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
5 package generics
6
7 func _[A, B any](a A, b B) int {}
8 func _[T any](x, y T) T
9
10 type T[P any] struct{}
11 type T[P1, P2, P3 any] struct{}
12
13 type T[P C] struct{}
14 type T[P1, P2, P3 C] struct{}
15
16 type T[P C[P]] struct{}
17 type T[P1, P2, P3 C[P1, P2, P3]] struct{}
18
19 func f[P any](x P)
20 func f[P1, P2, P3 any](x1 P1, x2 P2, x3 P3) struct{}
21
22 func f[P interface{}](x P)
23 func f[P1, P2, P3 interface{ m1(P1); ~P2|~P3 }](x1 P1, x2 P2, x3 P3) struct{}
24 func f[P any](T1[P], T2[P]) T3[P]
25
26 func (x T[P]) m()
27 func ((T[P])) m(x T[P]) P
28
29 func _() {
30 type _ []T[P]
31 var _ []T[P]
32 _ = []T[P]{}
33 }
34
35 // type constraint literals with elided interfaces
36 func _[P ~int, Q int | string]() {}
37 func _[P struct{f int}, Q *P]() {}
38
39 // various potentially ambiguous type parameter lists (issue #49482)
40 type _[P *T,] struct{}
41 type _[P T | T] struct{}
42 type _[P T | T | T | T] struct{}
43 type _[P *T, _ any] struct{}
44 type _[P (*T),] struct{}
45 type _[P ((*T)),] struct{}
46 type _[P ((~int)),] struct{}
47 type _[P (*T), _ any] struct{}
48 type _[P (T),] struct{}
49 type _[P (T), _ any] struct{}
50
51 type _[P *struct{}] struct{}
52 type _[P (*struct{})] struct{}
53 type _[P ([]int)] struct{}
54
55 // a type literal in an |-expression indicates a type parameter list (blank after type parameter list and type)
56 type _[P *[]int] struct{}
57 type _[P *T | T, Q T] struct{}
58 type _[P *[]T | T] struct{}
59 type _[P *T | T | T | T | ~T] struct{}
60 type _[P *T | T | T | ~T | T] struct{}
61 type _[P *T | T | struct{} | T] struct{}
62 type _[P <-chan int] struct{}
63 type _[P *T | struct{} | T] struct{}
64
65 // a trailing comma always indicates a (possibly invalid) type parameter list (blank after type parameter list and type)
66 type _[P *T,] struct{}
67 type _[P *T | T,] struct{}
68 type _[P *T | <-T | T,] struct{}
69
70 // slice/array type declarations (no blank between array length and element type)
71 type _ []byte
72 type _ [n]byte
73 type _ [P(T)]byte
74 type _ [P((T))]byte
75 type _ [P * *T]byte
76 type _ [P * T]byte
77 type _ [P(*T)]byte
78 type _ [P(**T)]byte
79 type _ [P * T - T]byte
80 type _ [P * T - T]byte
81 type _ [P * T | T]byte
82 type _ [P * T | <-T | T]byte
83
84 // equivalent test cases for potentially ambiguous type parameter lists, except
85 // for function declarations there is no ambiguity (issue #51548)
86 func _[P *T,]() {}
87 func _[P *T, _ any]() {}
88 func _[P (*T),]() {}
89 func _[P (*T), _ any]() {}
90 func _[P (T),]() {}
91 func _[P (T), _ any]() {}
92
93 func _[P *struct{}] () {}
94 func _[P (*struct{})] () {}
95 func _[P ([]int)] () {}
96
97 func _ [P(T)]() {}
98 func _ [P((T))]() {}
99 func _ [P * *T]() {}
100 func _ [P * T]() {}
101 func _ [P(*T)]() {}
102 func _ [P(**T)]() {}
103 func _ [P * T]() {}
104
105 func _[
106 P *T,
107 ]() {}
108
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