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go/cmd/vet/testdata/shadow.go
Rob Pike e239f1b3f2 go.tools/cmd/vet: don't check for shadowing of blank identifier
It's pointless.
Also this fixes a crash, because the blank identifier no longer appears as a
defined object after CL 74190043 so we were getting nil pointer violations.
Even better, we get to re-enable a disabled test.

LGTM=gri
R=gri
CC=golang-codereviews
https://golang.org/cl/75140043
2014-03-13 10:27:55 +11:00

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1.5 KiB
Go

// Copyright 2013 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.
// This file contains tests for the shadowed variable checker.
// Some of these errors are caught by the compiler (shadowed return parameters for example)
// but are nonetheless useful tests.
package testdata
import "os"
func ShadowRead(f *os.File, buf []byte) (err error) {
var x int
if f != nil {
err := 3 // OK - different type.
_ = err
}
if f != nil {
_, err := f.Read(buf) // ERROR "declaration of err shadows declaration at testdata/shadow.go:13"
if err != nil {
return err
}
i := 3 // OK
_ = i
}
if f != nil {
var _, err = f.Read(buf) // ERROR "declaration of err shadows declaration at testdata/shadow.go:13"
if err != nil {
return err
}
}
for i := 0; i < 10; i++ {
i := i // OK: obviously intentional idiomatic redeclaration
go func() {
println(i)
}()
}
var shadowTemp interface{}
switch shadowTemp := shadowTemp.(type) { // OK: obviously intentional idiomatic redeclaration
case int:
println("OK")
_ = shadowTemp
}
if shadowTemp := shadowTemp; true { // OK: obviously intentional idiomatic redeclaration
var f *os.File // OK because f is not mentioned later in the function.
// The declaration of x is a shadow because x is mentioned below.
var x int // ERROR "declaration of x shadows declaration at testdata/shadow.go:14"
_, _, _ = x, f, shadowTemp
}
// Use a couple of variables to trigger shadowing errors.
_, _ = err, x
return
}