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 illegal assignments with both explicit and implicit conversions of literals are detected. 8// Does not compile. 9 10package main 11 12import "unsafe" 13 14// explicit conversion of constants 15var x1 = string(1) 16var x2 string = string(1) 17var x3 = int(1.5) // ERROR "convert|truncate" 18var x4 int = int(1.5) // ERROR "convert|truncate" 19var x5 = "a" + string(1) 20var x6 = int(1e100) // ERROR "overflow|cannot convert" 21var x7 = float32(1e1000) // ERROR "overflow|cannot convert" 22 23// unsafe.Pointer can only convert to/from uintptr 24var _ = string(unsafe.Pointer(uintptr(65))) // ERROR "convert|conversion" 25var _ = float64(unsafe.Pointer(uintptr(65))) // ERROR "convert|conversion" 26var _ = int(unsafe.Pointer(uintptr(65))) // ERROR "convert|conversion" 27 28// implicit conversions merit scrutiny 29var s string 30var bad1 string = 1 // ERROR "conver|incompatible|invalid|cannot" 31var bad2 = s + 1 // ERROR "conver|incompatible|invalid|cannot" 32var bad3 = s + 'a' // ERROR "conver|incompatible|invalid|cannot" 33var bad4 = "a" + 1 // ERROR "literals|incompatible|convert|invalid" 34var bad5 = "a" + 'a' // ERROR "literals|incompatible|convert|invalid" 35 36var bad6 int = 1.5 // ERROR "convert|truncate" 37var bad7 int = 1e100 // ERROR "overflow|truncated to int|truncated" 38var bad8 float32 = 1e200 // ERROR "overflow" 39 40// but these implicit conversions are okay 41var good1 string = "a" 42var good2 int = 1.0 43var good3 int = 1e9 44var good4 float64 = 1e20 45 46// explicit conversion of string is okay 47var _ = []rune("abc") 48var _ = []byte("abc") 49 50// implicit is not 51var _ []int = "abc" // ERROR "cannot use|incompatible|invalid|cannot convert" 52var _ []byte = "abc" // ERROR "cannot use|incompatible|invalid|cannot convert" 53 54// named string is okay 55type Tstring string 56 57var ss Tstring = "abc" 58var _ = []rune(ss) 59var _ = []byte(ss) 60 61// implicit is still not 62var _ []rune = ss // ERROR "cannot use|incompatible|invalid" 63var _ []byte = ss // ERROR "cannot use|incompatible|invalid" 64 65// named slice is now ok 66type Trune []rune 67type Tbyte []byte 68 69var _ = Trune("abc") // ok 70var _ = Tbyte("abc") // ok 71 72// implicit is still not 73var _ Trune = "abc" // ERROR "cannot use|incompatible|invalid|cannot convert" 74var _ Tbyte = "abc" // ERROR "cannot use|incompatible|invalid|cannot convert" 75