}
  4787  		x = append(x, v.Interface())
  4788  	}
  4789  	runtime.GC()
  4790  
  4791  	for i, xi := range x {
  4792  		v := ValueOf(xi)
  4793  		for j := 0; j < v.Len(); j++ {
  4794  			k := v.Index(j).Elem().Interface()
  4795  			if k != uintptr(i*n+j) {
  4796  				t.Errorf("lost x[%d][%d] = %d, want %d", i, j, k, i*n+j)
  4797  			}
  4798  		}
  4799  	}
  4800  }
  4801  
  4802  func TestStructOfFieldName(t *testing.T) {
  4803  	// invalid field name "1nvalid"
  4804  	shouldPanic("has invalid name", func() {
  4805  		StructOf([]StructField{
  4806  			{Name: "Valid", Type: TypeOf("")},
  4807  			{Name: "1nvalid", Type: TypeOf("")},
  4808  		})
  4809  	})
  4810  
  4811  	// invalid field name "+"
  4812  	shouldPanic("has invalid name", func() {
  4813  		StructOf([]StructField{
  4814  			{Name: "Val1d", Type: TypeOf("")},
  4815  			{Name: "+", Type: TypeOf("")},
  4816  		})
  4817  	})
  4818  
  4819  	// no field name
  4820  	shouldPanic("has no name", func() {
  4821  		StructOf([]StructField{
  4822  			{Name: "", Type: TypeOf("")},
  4823  		})
  4824  	})
  4825  
  4826  	// verify creation of a struct with valid struct fields
  4827  	validFields := []StructField{
  4828  		{
  4829  			Name: "φ",
  4830  			Type: TypeOf(""),
  4831  		},
  4832  		{
  4833  			Name: "ValidName",
  4834  			Type: TypeOf(""),
  4835  		},
  4836  		{
  4837  			Name: "Val1dNam5",
  4838  			Type: TypeOf(""),
  4839  		},
  4840  	}
  4841  
  4842  	validStruct := StructOf(validFields)
  4843  
  4844  	const structStr = `struct { φ string; ValidName string; Val1dNam5 string }`
  4845  	if got, want := validStruct.String(), structStr; got != want {
  4846  		t.Errorf("StructOf(validFields).String()=%q, want %q", got, want)
  4847  	}
  4848  }
  4849  
  4850  func TestStructOf(t *testing.T) {
  4851  	// check construction and use of type not in binary
  4852  	fields := []StructField{
  4853  		{
  4854  			Name: "S",
  4855  			Tag:  "s",
  4856  			Type: TypeOf(""),
  4857  		},
  4858  		{
  4859  			Name: "X",
  4860  			Tag:  "x",
  4861  			Type: TypeOf(byte(0)),
  4862  		},
  4863  		{
  4864  			Name: "Y",
  4865  			Type: TypeOf(uint64(0)),
  4866  		},
  4867  		{
  4868  			Name: "Z",
  4869  			Type: TypeOf([3]uint16{}),
  4870  		},
  4871  	}
  4872  
  4873  	st := StructOf(fields)
  4874  	v := New(st).Elem()
  4875  	runtime.GC()
  4876  	v.FieldByName("X").Set(ValueOf(byte(2)))
  4877  	v.FieldByIndex([]int{1}).Set(ValueOf(byte(1)))
  4878  	runtime.GC()
  4879  
  4880  	s := fmt.Sprint(v.Interface())
  4881  	want := `{ 1 0 [0 0 0]}`
  4882  	if s != want {
  4883  		t.Errorf("constructed struct = %s, want %s", s, want)
  4884  	}
  4885  	const stStr = `struct { S string "s"; X uint8 "x"; Y uint64; Z [3]uint16 }`
  4886  	if got, want := st.String(), stStr; got != want {
  4887  		t.Errorf("StructOf(fields).String()=%q, want %q", got, want)
  4888  	}
  4889  
  4890  	// check the size, alignment and field offsets
  4891  	stt := TypeOf(struct {
  4892  		String string
  4893  		X      byte
  4894  		Y      uint64
  4895  		Z      [3]uint16
  4896  	}{})
  4897  	if st.Size() != stt.Size() {
  4898  		t.Errorf("constructed struct size = %v, want %v", st.Size(), stt.Size())
  4899  	}
  4900  	if st.Align() != stt.Align() {
  4901  		t.Errorf("constructed struct align = %v, want %v", st.Align(), stt.Align())
  4902  	}
  4903  	if st.FieldAlign() != stt.FieldAlign() {
  4904  		t.Errorf("constructed struct field align = %v, want %v", st.FieldAlign(), stt.FieldAlign())
  4905  	}
  4906  	for i := 0; i < st.NumField(); i++ {
  4907  		o1 := st.Field(i).Offset
  4908  		o2 := stt.Field(i).Offset
  4909  		if o1 != o2 {
  4910  			t.Errorf("constructed struct field %v offset = %v, want %v", i, o1, o2)
  4911  		}
  4912  	}
  4913  
  4914  	// Check size and alignment with a trailing zero-sized field.
  4915  	st = StructOf([]StructField{
  4916  		{
  4917  			Name: "F1",
  4918  			Type: TypeOf(byte(0)),
  4919  		},
  4920  		{
  4921  			Name: "F2",
  4922  			Type: TypeOf([0]*byte{}),
  4923  		},
  4924  	})
  4925  	stt = TypeOf(struct {
  4926  		G1 byte
  4927  		G2 [0]*byte
  4928  	}{})
  4929  	if st.Size() != stt.Size() {
  4930  		t.Errorf("constructed zero-padded struct size = %v, want %v", st.Size(), stt.Size())
  4931  	}
  4932  	if st.Align() != stt.Align() {
  4933  		t.Errorf("constructed zero-padded struct align = %v, want %v", st.Align(), stt.Align())
  4934  	}
  4935  	if st.FieldAlign() != stt.FieldAlign() {
  4936  		t.Errorf("constructed zero-padded struct field align = %v, want %v", st.FieldAlign(), stt.FieldAlign())
  4937  	}
  4938  	for i := 0; i < st.NumField(); i++ {
  4939  		o1 := st.Field(i).Offset
  4940  		o2 := stt.Field(i).Offset
  4941  		if o1 != o2 {
  4942  			t.Errorf("constructed zero-padded struct field %v offset = %v, want %v", i, o1, o2)
  4943  		}
  4944  	}
  4945  
  4946  	// check duplicate names
  4947  	shouldPanic("duplicate field", func() {
  4948  		StructOf([]StructField{
  4949  			{Name: "string", PkgPath: "p", Type: TypeOf("")},
  4950  			{Name: "string", PkgPath: "p", Type: TypeOf("")},
  4951  		})
  4952  	})
  4953  	shouldPanic("has no name", func() {
  4954  		StructOf([]StructField{
  4955  			{Type: TypeOf("")},
  4956  			{Name: "string", PkgPath: "p", Type: TypeOf("")},
  4957  		})
  4958  	})
  4959  	shouldPanic("has no name", func() {
  4960  		StructOf([]StructField{
  4961  			{Type: TypeOf("")},
  4962  			{Type: TypeOf("")},
  4963  		})
  4964  	})
  4965  	// check that type already in binary is found
  4966  	checkSameType(t, StructOf(fields[2:3]), struct{ Y uint64 }{})
  4967  
  4968  	// gccgo used to fail this test.
  4969  	type structFieldType interface{}
  4970  	checkSameType(t,
  4971  		StructOf([]StructField{
  4972  			{
  4973  				Name: "F",
  4974  				Type: TypeOf((*structFieldType)(nil)).Elem(),
  4975  			},
  4976  		}),
  4977  		struct{ F structFieldType }{})
  4978  }
  4979  
  4980  func TestStructOfExportRules(t *testing.T) {
  4981  	type S1 struct{}
  4982  	type s2 struct{}
  4983  	type ΦType struct{}
  4984  	type φType struct{}
  4985  
  4986  	testPanic := func(i int, mustPanic bool, f func()) {
  4987  		defer func() {
  4988  			err := recover()
  4989  			if err == nil && mustPanic {
  4990  				t.Errorf("test-%d did not panic", i)
  4991  			}
  4992  			if err != nil && !mustPanic {
  4993  				t.Errorf("test-%d panicked: %v\n", i, err)
  4994  			}
  4995  		}()
  4996  		f()
  4997  	}
  4998  
  4999  	tests := []struct {
  5000  		field     StructField
  5001  		mustPanic bool
  5002  		exported  bool
  5003  	}{
  5004  		{
  5005  			field:    StructField{Name: "S1", Anonymous: true, Type: TypeOf(S1{})},
  5006  			exported: true,
  5007  		},
  5008  		{
  5009  			field:    StructField{Name: "S1", Anonymous: true, Type: TypeOf((*S1)(nil))},
  5010  			exported: true,
  5011  		},
  5012  		{
  5013  			field:     StructField{Name: "s2", Anonymous: true, Type: TypeOf(s2{})},
  5014  			mustPanic: true,
  5015  		},
  5016  		{
  5017  			field:     StructField{Name: "s2", Anonymous: true, Type: TypeOf((*s2)(nil))},
  5018  			mustPanic: true,
  5019  		},
  5020  		{
  5021  			field:     StructField{Name: "Name", Type: nil, PkgPath: ""},
  5022  			mustPanic: true,
  5023  		},
  5024  		{
  5025  			field:     StructField{Name: "", Type: TypeOf(S1{}), PkgPath: ""},
  5026  			mustPanic: true,
  5027  		},
  5028  		{
  5029  			field:     StructField{Name: "S1", Anonymous: true, Type: TypeOf(S1{}), PkgPath: "other/pkg"},
  5030  			mustPanic: true,
  5031  		},
  5032  		{
  5033  			field:     StructField{Name: "S1", Anonymous: true, Type: TypeOf((*S1)(nil)), PkgPath: "other/pkg"},
  5034  			mustPanic: true,
  5035  		},
  5036  		{
  5037  			field:     StructField{Name: "s2", Anonymous: true, Type: TypeOf(s2{}), PkgPath: "other/pkg"},
  5038  			mustPanic: true,
  5039  		},
  5040  		{
  5041  			field:     StructField{Name: "s2", Anonymous: true, Type: TypeOf((*s2)(nil)), PkgPath: "other/pkg"},
  5042  			mustPanic: true,
  5043  		},
  5044  		{
  5045  			field: StructField{Name: "s2", Type: TypeOf(int(0)), PkgPath: "other/pkg"},
  5046  		},
  5047  		{
  5048  			field: StructField{Name: "s2", Type: TypeOf(int(0)), PkgPath: "other/pkg"},
  5049  		},
  5050  		{
  5051  			field:    StructField{Name: "S", Type: TypeOf(S1{})},
  5052  			exported: true,
  5053  		},
  5054  		{
  5055  			field:    StructField{Name: "S", Type: TypeOf((*S1)(nil))},
  5056  			exported: true,
  5057  		},
  5058  		{
  5059  			field:    StructField{Name: "S", Type: TypeOf(s2{})},
  5060  			exported: true,
  5061  		},
  5062  		{
  5063  			field:    StructField{Name: "S", Type: TypeOf((*s2)(nil))},
  5064  			exported: true,
  5065  		},
  5066  		{
  5067  			field:     StructField{Name: "s", Type: TypeOf(S1{})},
  5068  			mustPanic: true,
  5069  		},
  5070  		{
  5071  			field:     StructField{Name: "s", Type: TypeOf((*S1)(nil))},
  5072  			mustPanic: true,
  5073  		},
  5074  		{
  5075  			field:     StructField{Name: "s", Type: TypeOf(s2{})},
  5076  			mustPanic: true,
  5077  		},
  5078  		{
  5079  			field:     StructField{Name: "s", Type: TypeOf((*s2)(nil))},
  5080  			mustPanic: true,
  5081  		},
  5082  		{
  5083  			field: StructField{Name: "s", Type: TypeOf(S1{}), PkgPath: "other/pkg"},
  5084  		},
  5085  		{
  5086  			field: StructField{Name: "s", Type: TypeOf((*S1)(nil)), PkgPath: "other/pkg"},
  5087  		},
  5088  		{
  5089  			field: StructField{Name: "s", Type: TypeOf(s2{}), PkgPath: "other/pkg"},
  5090  		},
  5091  		{
  5092  			field: StructField{Name: "s", Type: TypeOf((*s2)(nil)), PkgPath: "other/pkg"},
  5093  		},
  5094  		{
  5095  			field:     StructField{Name: "", Type: TypeOf(ΦType{})},
  5096  			mustPanic: true,
  5097  		},
  5098  		{
  5099  			field:     StructField{Name: "", Type: TypeOf(φType{})},
  5100  			mustPanic: true,
  5101  		},
  5102  		{
  5103  			field:    StructField{Name: "Φ", Type: TypeOf(0)},
  5104  			exported: true,
  5105  		},
  5106  		{
  5107  			field:    StructField{Name: "φ", Type: TypeOf(0)},
  5108  			exported: false,
  5109  		},
  5110  	}
  5111  
  5112  	for i, test := range tests {
  5113  		testPanic(i, test.mustPanic, func() {
  5114  			typ := StructOf([]StructField{test.field})
  5115  			if typ == nil {
  5116  				t.Errorf("test-%d: error creating struct type", i)
