issue66751.go

     1  // Copyright 2024 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 p
     6  
     7  type S struct{}
     8  
     9  func (*S) m(int) {}
    10  
    11  func f[A interface {
    12  	~*B
    13  	m(C)
    14  }, B, C any]() {
    15  }
    16  
    17  var _ = f[*S] // must be able to infer all remaining type arguments
    18  
    19  // original test case from issue
    20  
    21  type ptrTo[A any] interface{ ~*A }
    22  type hasFoo[A any] interface{ foo(A) }
    23  type both[A, B any] interface {
    24  	ptrTo[A]
    25  	hasFoo[B]
    26  }
    27  
    28  type fooer[A any] struct{}
    29  
    30  func (f *fooer[A]) foo(A) {}
    31  
    32  func withPtr[A ptrTo[B], B any]()       {}
    33  func withFoo[A hasFoo[B], B any]()      {}
    34  func withBoth[A both[B, C], B, C any]() {}
    35  
    36  func _() {
    37  	withPtr[*fooer[int]]()  // ok
    38  	withFoo[*fooer[int]]()  // ok
    39  	withBoth[*fooer[int]]() // should be able to infer C
    40  }
    41  
    42  // related test case reported in issue
    43  
    44  type X struct{}
    45  
    46  func (x X) M() int { return 42 }
    47  
    48  func CallM1[T interface{ M() R }, R any](t T) R {
    49  	return t.M()
    50  }
    51  
    52  func CallM2[T interface {
    53  	X
    54  	M() R
    55  }, R any](t T) R {
    56  	return t.M()
    57  }
    58  
    59  func _() {
    60  	CallM1(X{}) // ok
    61  	CallM2(X{}) // should be able to infer R
    62  }
    63
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