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go/test/cmp6.go
Russ Cox 7e84666df1 gc: clearer error for struct == struct
cmp6.go:48: invalid operation: t3 == t3 (operator == not defined on struct)

Fixes #1438.

R=ken2
CC=golang-dev
https://golang.org/cl/4003045
2011-01-21 18:15:59 -05:00

50 lines
1.0 KiB
Go

// errchk $G -e $D/$F.go
// Copyright 2010 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
func use(bool) {}
type T1 *int
type T2 *int
type T3 struct {}
var t3 T3
func main() {
// Arguments to comparison must be
// assignable one to the other (or vice versa)
// so chan int can be compared against
// directional channels but channel of different
// direction cannot be compared against each other.
var c1 chan <-int
var c2 <-chan int
var c3 chan int
use(c1 == c2) // ERROR "invalid operation"
use(c2 == c1) // ERROR "invalid operation"
use(c1 == c3)
use(c2 == c2)
use(c3 == c1)
use(c3 == c2)
// Same applies to named types.
var p1 T1
var p2 T2
var p3 *int
use(p1 == p2) // ERROR "invalid operation"
use(p2 == p1) // ERROR "invalid operation"
use(p1 == p3)
use(p2 == p2)
use(p3 == p1)
use(p3 == p2)
// Comparison of structs should have a good message
use(t3 == t3) // ERROR "struct"
}