go/test/typeswitch3.go
Rob Pike 80a9783f84 test/[n-z]*.go: add documentation
R=golang-dev, bradfitz, r
CC=golang-dev
https://golang.org/cl/5700056
2012-02-24 11:48:19 +11:00

44 lines
699 B
Go

// errorcheck
// Copyright 2011 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.
// Verify that erroneous type switches are caught be the compiler.
// Issue 2700, among other things.
// Does not compile.
package main
import (
"io"
)
type I interface {
M()
}
func main(){
var x I
switch x.(type) {
case string: // ERROR "impossible"
println("FAIL")
}
// Issue 2700: if the case type is an interface, nothing is impossible
var r io.Reader
_, _ = r.(io.Writer)
switch r.(type) {
case io.Writer:
}
// Issue 2827.
switch _ := r.(type) { // ERROR "invalid variable name _"
}
}