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reflect: StructOf with interface fields panics at run time #25400

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dotaheor opened this issue May 15, 2018 · 2 comments
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reflect: StructOf with interface fields panics at run time #25400

dotaheor opened this issue May 15, 2018 · 2 comments
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FrozenDueToAge NeedsFix The path to resolution is known, but the work has not been done. release-blocker
Milestone
Go1.11

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@dotaheor
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dotaheor commented May 15, 2018 •
edited
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Please answer these questions before submitting your issue. Thanks!

What version of Go are you using (go version)?

go version go1.10.2 linux/amd64

Does this issue reproduce with the latest release?

yes

What did you do?

package main

import "fmt"
import "reflect"

func main() {
	type T = struct {
		error
	}
	fmt.Println(reflect.TypeOf(T{})) // struct { error }
	
	var err error
	te := reflect.TypeOf(err)
	// panic: reflect.StructOf: field 0 has no type
	tt := reflect.StructOf([]reflect.StructField{
		{Name: "E", Type: te, Anonymous: true},
	})
	fmt.Println(tt)
}

What did you expect to see?

not panic

What did you see instead?

panic
@dotaheor
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Looks, it also panics for non-anonymous interface fields.

@dotaheor dotaheor changed the title reflect: StructOf with anonymous interface fields panics at run time reflect: StructOf with interface fields panics at run time May 15, 2018
@ianlancetaylor ianlancetaylor added NeedsFix The path to resolution is known, but the work has not been done. release-blocker labels May 15, 2018
@ianlancetaylor ianlancetaylor added this to the Go1.11 milestone May 15, 2018
@dotaheor
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dotaheor commented May 15, 2018 •
edited
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sorry, It looks I made a mistake for this example.
This is not a bug.

package main

import "fmt"
import "reflect"

func main() {
	type T = struct {
		error
	}
	fmt.Println(reflect.TypeOf(T{})) // struct { error }
	
	var err *error
	te := reflect.TypeOf(err).Elem()
	// panic: reflect.StructOf: field 0 has no type
	tt := reflect.StructOf([]reflect.StructField{
		{Name: "E", Type: te, Anonymous: true},
	})
	fmt.Println(tt) // struct { E error }
}

The only problem of it is the string presentation of tt,
which is a duplication of #25403

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FrozenDueToAge NeedsFix The path to resolution is known, but the work has not been done. release-blocker
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Milestone
Go1.11
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@ianlancetaylor @gopherbot @dotaheor