// errorcheck // Copyright 2011 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 erroneous switch statements are detected by the compiler. // Does not compile. package main type I interface { M() } func bad() { var i I var s string switch i { case s: // ERROR "mismatched types string and I|incompatible types" } switch s { case i: // ERROR "mismatched types I and string|incompatible types" } var m, m1 map[int]int switch m { case nil: case m1: // ERROR "can only compare map m to nil|map can only be compared to nil|cannot compare" default: } var a, a1 []int switch a { case nil: case a1: // ERROR "can only compare slice a to nil|slice can only be compared to nil|cannot compare" default: } var f, f1 func() switch f { case nil: case f1: // ERROR "can only compare func f to nil|func can only be compared to nil|cannot compare" default: } var ar, ar1 [4]func() switch ar { // ERROR "cannot switch on" case ar1: default: } var st, st1 struct{ f func() } switch st { // ERROR "cannot switch on" case st1: } } func good() { var i interface{} var s string switch i { case s: } switch s { case i: } }