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// $G $D/$F.go && $L $F.$A && ./$A.out
// Copyright 2009 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.
package main
import "unsafe"
func use(bool) {}
func stringptr(s string) uintptr { return *(*uintptr)(unsafe.Pointer(&s)) }
func isfalse(b bool) {
if b {
// stack will explain where
panic("wanted false, got true")
}
}
func istrue(b bool) {
if !b {
// stack will explain where
panic("wanted true, got false")
}
}
type T *int
func main() {
var a []int
var b map[string]int
var c string = "hello"
var d string = "hel" // try to get different pointer
d = d + "lo"
if stringptr(c) == stringptr(d) {
panic("compiler too smart -- got same string")
}
var e = make(chan int)
var ia interface{} = a
var ib interface{} = b
var ic interface{} = c
var id interface{} = d
var ie interface{} = e
// these comparisons are okay because
// string compare is okay and the others
// are comparisons where the types differ.
isfalse(ia == ib)
isfalse(ia == ic)
isfalse(ia == id)
isfalse(ib == ic)
isfalse(ib == id)
istrue(ic == id)
istrue(ie == ie)
// these are okay because one side of the
// comparison need only be assignable to the other.
isfalse(a == ib)
isfalse(a == ic)
isfalse(a == id)
isfalse(b == ic)
isfalse(b == id)
istrue(c == id)
istrue(e == ie)
isfalse(ia == b)
isfalse(ia == c)
isfalse(ia == d)
isfalse(ib == c)
isfalse(ib == d)
istrue(ic == d)
istrue(ie == e)
// 6g used to let this go through as true.
var g uint64 = 123
var h int64 = 123
var ig interface{} = g
var ih interface{} = h
isfalse(ig == ih)
// map of interface should use == on interface values,
// not memory.
// TODO: should m[c], m[d] be valid here?
var m = make(map[interface{}]int)
m[ic] = 1
m[id] = 2
if m[ic] != 2 {
println("m[ic] = ", m[ic])
panic("bad m[ic]")
}
// non-interface comparisons
{
c := make(chan int)
c1 := (<-chan int)(c)
c2 := (chan<- int)(c)
istrue(c == c1)
istrue(c == c2)
istrue(c1 == c)
istrue(c2 == c)
d := make(chan int)
isfalse(c == d)
isfalse(d == c)
isfalse(d == c1)
isfalse(d == c2)
isfalse(c1 == d)
isfalse(c2 == d)
}
// named types vs not
{
var x = new(int)
var y T
var z T = x
isfalse(x == y)
istrue(x == z)
isfalse(y == z)
isfalse(y == x)
istrue(z == x)
isfalse(z == y)
}
}
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