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https://github.com/golang/go
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09834d1c08
A straight conversion from a type T to an interface type I, where T does not implement I, should always panic with an interface conversion error that shows the missing method. This was not happening if the conversion was done once using the comma-ok form (the result would not be OK) and then again in a straight conversion. Due to an error in the runtime package the second conversion was failing with a nil pointer dereference. Fixes #16130. Change-Id: I8b9fca0f1bb635a6181b8b76de8c2385bb7ac2d2 Reviewed-on: https://go-review.googlesource.com/24284 Run-TryBot: Ian Lance Taylor <iant@golang.org> Reviewed-by: Michel Lespinasse <walken@google.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Andrew Gerrand <adg@golang.org> Reviewed-by: Keith Randall <khr@golang.org>
44 lines
947 B
Go
44 lines
947 B
Go
// run
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// Copyright 2016 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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// Test that an interface conversion error panics with an "interface
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// conversion" run-time error. It was (incorrectly) panicing with a
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// "nil pointer dereference."
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package main
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import (
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"fmt"
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"runtime"
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"strings"
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)
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type I interface {
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Get() int
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}
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func main() {
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defer func() {
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r := recover()
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if r == nil {
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panic("expected panic")
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}
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re, ok := r.(runtime.Error)
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if !ok {
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panic(fmt.Sprintf("got %T, expected runtime.Error", r))
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}
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if !strings.Contains(re.Error(), "interface conversion") {
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panic(fmt.Sprintf("got %q, expected interface conversion error", re.Error()))
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}
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}()
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e := (interface{})(0)
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if _, ok := e.(I); ok {
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panic("unexpected interface conversion success")
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}
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fmt.Println(e.(I))
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panic("unexpected interface conversion success")
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}
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