codekingpro/portable-devtools

1// errorcheck2 3// Copyright 2010 The Go Authors. All rights reserved.4// Use of this source code is governed by a BSD-style5// license that can be found in the LICENSE file.6 7// Verify that incorrect comparisons are detected.8// Does not compile.9 10package main11 12func use(bool) {}13 14type T1 *int15type T2 *int16 17type T3 struct{ z []int }18 19var t3 T320 21type T4 struct {22	_ []int23	a float6424}25 26var t4 T427 28func main() {29	// Arguments to comparison must be30	// assignable one to the other (or vice versa)31	// so chan int can be compared against32	// directional channels but channel of different33	// direction cannot be compared against each other.34	var c1 chan<- int35	var c2 <-chan int36	var c3 chan int37 38	use(c1 == c2) // ERROR "invalid operation|incompatible"39	use(c2 == c1) // ERROR "invalid operation|incompatible"40	use(c1 == c3)41	use(c2 == c2)42	use(c3 == c1)43	use(c3 == c2)44 45	// Same applies to named types.46	var p1 T147	var p2 T248	var p3 *int49 50	use(p1 == p2) // ERROR "invalid operation|incompatible"51	use(p2 == p1) // ERROR "invalid operation|incompatible"52	use(p1 == p3)53	use(p2 == p2)54	use(p3 == p1)55	use(p3 == p2)56 57	// Arrays are comparable if and only if their element type is comparable.58	var a1 [1]int59	var a2 [1]func()60	var a3 [0]func()61	use(a1 == a1)62	use(a2 == a2) // ERROR "invalid operation|invalid comparison"63	use(a3 == a3) // ERROR "invalid operation|invalid comparison"64 65	// Comparison of structs should have a good message66	use(t3 == t3) // ERROR "struct|expected|cannot compare"67	use(t4 == t4) // ERROR "cannot be compared|non-comparable|cannot compare"68 69	// Slices, functions, and maps too.70	var x []int71	var f func()72	var m map[int]int73	use(x == x) // ERROR "slice can only be compared to nil|cannot compare"74	use(f == f) // ERROR "func can only be compared to nil|cannot compare"75	use(m == m) // ERROR "map can only be compared to nil|cannot compare"76 77	// Comparison with interface that cannot return true78	// (would panic).79	var i interface{}80	use(i == x) // ERROR "invalid operation"81	use(x == i) // ERROR "invalid operation"82	use(i == f) // ERROR "invalid operation"83	use(f == i) // ERROR "invalid operation"84	use(i == m) // ERROR "invalid operation"85	use(m == i) // ERROR "invalid operation"86}87