  5117  				return
  5118  			}
  5119  			field := typ.Field(0)
  5120  			n := field.Name
  5121  			if n == "" {
  5122  				panic("field.Name must not be empty")
  5123  			}
  5124  			exported := token.IsExported(n)
  5125  			if exported != test.exported {
  5126  				t.Errorf("test-%d: got exported=%v want exported=%v", i, exported, test.exported)
  5127  			}
  5128  			if field.PkgPath != test.field.PkgPath {
  5129  				t.Errorf("test-%d: got PkgPath=%q want pkgPath=%q", i, field.PkgPath, test.field.PkgPath)
  5130  			}
  5131  		})
  5132  	}
  5133  }
  5134  
  5135  func TestStructOfGC(t *testing.T) {
  5136  	type T *uintptr
  5137  	tt := TypeOf(T(nil))
  5138  	fields := []StructField{
  5139  		{Name: "X", Type: tt},
  5140  		{Name: "Y", Type: tt},
  5141  	}
  5142  	st := StructOf(fields)
  5143  
  5144  	const n = 10000
  5145  	var x []interface{}
  5146  	for i := 0; i < n; i++ {
  5147  		v := New(st).Elem()
  5148  		for j := 0; j < v.NumField(); j++ {
  5149  			p := new(uintptr)
  5150  			*p = uintptr(i*n + j)
  5151  			v.Field(j).Set(ValueOf(p).Convert(tt))
  5152  		}
  5153  		x = append(x, v.Interface())
  5154  	}
  5155  	runtime.GC()
  5156  
  5157  	for i, xi := range x {
  5158  		v := ValueOf(xi)
  5159  		for j := 0; j < v.NumField(); j++ {
  5160  			k := v.Field(j).Elem().Interface()
  5161  			if k != uintptr(i*n+j) {
  5162  				t.Errorf("lost x[%d].%c = %d, want %d", i, "XY"[j], k, i*n+j)
  5163  			}
  5164  		}
  5165  	}
  5166  }
  5167  
  5168  func TestStructOfAlg(t *testing.T) {
  5169  	st := StructOf([]StructField{{Name: "X", Tag: "x", Type: TypeOf(int(0))}})
  5170  	v1 := New(st).Elem()
  5171  	v2 := New(st).Elem()
  5172  	if !DeepEqual(v1.Interface(), v1.Interface()) {
  5173  		t.Errorf("constructed struct %v not equal to itself", v1.Interface())
  5174  	}
  5175  	v1.FieldByName("X").Set(ValueOf(int(1)))
  5176  	if i1, i2 := v1.Interface(), v2.Interface(); DeepEqual(i1, i2) {
  5177  		t.Errorf("constructed structs %v and %v should not be equal", i1, i2)
  5178  	}
  5179  
  5180  	st = StructOf([]StructField{{Name: "X", Tag: "x", Type: TypeOf([]int(nil))}})
  5181  	v1 = New(st).Elem()
  5182  	shouldPanic("", func() { _ = v1.Interface() == v1.Interface() })
  5183  }
  5184  
  5185  func TestStructOfGenericAlg(t *testing.T) {
  5186  	st1 := StructOf([]StructField{
  5187  		{Name: "X", Tag: "x", Type: TypeOf(int64(0))},
  5188  		{Name: "Y", Type: TypeOf(string(""))},
  5189  	})
  5190  	st := StructOf([]StructField{
  5191  		{Name: "S0", Type: st1},
  5192  		{Name: "S1", Type: st1},
  5193  	})
  5194  
  5195  	tests := []struct {
  5196  		rt  Type
  5197  		idx []int
  5198  	}{
  5199  		{
  5200  			rt:  st,
  5201  			idx: []int{0, 1},
  5202  		},
  5203  		{
  5204  			rt:  st1,
  5205  			idx: []int{1},
  5206  		},
  5207  		{
  5208  			rt: StructOf(
  5209  				[]StructField{
  5210  					{Name: "XX", Type: TypeOf([0]int{})},
  5211  					{Name: "YY", Type: TypeOf("")},
  5212  				},
  5213  			),
  5214  			idx: []int{1},
  5215  		},
  5216  		{
  5217  			rt: StructOf(
  5218  				[]StructField{
  5219  					{Name: "XX", Type: TypeOf([0]int{})},
  5220  					{Name: "YY", Type: TypeOf("")},
  5221  					{Name: "ZZ", Type: TypeOf([2]int{})},
  5222  				},
  5223  			),
  5224  			idx: []int{1},
  5225  		},
  5226  		{
  5227  			rt: StructOf(
  5228  				[]StructField{
  5229  					{Name: "XX", Type: TypeOf([1]int{})},
  5230  					{Name: "YY", Type: TypeOf("")},
  5231  				},
  5232  			),
  5233  			idx: []int{1},
  5234  		},
  5235  		{
  5236  			rt: StructOf(
  5237  				[]StructField{
  5238  					{Name: "XX", Type: TypeOf([1]int{})},
  5239  					{Name: "YY", Type: TypeOf("")},
  5240  					{Name: "ZZ", Type: TypeOf([1]int{})},
  5241  				},
  5242  			),
  5243  			idx: []int{1},
  5244  		},
  5245  		{
  5246  			rt: StructOf(
  5247  				[]StructField{
  5248  					{Name: "XX", Type: TypeOf([2]int{})},
  5249  					{Name: "YY", Type: TypeOf("")},
  5250  					{Name: "ZZ", Type: TypeOf([2]int{})},
  5251  				},
  5252  			),
  5253  			idx: []int{1},
  5254  		},
  5255  		{
  5256  			rt: StructOf(
  5257  				[]StructField{
  5258  					{Name: "XX", Type: TypeOf(int64(0))},
  5259  					{Name: "YY", Type: TypeOf(byte(0))},
  5260  					{Name: "ZZ", Type: TypeOf("")},
  5261  				},
  5262  			),
  5263  			idx: []int{2},
  5264  		},
  5265  		{
  5266  			rt: StructOf(
  5267  				[]StructField{
  5268  					{Name: "XX", Type: TypeOf(int64(0))},
  5269  					{Name: "YY", Type: TypeOf(int64(0))},
  5270  					{Name: "ZZ", Type: TypeOf("")},
  5271  					{Name: "AA", Type: TypeOf([1]int64{})},
  5272  				},
  5273  			),
  5274  			idx: []int{2},
  5275  		},
  5276  	}
  5277  
  5278  	for _, table := range tests {
  5279  		v1 := New(table.rt).Elem()
  5280  		v2 := New(table.rt).Elem()
  5281  
  5282  		if !DeepEqual(v1.Interface(), v1.Interface()) {
  5283  			t.Errorf("constructed struct %v not equal to itself", v1.Interface())
  5284  		}
  5285  
  5286  		v1.FieldByIndex(table.idx).Set(ValueOf("abc"))
  5287  		v2.FieldByIndex(table.idx).Set(ValueOf("def"))
  5288  		if i1, i2 := v1.Interface(), v2.Interface(); DeepEqual(i1, i2) {
  5289  			t.Errorf("constructed structs %v and %v should not be equal", i1, i2)
  5290  		}
  5291  
  5292  		abc := "abc"
  5293  		v1.FieldByIndex(table.idx).Set(ValueOf(abc))
  5294  		val := "+" + abc + "-"
  5295  		v2.FieldByIndex(table.idx).Set(ValueOf(val[1:4]))
  5296  		if i1, i2 := v1.Interface(), v2.Interface(); !DeepEqual(i1, i2) {
  5297  			t.Errorf("constructed structs %v and %v should be equal", i1, i2)
  5298  		}
  5299  
  5300  		// Test hash
  5301  		m := MakeMap(MapOf(table.rt, TypeOf(int(0))))
  5302  		m.SetMapIndex(v1, ValueOf(1))
  5303  		if i1, i2 := v1.Interface(), v2.Interface(); !m.MapIndex(v2).IsValid() {
  5304  			t.Errorf("constructed structs %#v and %#v have different hashes", i1, i2)
  5305  		}
  5306  
  5307  		v2.FieldByIndex(table.idx).Set(ValueOf("abc"))
  5308  		if i1, i2 := v1.Interface(), v2.Interface(); !DeepEqual(i1, i2) {
  5309  			t.Errorf("constructed structs %v and %v should be equal", i1, i2)
  5310  		}
  5311  
  5312  		if i1, i2 := v1.Interface(), v2.Interface(); !m.MapIndex(v2).IsValid() {
  5313  			t.Errorf("constructed structs %v and %v have different hashes", i1, i2)
  5314  		}
  5315  	}
  5316  }
  5317  
  5318  func TestStructOfDirectIface(t *testing.T) {
  5319  	{
  5320  		type T struct{ X [1]*byte }
  5321  		i1 := Zero(TypeOf(T{})).Interface()
  5322  		v1 := ValueOf(&i1).Elem()
  5323  		p1 := v1.InterfaceData()[1]
  5324  
  5325  		i2 := Zero(StructOf([]StructField{
  5326  			{
  5327  				Name: "X",
  5328  				Type: ArrayOf(1, TypeOf((*int8)(nil))),
  5329  			},
  5330  		})).Interface()
  5331  		v2 := ValueOf(&i2).Elem()
  5332  		p2 := v2.InterfaceData()[1]
  5333  
  5334  		if p1 != 0 {
  5335  			t.Errorf("got p1=%v. want=%v", p1, nil)
  5336  		}
  5337  
  5338  		if p2 != 0 {
  5339  			t.Errorf("got p2=%v. want=%v", p2, nil)
  5340  		}
  5341  	}
  5342  	{
  5343  		type T struct{ X [0]*byte }
  5344  		i1 := Zero(TypeOf(T{})).Interface()
  5345  		v1 := ValueOf(&i1).Elem()
  5346  		p1 := v1.InterfaceData()[1]
  5347  
  5348  		i2 := Zero(StructOf([]StructField{
  5349  			{
  5350  				Name: "X",
  5351  				Type: ArrayOf(0, TypeOf((*int8)(nil))),
  5352  			},
  5353  		})).Interface()
  5354  		v2 := ValueOf(&i2).Elem()
  5355  		p2 := v2.InterfaceData()[1]
  5356  
  5357  		if p1 == 0 {
  5358  			t.Errorf("got p1=%v. want=not-%v", p1, nil)
  5359  		}
  5360  
  5361  		if p2 == 0 {
  5362  			t.Errorf("got p2=%v. want=not-%v", p2, nil)
  5363  		}
  5364  	}
  5365  }
  5366  
  5367  type StructI int
  5368  
  5369  func (i StructI) Get() int { return int(i) }
  5370  
  5371  type StructIPtr int
  5372  
  5373  func (i *StructIPtr) Get() int  { return int(*i) }
  5374  func (i *StructIPtr) Set(v int) { *(*int)(i) = v }
  5375  
  5376  type SettableStruct struct {
  5377  	SettableField int
  5378  }
  5379  
  5380  func (p *SettableStruct) Set(v int) { p.SettableField = v }
  5381  
  5382  type SettablePointer struct {
  5383  	SettableField *int
  5384  }
  5385  
  5386  func (p *SettablePointer) Set(v int) { *p.SettableField = v }
  5387  
  5388  func TestStructOfWithInterface(t *testing.T) {
  5389  	const want = 42
  5390  	type Iface interface {
  5391  		Get() int
  5392  	}
  5393  	type IfaceSet interface {
  5394  		Set(int)
  5395  	}
  5396  	tests := []struct {
  5397  		name string
  5398  		typ  Type
  5399  		val  Value
  5400  		impl bool
  5401  	}{
  5402  		{
  5403  			name: "StructI",
  5404  			typ:  TypeOf(StructI(want)),
  5405  			val:  ValueOf(StructI(want)),
  5406  			impl: true,
  5407  		},
  5408  		{
  5409  			name: "StructI",
  5410  			typ:  PtrTo(TypeOf(StructI(want))),
  5411  			val: ValueOf(func() interface{} {
  5412  				v := StructI(want)
  5413  				return &v
  5414  			}()),
  5415  			impl: true,
  5416  		},
  5417  		{
  5418  			name: "StructIPtr",
  5419  			typ:  PtrTo(TypeOf(StructIPtr(want))),
  5420  			val: ValueOf(func() interface{} {
  5421  				v := StructIPtr(want)
  5422  				return &v
  5423  			}()),
  5424  			impl: true,
  5425  		},
  5426  		{
  5427  			name: "StructIPtr",
  5428  			typ:  TypeOf(StructIPtr(want)),
  5429  			val:  ValueOf(StructIPtr(want)),
  5430  			impl: false,
  5431  		},
  5432  		// {
  5433  		//	typ:  TypeOf((*Iface)(nil)).Elem(), // FIXME(sbinet): fix method.ifn/tfn
  5434  		//	val:  ValueOf(StructI(want)),
  5435  		//	impl: true,
  5436  		// },
  5437  	}
  5438  
  5439  	for i, table := range tests {
  5440  		for j := 0; j < 2; j++ {
  5441  			var fields []StructField
  5442  			if j == 1 {
  5443  				fields = append(fields, StructField{
  5444  					Name:    "Dummy",
  5445  					PkgPath: "",
  5446  					Type:    TypeOf(int(0)),
  5447  				})
  5448  			}
  5449  			fields = append(fields, StructField{
  5450  				Name:      table.name,
  5451  				Anonymous: true,
  5452  				PkgPath:   "",
  5453  				Type:      table.typ,
  5454  			})
  5455  
  5456  			// We currently do not correctly implement methods
  5457  			// for embedded fields other than the first.
  5458  			// Therefore, for now, we expect those methods
  5459  			// to not exist.  See issues 15924 and 20824.
  5460  			// When those issues are fixed, this test of panic
  5461  			// should be removed.
