eface.go

     1  // run
     2  
     3  // Copyright 2021 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 we handle instantiated empty interfaces.
     8  
     9  package main
    10  
    11  type E[T any] interface {
    12  }
    13  
    14  //go:noinline
    15  func f[T any](x E[T]) interface{} {
    16  	return x
    17  }
    18  
    19  //go:noinline
    20  func g[T any](x interface{}) E[T] {
    21  	return x
    22  }
    23  
    24  type I[T any] interface {
    25  	foo()
    26  }
    27  
    28  type myint int
    29  
    30  func (x myint) foo() {}
    31  
    32  //go:noinline
    33  func h[T any](x I[T]) interface{ foo() } {
    34  	return x
    35  }
    36  
    37  //go:noinline
    38  func i[T any](x interface{ foo() }) I[T] {
    39  	return x
    40  }
    41  
    42  func main() {
    43  	if f[int](1) != 1 {
    44  		println("test 1 failed")
    45  	}
    46  	if f[int](2) != (interface{})(2) {
    47  		println("test 2 failed")
    48  	}
    49  	if g[int](3) != 3 {
    50  		println("test 3 failed")
    51  	}
    52  	if g[int](4) != (E[int])(4) {
    53  		println("test 4 failed")
    54  	}
    55  	if h[int](myint(5)) != myint(5) {
    56  		println("test 5 failed")
    57  	}
    58  	if h[int](myint(6)) != interface{ foo() }(myint(6)) {
    59  		println("test 6 failed")
    60  	}
    61  	if i[int](myint(7)) != myint(7) {
    62  		println("test 7 failed")
    63  	}
    64  	if i[int](myint(8)) != I[int](myint(8)) {
    65  		println("test 8 failed")
    66  	}
    67  }
    68
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