mirror of
https://github.com/golang/go
synced 2024-11-22 07:04:40 -07:00
a2a7d473f4
* disallow surrogate pair runes. * diagnose impossible type assertions * eliminate another static buffer. * do not overflow lexbuf. * add -u flag to disable package unsafe. R=ken2 CC=golang-dev https://golang.org/cl/1619042
72 lines
1.2 KiB
Go
72 lines
1.2 KiB
Go
// errchk $G -e $D/$F.go
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// Copyright 2009 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// Static error messages about interface conversions.
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package main
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type T struct {
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a int
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}
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var t *T
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type I interface {
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M()
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}
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var i I
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type I2 interface {
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M()
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N()
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}
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var i2 I2
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type E interface{}
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var e E
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func main() {
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e = t // ok
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t = e // ERROR "need explicit|need type assertion"
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// neither of these can work,
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// because i has an extra method
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// that t does not, so i cannot contain a t.
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i = t // ERROR "incompatible|missing M method"
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t = i // ERROR "incompatible|need type assertion"
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i = i2 // ok
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i2 = i // ERROR "missing N method"
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i = I(i2) // ok
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i2 = I2(i) // ERROR "missing N method"
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e = E(t) // ok
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t = T(e) // ERROR "need explicit|need type assertion|incompatible"
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}
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type M interface { M() }
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var m M
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var _ = m.(int) // ERROR "impossible type assertion"
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type Int int
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func (Int) M(float) {}
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var _ = m.(Int) // ERROR "impossible type assertion"
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var ii int
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var jj Int
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var m1 M = ii // ERROR "missing"
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var m2 M = jj // ERROR "wrong type for M method"
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var m3 = M(ii) // ERROR "missing"
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var m4 = M(jj) // ERROR "wrong type for M method"
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