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