// errorcheck // Copyright 2016 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. // Check the compiler's switch handling that happens // at typechecking time. // This must be separate from other checks, // because errors during typechecking // prevent other errors from being discovered. package main // Verify that type switch statements with impossible cases are detected by the compiler. func f0(e error) { switch e.(type) { case int: // ERROR "impossible type switch case: (int\n\t)?e \(.*type error\) cannot have dynamic type int \(missing method Error\)" } } // Verify that the compiler rejects multiple default cases. func f1(e interface{}) { switch e { default: default: // ERROR "multiple defaults( in switch)?" } switch e.(type) { default: default: // ERROR "multiple defaults( in switch)?" } } type I interface { Foo() } type X int func (*X) Foo() {} func f2() { var i I switch i.(type) { case X: // ERROR "impossible type switch case: (X\n\t)?i \(.*type I\) cannot have dynamic type X \(method Foo has pointer receiver\)" } }