1 // errorcheck 2 3 // Copyright 2016 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 // Check the compiler's switch handling that happens 8 // at typechecking time. 9 // This must be separate from other checks, 10 // because errors during typechecking 11 // prevent other errors from being discovered. 12 13 package main 14 15 // Verify that type switch statements with impossible cases are detected by the compiler. 16 func f0(e error) { 17 switch e.(type) { 18 case int: // ERROR "impossible type switch case: e \(type error\) cannot have dynamic type int \(missing Error method\)" 19 } 20 } 21 22 // Verify that the compiler rejects multiple default cases. 23 func f1(e interface{}) { 24 switch e { 25 default: 26 default: // ERROR "multiple defaults in switch" 27 } 28 switch e.(type) { 29 default: 30 default: // ERROR "multiple defaults in switch" 31 } 32 } 33 34 type I interface { 35 Foo() 36 } 37 38 type X int 39 40 func (*X) Foo() {} 41 func f2() { 42 var i I 43 switch i.(type) { 44 case X: // ERROR "impossible type switch case: i \(type I\) cannot have dynamic type X \(Foo method has pointer receiver\)" 45 } 46 } 47