  5462  			if j == 1 && table.impl {
  5463  				func() {
  5464  					defer func() {
  5465  						if err := recover(); err == nil {
  5466  							t.Errorf("test-%d-%d did not panic", i, j)
  5467  						}
  5468  					}()
  5469  					_ = StructOf(fields)
  5470  				}()
  5471  				continue
  5472  			}
  5473  
  5474  			rt := StructOf(fields)
  5475  			rv := New(rt).Elem()
  5476  			rv.Field(j).Set(table.val)
  5477  
  5478  			if _, ok := rv.Interface().(Iface); ok != table.impl {
  5479  				if table.impl {
  5480  					t.Errorf("test-%d-%d: type=%v fails to implement Iface.\n", i, j, table.typ)
  5481  				} else {
  5482  					t.Errorf("test-%d-%d: type=%v should NOT implement Iface\n", i, j, table.typ)
  5483  				}
  5484  				continue
  5485  			}
  5486  
  5487  			if !table.impl {
  5488  				continue
  5489  			}
  5490  
  5491  			v := rv.Interface().(Iface).Get()
  5492  			if v != want {
  5493  				t.Errorf("test-%d-%d: x.Get()=%v. want=%v\n", i, j, v, want)
  5494  			}
  5495  
  5496  			fct := rv.MethodByName("Get")
  5497  			out := fct.Call(nil)
  5498  			if !DeepEqual(out[0].Interface(), want) {
  5499  				t.Errorf("test-%d-%d: x.Get()=%v. want=%v\n", i, j, out[0].Interface(), want)
  5500  			}
  5501  		}
  5502  	}
  5503  
  5504  	// Test an embedded nil pointer with pointer methods.
  5505  	fields := []StructField{{
  5506  		Name:      "StructIPtr",
  5507  		Anonymous: true,
  5508  		Type:      PtrTo(TypeOf(StructIPtr(want))),
  5509  	}}
  5510  	rt := StructOf(fields)
  5511  	rv := New(rt).Elem()
  5512  	// This should panic since the pointer is nil.
  5513  	shouldPanic("", func() {
  5514  		rv.Interface().(IfaceSet).Set(want)
  5515  	})
  5516  
  5517  	// Test an embedded nil pointer to a struct with pointer methods.
  5518  
  5519  	fields = []StructField{{
  5520  		Name:      "SettableStruct",
  5521  		Anonymous: true,
  5522  		Type:      PtrTo(TypeOf(SettableStruct{})),
  5523  	}}
  5524  	rt = StructOf(fields)
  5525  	rv = New(rt).Elem()
  5526  	// This should panic since the pointer is nil.
  5527  	shouldPanic("", func() {
  5528  		rv.Interface().(IfaceSet).Set(want)
  5529  	})
  5530  
  5531  	// The behavior is different if there is a second field,
  5532  	// since now an interface value holds a pointer to the struct
  5533  	// rather than just holding a copy of the struct.
  5534  	fields = []StructField{
  5535  		{
  5536  			Name:      "SettableStruct",
  5537  			Anonymous: true,
  5538  			Type:      PtrTo(TypeOf(SettableStruct{})),
  5539  		},
  5540  		{
  5541  			Name:      "EmptyStruct",
  5542  			Anonymous: true,
  5543  			Type:      StructOf(nil),
  5544  		},
  5545  	}
  5546  	// With the current implementation this is expected to panic.
  5547  	// Ideally it should work and we should be able to see a panic
  5548  	// if we call the Set method.
  5549  	shouldPanic("", func() {
  5550  		StructOf(fields)
  5551  	})
  5552  
  5553  	// Embed a field that can be stored directly in an interface,
  5554  	// with a second field.
  5555  	fields = []StructField{
  5556  		{
  5557  			Name:      "SettablePointer",
  5558  			Anonymous: true,
  5559  			Type:      TypeOf(SettablePointer{}),
  5560  		},
  5561  		{
  5562  			Name:      "EmptyStruct",
  5563  			Anonymous: true,
  5564  			Type:      StructOf(nil),
  5565  		},
  5566  	}
  5567  	// With the current implementation this is expected to panic.
  5568  	// Ideally it should work and we should be able to call the
  5569  	// Set and Get methods.
  5570  	shouldPanic("", func() {
  5571  		StructOf(fields)
  5572  	})
  5573  }
  5574  
  5575  func TestStructOfTooManyFields(t *testing.T) {
  5576  	// Bug Fix: #25402 - this should not panic
  5577  	tt := StructOf([]StructField{
  5578  		{Name: "Time", Type: TypeOf(time.Time{}), Anonymous: true},
  5579  	})
  5580  
  5581  	if _, present := tt.MethodByName("After"); !present {
  5582  		t.Errorf("Expected method `After` to be found")
  5583  	}
  5584  }
  5585  
  5586  func TestStructOfDifferentPkgPath(t *testing.T) {
  5587  	fields := []StructField{
  5588  		{
  5589  			Name:    "f1",
  5590  			PkgPath: "p1",
  5591  			Type:    TypeOf(int(0)),
  5592  		},
  5593  		{
  5594  			Name:    "f2",
  5595  			PkgPath: "p2",
  5596  			Type:    TypeOf(int(0)),
  5597  		},
  5598  	}
  5599  	shouldPanic("different PkgPath", func() {
  5600  		StructOf(fields)
  5601  	})
  5602  }
  5603  
  5604  func TestChanOf(t *testing.T) {
  5605  	// check construction and use of type not in binary
  5606  	type T string
  5607  	ct := ChanOf(BothDir, TypeOf(T("")))
  5608  	v := MakeChan(ct, 2)
  5609  	runtime.GC()
  5610  	v.Send(ValueOf(T("hello")))
  5611  	runtime.GC()
  5612  	v.Send(ValueOf(T("world")))
  5613  	runtime.GC()
  5614  
  5615  	sv1, _ := v.Recv()
  5616  	sv2, _ := v.Recv()
  5617  	s1 := sv1.String()
  5618  	s2 := sv2.String()
  5619  	if s1 != "hello" || s2 != "world" {
  5620  		t.Errorf("constructed chan: have %q, %q, want %q, %q", s1, s2, "hello", "world")
  5621  	}
  5622  
  5623  	// check that type already in binary is found
  5624  	type T1 int
  5625  	checkSameType(t, ChanOf(BothDir, TypeOf(T1(1))), (chan T1)(nil))
  5626  
  5627  	// Check arrow token association in undefined chan types.
  5628  	var left chan<- chan T
  5629  	var right chan (<-chan T)
  5630  	tLeft := ChanOf(SendDir, ChanOf(BothDir, TypeOf(T(""))))
  5631  	tRight := ChanOf(BothDir, ChanOf(RecvDir, TypeOf(T(""))))
  5632  	if tLeft != TypeOf(left) {
  5633  		t.Errorf("chan<-chan: have %s, want %T", tLeft, left)
  5634  	}
  5635  	if tRight != TypeOf(right) {
  5636  		t.Errorf("chan<-chan: have %s, want %T", tRight, right)
  5637  	}
  5638  }
  5639  
  5640  func TestChanOfDir(t *testing.T) {
  5641  	// check construction and use of type not in binary
  5642  	type T string
  5643  	crt := ChanOf(RecvDir, TypeOf(T("")))
  5644  	cst := ChanOf(SendDir, TypeOf(T("")))
  5645  
  5646  	// check that type already in binary is found
  5647  	type T1 int
  5648  	checkSameType(t, ChanOf(RecvDir, TypeOf(T1(1))), (<-chan T1)(nil))
  5649  	checkSameType(t, ChanOf(SendDir, TypeOf(T1(1))), (chan<- T1)(nil))
  5650  
  5651  	// check String form of ChanDir
  5652  	if crt.ChanDir().String() != "<-chan" {
  5653  		t.Errorf("chan dir: have %q, want %q", crt.ChanDir().String(), "<-chan")
  5654  	}
  5655  	if cst.ChanDir().String() != "chan<-" {
  5656  		t.Errorf("chan dir: have %q, want %q", cst.ChanDir().String(), "chan<-")
  5657  	}
  5658  }
  5659  
  5660  func TestChanOfGC(t *testing.T) {
  5661  	done := make(chan bool, 1)
  5662  	go func() {
  5663  		select {
  5664  		case <-done:
  5665  		case <-time.After(5 * time.Second):
  5666  			panic("deadlock in TestChanOfGC")
  5667  		}
  5668  	}()
  5669  
  5670  	defer func() {
  5671  		done <- true
  5672  	}()
  5673  
  5674  	type T *uintptr
  5675  	tt := TypeOf(T(nil))
  5676  	ct := ChanOf(BothDir, tt)
  5677  
  5678  	// NOTE: The garbage collector handles allocated channels specially,
  5679  	// so we have to save pointers to channels in x; the pointer code will
  5680  	// use the gc info in the newly constructed chan type.
  5681  	const n = 100
  5682  	var x []interface{}
  5683  	for i := 0; i < n; i++ {
  5684  		v := MakeChan(ct, n)
  5685  		for j := 0; j < n; j++ {
  5686  			p := new(uintptr)
  5687  			*p = uintptr(i*n + j)
  5688  			v.Send(ValueOf(p).Convert(tt))
  5689  		}
  5690  		pv := New(ct)
  5691  		pv.Elem().Set(v)
  5692  		x = append(x, pv.Interface())
  5693  	}
  5694  	runtime.GC()
  5695  
  5696  	for i, xi := range x {
  5697  		v := ValueOf(xi).Elem()
  5698  		for j := 0; j < n; j++ {
  5699  			pv, _ := v.Recv()
  5700  			k := pv.Elem().Interface()
  5701  			if k != uintptr(i*n+j) {
  5702  				t.Errorf("lost x[%d][%d] = %d, want %d", i, j, k, i*n+j)
  5703  			}
  5704  		}
  5705  	}
  5706  }
  5707  
  5708  func TestMapOf(t *testing.T) {
  5709  	// check construction and use of type not in binary
  5710  	type K string
  5711  	type V float64
  5712  
  5713  	v := MakeMap(MapOf(TypeOf(K("")), TypeOf(V(0))))
  5714  	runtime.GC()
  5715  	v.SetMapIndex(ValueOf(K("a")), ValueOf(V(1)))
  5716  	runtime.GC()
  5717  
  5718  	s := fmt.Sprint(v.Interface())
  5719  	want := "map[a:1]"
  5720  	if s != want {
  5721  		t.Errorf("constructed map = %s, want %s", s, want)
  5722  	}
  5723  
  5724  	// check that type already in binary is found
  5725  	checkSameType(t, MapOf(TypeOf(V(0)), TypeOf(K(""))), map[V]K(nil))
  5726  
  5727  	// check that invalid key type panics
  5728  	shouldPanic("invalid key type", func() { MapOf(TypeOf((func())(nil)), TypeOf(false)) })
  5729  }
  5730  
  5731  func TestMapOfGCKeys(t *testing.T) {
  5732  	type T *uintptr
  5733  	tt := TypeOf(T(nil))
  5734  	mt := MapOf(tt, TypeOf(false))
  5735  
  5736  	// NOTE: The garbage collector handles allocated maps specially,
  5737  	// so we have to save pointers to maps in x; the pointer code will
  5738  	// use the gc info in the newly constructed map type.
  5739  	const n = 100
  5740  	var x []interface{}
  5741  	for i := 0; i < n; i++ {
  5742  		v := MakeMap(mt)
  5743  		for j := 0; j < n; j++ {
  5744  			p := new(uintptr)
  5745  			*p = uintptr(i*n + j)
  5746  			v.SetMapIndex(ValueOf(p).Convert(tt), ValueOf(true))
  5747  		}
  5748  		pv := New(mt)
  5749  		pv.Elem().Set(v)
  5750  		x = append(x, pv.Interface())
  5751  	}
  5752  	runtime.GC()
  5753  
  5754  	for i, xi := range x {
  5755  		v := ValueOf(xi).Elem()
  5756  		var out []int
  5757  		for _, kv := range v.MapKeys() {
  5758  			out = append(out, int(kv.Elem().Interface().(uintptr)))
  5759  		}
  5760  		sort.Ints(out)
  5761  		for j, k := range out {
  5762  			if k != i*n+j {
  5763  				t.Errorf("lost x[%d][%d] = %d, want %d", i, j, k, i*n+j)
  5764  			}
  5765  		}
  5766  	}
  5767  }
  5768  
  5769  func TestMapOfGCValues(t *testing.T) {
  5770  	type T *uintptr
  5771  	tt := TypeOf(T(nil))
  5772  	mt := MapOf(TypeOf(1), tt)
  5773  
  5774  	// NOTE: The garbage collector handles allocated maps specially,
  5775  	// so we have to save pointers to maps in x; the pointer code will
  5776  	// use the gc info in the newly constructed map type.
