reflect: artifact in Type.String() for nested generic local type

[d-enk]

Go version

go version go1.22.3 linux/amd64

Output of go env in your module/workspace:

GO111MODULE=''
GOARCH='amd64'
GOBIN=''
GOEXE=''
GOEXPERIMENT=''
GOFLAGS=''
GOHOSTARCH='amd64'
GOHOSTOS='linux'
GOINSECURE=''
GONOPROXY='*.r-99.com'
GONOSUMDB='*.r-99.com'
GOOS='linux'
GOPRIVATE=''
GOPROXY='https://proxy.golang.org,direct'
GOROOT='/home/linuxbrew/.linuxbrew/Cellar/go/1.22.3/libexec'
GOSUMDB='sum.golang.org'
GOTMPDIR=''
GOTOOLCHAIN='auto'
GOTOOLDIR='/home/linuxbrew/.linuxbrew/Cellar/go/1.22.3/libexec/pkg/tool/linux_amd64'
GOVCS=''
GOVERSION='go1.22.3'
GCCGO='/usr/bin/gccgo'
GOAMD64='v1'
AR='ar'
CC='cc'
CXX='c++'
CGO_ENABLED='1'
GOWORK=''
CGO_CFLAGS='-O2 -g'
CGO_CPPFLAGS=''
CGO_CXXFLAGS='-O2 -g'
CGO_FFLAGS='-O2 -g'
CGO_LDFLAGS='-O2 -g'
PKG_CONFIG='pkg-config'
GOGCCFLAGS='-fPIC -m64 -pthread -Wl,--no-gc-sections -fmessage-length=0 -ffile-prefix-map=/tmp/go-build1045386246=/tmp/go-build -gno-record-gcc-switches

What did you do?

package main

import "reflect"

func main() {
    type Type[T any] struct{ t T }

    println(
        reflect.TypeOf(Type[Type[int]]{}).String(),
    )
    // main.Type[main.Type[int]·1]
}

playground

Reproduced since 1.20 (no 18/19)

What did you see happen?

unexpected ·1

What did you expect to see?

no artifact

[ianlancetaylor]

This is not a bug. It's possible to have identically named types, and we need some way to distinguish them. Consider

https://go.dev/play/p/B-LoKA1n2LE