1// run
2
3// Copyright 2023 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// Smoke test for reverse type inference.
8// The type checker has more expansive tests.
9
10package main
11
12func main() {
13	var f1 func(int) int
14	f1 = g1
15	if f1(1) != g1(1) {
16		panic(1)
17	}
18
19	var f2 func(int) string = g2
20	if f2(2) != "" {
21		panic(2)
22	}
23
24	if g3(g1, 3) != g1(3) {
25		panic(3)
26	}
27
28	if g4(g2, 4) != "" {
29		panic(4)
30	}
31}
32
33func g1[P any](x P) P    { return x }
34func g2[P, Q any](x P) Q { var q Q; return q }
35
36func g3(f1 func(int) int, x int) int       { return f1(x) }
37func g4(f2 func(int) string, x int) string { return f2(x) }
38