  5777  	const n = 100
  5778  	var x []interface{}
  5779  	for i := 0; i < n; i++ {
  5780  		v := MakeMap(mt)
  5781  		for j := 0; j < n; j++ {
  5782  			p := new(uintptr)
  5783  			*p = uintptr(i*n + j)
  5784  			v.SetMapIndex(ValueOf(j), ValueOf(p).Convert(tt))
  5785  		}
  5786  		pv := New(mt)
  5787  		pv.Elem().Set(v)
  5788  		x = append(x, pv.Interface())
  5789  	}
  5790  	runtime.GC()
  5791  
  5792  	for i, xi := range x {
  5793  		v := ValueOf(xi).Elem()
  5794  		for j := 0; j < n; j++ {
  5795  			k := v.MapIndex(ValueOf(j)).Elem().Interface().(uintptr)
  5796  			if k != uintptr(i*n+j) {
  5797  				t.Errorf("lost x[%d][%d] = %d, want %d", i, j, k, i*n+j)
  5798  			}
  5799  		}
  5800  	}
  5801  }
  5802  
  5803  func TestTypelinksSorted(t *testing.T) {
  5804  	var last string
  5805  	for i, n := range TypeLinks() {
  5806  		if n < last {
  5807  			t.Errorf("typelinks not sorted: %q [%d] > %q [%d]", last, i-1, n, i)
  5808  		}
  5809  		last = n
  5810  	}
  5811  }
  5812  
  5813  func TestFuncOf(t *testing.T) {
  5814  	// check construction and use of type not in binary
  5815  	type K string
  5816  	type V float64
  5817  
  5818  	fn := func(args []Value) []Value {
  5819  		if len(args) != 1 {
  5820  			t.Errorf("args == %v, want exactly one arg", args)
  5821  		} else if args[0].Type() != TypeOf(K("")) {
  5822  			t.Errorf("args[0] is type %v, want %v", args[0].Type(), TypeOf(K("")))
  5823  		} else if args[0].String() != "gopher" {
  5824  			t.Errorf("args[0] = %q, want %q", args[0].String(), "gopher")
  5825  		}
  5826  		return []Value{ValueOf(V(3.14))}
  5827  	}
  5828  	v := MakeFunc(FuncOf([]Type{TypeOf(K(""))}, []Type{TypeOf(V(0))}, false), fn)
  5829  
  5830  	outs := v.Call([]Value{ValueOf(K("gopher"))})
  5831  	if len(outs) != 1 {
  5832  		t.Fatalf("v.Call returned %v, want exactly one result", outs)
  5833  	} else if outs[0].Type() != TypeOf(V(0)) {
  5834  		t.Fatalf("c.Call[0] is type %v, want %v", outs[0].Type(), TypeOf(V(0)))
  5835  	}
  5836  	f := outs[0].Float()
  5837  	if f != 3.14 {
  5838  		t.Errorf("constructed func returned %f, want %f", f, 3.14)
  5839  	}
  5840  
  5841  	// check that types already in binary are found
  5842  	type T1 int
  5843  	testCases := []struct {
  5844  		in, out  []Type
  5845  		variadic bool
  5846  		want     interface{}
  5847  	}{
  5848  		{in: []Type{TypeOf(T1(0))}, want: (func(T1))(nil)},
  5849  		{in: []Type{TypeOf(int(0))}, want: (func(int))(nil)},
  5850  		{in: []Type{SliceOf(TypeOf(int(0)))}, variadic: true, want: (func(...int))(nil)},
  5851  		{in: []Type{TypeOf(int(0))}, out: []Type{TypeOf(false)}, want: (func(int) bool)(nil)},
  5852  		{in: []Type{TypeOf(int(0))}, out: []Type{TypeOf(false), TypeOf("")}, want: (func(int) (bool, string))(nil)},
  5853  	}
  5854  	for _, tt := range testCases {
  5855  		checkSameType(t, FuncOf(tt.in, tt.out, tt.variadic), tt.want)
  5856  	}
  5857  
  5858  	// check that variadic requires last element be a slice.
  5859  	FuncOf([]Type{TypeOf(1), TypeOf(""), SliceOf(TypeOf(false))}, nil, true)
  5860  	shouldPanic("must be slice", func() { FuncOf([]Type{TypeOf(0), TypeOf(""), TypeOf(false)}, nil, true) })
  5861  	shouldPanic("must be slice", func() { FuncOf(nil, nil, true) })
  5862  }
  5863  
  5864  type B1 struct {
  5865  	X int
  5866  	Y int
  5867  	Z int
  5868  }
  5869  
  5870  func BenchmarkFieldByName1(b *testing.B) {
  5871  	t := TypeOf(B1{})
  5872  	b.RunParallel(func(pb *testing.PB) {
  5873  		for pb.Next() {
  5874  			t.FieldByName("Z")
  5875  		}
  5876  	})
  5877  }
  5878  
  5879  func BenchmarkFieldByName2(b *testing.B) {
  5880  	t := TypeOf(S3{})
  5881  	b.RunParallel(func(pb *testing.PB) {
  5882  		for pb.Next() {
  5883  			t.FieldByName("B")
  5884  		}
  5885  	})
  5886  }
  5887  
  5888  type R0 struct {
  5889  	*R1
  5890  	*R2
  5891  	*R3
  5892  	*R4
  5893  }
  5894  
  5895  type R1 struct {
  5896  	*R5
  5897  	*R6
  5898  	*R7
  5899  	*R8
  5900  }
  5901  
  5902  type R2 R1
  5903  type R3 R1
  5904  type R4 R1
  5905  
  5906  type R5 struct {
  5907  	*R9
  5908  	*R10
  5909  	*R11
  5910  	*R12
  5911  }
  5912  
  5913  type R6 R5
  5914  type R7 R5
  5915  type R8 R5
  5916  
  5917  type R9 struct {
  5918  	*R13
  5919  	*R14
  5920  	*R15
  5921  	*R16
  5922  }
  5923  
  5924  type R10 R9
  5925  type R11 R9
  5926  type R12 R9
  5927  
  5928  type R13 struct {
  5929  	*R17
  5930  	*R18
  5931  	*R19
  5932  	*R20
  5933  }
  5934  
  5935  type R14 R13
  5936  type R15 R13
  5937  type R16 R13
  5938  
  5939  type R17 struct {
  5940  	*R21
  5941  	*R22
  5942  	*R23
  5943  	*R24
  5944  }
  5945  
  5946  type R18 R17
  5947  type R19 R17
  5948  type R20 R17
  5949  
  5950  type R21 struct {
  5951  	X int
  5952  }
  5953  
  5954  type R22 R21
  5955  type R23 R21
  5956  type R24 R21
  5957  
  5958  func TestEmbed(t *testing.T) {
  5959  	typ := TypeOf(R0{})
  5960  	f, ok := typ.FieldByName("X")
  5961  	if ok {
  5962  		t.Fatalf(`FieldByName("X") should fail, returned %v`, f.Index)
  5963  	}
  5964  }
  5965  
  5966  func BenchmarkFieldByName3(b *testing.B) {
  5967  	t := TypeOf(R0{})
  5968  	b.RunParallel(func(pb *testing.PB) {
  5969  		for pb.Next() {
  5970  			t.FieldByName("X")
  5971  		}
  5972  	})
  5973  }
  5974  
  5975  type S struct {
  5976  	i1 int64
  5977  	i2 int64
  5978  }
  5979  
  5980  func BenchmarkInterfaceBig(b *testing.B) {
  5981  	v := ValueOf(S{})
  5982  	b.RunParallel(func(pb *testing.PB) {
  5983  		for pb.Next() {
  5984  			v.Interface()
  5985  		}
  5986  	})
  5987  	b.StopTimer()
  5988  }
  5989  
  5990  func TestAllocsInterfaceBig(t *testing.T) {
  5991  	if testing.Short() {
  5992  		t.Skip("skipping malloc count in short mode")
  5993  	}
  5994  	v := ValueOf(S{})
  5995  	if allocs := testing.AllocsPerRun(100, func() { v.Interface() }); allocs > 0 {
  5996  		t.Error("allocs:", allocs)
  5997  	}
  5998  }
  5999  
  6000  func BenchmarkInterfaceSmall(b *testing.B) {
  6001  	v := ValueOf(int64(0))
  6002  	b.RunParallel(func(pb *testing.PB) {
  6003  		for pb.Next() {
  6004  			v.Interface()
  6005  		}
  6006  	})
  6007  }
  6008  
  6009  func TestAllocsInterfaceSmall(t *testing.T) {
  6010  	if testing.Short() {
  6011  		t.Skip("skipping malloc count in short mode")
  6012  	}
  6013  	v := ValueOf(int64(0))
  6014  	if allocs := testing.AllocsPerRun(100, func() { v.Interface() }); allocs > 0 {
  6015  		t.Error("allocs:", allocs)
  6016  	}
  6017  }
  6018  
  6019  // An exhaustive is a mechanism for writing exhaustive or stochastic tests.
  6020  // The basic usage is:
  6021  //
  6022  //	for x.Next() {
  6023  //		... code using x.Maybe() or x.Choice(n) to create test cases ...
  6024  //	}
  6025  //
  6026  // Each iteration of the loop returns a different set of results, until all
  6027  // possible result sets have been explored. It is okay for different code paths
  6028  // to make different method call sequences on x, but there must be no
  6029  // other source of non-determinism in the call sequences.
  6030  //
  6031  // When faced with a new decision, x chooses randomly. Future explorations
  6032  // of that path will choose successive values for the result. Thus, stopping
  6033  // the loop after a fixed number of iterations gives somewhat stochastic
  6034  // testing.
  6035  //
  6036  // Example:
  6037  //
  6038  //	for x.Next() {
  6039  //		v := make([]bool, x.Choose(4))
  6040  //		for i := range v {
  6041  //			v[i] = x.Maybe()
  6042  //		}
  6043  //		fmt.Println(v)
  6044  //	}
  6045  //
  6046  // prints (in some order):
  6047  //
  6048  //	[]
  6049  //	[false]
  6050  //	[true]
  6051  //	[false false]
  6052  //	[false true]
  6053  //	...
  6054  //	[true true]
  6055  //	[false false false]
  6056  //	...
  6057  //	[true true true]
  6058  //	[false false false false]
  6059  //	...
  6060  //	[true true true true]
  6061  //
  6062  type exhaustive struct {
  6063  	r    *rand.Rand
  6064  	pos  int
  6065  	last []choice
  6066  }
  6067  
  6068  type choice struct {
  6069  	off int
  6070  	n   int
  6071  	max int
  6072  }
  6073  
  6074  func (x *exhaustive) Next() bool {
  6075  	if x.r == nil {
  6076  		x.r = rand.New(rand.NewSource(time.Now().UnixNano()))
  6077  	}
  6078  	x.pos = 0
  6079  	if x.last == nil {
  6080  		x.last = []choice{}
  6081  		return true
  6082  	}
  6083  	for i := len(x.last) - 1; i >= 0; i-- {
  6084  		c := &x.last[i]
  6085  		if c.n+1 < c.max {
  6086  			c.n++
  6087  			x.last = x.last[:i+1]
  6088  			return true
  6089  		}
  6090  	}
  6091  	return false
  6092  }
  6093  
  6094  func (x *exhaustive) Choose(max int) int {
  6095  	if x.pos >= len(x.last) {
  6096  		x.last = append(x.last, choice{x.r.Intn(max), 0, max})
  6097  	}
  6098  	c := &x.last[x.pos]
  6099  	x.pos++
  6100  	if c.max != max {
  6101  		panic("inconsistent use of exhaustive tester")
  6102  	}
  6103  	return (c.n + c.off) % max
  6104  }
  6105  
  6106  func (x *exhaustive) Maybe() bool {
  6107  	return x.Choose(2) == 1
  6108  }
  6109  
  6110  func GCFunc(args []Value) []Value {
  6111  	runtime.GC()
  6112  	return []Value{}
  6113  }
  6114  
  6115  func TestReflectFuncTraceback(t *testing.T) {
  6116  	f := MakeFunc(TypeOf(func() {}), GCFunc)
  6117  	f.Call([]Value{})
  6118  }
  6119  
  6120  func TestReflectMethodTraceback(t *testing.T) {
  6121  	p := Point{3, 4}
  6122  	m := ValueOf(p).MethodByName("GCMethod")
  6123  	i := ValueOf(m.Interface()).Call([]Value{ValueOf(5)})[0].Int()
  6124  	if i != 8 {
  6125  		t.Errorf("Call returned %d; want 8", i)
  6126  	}
  6127  }
  6128  
  6129  func TestSmallZero(t *testing.T) {
  6130  	type T [10]byte
  6131  	typ := TypeOf(T{})
  6132  	if allocs := testing.AllocsPerRun(100, func() { Zero(typ) }); allocs > 0 {
  6133  		t.Errorf("Creating small zero values caused %f allocs, want 0", allocs)
  6134  	}
  6135  }
  6136  
  6137  func TestBigZero(t *testing.T) {
  6138  	const size = 1 << 10
  6139  	var v [size]byte
  6140  	z := Zero(ValueOf(v).Type()).Interface().([size]byte)
  6141  	for i := 0; i < size; i++ {
  6142  		if z[i] != 0 {
  6143  			t.Fatalf("Zero object not all zero, index %d", i)
  6144  		}
  6145  	}
  6146  }
  6147  
  6148  func TestZeroSet(t *testing.T) {
  6149  	type T [16]byte
  6150  	type S struct {
  6151  		a uint64
  6152  		T T
  6153  		b uint64
  6154  	}
  6155  	v := S{
  6156  		a: 0xaaaaaaaaaaaaaaaa,
  6157  		T: T{9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9},
  6158  		b: 0xbbbbbbbbbbbbbbbb,
  6159  	}
  6160  	ValueOf(&v).Elem().Field(1).Set(Zero(TypeOf(T{})))
  6161  	if v != (S{
  6162  		a: 0xaaaaaaaaaaaaaaaa,
  6163  		b: 0xbbbbbbbbbbbbbbbb,
  6164  	}) {
  6165  		t.Fatalf("Setting a field to a Zero value didn't work")
  6166  	}
  6167  }
  6168  
  6169  func TestFieldByIndexNil(t *testing.T) {
  6170  	type P struct {
  6171  		F int
  6172  	}
  6173  	type T struct {
  6174  		*P
  6175  	}
  6176  	v := ValueOf(T{})
  6177  
  6178  	v.FieldByName("P") // should be fine
  6179  
  6180  	defer func() {
  6181  		if err := recover(); err == nil {
  6182  			t.Fatalf("no error")
  6183  		} else if !strings.Contains(fmt.Sprint(err), "nil pointer to embedded struct") {
  6184  			t.Fatalf(`err=%q, wanted error containing "nil pointer to embedded struct"`, err)
  6185  		}
  6186  	}()
  6187  	v.FieldByName("F") // should panic
  6188  
  6189  	t.Fatalf("did not panic")
  6190  }
  6191  
  6192  // Given
  6193  //	type Outer struct {
  6194  //		*Inner
  6195  //		...
