diff --git a/src/reflect/value.go b/src/reflect/value.go index f0db434009..c58b2d2567 100644 --- a/src/reflect/value.go +++ b/src/reflect/value.go @@ -560,6 +560,10 @@ func callReflect(ctxt *makeFuncImpl, frame unsafe.Pointer, retValid *bool) { } for i, typ := range ftyp.out() { v := out[i] + if v.typ == nil { + panic("reflect: function created by MakeFunc using " + funcName(f) + + " returned zero Value") + } if v.flag&flagRO != 0 { panic("reflect: function created by MakeFunc using " + funcName(f) + " returned value obtained from unexported field") diff --git a/test/fixedbugs/issue28748.go b/test/fixedbugs/issue28748.go new file mode 100644 index 0000000000..4f9b0222ab --- /dev/null +++ b/test/fixedbugs/issue28748.go @@ -0,0 +1,32 @@ +// 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() +}