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