  6196  //	}
  6197  // the compiler generates the implementation of (*Outer).M dispatching to the embedded Inner.
  6198  // The implementation is logically:
  6199  //	func (p *Outer) M() {
  6200  //		(p.Inner).M()
  6201  //	}
  6202  // but since the only change here is the replacement of one pointer receiver with another,
  6203  // the actual generated code overwrites the original receiver with the p.Inner pointer and
  6204  // then jumps to the M method expecting the *Inner receiver.
  6205  //
  6206  // During reflect.Value.Call, we create an argument frame and the associated data structures
  6207  // to describe it to the garbage collector, populate the frame, call reflect.call to
  6208  // run a function call using that frame, and then copy the results back out of the frame.
  6209  // The reflect.call function does a memmove of the frame structure onto the
  6210  // stack (to set up the inputs), runs the call, and the memmoves the stack back to
  6211  // the frame structure (to preserve the outputs).
  6212  //
  6213  // Originally reflect.call did not distinguish inputs from outputs: both memmoves
  6214  // were for the full stack frame. However, in the case where the called function was
  6215  // one of these wrappers, the rewritten receiver is almost certainly a different type
  6216  // than the original receiver. This is not a problem on the stack, where we use the
  6217  // program counter to determine the type information and understand that
  6218  // during (*Outer).M the receiver is an *Outer while during (*Inner).M the receiver in the same
  6219  // memory word is now an *Inner. But in the statically typed argument frame created
  6220  // by reflect, the receiver is always an *Outer. Copying the modified receiver pointer
  6221  // off the stack into the frame will store an *Inner there, and then if a garbage collection
  6222  // happens to scan that argument frame before it is discarded, it will scan the *Inner
  6223  // memory as if it were an *Outer. If the two have different memory layouts, the
  6224  // collection will interpret the memory incorrectly.
  6225  //
  6226  // One such possible incorrect interpretation is to treat two arbitrary memory words
  6227  // (Inner.P1 and Inner.P2 below) as an interface (Outer.R below). Because interpreting
  6228  // an interface requires dereferencing the itab word, the misinterpretation will try to
  6229  // deference Inner.P1, causing a crash during garbage collection.
  6230  //
  6231  // This came up in a real program in issue 7725.
  6232  
  6233  type Outer struct {
  6234  	*Inner
  6235  	R io.Reader
  6236  }
  6237  
  6238  type Inner struct {
  6239  	X  *Outer
  6240  	P1 uintptr
  6241  	P2 uintptr
  6242  }
  6243  
  6244  func (pi *Inner) M() {
  6245  	// Clear references to pi so that the only way the
  6246  	// garbage collection will find the pointer is in the
  6247  	// argument frame, typed as a *Outer.
  6248  	pi.X.Inner = nil
  6249  
  6250  	// Set up an interface value that will cause a crash.
  6251  	// P1 = 1 is a non-zero, so the interface looks non-nil.
  6252  	// P2 = pi ensures that the data word points into the
  6253  	// allocated heap; if not the collection skips the interface
  6254  	// value as irrelevant, without dereferencing P1.
  6255  	pi.P1 = 1
  6256  	pi.P2 = uintptr(unsafe.Pointer(pi))
  6257  }
  6258  
  6259  func TestCallMethodJump(t *testing.T) {
  6260  	// In reflect.Value.Call, trigger a garbage collection after reflect.call
  6261  	// returns but before the args frame has been discarded.
  6262  	// This is a little clumsy but makes the failure repeatable.
  6263  	*CallGC = true
  6264  
  6265  	p := &Outer{Inner: new(Inner)}
  6266  	p.Inner.X = p
  6267  	ValueOf(p).Method(0).Call(nil)
  6268  
  6269  	// Stop garbage collecting during reflect.call.
  6270  	*CallGC = false
  6271  }
  6272  
  6273  func TestCallArgLive(t *testing.T) {
  6274  	type T struct{ X, Y *string } // pointerful aggregate
  6275  
  6276  	F := func(t T) { *t.X = "ok" }
  6277  
  6278  	// In reflect.Value.Call, trigger a garbage collection in reflect.call
  6279  	// between marshaling argument and the actual call.
  6280  	*CallGC = true
  6281  
  6282  	x := new(string)
  6283  	runtime.SetFinalizer(x, func(p *string) {
  6284  		if *p != "ok" {
  6285  			t.Errorf("x dead prematurely")
  6286  		}
  6287  	})
  6288  	v := T{x, nil}
  6289  
  6290  	ValueOf(F).Call([]Value{ValueOf(v)})
  6291  
  6292  	// Stop garbage collecting during reflect.call.
  6293  	*CallGC = false
  6294  }
  6295  
  6296  func TestMakeFuncStackCopy(t *testing.T) {
  6297  	target := func(in []Value) []Value {
  6298  		runtime.GC()
  6299  		useStack(16)
  6300  		return []Value{ValueOf(9)}
  6301  	}
  6302  
  6303  	var concrete func(*int, int) int
  6304  	fn := MakeFunc(ValueOf(concrete).Type(), target)
  6305  	ValueOf(&concrete).Elem().Set(fn)
  6306  	x := concrete(nil, 7)
  6307  	if x != 9 {
  6308  		t.Errorf("have %#q want 9", x)
  6309  	}
  6310  }
  6311  
  6312  // use about n KB of stack
  6313  func useStack(n int) {
  6314  	if n == 0 {
  6315  		return
  6316  	}
  6317  	var b [1024]byte // makes frame about 1KB
  6318  	useStack(n - 1 + int(b[99]))
  6319  }
  6320  
  6321  type Impl struct{}
  6322  
  6323  func (Impl) F() {}
  6324  
  6325  func TestValueString(t *testing.T) {
  6326  	rv := ValueOf(Impl{})
  6327  	if rv.String() != "<reflect_test.Impl Value>" {
  6328  		t.Errorf("ValueOf(Impl{}).String() = %q, want %q", rv.String(), "<reflect_test.Impl Value>")
  6329  	}
  6330  
  6331  	method := rv.Method(0)
  6332  	if method.String() != "<func() Value>" {
  6333  		t.Errorf("ValueOf(Impl{}).Method(0).String() = %q, want %q", method.String(), "<func() Value>")
  6334  	}
  6335  }
  6336  
  6337  func TestInvalid(t *testing.T) {
  6338  	// Used to have inconsistency between IsValid() and Kind() != Invalid.
  6339  	type T struct{ v interface{} }
  6340  
  6341  	v := ValueOf(T{}).Field(0)
  6342  	if v.IsValid() != true || v.Kind() != Interface {
  6343  		t.Errorf("field: IsValid=%v, Kind=%v, want true, Interface", v.IsValid(), v.Kind())
  6344  	}
  6345  	v = v.Elem()
  6346  	if v.IsValid() != false || v.Kind() != Invalid {
  6347  		t.Errorf("field elem: IsValid=%v, Kind=%v, want false, Invalid", v.IsValid(), v.Kind())
  6348  	}
  6349  }
  6350  
  6351  // Issue 8917.
  6352  func TestLargeGCProg(t *testing.T) {
  6353  	fv := ValueOf(func([256]*byte) {})
  6354  	fv.Call([]Value{ValueOf([256]*byte{})})
  6355  }
  6356  
  6357  func fieldIndexRecover(t Type, i int) (recovered interface{}) {
  6358  	defer func() {
  6359  		recovered = recover()
  6360  	}()
  6361  
  6362  	t.Field(i)
  6363  	return
  6364  }
  6365  
  6366  // Issue 15046.
  6367  func TestTypeFieldOutOfRangePanic(t *testing.T) {
  6368  	typ := TypeOf(struct{ X int }{10})
  6369  	testIndices := [...]struct {
  6370  		i         int
  6371  		mustPanic bool
  6372  	}{
  6373  		0: {-2, true},
  6374  		1: {0, false},
  6375  		2: {1, true},
  6376  		3: {1 << 10, true},
  6377  	}
  6378  	for i, tt := range testIndices {
  6379  		recoveredErr := fieldIndexRecover(typ, tt.i)
  6380  		if tt.mustPanic {
  6381  			if recoveredErr == nil {
  6382  				t.Errorf("#%d: fieldIndex %d expected to panic", i, tt.i)
  6383  			}
  6384  		} else {
  6385  			if recoveredErr != nil {
  6386  				t.Errorf("#%d: got err=%v, expected no panic", i, recoveredErr)
  6387  			}
  6388  		}
  6389  	}
  6390  }
  6391  
  6392  // Issue 9179.
  6393  func TestCallGC(t *testing.T) {
  6394  	f := func(a, b, c, d, e string) {
  6395  	}
  6396  	g := func(in []Value) []Value {
  6397  		runtime.GC()
  6398  		return nil
  6399  	}
  6400  	typ := ValueOf(f).Type()
  6401  	f2 := MakeFunc(typ, g).Interface().(func(string, string, string, string, string))
  6402  	f2("four", "five5", "six666", "seven77", "eight888")
  6403  }
  6404  
  6405  // Issue 18635 (function version).
  6406  func TestKeepFuncLive(t *testing.T) {
  6407  	// Test that we keep makeFuncImpl live as long as it is
  6408  	// referenced on the stack.
  6409  	typ := TypeOf(func(i int) {})
  6410  	var f, g func(in []Value) []Value
  6411  	f = func(in []Value) []Value {
  6412  		clobber()
  6413  		i := int(in[0].Int())
  6414  		if i > 0 {
  6415  			// We can't use Value.Call here because
  6416  			// runtime.call* will keep the makeFuncImpl
  6417  			// alive. However, by converting it to an
  6418  			// interface value and calling that,
  6419  			// reflect.callReflect is the only thing that
  6420  			// can keep the makeFuncImpl live.
  6421  			//
  6422  			// Alternate between f and g so that if we do
  6423  			// reuse the memory prematurely it's more
  6424  			// likely to get obviously corrupted.
  6425  			MakeFunc(typ, g).Interface().(func(i int))(i - 1)
  6426  		}
  6427  		return nil
  6428  	}
  6429  	g = func(in []Value) []Value {
  6430  		clobber()
  6431  		i := int(in[0].Int())
  6432  		MakeFunc(typ, f).Interface().(func(i int))(i)
  6433  		return nil
  6434  	}
  6435  	MakeFunc(typ, f).Call([]Value{ValueOf(10)})
  6436  }
  6437  
  6438  type UnExportedFirst int
  6439  
  6440  func (i UnExportedFirst) ΦExported()  {}
  6441  func (i UnExportedFirst) unexported() {}
  6442  
  6443  // Issue 21177
  6444  func TestMethodByNameUnExportedFirst(t *testing.T) {
  6445  	defer func() {
  6446  		if recover() != nil {
  6447  			t.Errorf("should not panic")
  6448  		}
  6449  	}()
  6450  	typ := TypeOf(UnExportedFirst(0))
  6451  	m, _ := typ.MethodByName("ΦExported")
  6452  	if m.Name != "ΦExported" {
  6453  		t.Errorf("got %s, expected ΦExported", m.Name)
  6454  	}
  6455  }
  6456  
  6457  // Issue 18635 (method version).
  6458  type KeepMethodLive struct{}
  6459  
  6460  func (k KeepMethodLive) Method1(i int) {
  6461  	clobber()
  6462  	if i > 0 {
  6463  		ValueOf(k).MethodByName("Method2").Interface().(func(i int))(i - 1)
  6464  	}
  6465  }
  6466  
  6467  func (k KeepMethodLive) Method2(i int) {
  6468  	clobber()
  6469  	ValueOf(k).MethodByName("Method1").Interface().(func(i int))(i)
  6470  }
  6471  
  6472  func TestKeepMethodLive(t *testing.T) {
  6473  	// Test that we keep methodValue live as long as it is
  6474  	// referenced on the stack.
  6475  	KeepMethodLive{}.Method1(10)
  6476  }
  6477  
  6478  // clobber tries to clobber unreachable memory.
