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go/test/typeswitch2.go
Russ Cox 1912632019 runtime, type switch: eliminate package global name space assumption
bonus: type switch now detects multiple uses of identical interface types.
bonus: interface types are now order-independent, following the spec.

R=ken2
CC=golang-dev
https://golang.org/cl/194053
2010-01-25 18:23:20 -08:00

29 lines
562 B
Go

// errchk $G -e $D/$F.go
// 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 "io"
func whatis(x interface{}) string {
switch x.(type) {
case int:
return "int"
case int: // ERROR "duplicate"
return "int8"
case io.Reader:
return "Reader1"
case io.Reader: // ERROR "duplicate"
return "Reader2"
case interface { r(); w() }:
return "rw"
case interface { w(); r() }: // ERROR "duplicate"
return "wr"
}
return ""
}