go/test/convert1.go
Russ Cox 6e3e380923 allow direct conversion between string and named []byte, []rune
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
2011-11-22 12:30:02 -05:00

97 lines
2.6 KiB
Go

// errchk $G -e $D/$F.go
// Copyright 2011 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
type Tbyte []byte
type Trune []rune
type Tint64 []int64
type Tstring string
func main() {
s := "hello"
sb := []byte("hello")
sr := []rune("hello")
si := []int64{'h', 'e', 'l', 'l', 'o'}
ts := Tstring(s)
tsb := Tbyte(sb)
tsr := Trune(sr)
tsi := Tint64(si)
_ = string(s)
_ = []byte(s)
_ = []rune(s)
_ = []int64(s) // ERROR "cannot convert.*\[\]int64"
_ = Tstring(s)
_ = Tbyte(s)
_ = Trune(s)
_ = Tint64(s) // ERROR "cannot convert.*Tint64"
_ = string(sb)
_ = []byte(sb)
_ = []rune(sb) // ERROR "cannot convert.*\[\]rune"
_ = []int64(sb) // ERROR "cannot convert.*\[\]int64"
_ = Tstring(sb)
_ = Tbyte(sb)
_ = Trune(sb) // ERROR "cannot convert.*Trune"
_ = Tint64(sb) // ERROR "cannot convert.*Tint64"
_ = string(sr)
_ = []byte(sr) // ERROR "cannot convert.*\[\]byte"
_ = []rune(sr)
_ = []int64(sr) // ERROR "cannot convert.*\[\]int64"
_ = Tstring(sr)
_ = Tbyte(sr) // ERROR "cannot convert.*Tbyte"
_ = Trune(sr)
_ = Tint64(sr) // ERROR "cannot convert.*Tint64"
_ = string(si) // ERROR "cannot convert.* string"
_ = []byte(si) // ERROR "cannot convert.*\[\]byte"
_ = []rune(si) // ERROR "cannot convert.*\[\]rune"
_ = []int64(si)
_ = Tstring(si) // ERROR "cannot convert.*Tstring"
_ = Tbyte(si) // ERROR "cannot convert.*Tbyte"
_ = Trune(si) // ERROR "cannot convert.*Trune"
_ = Tint64(si)
_ = string(ts)
_ = []byte(ts)
_ = []rune(ts)
_ = []int64(ts) // ERROR "cannot convert.*\[\]int64"
_ = Tstring(ts)
_ = Tbyte(ts)
_ = Trune(ts)
_ = Tint64(ts) // ERROR "cannot convert.*Tint64"
_ = string(tsb)
_ = []byte(tsb)
_ = []rune(tsb) // ERROR "cannot convert.*\[\]rune"
_ = []int64(tsb) // ERROR "cannot convert.*\[\]int64"
_ = Tstring(tsb)
_ = Tbyte(tsb)
_ = Trune(tsb) // ERROR "cannot convert.*Trune"
_ = Tint64(tsb) // ERROR "cannot convert.*Tint64"
_ = string(tsr)
_ = []byte(tsr) // ERROR "cannot convert.*\[\]byte"
_ = []rune(tsr)
_ = []int64(tsr) // ERROR "cannot convert.*\[\]int64"
_ = Tstring(tsr)
_ = Tbyte(tsr) // ERROR "cannot convert.*Tbyte"
_ = Trune(tsr)
_ = Tint64(tsr) // ERROR "cannot convert.*Tint64"
_ = string(tsi) // ERROR "cannot convert.* string"
_ = []byte(tsi) // ERROR "cannot convert.*\[\]byte"
_ = []rune(tsi) // ERROR "cannot convert.*\[\]rune"
_ = []int64(tsi)
_ = Tstring(tsi) // ERROR "cannot convert.*Tstring"
_ = Tbyte(tsi) // ERROR "cannot convert.*Tbyte"
_ = Trune(tsi) // ERROR "cannot convert.*Trune"
_ = Tint64(tsi)
}