  6479  func clobber() {
  6480  	runtime.GC()
  6481  	for i := 1; i < 32; i++ {
  6482  		for j := 0; j < 10; j++ {
  6483  			obj := make([]*byte, i)
  6484  			sink = obj
  6485  		}
  6486  	}
  6487  	runtime.GC()
  6488  }
  6489  
  6490  func TestFuncLayout(t *testing.T) {
  6491  	align := func(x uintptr) uintptr {
  6492  		return (x + PtrSize - 1) &^ (PtrSize - 1)
  6493  	}
  6494  	var r []byte
  6495  	if PtrSize == 4 {
  6496  		r = []byte{0, 0, 0, 1}
  6497  	} else {
  6498  		r = []byte{0, 0, 1}
  6499  	}
  6500  
  6501  	type S struct {
  6502  		a, b uintptr
  6503  		c, d *byte
  6504  	}
  6505  
  6506  	type test struct {
  6507  		rcvr, typ                  Type
  6508  		size, argsize, retOffset   uintptr
  6509  		stack, gc, inRegs, outRegs []byte // pointer bitmap: 1 is pointer, 0 is scalar
  6510  		intRegs, floatRegs         int
  6511  		floatRegSize               uintptr
  6512  	}
  6513  	tests := []test{
  6514  		{
  6515  			typ:       ValueOf(func(a, b string) string { return "" }).Type(),
  6516  			size:      6 * PtrSize,
  6517  			argsize:   4 * PtrSize,
  6518  			retOffset: 4 * PtrSize,
  6519  			stack:     []byte{1, 0, 1, 0, 1},
  6520  			gc:        []byte{1, 0, 1, 0, 1},
  6521  		},
  6522  		{
  6523  			typ:       ValueOf(func(a, b, c uint32, p *byte, d uint16) {}).Type(),
  6524  			size:      align(align(3*4) + PtrSize + 2),
  6525  			argsize:   align(3*4) + PtrSize + 2,
  6526  			retOffset: align(align(3*4) + PtrSize + 2),
  6527  			stack:     r,
  6528  			gc:        r,
  6529  		},
  6530  		{
  6531  			typ:       ValueOf(func(a map[int]int, b uintptr, c interface{}) {}).Type(),
  6532  			size:      4 * PtrSize,
  6533  			argsize:   4 * PtrSize,
  6534  			retOffset: 4 * PtrSize,
  6535  			stack:     []byte{1, 0, 1, 1},
  6536  			gc:        []byte{1, 0, 1, 1},
  6537  		},
  6538  		{
  6539  			typ:       ValueOf(func(a S) {}).Type(),
  6540  			size:      4 * PtrSize,
  6541  			argsize:   4 * PtrSize,
  6542  			retOffset: 4 * PtrSize,
  6543  			stack:     []byte{0, 0, 1, 1},
  6544  			gc:        []byte{0, 0, 1, 1},
  6545  		},
  6546  		{
  6547  			rcvr:      ValueOf((*byte)(nil)).Type(),
  6548  			typ:       ValueOf(func(a uintptr, b *int) {}).Type(),
  6549  			size:      3 * PtrSize,
  6550  			argsize:   3 * PtrSize,
  6551  			retOffset: 3 * PtrSize,
  6552  			stack:     []byte{1, 0, 1},
  6553  			gc:        []byte{1, 0, 1},
  6554  		},
  6555  		{
  6556  			typ:       ValueOf(func(a uintptr) {}).Type(),
  6557  			size:      PtrSize,
  6558  			argsize:   PtrSize,
  6559  			retOffset: PtrSize,
  6560  			stack:     []byte{},
  6561  			gc:        []byte{},
  6562  		},
  6563  		{
  6564  			typ:       ValueOf(func() uintptr { return 0 }).Type(),
  6565  			size:      PtrSize,
  6566  			argsize:   0,
  6567  			retOffset: 0,
  6568  			stack:     []byte{},
  6569  			gc:        []byte{},
  6570  		},
  6571  		{
  6572  			rcvr:      ValueOf(uintptr(0)).Type(),
  6573  			typ:       ValueOf(func(a uintptr) {}).Type(),
  6574  			size:      2 * PtrSize,
  6575  			argsize:   2 * PtrSize,
  6576  			retOffset: 2 * PtrSize,
  6577  			stack:     []byte{1},
  6578  			gc:        []byte{1},
  6579  			// Note: this one is tricky, as the receiver is not a pointer. But we
  6580  			// pass the receiver by reference to the autogenerated pointer-receiver
  6581  			// version of the function.
  6582  		},
  6583  		// TODO(mknyszek): Add tests for non-zero register count.
  6584  	}
  6585  	for _, lt := range tests {
  6586  		name := lt.typ.String()
  6587  		if lt.rcvr != nil {
  6588  			name = lt.rcvr.String() + "." + name
  6589  		}
  6590  		t.Run(name, func(t *testing.T) {
  6591  			defer SetArgRegs(SetArgRegs(lt.intRegs, lt.floatRegs, lt.floatRegSize))
  6592  
  6593  			typ, argsize, retOffset, stack, gc, inRegs, outRegs, ptrs := FuncLayout(lt.typ, lt.rcvr)
  6594  			if typ.Size() != lt.size {
  6595  				t.Errorf("funcLayout(%v, %v).size=%d, want %d", lt.typ, lt.rcvr, typ.Size(), lt.size)
  6596  			}
  6597  			if argsize != lt.argsize {
  6598  				t.Errorf("funcLayout(%v, %v).argsize=%d, want %d", lt.typ, lt.rcvr, argsize, lt.argsize)
  6599  			}
  6600  			if retOffset != lt.retOffset {
  6601  				t.Errorf("funcLayout(%v, %v).retOffset=%d, want %d", lt.typ, lt.rcvr, retOffset, lt.retOffset)
  6602  			}
  6603  			if !bytes.Equal(stack, lt.stack) {
  6604  				t.Errorf("funcLayout(%v, %v).stack=%v, want %v", lt.typ, lt.rcvr, stack, lt.stack)
  6605  			}
  6606  			if !bytes.Equal(gc, lt.gc) {
  6607  				t.Errorf("funcLayout(%v, %v).gc=%v, want %v", lt.typ, lt.rcvr, gc, lt.gc)
  6608  			}
  6609  			if !bytes.Equal(inRegs, lt.inRegs) {
  6610  				t.Errorf("funcLayout(%v, %v).inRegs=%v, want %v", lt.typ, lt.rcvr, inRegs, lt.inRegs)
  6611  			}
  6612  			if !bytes.Equal(outRegs, lt.outRegs) {
  6613  				t.Errorf("funcLayout(%v, %v).outRegs=%v, want %v", lt.typ, lt.rcvr, outRegs, lt.outRegs)
  6614  			}
  6615  			if ptrs && len(stack) == 0 || !ptrs && len(stack) > 0 {
  6616  				t.Errorf("funcLayout(%v, %v) pointers flag=%v, want %v", lt.typ, lt.rcvr, ptrs, !ptrs)
  6617  			}
  6618  		})
  6619  	}
  6620  }
  6621  
  6622  func verifyGCBits(t *testing.T, typ Type, bits []byte) {
  6623  	heapBits := GCBits(New(typ).Interface())
  6624  	if !bytes.Equal(heapBits, bits) {
  6625  		_, _, line, _ := runtime.Caller(1)
  6626  		t.Errorf("line %d: heapBits incorrect for %v\nhave %v\nwant %v", line, typ, heapBits, bits)
  6627  	}
  6628  }
  6629  
  6630  func verifyGCBitsSlice(t *testing.T, typ Type, cap int, bits []byte) {
  6631  	// Creating a slice causes the runtime to repeat a bitmap,
  6632  	// which exercises a different path from making the compiler
  6633  	// repeat a bitmap for a small array or executing a repeat in
  6634  	// a GC program.
  6635  	val := MakeSlice(typ, 0, cap)
  6636  	data := NewAt(ArrayOf(cap, typ), unsafe.Pointer(val.Pointer()))
  6637  	heapBits := GCBits(data.Interface())
  6638  	// Repeat the bitmap for the slice size, trimming scalars in
  6639  	// the last element.
  6640  	bits = rep(cap, bits)
  6641  	for len(bits) > 0 && bits[len(bits)-1] == 0 {
  6642  		bits = bits[:len(bits)-1]
  6643  	}
  6644  	if !bytes.Equal(heapBits, bits) {
  6645  		t.Errorf("heapBits incorrect for make(%v, 0, %v)\nhave %v\nwant %v", typ, cap, heapBits, bits)
  6646  	}
  6647  }
  6648  
  6649  func TestGCBits(t *testing.T) {
  6650  	verifyGCBits(t, TypeOf((*byte)(nil)), []byte{1})
  6651  
  6652  	// Building blocks for types seen by the compiler (like [2]Xscalar).
  6653  	// The compiler will create the type structures for the derived types,
  6654  	// including their GC metadata.
  6655  	type Xscalar struct{ x uintptr }
  6656  	type Xptr struct{ x *byte }
  6657  	type Xptrscalar struct {
  6658  		*byte
  6659  		uintptr
  6660  	}
  6661  	type Xscalarptr struct {
  6662  		uintptr
  6663  		*byte
  6664  	}
  6665  	type Xbigptrscalar struct {
  6666  		_ [100]*byte
  6667  		_ [100]uintptr
  6668  	}
  6669  
  6670  	var Tscalar, Tint64, Tptr, Tscalarptr, Tptrscalar, Tbigptrscalar Type
  6671  	{
  6672  		// Building blocks for types constructed by reflect.
  6673  		// This code is in a separate block so that code below
  6674  		// cannot accidentally refer to these.
  6675  		// The compiler must NOT see types derived from these
  6676  		// (for example, [2]Scalar must NOT appear in the program),
  6677  		// or else reflect will use it instead of having to construct one.
  6678  		// The goal is to test the construction.
  6679  		type Scalar struct{ x uintptr }
  6680  		type Ptr struct{ x *byte }
  6681  		type Ptrscalar struct {
  6682  			*byte
  6683  			uintptr
  6684  		}
  6685  		type Scalarptr struct {
  6686  			uintptr
  6687  			*byte
  6688  		}
  6689  		type Bigptrscalar struct {
  6690  			_ [100]*byte
  6691  			_ [100]uintptr
  6692  		}
  6693  		type Int64 int64
  6694  		Tscalar = TypeOf(Scalar{})
  6695  		Tint64 = TypeOf(Int64(0))
  6696  		Tptr = TypeOf(Ptr{})
  6697  		Tscalarptr = TypeOf(Scalarptr{})
  6698  		Tptrscalar = TypeOf(Ptrscalar{})
  6699  		Tbigptrscalar = TypeOf(Bigptrscalar{})
  6700  	}
  6701  
  6702  	empty := []byte{}
  6703  
  6704  	verifyGCBits(t, TypeOf(Xscalar{}), empty)
  6705  	verifyGCBits(t, Tscalar, empty)
  6706  	verifyGCBits(t, TypeOf(Xptr{}), lit(1))
  6707  	verifyGCBits(t, Tptr, lit(1))
  6708  	verifyGCBits(t, TypeOf(Xscalarptr{}), lit(0, 1))
  6709  	verifyGCBits(t, Tscalarptr, lit(0, 1))
  6710  	verifyGCBits(t, TypeOf(Xptrscalar{}), lit(1))
  6711  	verifyGCBits(t, Tptrscalar, lit(1))
  6712  
  6713  	verifyGCBits(t, TypeOf([0]Xptr{}), empty)
  6714  	verifyGCBits(t, ArrayOf(0, Tptr), empty)
  6715  	verifyGCBits(t, TypeOf([1]Xptrscalar{}), lit(1))
  6716  	verifyGCBits(t, ArrayOf(1, Tptrscalar), lit(1))
  6717  	verifyGCBits(t, TypeOf([2]Xscalar{}), empty)
  6718  	verifyGCBits(t, ArrayOf(2, Tscalar), empty)
  6719  	verifyGCBits(t, TypeOf([10000]Xscalar{}), empty)
  6720  	verifyGCBits(t, ArrayOf(10000, Tscalar), empty)
  6721  	verifyGCBits(t, TypeOf([2]Xptr{}), lit(1, 1))
  6722  	verifyGCBits(t, ArrayOf(2, Tptr), lit(1, 1))
  6723  	verifyGCBits(t, TypeOf([10000]Xptr{}), rep(10000, lit(1)))
  6724  	verifyGCBits(t, ArrayOf(10000, Tptr), rep(10000, lit(1)))
