mirror of
https://github.com/golang/go
synced 2024-11-13 17:10:21 -07:00
6e3e380923
The allowed conversions before and after are:
type Tstring string
type Tbyte []byte
type Trune []rune
string <-> string // ok
string <-> []byte // ok
string <-> []rune // ok
string <-> Tstring // ok
string <-> Tbyte // was illegal, now ok
string <-> Trune // was illegal, now ok
Tstring <-> string // ok
Tstring <-> []byte // ok
Tstring <-> []rune // ok
Tstring <-> Tstring // ok
Tstring <-> Tbyte // was illegal, now ok
Tstring <-> Trune // was illegal, now ok
Update spec, compiler, tests. Use in a few packages.
We agreed on this a few months ago but never implemented it.
Fixes #1707.
R=golang-dev, gri, r
CC=golang-dev
https://golang.org/cl/5421057
67 lines
2.0 KiB
Go
67 lines
2.0 KiB
Go
// errchk $G -e $D/$F.go
|
|
|
|
// Copyright 2009 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.
|
|
|
|
package main
|
|
|
|
// explicit conversion of constants is work in progress.
|
|
// the ERRORs in this block are debatable, but they're what
|
|
// the language spec says for now.
|
|
var x1 = string(1)
|
|
var x2 string = string(1)
|
|
var x3 = int(1.5) // ERROR "convert|truncate"
|
|
var x4 int = int(1.5) // ERROR "convert|truncate"
|
|
var x5 = "a" + string(1)
|
|
var x6 = int(1e100) // ERROR "overflow"
|
|
var x7 = float32(1e1000) // ERROR "overflow"
|
|
|
|
// implicit conversions merit scrutiny
|
|
var s string
|
|
var bad1 string = 1 // ERROR "conver|incompatible|invalid|cannot"
|
|
var bad2 = s + 1 // ERROR "conver|incompatible|invalid"
|
|
var bad3 = s + 'a' // ERROR "conver|incompatible|invalid"
|
|
var bad4 = "a" + 1 // ERROR "literals|incompatible|convert|invalid"
|
|
var bad5 = "a" + 'a' // ERROR "literals|incompatible|convert|invalid"
|
|
|
|
var bad6 int = 1.5 // ERROR "convert|truncate"
|
|
var bad7 int = 1e100 // ERROR "overflow"
|
|
var bad8 float32 = 1e200 // ERROR "overflow"
|
|
|
|
// but these implicit conversions are okay
|
|
var good1 string = "a"
|
|
var good2 int = 1.0
|
|
var good3 int = 1e9
|
|
var good4 float64 = 1e20
|
|
|
|
// explicit conversion of string is okay
|
|
var _ = []rune("abc")
|
|
var _ = []byte("abc")
|
|
|
|
// implicit is not
|
|
var _ []int = "abc" // ERROR "cannot use|incompatible|invalid"
|
|
var _ []byte = "abc" // ERROR "cannot use|incompatible|invalid"
|
|
|
|
// named string is okay
|
|
type Tstring string
|
|
|
|
var ss Tstring = "abc"
|
|
var _ = []rune(ss)
|
|
var _ = []byte(ss)
|
|
|
|
// implicit is still not
|
|
var _ []rune = ss // ERROR "cannot use|incompatible|invalid"
|
|
var _ []byte = ss // ERROR "cannot use|incompatible|invalid"
|
|
|
|
// named slice is now ok
|
|
type Trune []rune
|
|
type Tbyte []byte
|
|
|
|
var _ = Trune("abc") // ok
|
|
var _ = Tbyte("abc") // ok
|
|
|
|
// implicit is still not
|
|
var _ Trune = "abc" // ERROR "cannot use|incompatible|invalid"
|
|
var _ Tbyte = "abc" // ERROR "cannot use|incompatible|invalid"
|