issue37975.go

     1  // run
     2  
     3  // Copyright 2020 The Go Authors. All rights reserved.
     4  // Use of this source code is governed by a BSD-style
     5  // license that can be found in the LICENSE file.
     6  
     7  // Make sure runtime.panicmakeslice* are called.
     8  
     9  package main
    10  
    11  import "strings"
    12  
    13  func main() {
    14  	// Test typechecking passes if len is valid
    15  	// but cap is out of range for len's type.
    16  	var x byte
    17  	_ = make([]int, x, 300)
    18  
    19  	capOutOfRange := func() {
    20  		i := 2
    21  		s := make([]int, i, 1)
    22  		s[0] = 1
    23  	}
    24  	lenOutOfRange := func() {
    25  		i := -1
    26  		s := make([]int, i, 3)
    27  		s[0] = 1
    28  	}
    29  
    30  	tests := []struct {
    31  		f        func()
    32  		panicStr string
    33  	}{
    34  		{capOutOfRange, "cap out of range"},
    35  		{lenOutOfRange, "len out of range"},
    36  	}
    37  
    38  	for _, tc := range tests {
    39  		shouldPanic(tc.panicStr, tc.f)
    40  	}
    41  
    42  }
    43  
    44  func shouldPanic(str string, f func()) {
    45  	defer func() {
    46  		err := recover()
    47  		runtimeErr := err.(error).Error()
    48  		if !strings.Contains(runtimeErr, str) {
    49  			panic("got panic " + runtimeErr + ", want " + str)
    50  		}
    51  	}()
    52  
    53  	f()
    54  }
    55
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