// errorcheck // 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. // Verify that various erroneous type switches are caught be the compiler. // Does not compile. 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 { // GCCGO_ERROR "duplicate" w() r() }: // GC_ERROR "duplicate" return "wr" } return "" } func notused(x interface{}) { // The first t is in a different scope than the 2nd t; it cannot // be accessed (=> declared and not used error); but it is legal // to declare it. switch t := 0; t := x.(type) { // ERROR "declared and not used" case int: _ = t // this is using the t of "t := x.(type)" } }