1 // errorcheck 2 3 // Copyright 2009 The Go Authors. All rights reserved. 4 // Use of this source code is governed by a BSD-style 5 // license that can be found in the LICENSE file. 6 7 // Verify that various erroneous type switches are caught be the compiler. 8 // Does not compile. 9 10 package main 11 12 import "io" 13 14 func whatis(x interface{}) string { 15 switch x.(type) { 16 case int: 17 return "int" 18 case int: // ERROR "duplicate" 19 return "int8" 20 case io.Reader: 21 return "Reader1" 22 case io.Reader: // ERROR "duplicate" 23 return "Reader2" 24 case interface { 25 r() 26 w() 27 }: 28 return "rw" 29 case interface { // GCCGO_ERROR "duplicate" 30 w() 31 r() 32 }: // GC_ERROR "duplicate" 33 return "wr" 34 35 } 36 return "" 37 } 38 39 func notused(x interface{}) { 40 // The first t is in a different scope than the 2nd t; it cannot 41 // be accessed (=> declared and not used error); but it is legal 42 // to declare it. 43 switch t := 0; t := x.(type) { // ERROR "declared and not used" 44 case int: 45 _ = t // this is using the t of "t := x.(type)" 46 } 47 } 48
