2021-07-12 23:12:55 +00:00
|
|
|
// run -gcflags=-G=3
|
|
|
|
|
|
|
|
// Copyright 2021 The Go Authors. All rights reserved.
|
|
|
|
// Use of this source code is governed by a BSD-style
|
|
|
|
// license that can be found in the LICENSE file.
|
|
|
|
|
|
|
|
// comparisons of type parameters to interfaces
|
|
|
|
|
|
|
|
package main
|
|
|
|
|
|
|
|
func f[T comparable](t, u T) bool {
|
|
|
|
// Comparing two type parameters directly.
|
|
|
|
// (Not really testing comparisons to interfaces, but just 'cause we're here.)
|
|
|
|
return t == u
|
|
|
|
}
|
|
|
|
|
|
|
|
func g[T comparable](t T, i interface{}) bool {
|
|
|
|
// Compare type parameter value to empty interface.
|
|
|
|
return t == i
|
|
|
|
}
|
|
|
|
|
|
|
|
type I interface {
|
|
|
|
foo()
|
|
|
|
}
|
|
|
|
|
|
|
|
type C interface {
|
|
|
|
comparable
|
|
|
|
I
|
|
|
|
}
|
|
|
|
|
|
|
|
func h[T C](t T, i I) bool {
|
|
|
|
// Compare type parameter value to nonempty interface.
|
|
|
|
return t == i
|
|
|
|
}
|
|
|
|
|
|
|
|
type myint int
|
|
|
|
|
|
|
|
func (x myint) foo() {
|
|
|
|
}
|
|
|
|
|
|
|
|
func k[T comparable](t T, i interface{}) bool {
|
|
|
|
// Compare derived type value to interface.
|
2021-07-28 20:39:30 +00:00
|
|
|
return struct{ a, b T }{t, t} == i
|
2021-07-12 23:12:55 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
func main() {
|
|
|
|
assert(f(3, 3))
|
|
|
|
assert(!f(3, 5))
|
|
|
|
assert(g(3, 3))
|
|
|
|
assert(!g(3, 5))
|
|
|
|
assert(h(myint(3), myint(3)))
|
|
|
|
assert(!h(myint(3), myint(5)))
|
|
|
|
|
2021-07-28 20:39:30 +00:00
|
|
|
type S struct{ a, b float64 }
|
2021-07-12 23:12:55 +00:00
|
|
|
|
2021-07-28 20:39:30 +00:00
|
|
|
assert(f(S{3, 5}, S{3, 5}))
|
|
|
|
assert(!f(S{3, 5}, S{4, 6}))
|
|
|
|
assert(g(S{3, 5}, S{3, 5}))
|
|
|
|
assert(!g(S{3, 5}, S{4, 6}))
|
2021-07-12 23:12:55 +00:00
|
|
|
|
2021-07-28 20:39:30 +00:00
|
|
|
assert(k(3, struct{ a, b int }{3, 3}))
|
|
|
|
assert(!k(3, struct{ a, b int }{3, 4}))
|
2021-07-12 23:12:55 +00:00
|
|
|
}
|
|
|
|
|
2021-07-28 20:39:30 +00:00
|
|
|
func assert(b bool) {
|
2021-07-12 23:12:55 +00:00
|
|
|
if !b {
|
|
|
|
panic("assertion failed")
|
|
|
|
}
|
|
|
|
}
|