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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.
// Interface comparisons using types hidden
// inside reflected-on structs.
package main
import "reflect"
type T struct {
f float32
g float32
s string
t string
u uint32
v uint32
w uint32
x uint32
y uint32
z uint32
}
func add(s, t string) string {
return s + t
}
func assert(b bool) {
if !b {
panic("assert")
}
}
func main() {
var x T
x.f = 1.0
x.g = x.f
x.s = add("abc", "def")
x.t = add("abc", "def")
x.u = 1
x.v = 2
x.w = 1 << 28
x.x = 2 << 28
x.y = 0x12345678
x.z = x.y
// check mem and string
v := reflect.ValueOf(x)
i := v.Field(0)
j := v.Field(1)
assert(i.Interface() == j.Interface())
s := v.Field(2)
t := v.Field(3)
assert(s.Interface() == t.Interface())
// make sure different values are different.
// make sure whole word is being compared,
// not just a single byte.
i = v.Field(4)
j = v.Field(5)
assert(i.Interface() != j.Interface())
i = v.Field(6)
j = v.Field(7)
assert(i.Interface() != j.Interface())
i = v.Field(8)
j = v.Field(9)
assert(i.Interface() == j.Interface())
}
/*
comparing uncomparable type float32
throw: interface compare
panic PC=0x28ceb8 [1]
throw+0x41 /Users/rsc/goX/src/runtime/runtime.c:54
throw(0x3014a, 0x0)
ifaceeq+0x15c /Users/rsc/goX/src/runtime/iface.c:501
ifaceeq(0x2aa7c0, 0x0, 0x0, 0x0, 0x2aa7c0, ...)
sys·ifaceeq+0x48 /Users/rsc/goX/src/runtime/iface.c:527
sys·ifaceeq(0x2aa7c0, 0x0, 0x0, 0x0, 0x2aa7c0, ...)
main·main+0x190 /Users/rsc/goX/src/cmd/gc/x.go:10
main·main()
mainstart+0xf /Users/rsc/goX/src/runtime/amd64/asm.s:53
mainstart()
sys·Goexit /Users/rsc/goX/src/runtime/proc.c:124
sys·Goexit()
*/
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