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go/test/fixedbugs/issue28748.go
Keith Randall 04845fe78a reflect: special-case panic message when returning Value{} from MakeFunc function
Before this CL we used to panic with "nil pointer dereference" because
the value we're calling assignTo on is the zero Value. Provide a better
error message.

Fixes #28748

Change-Id: I7dd4c9e30b599863664d91e78cc45878d8b0052e
Reviewed-on: https://go-review.googlesource.com/c/go/+/175440
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2019-05-06 21:23:29 +00:00

33 lines
712 B
Go

// run
package main
import (
"fmt"
"reflect"
"strings"
)
// Copyright 2019 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.
func main() {
defer func() {
e := recover()
if e == nil {
panic("should have panicked")
}
text := fmt.Sprintf("%s", e) // handles both string and runtime.errorString
if !strings.HasPrefix(text, "reflect:") {
panic("wanted a reflect error, got this instead:\n" + text)
}
}()
r := reflect.MakeFunc(reflect.TypeOf(func() error { return nil }),
func(args []reflect.Value) []reflect.Value {
var x [1]reflect.Value
return x[:]
}).Interface().(func() error)
r()
}