1// Copyright 2020 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
5package generics
6
7func _[A, B any](a A, b B) int {}
8func _[T any](x, y T) T
9
10type T[P any] struct{}
11type T[P1, P2, P3 any] struct{}
12
13type T[P C] struct{}
14type T[P1, P2, P3 C] struct{}
15
16type T[P C[P]] struct{}
17type T[P1, P2, P3 C[P1, P2, P3]] struct{}
18
19func f[P any](x P)
20func f[P1, P2, P3 any](x1 P1, x2 P2, x3 P3) struct{}
21
22func f[P interface{}](x P)
23func f[P1, P2, P3 interface{ m1(P1); ~P2|~P3 }](x1 P1, x2 P2, x3 P3) struct{}
24func f[P any](T1[P], T2[P]) T3[P]
25
26func (x T[P]) m()
27func ((T[P])) m(x T[P]) P
28
29func _() {
30 type _ []T[P]
31 var _ []T[P]
32 _ = []T[P]{}
33}
34
35// type constraint literals with elided interfaces
36func _[P ~int, Q int | string]() {}
37func _[P struct{f int}, Q *P]() {}
38
39// various potentially ambiguous type parameter lists (issue #49482)
40type _[P *T,] struct{}
41type _[P T | T] struct{}
42type _[P T | T | T | T] struct{}
43type _[P *T, _ any] struct{}
44type _[P (*T),] struct{}
45type _[P (*T), _ any] struct{}
46type _[P (T),] struct{}
47type _[P (T), _ any] struct{}
48
49type _[P *struct{}] struct{}
50type _[P (*struct{})] struct{}
51type _[P ([]int)] struct{}
52
53// a type literal in an |-expression indicates a type parameter list (blank after type parameter list and type)
54type _[P *[]int] struct{}
55type _[P *T | T, Q T] struct{}
56type _[P *[]T | T] struct{}
57type _[P *T | T | T | T | ~T] struct{}
58type _[P *T | T | T | ~T | T] struct{}
59type _[P *T | T | struct{} | T] struct{}
60type _[P <-chan int] struct{}
61type _[P *T | struct{} | T] struct{}
62
63// a trailing comma always indicates a (possibly invalid) type parameter list (blank after type parameter list and type)
64type _[P *T,] struct{}
65type _[P *T | T,] struct{}
66type _[P *T | <-T | T,] struct{}
67
68// slice/array type declarations (no blank between array length and element type)
69type _ []byte
70type _ [n]byte
71type _ [P(T)]byte
72type _ [P((T))]byte
73type _ [P * *T]byte
74type _ [P * T]byte
75type _ [P(*T)]byte
76type _ [P(**T)]byte
77type _ [P * T - T]byte
78type _ [P * T - T]byte
79type _ [P * T | T]byte
80type _ [P * T | <-T | T]byte
81
82// equivalent test cases for potentially ambiguous type parameter lists, except
83// for function declarations there is no ambiguity (issue #51548)
84func _[P *T,]() {}
85func _[P *T, _ any]() {}
86func _[P (*T),]() {}
87func _[P (*T), _ any]() {}
88func _[P (T),]() {}
89func _[P (T), _ any]() {}
90
91func _[P *struct{}] () {}
92func _[P (*struct{})] () {}
93func _[P ([]int)] () {}
94
95func _ [P(T)]() {}
96func _ [P((T))]() {}
97func _ [P * *T]() {}
98func _ [P * T]() {}
99func _ [P(*T)]() {}
100func _ [P(**T)]() {}
101func _ [P * T]() {}
102
103func _[
104 P *T,
105]() {}
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