  6725  	verifyGCBits(t, TypeOf([2]Xscalarptr{}), lit(0, 1, 0, 1))
  6726  	verifyGCBits(t, ArrayOf(2, Tscalarptr), lit(0, 1, 0, 1))
  6727  	verifyGCBits(t, TypeOf([10000]Xscalarptr{}), rep(10000, lit(0, 1)))
  6728  	verifyGCBits(t, ArrayOf(10000, Tscalarptr), rep(10000, lit(0, 1)))
  6729  	verifyGCBits(t, TypeOf([2]Xptrscalar{}), lit(1, 0, 1))
  6730  	verifyGCBits(t, ArrayOf(2, Tptrscalar), lit(1, 0, 1))
  6731  	verifyGCBits(t, TypeOf([10000]Xptrscalar{}), rep(10000, lit(1, 0)))
  6732  	verifyGCBits(t, ArrayOf(10000, Tptrscalar), rep(10000, lit(1, 0)))
  6733  	verifyGCBits(t, TypeOf([1][10000]Xptrscalar{}), rep(10000, lit(1, 0)))
  6734  	verifyGCBits(t, ArrayOf(1, ArrayOf(10000, Tptrscalar)), rep(10000, lit(1, 0)))
  6735  	verifyGCBits(t, TypeOf([2][10000]Xptrscalar{}), rep(2*10000, lit(1, 0)))
  6736  	verifyGCBits(t, ArrayOf(2, ArrayOf(10000, Tptrscalar)), rep(2*10000, lit(1, 0)))
  6737  	verifyGCBits(t, TypeOf([4]Xbigptrscalar{}), join(rep(3, join(rep(100, lit(1)), rep(100, lit(0)))), rep(100, lit(1))))
  6738  	verifyGCBits(t, ArrayOf(4, Tbigptrscalar), join(rep(3, join(rep(100, lit(1)), rep(100, lit(0)))), rep(100, lit(1))))
  6739  
  6740  	verifyGCBitsSlice(t, TypeOf([]Xptr{}), 0, empty)
  6741  	verifyGCBitsSlice(t, SliceOf(Tptr), 0, empty)
  6742  	verifyGCBitsSlice(t, TypeOf([]Xptrscalar{}), 1, lit(1))
  6743  	verifyGCBitsSlice(t, SliceOf(Tptrscalar), 1, lit(1))
  6744  	verifyGCBitsSlice(t, TypeOf([]Xscalar{}), 2, lit(0))
  6745  	verifyGCBitsSlice(t, SliceOf(Tscalar), 2, lit(0))
  6746  	verifyGCBitsSlice(t, TypeOf([]Xscalar{}), 10000, lit(0))
  6747  	verifyGCBitsSlice(t, SliceOf(Tscalar), 10000, lit(0))
  6748  	verifyGCBitsSlice(t, TypeOf([]Xptr{}), 2, lit(1))
  6749  	verifyGCBitsSlice(t, SliceOf(Tptr), 2, lit(1))
  6750  	verifyGCBitsSlice(t, TypeOf([]Xptr{}), 10000, lit(1))
  6751  	verifyGCBitsSlice(t, SliceOf(Tptr), 10000, lit(1))
  6752  	verifyGCBitsSlice(t, TypeOf([]Xscalarptr{}), 2, lit(0, 1))
  6753  	verifyGCBitsSlice(t, SliceOf(Tscalarptr), 2, lit(0, 1))
  6754  	verifyGCBitsSlice(t, TypeOf([]Xscalarptr{}), 10000, lit(0, 1))
  6755  	verifyGCBitsSlice(t, SliceOf(Tscalarptr), 10000, lit(0, 1))
  6756  	verifyGCBitsSlice(t, TypeOf([]Xptrscalar{}), 2, lit(1, 0))
  6757  	verifyGCBitsSlice(t, SliceOf(Tptrscalar), 2, lit(1, 0))
  6758  	verifyGCBitsSlice(t, TypeOf([]Xptrscalar{}), 10000, lit(1, 0))
  6759  	verifyGCBitsSlice(t, SliceOf(Tptrscalar), 10000, lit(1, 0))
  6760  	verifyGCBitsSlice(t, TypeOf([][10000]Xptrscalar{}), 1, rep(10000, lit(1, 0)))
  6761  	verifyGCBitsSlice(t, SliceOf(ArrayOf(10000, Tptrscalar)), 1, rep(10000, lit(1, 0)))
  6762  	verifyGCBitsSlice(t, TypeOf([][10000]Xptrscalar{}), 2, rep(10000, lit(1, 0)))
  6763  	verifyGCBitsSlice(t, SliceOf(ArrayOf(10000, Tptrscalar)), 2, rep(10000, lit(1, 0)))
  6764  	verifyGCBitsSlice(t, TypeOf([]Xbigptrscalar{}), 4, join(rep(100, lit(1)), rep(100, lit(0))))
  6765  	verifyGCBitsSlice(t, SliceOf(Tbigptrscalar), 4, join(rep(100, lit(1)), rep(100, lit(0))))
  6766  
  6767  	verifyGCBits(t, TypeOf((chan [100]Xscalar)(nil)), lit(1))
  6768  	verifyGCBits(t, ChanOf(BothDir, ArrayOf(100, Tscalar)), lit(1))
  6769  
  6770  	verifyGCBits(t, TypeOf((func([10000]Xscalarptr))(nil)), lit(1))
  6771  	verifyGCBits(t, FuncOf([]Type{ArrayOf(10000, Tscalarptr)}, nil, false), lit(1))
  6772  
  6773  	verifyGCBits(t, TypeOf((map[[10000]Xscalarptr]Xscalar)(nil)), lit(1))
  6774  	verifyGCBits(t, MapOf(ArrayOf(10000, Tscalarptr), Tscalar), lit(1))
  6775  
  6776  	verifyGCBits(t, TypeOf((*[10000]Xscalar)(nil)), lit(1))
  6777  	verifyGCBits(t, PtrTo(ArrayOf(10000, Tscalar)), lit(1))
  6778  
  6779  	verifyGCBits(t, TypeOf(([][10000]Xscalar)(nil)), lit(1))
  6780  	verifyGCBits(t, SliceOf(ArrayOf(10000, Tscalar)), lit(1))
  6781  
  6782  	hdr := make([]byte, 8/PtrSize)
  6783  
  6784  	verifyMapBucket := func(t *testing.T, k, e Type, m interface{}, want []byte) {
  6785  		verifyGCBits(t, MapBucketOf(k, e), want)
  6786  		verifyGCBits(t, CachedBucketOf(TypeOf(m)), want)
  6787  	}
  6788  	verifyMapBucket(t,
  6789  		Tscalar, Tptr,
  6790  		map[Xscalar]Xptr(nil),
  6791  		join(hdr, rep(8, lit(0)), rep(8, lit(1)), lit(1)))
  6792  	verifyMapBucket(t,
  6793  		Tscalarptr, Tptr,
  6794  		map[Xscalarptr]Xptr(nil),
  6795  		join(hdr, rep(8, lit(0, 1)), rep(8, lit(1)), lit(1)))
  6796  	verifyMapBucket(t, Tint64, Tptr,
  6797  		map[int64]Xptr(nil),
  6798  		join(hdr, rep(8, rep(8/PtrSize, lit(0))), rep(8, lit(1)), lit(1)))
  6799  	verifyMapBucket(t,
  6800  		Tscalar, Tscalar,
  6801  		map[Xscalar]Xscalar(nil),
  6802  		empty)
  6803  	verifyMapBucket(t,
  6804  		ArrayOf(2, Tscalarptr), ArrayOf(3, Tptrscalar),
  6805  		map[[2]Xscalarptr][3]Xptrscalar(nil),
  6806  		join(hdr, rep(8*2, lit(0, 1)), rep(8*3, lit(1, 0)), lit(1)))
  6807  	verifyMapBucket(t,
  6808  		ArrayOf(64/PtrSize, Tscalarptr), ArrayOf(64/PtrSize, Tptrscalar),
  6809  		map[[64 / PtrSize]Xscalarptr][64 / PtrSize]Xptrscalar(nil),
  6810  		join(hdr, rep(8*64/PtrSize, lit(0, 1)), rep(8*64/PtrSize, lit(1, 0)), lit(1)))
  6811  	verifyMapBucket(t,
  6812  		ArrayOf(64/PtrSize+1, Tscalarptr), ArrayOf(64/PtrSize, Tptrscalar),
  6813  		map[[64/PtrSize + 1]Xscalarptr][64 / PtrSize]Xptrscalar(nil),
  6814  		join(hdr, rep(8, lit(1)), rep(8*64/PtrSize, lit(1, 0)), lit(1)))
  6815  	verifyMapBucket(t,
  6816  		ArrayOf(64/PtrSize, Tscalarptr), ArrayOf(64/PtrSize+1, Tptrscalar),
  6817  		map[[64 / PtrSize]Xscalarptr][64/PtrSize + 1]Xptrscalar(nil),
  6818  		join(hdr, rep(8*64/PtrSize, lit(0, 1)), rep(8, lit(1)), lit(1)))
  6819  	verifyMapBucket(t,
  6820  		ArrayOf(64/PtrSize+1, Tscalarptr), ArrayOf(64/PtrSize+1, Tptrscalar),
  6821  		map[[64/PtrSize + 1]Xscalarptr][64/PtrSize + 1]Xptrscalar(nil),
  6822  		join(hdr, rep(8, lit(1)), rep(8, lit(1)), lit(1)))
  6823  }
  6824  
  6825  func rep(n int, b []byte) []byte { return bytes.Repeat(b, n) }
  6826  func join(b ...[]byte) []byte    { return bytes.Join(b, nil) }
  6827  func lit(x ...byte) []byte       { return x }
  6828  
  6829  func TestTypeOfTypeOf(t *testing.T) {
  6830  	// Check that all the type constructors return concrete *rtype implementations.
  6831  	// It's difficult to test directly because the reflect package is only at arm's length.
  6832  	// The easiest thing to do is just call a function that crashes if it doesn't get an *rtype.
  6833  	check := func(name string, typ Type) {
  6834  		if underlying := TypeOf(typ).String(); underlying != "*reflect.rtype" {
  6835  			t.Errorf("%v returned %v, not *reflect.rtype", name, underlying)
  6836  		}
  6837  	}
  6838  
  6839  	type T struct{ int }
  6840  	check("TypeOf", TypeOf(T{}))
  6841  
  6842  	check("ArrayOf", ArrayOf(10, TypeOf(T{})))
  6843  	check("ChanOf", ChanOf(BothDir, TypeOf(T{})))
  6844  	check("FuncOf", FuncOf([]Type{TypeOf(T{})}, nil, false))
  6845  	check("MapOf", MapOf(TypeOf(T{}), TypeOf(T{})))
  6846  	check("PtrTo", PtrTo(TypeOf(T{})))
  6847  	check("SliceOf", SliceOf(TypeOf(T{})))
  6848  }
  6849  
  6850  type XM struct{ _ bool }
  6851  
  6852  func (*XM) String() string { return "" }
  6853  
  6854  func TestPtrToMethods(t *testing.T) {
  6855  	var y struct{ XM }
  6856  	yp := New(TypeOf(y)).Interface()
  6857  	_, ok := yp.(fmt.Stringer)
  6858  	if !ok {
  6859  		t.Fatal("does not implement Stringer, but should")
  6860  	}
  6861  }
  6862  
  6863  func TestMapAlloc(t *testing.T) {
  6864  	m := ValueOf(make(map[int]int, 10))
  6865  	k := ValueOf(5)
  6866  	v := ValueOf(7)
  6867  	allocs := testing.AllocsPerRun(100, func() {
  6868  		m.SetMapIndex(k, v)
  6869  	})
  6870  	if allocs > 0.5 {
  6871  		t.Errorf("allocs per map assignment: want 0 got %f", allocs)
  6872  	}
  6873  
  6874  	const size = 1000
  6875  	tmp := 0
  6876  	val := ValueOf(&tmp).Elem()
  6877  	allocs = testing.AllocsPerRun(100, func() {
  6878  		mv := MakeMapWithSize(TypeOf(map[int]int{}), size)
  6879  		// Only adding half of the capacity to not trigger re-allocations due too many overloaded buckets.
  6880  		for i := 0; i < size/2; i++ {
  6881  			val.SetInt(int64(i))
  6882  			mv.SetMapIndex(val, val)
  6883  		}
  6884  	})
  6885  	if allocs > 10 {
  6886  		t.Errorf("allocs per map assignment: want at most 10 got %f", allocs)
  6887  	}
  6888  	// Empirical testing shows that with capacity hint single run will trigger 3 allocations and without 91. I set
  6889  	// the threshold to 10, to not make it overly brittle if something changes in the initial allocation of the
  6890  	// map, but to still catch a regression where we keep re-allocating in the hashmap as new entries are added.
  6891  }
  6892  
  6893  func TestChanAlloc(t *testing.T) {
  6894  	// Note: for a chan int, the return Value must be allocated, so we
  6895  	// use a chan *int instead.
  6896  	c := ValueOf(make(chan *int, 1))
  6897  	v := ValueOf(new(int))
  6898  	allocs := testing.AllocsPerRun(100, func() {
  6899  		c.Send(v)
  6900  		_, _ = c.Recv()
  6901  	})
  6902  	if allocs < 0.5 || allocs > 1.5 {
  6903  		t.Errorf("allocs per chan send/recv: want 1 got %f", allocs)
  6904  	}
  6905  	// Note: there is one allocation in reflect.recv which seems to be
  6906  	// a limitation of escape analysis. If that is ever fixed the
  6907  	// allocs < 0.5 condition will trigger and this test should be fixed.
