reflect: generate runtime [circle refrence] types similar to compile time.

[Neightly]

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

$ go version
go version go1.23.2 windows/amd64

Does this issue reproduce with the latest release?

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

go env Output

$ go env
set GO111MODULE=on
set GOARCH=amd64
set GOBIN=D:\GOPATH\GOBIN
set GOCACHE=D:\GOPATH\GOCACHE
set GOENV=C:\Users\PC\AppData\Roaming\go\env
set GOEXE=.exe
set GOEXPERIMENT=
set GOFLAGS=
set GOHOSTARCH=amd64
set GOHOSTOS=windows
set GOINSECURE=
set GOMODCACHE=D:\GOPATH\GOMODCACHE
set GONOPROXY=
set GONOSUMDB=
set GOOS=windows
set GOPATH=D:\GOPATH
set GOPRIVATE=
set GOPROXY=https://goproxy.cn,direct
set GOROOT=D:\DEVELOPMENT\GO
set GOSUMDB=sum.golang.org
set GOTMPDIR=
set GOTOOLCHAIN=auto
set GOTOOLDIR=D:\DEVELOPMENT\GO\pkg\tool\windows_amd64
set GOVCS=
set GOVERSION=go1.23.2
set GODEBUG=
set GOTELEMETRY=local
set GOTELEMETRYDIR=C:\Users\PC\AppData\Roaming\go\telemetry
set GCCGO=gccgo
set GOAMD64=v1
set AR=ar
set CC=zig cc -target x86_64-windows-gnu
set CXX=g++
set CGO_ENABLED=0
set GOMOD=NUL
set GOWORK=
set CGO_CFLAGS=-O2 -g
set CGO_CPPFLAGS=
set CGO_CXXFLAGS=-O2 -g
set CGO_FFLAGS=-O2 -g
set CGO_LDFLAGS=-O2 -g
set PKG_CONFIG=pkg-config
set GOGCCFLAGS=x86_64-windows-gnu -I . -m64 -fno-caret-diagnostics -Qunused-arguments -Wl,--no-gc-sections -fmessage-length=0 -ffile-prefix-map=C:\Users\PC\AppData\Local\Temp\go-build581384153=/tmp/go-build -gno-record-gcc-switches

What did you do?

https://go.dev/play/p/-Xxe-Pmh0lG

package main

import "reflect"

// we can write static codes.

type A struct {
	ID      uint64
	Related []B
}

type B struct {
	Name    string
	Related *A
}

type C struct {
	Data uintptr
	*C
}

// how can we write dynamic codes?
func ExampleDynamic() {
	A := reflect.StructOf([]reflect.StructField{
		{Name: "ID", Type: reflect.TypeFor[uint64]()},
		{
			Name: "Related",
			Type: reflect.SliceOf(nil), // how can we do here?
		},
	})
	B := reflect.StructOf([]reflect.StructField{
		{Name: "Name", Type: reflect.TypeFor[string]()},
		{
			Name: "Related",
			Type: reflect.PointerTo(nil), // how can we do here?
		},
	})
	C := reflect.StructOf([]reflect.StructField{
		{Name: "Data", Type: reflect.TypeFor[uintptr]()},
		{
			Name:      "C",
			Type:      reflect.PointerTo(nil), // how can we do here?
			Anonymous: true,
		},
	})
	_, _, _ = A, B, C
}

statically, types are in package scope, calculation can be lazy.
dynamically, type in StructField muse be immediate.

What did you expect to see?

we can write runtime types similar to compile time types.

What did you see instead?

[gabyhelp]

Related Issues

• reflect: reflect.StructOf fields with Anonymous=true has not got Their func #59046 (closed)
• cmd/compile: Devirtualize calls when concrete type behind interface is statically known #19361 (closed)
• Point value of struct with anonymous interface field created by reflect not AssignableTo the interface type #47343 (closed)
• I want to get member's reflect.Type via struct definition, but not it's instance. #34521 (closed)
• reflect: StructTag.Get does not return 1st tag of dynamic structure created with StructOf #66645 (closed)
• Struct Reflection result is wrong #41667 (closed)
• reflect: reflect.StructOf makes incorrect type with embedded interface #61434 (closed)
• types2, go/types: panic when using reflect.TypeOf in unexported struct #48351 (closed)
• reflect: inconsistent results between reflection and non-reflection #35488 (closed)

Related Code Changes

• reflect: implement StructOf

_{(Emoji vote if this was helpful or unhelpful; more detailed feedback welcome in this discussion.)}

[seankhliao]

Duplicate of #39717