reflect: reflect.StructOf fields with Anonymous=true has not got Their func

[ssbeatty]

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

$ go version
go version go1.19.5 windows/amd64

Does this issue reproduce with the latest release?

yes

What operating system and processor architecture are you using (go env)?

go env Output

$ go env
set GO111MODULE=on
set GOARCH=amd64
set GOBIN=
set GOCACHE=C:\Users\wang\AppData\Local\go-build
set GOENV=C:\Users\wang\AppData\Roaming\go\env
set GOEXE=.exe
set GOEXPERIMENT=
set GOFLAGS=
set GOHOSTARCH=amd64
set GOHOSTOS=windows
set GOINSECURE=
set GOMODCACHE=C:\Users\wang\go\pkg\mod
set GONOPROXY=*.gitlab.com,*.gitee.com
set GONOSUMDB=*.gitlab.com,*.gitee.com
set GOOS=windows
set CXX=g++
set CGO_ENABLED=1
set GOMOD=D:\PROJECTS\GO\gateway_test\go.mod
set GOWORK=
set CGO_CFLAGS=-g -O2
set CGO_CPPFLAGS=
set CGO_CXXFLAGS=-g -O2
set CGO_FFLAGS=-g -O2
set CGO_LDFLAGS=-g -O2
set PKG_CONFIG=pkg-config
set GOGCCFLAGS=-m64 -mthreads -Wl,--no-gc-sections -fmessage-length=0 -fdebug-prefix-map=C:\Users\wang\AppData\Local\Temp\go-build881389354=/tmp/go-build -gno-record-gcc-switches

What did you do?

I have a piece of code that has unexpected execution results
refer to the example in

go/src/reflect/all_test.go

Line 5920 in 9ae97f8

func TestStructOfTooManyFields(t *testing.T) {

package main

import (
	"bytes"
	"reflect"
	"time"
)

func main() {
	tt := reflect.StructOf([]reflect.StructField{
		{Name: "Time", Type: reflect.TypeOf(time.Time{}), Anonymous: true},
	})

	if _, present := tt.MethodByName("After"); present {
		println("tt has After func")
	} else {
		println("tt has not After func")
	}

	bt := reflect.StructOf([]reflect.StructField{
		{Name: "Buffer", Type: reflect.TypeOf(bytes.Buffer{}), Anonymous: true},
	})

	if _, present := bt.MethodByName("Write"); present {
		println("bt has Write func")
	} else {
		println("bt has not Write func")
	}
}

What did you expect to see?

// output
// tt has After func
// bt has Write func

What did you see instead?

// output
// tt has After func
// bt has not Write func

[shawnh2]

Here's the methods signature of Time.After and Buffer.Write:

go/src/bytes/buffer.go

Line 175 in 71f82df

func (b *Buffer) Write(p []byte) (n int, err error) {

go/src/time/time.go

Line 250 in 71f82df

func (t Time) After(u Time) bool {

You can see their receivers are not the same type, if you expect to see "bt has Write func", change type of Buffer to *Buffer:

bt := reflect.StructOf([]reflect.StructField{
	{Name: "Buffer", Type: reflect.PtrTo(reflect.TypeOf(bytes.Buffer{})), Anonymous: true},  // <=
})

[ssbeatty]

Thanks