  6908  }
  6909  
  6910  type TheNameOfThisTypeIsExactly255BytesLongSoWhenTheCompilerPrependsTheReflectTestPackageNameAndExtraStarTheLinkerRuntimeAndReflectPackagesWillHaveToCorrectlyDecodeTheSecondLengthByte0123456789_0123456789_0123456789_0123456789_0123456789_012345678 int
  6911  
  6912  type nameTest struct {
  6913  	v    interface{}
  6914  	want string
  6915  }
  6916  
  6917  var nameTests = []nameTest{
  6918  	{(*int32)(nil), "int32"},
  6919  	{(*D1)(nil), "D1"},
  6920  	{(*[]D1)(nil), ""},
  6921  	{(*chan D1)(nil), ""},
  6922  	{(*func() D1)(nil), ""},
  6923  	{(*<-chan D1)(nil), ""},
  6924  	{(*chan<- D1)(nil), ""},
  6925  	{(*interface{})(nil), ""},
  6926  	{(*interface {
  6927  		F()
  6928  	})(nil), ""},
  6929  	{(*TheNameOfThisTypeIsExactly255BytesLongSoWhenTheCompilerPrependsTheReflectTestPackageNameAndExtraStarTheLinkerRuntimeAndReflectPackagesWillHaveToCorrectlyDecodeTheSecondLengthByte0123456789_0123456789_0123456789_0123456789_0123456789_012345678)(nil), "TheNameOfThisTypeIsExactly255BytesLongSoWhenTheCompilerPrependsTheReflectTestPackageNameAndExtraStarTheLinkerRuntimeAndReflectPackagesWillHaveToCorrectlyDecodeTheSecondLengthByte0123456789_0123456789_0123456789_0123456789_0123456789_012345678"},
  6930  }
  6931  
  6932  func TestNames(t *testing.T) {
  6933  	for _, test := range nameTests {
  6934  		typ := TypeOf(test.v).Elem()
  6935  		if got := typ.Name(); got != test.want {
  6936  			t.Errorf("%v Name()=%q, want %q", typ, got, test.want)
  6937  		}
  6938  	}
  6939  }
  6940  
  6941  func TestExported(t *testing.T) {
  6942  	type ΦExported struct{}
  6943  	type φUnexported struct{}
  6944  	type BigP *big
  6945  	type P int
  6946  	type p *P
  6947  	type P2 p
  6948  	type p3 p
  6949  
  6950  	type exportTest struct {
  6951  		v    interface{}
  6952  		want bool
  6953  	}
  6954  	exportTests := []exportTest{
  6955  		{D1{}, true},
  6956  		{(*D1)(nil), true},
  6957  		{big{}, false},
  6958  		{(*big)(nil), false},
  6959  		{(BigP)(nil), true},
  6960  		{(*BigP)(nil), true},
  6961  		{ΦExported{}, true},
  6962  		{φUnexported{}, false},
  6963  		{P(0), true},
  6964  		{(p)(nil), false},
  6965  		{(P2)(nil), true},
  6966  		{(p3)(nil), false},
  6967  	}
  6968  
  6969  	for i, test := range exportTests {
  6970  		typ := TypeOf(test.v)
  6971  		if got := IsExported(typ); got != test.want {
  6972  			t.Errorf("%d: %s exported=%v, want %v", i, typ.Name(), got, test.want)
  6973  		}
  6974  	}
  6975  }
  6976  
  6977  func TestTypeStrings(t *testing.T) {
  6978  	type stringTest struct {
  6979  		typ  Type
  6980  		want string
  6981  	}
  6982  	stringTests := []stringTest{
  6983  		{TypeOf(func(int) {}), "func(int)"},
  6984  		{FuncOf([]Type{TypeOf(int(0))}, nil, false), "func(int)"},
  6985  		{TypeOf(XM{}), "reflect_test.XM"},
  6986  		{TypeOf(new(XM)), "*reflect_test.XM"},
  6987  		{TypeOf(new(XM).String), "func() string"},
  6988  		{TypeOf(new(XM)).Method(0).Type, "func(*reflect_test.XM) string"},
  6989  		{ChanOf(3, TypeOf(XM{})), "chan reflect_test.XM"},
  6990  		{MapOf(TypeOf(int(0)), TypeOf(XM{})), "map[int]reflect_test.XM"},
  6991  		{ArrayOf(3, TypeOf(XM{})), "[3]reflect_test.XM"},
  6992  		{ArrayOf(3, TypeOf(struct{}{})), "[3]struct {}"},
  6993  	}
  6994  
  6995  	for i, test := range stringTests {
  6996  		if got, want := test.typ.String(), test.want; got != want {
  6997  			t.Errorf("type %d String()=%q, want %q", i, got, want)
  6998  		}
  6999  	}
  7000  }
  7001  
  7002  func TestOffsetLock(t *testing.T) {
  7003  	var wg sync.WaitGroup
  7004  	for i := 0; i < 4; i++ {
  7005  		i := i
  7006  		wg.Add(1)
  7007  		go func() {
  7008  			for j := 0; j < 50; j++ {
  7009  				ResolveReflectName(fmt.Sprintf("OffsetLockName:%d:%d", i, j))
  7010  			}
  7011  			wg.Done()
  7012  		}()
  7013  	}
  7014  	wg.Wait()
  7015  }
  7016  
  7017  func BenchmarkNew(b *testing.B) {
  7018  	v := TypeOf(XM{})
  7019  	b.RunParallel(func(pb *testing.PB) {
  7020  		for pb.Next() {
  7021  			New(v)
  7022  		}
  7023  	})
  7024  }
  7025  
  7026  func TestSwapper(t *testing.T) {
  7027  	type I int
  7028  	var a, b, c I
  7029  	type pair struct {
  7030  		x, y int
  7031  	}
  7032  	type pairPtr struct {
  7033  		x, y int
  7034  		p    *I
  7035  	}
  7036  	type S string
  7037  
  7038  	tests := []struct {
  7039  		in   interface{}
  7040  		i, j int
  7041  		want interface{}
  7042  	}{
  7043  		{
  7044  			in:   []int{1, 20, 300},
  7045  			i:    0,
  7046  			j:    2,
  7047  			want: []int{300, 20, 1},
  7048  		},
  7049  		{
  7050  			in:   []uintptr{1, 20, 300},
  7051  			i:    0,
  7052  			j:    2,
  7053  			want: []uintptr{300, 20, 1},
  7054  		},
  7055  		{
  7056  			in:   []int16{1, 20, 300},
  7057  			i:    0,
  7058  			j:    2,
  7059  			want: []int16{300, 20, 1},
  7060  		},
  7061  		{
  7062  			in:   []int8{1, 20, 100},
  7063  			i:    0,
  7064  			j:    2,
  7065  			want: []int8{100, 20, 1},
  7066  		},
  7067  		{
  7068  			in:   []*I{&a, &b, &c},
  7069  			i:    0,
  7070  			j:    2,
  7071  			want: []*I{&c, &b, &a},
  7072  		},
  7073  		{
  7074  			in:   []string{"eric", "sergey", "larry"},
  7075  			i:    0,
  7076  			j:    2,
  7077  			want: []string{"larry", "sergey", "eric"},
  7078  		},
  7079  		{
  7080  			in:   []S{"eric", "sergey", "larry"},
  7081  			i:    0,
  7082  			j:    2,
  7083  			want: []S{"larry", "sergey", "eric"},
  7084  		},
  7085  		{
  7086  			in:   []pair{{1, 2}, {3, 4}, {5, 6}},
  7087  			i:    0,
  7088  			j:    2,
  7089  			want: []pair{{5, 6}, {3, 4}, {1, 2}},
  7090  		},
  7091  		{
  7092  			in:   []pairPtr{{1, 2, &a}, {3, 4, &b}, {5, 6, &c}},
  7093  			i:    0,
  7094  			j:    2,
  7095  			want: []pairPtr{{5, 6, &c}, {3, 4, &b}, {1, 2, &a}},
  7096  		},
  7097  	}
  7098  
  7099  	for i, tt := range tests {
  7100  		inStr := fmt.Sprint(tt.in)
  7101  		Swapper(tt.in)(tt.i, tt.j)
  7102  		if !DeepEqual(tt.in, tt.want) {
  7103  			t.Errorf("%d. swapping %v and %v of %v = %v; want %v", i, tt.i, tt.j, inStr, tt.in, tt.want)
  7104  		}
  7105  	}
  7106  }
  7107  
  7108  // TestUnaddressableField tests that the reflect package will not allow
  7109  // a type from another package to be used as a named type with an
  7110  // unexported field.
  7111  //
  7112  // This ensures that unexported fields cannot be modified by other packages.
  7113  func TestUnaddressableField(t *testing.T) {
  7114  	var b Buffer // type defined in reflect, a different package
  7115  	var localBuffer struct {
  7116  		buf []byte
  7117  	}
  7118  	lv := ValueOf(&localBuffer).Elem()
  7119  	rv := ValueOf(b)
  7120  	shouldPanic("Set", func() {
  7121  		lv.Set(rv)
  7122  	})
  7123  }
  7124  
  7125  type Tint int
  7126  
  7127  type Tint2 = Tint
  7128  
  7129  type Talias1 struct {
  7130  	byte
  7131  	uint8
  7132  	int
  7133  	int32
  7134  	rune
  7135  }
  7136  
  7137  type Talias2 struct {
  7138  	Tint
  7139  	Tint2
  7140  }
  7141  
  7142  func TestAliasNames(t *testing.T) {
  7143  	t1 := Talias1{byte: 1, uint8: 2, int: 3, int32: 4, rune: 5}
  7144  	out := fmt.Sprintf("%#v", t1)
  7145  	want := "reflect_test.Talias1{byte:0x1, uint8:0x2, int:3, int32:4, rune:5}"
  7146  	if out != want {
  7147  		t.Errorf("Talias1 print:\nhave: %s\nwant: %s", out, want)
  7148  	}
  7149  
  7150  	t2 := Talias2{Tint: 1, Tint2: 2}
  7151  	out = fmt.Sprintf("%#v", t2)
  7152  	want = "reflect_test.Talias2{Tint:1, Tint2:2}"
  7153  	if out != want {
  7154  		t.Errorf("Talias2 print:\nhave: %s\nwant: %s", out, want)
  7155  	}
  7156  }
  7157  
  7158  func TestIssue22031(t *testing.T) {
  7159  	type s []struct{ C int }
  7160  
  7161  	type t1 struct{ s }
  7162  	type t2 struct{ f s }
  7163  
  7164  	tests := []Value{
  7165  		ValueOf(t1{s{{}}}).Field(0).Index(0).Field(0),
  7166  		ValueOf(t2{s{{}}}).Field(0).Index(0).Field(0),
  7167  	}
  7168  
  7169  	for i, test := range tests {
  7170  		if test.CanSet() {
  7171  			t.Errorf("%d: CanSet: got true, want false", i)
  7172  		}
  7173  	}
  7174  }
  7175  
  7176  type NonExportedFirst int
  7177  
  7178  func (i NonExportedFirst) ΦExported()       {}
  7179  func (i NonExportedFirst) nonexported() int { panic("wrong") }
  7180  
  7181  func TestIssue22073(t *testing.T) {
  7182  	m := ValueOf(NonExportedFirst(0)).Method(0)
  7183  
  7184  	if got := m.Type().NumOut(); got != 0 {
  7185  		t.Errorf("NumOut: got %v, want 0", got)
  7186  	}
  7187  
  7188  	// Shouldn't panic.
  7189  	m.Call(nil)
  7190  }
  7191  
  7192  func TestMapIterNonEmptyMap(t *testing.T) {
  7193  	m := map[string]int{"one": 1, "two": 2, "three": 3}
  7194  	iter := ValueOf(m).MapRange()
  7195  	if got, want := iterateToString(iter), `[one: 1, three: 3, two: 2]`; got != want {
  7196  		t.Errorf("iterator returned %s (after sorting), want %s", got, want)
  7197  	}
  7198  }
  7199  
  7200  func TestMapIterNilMap(t *testing.T) {
  7201  	var m map[string]int
  7202  	iter := ValueOf(m).MapRange()
  7203  	if got, want := iterateToString(iter), `[]`; got != want {
  7204  		t.Errorf("non-empty result iteratoring nil map: %s", got)
  7205  	}
  7206  }
  7207  
  7208  func TestMapIterSafety(t *testing.T) {
  7209  	// Using a zero MapIter causes a panic, but not a crash.
  7210  	func() {
  7211  		defer func() { recover() }()
  7212  		new(MapIter).Key()
  7213  		t.Fatal("Key did not panic")
  7214  	}()
  7215  	func() {
  7216  		defer func() { recover() }()
  7217  		new(MapIter).Value()
  7218  		t.Fatal("Value did not panic")
  7219  	}()
  7220  	func() {
  7221  		defer func() { recover() }()
  7222  		new(MapIter).Next()
  7223  		t.Fatal("Next did not panic")
  7224  	}()
  7225  
  7226  	// Calling Key/Value on a MapIter before Next
  7227  	// causes a panic, but not a crash.
  7228  	var m map[string]int
  7229  	iter := ValueOf(m).MapRange()
  7230  
  7231  	func() {
  7232  		defer func() { recover() }()
  7233  		iter.Key()
  7234  		t.Fatal("Key did not panic")
  7235  	}()
  7236  	func() {
  7237  		defer func() { recover() }()
  7238  		iter.Value()
  7239  		t.Fatal("Value did not panic")
  7240  	}()
  7241  
  7242  	// Calling Next, Key, or Value on an exhausted iterator
  7243  	// causes a panic, but not a crash.
  7244  	iter.Next() // -> false
  7245  	func() {
  7246  		defer func() { recover() }()
  7247  		iter.Key()
  7248  		t.Fatal("Key did not panic")
  7249  	}()
  7250  	func() {
  7251  		defer func() { recover() }()
  7252  		iter.Value()
  7253  		t.Fatal("Value did not panic")
  7254  	}()
  7255  	func() {
  7256  		defer func() { recover() }()
  7257  		iter.Next()
  7258  		t.Fatal("Next did not panic")
  7259  	}()
  7260  }
  7261  
  7262  func TestMapIterNext(t *testing.T) {
  7263  	// The first call to Next should reflect any
  7264  	// insertions to the map since the iterator was created.
  7265  	m := map[string]int{}
  7266  	iter := ValueOf(m).MapRange()
  7267  	m["one"] = 1
  7268  	if got, want := iterateToString(iter), `[one: 1]`; got != want {
  7269  		t.Errorf("iterator returned deleted elements: got %s, want %s", got, want)
  7270  	}
  7271  }
  7272  
  7273  func TestMapIterDelete0(t *testing.T) {
  7274  	// Delete all elements before first iteration.
  7275  	m := map[string]int{"one": 1, "two": 2, "three": 3}
  7276  	iter := ValueOf(m).MapRange()
  7277  	delete(m, "one")
  7278  	delete(m, "two")
  7279  	delete(m, "three")
  7280  	if got, want := iterateToString(iter), `[]`; got != want {
  7281  		t.Errorf("iterator returned deleted elements: got %s, want %s", got, want)
  7282  	}
  7283  }
  7284  
  7285  func TestMapIterDelete1(t *testing.T) {
  7286  	// Delete all elements after first iteration.
  7287  	m := map[string]int{"one": 1, "two": 2, "three": 3}
  7288  	iter := ValueOf(m).MapRange()
  7289  	var got []string
  7290  	for iter.Next() {
  7291  		got = append(got, fmt.Sprint(iter.Key(), iter.Value()))
  7292  		delete(m, "one")
  7293  		delete(m, "two")
  7294  		delete(m, "three")
  7295  	}
  7296  	if len(got) != 1 {
  7297  		t.Errorf("iterator returned wrong number of elements: got %d, want 1", len(got))
  7298  	}
  7299  }
  7300  
  7301  // iterateToString returns the set of elements
  7302  // returned by an iterator in readable form.
  7303  func iterateToString(it *MapIter) string {
  7304  	var got []string
  7305  	for it.Next() {
  7306  		line := fmt.Sprintf("%v: %v", it.Key(), it.Value())
  7307  		got = append(got, line)
  7308  	}
  7309  	sort.Strings(got)
  7310  	return "[" + strings.Join(got, ", ") + "]"
  7311  }
  7312  
  7313  func TestConvertibleTo(t *testing.T) {
  7314  	t1 := ValueOf(example1.MyStruct{}).Type()
  7315  	t2 := ValueOf(example2.MyStruct{}).Type()
  7316  
  7317  	// Shouldn't raise stack overflow
  7318  	if t1.ConvertibleTo(t2) {
  7319  		t.Fatalf("(%s).ConvertibleTo(%s) = true, want false", t1, t2)
  7320  	}
  7321  }
  7322  

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