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

$ go version
1.15.4

Does this issue reproduce with the latest release?

Yes

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

$ go env
set GO111MODULE=
set GOARCH=amd64
set GOBIN=
set GOCACHE=C:\Users\--\AppData\Local\go-build
set GOENV=C:\Users\--\AppData\Roaming\go\env
set GOEXE=.exe
set GOFLAGS=
set GOHOSTARCH=amd64
set GOHOSTOS=windows
set GOINSECURE=
set GOMODCACHE=C:\Users\--\go\pkg\mod
set GONOPROXY=
set GONOSUMDB=
set GOOS=windows
set GOPATH=C:\Users\--\go
set GOPRIVATE=
set GOPROXY=https://proxy.golang.org,direct
set GOROOT=c:\go
set GOSUMDB=sum.golang.org
set GOTMPDIR=
set GOTOOLDIR=c:\go\pkg\tool\windows_amd64
set GCCGO=gccgo
set AR=ar
set CC=gcc
set CXX=g++
set CGO_ENABLED=1
set GOMOD=
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 -fmessage-length=0 -fdebug-prefix-map=C:\Users\--\AppData\Local\Temp\go-build775205982=/tmp/go-build -gno-record-gcc-switches

What did you do?

0. Renamed the (previously go.mod containing) repository github.com/4kills/libdeflate -> github.com/4kills/go-libdeflate

1. Try to import this project https://github.com/4kills/go-libdeflate

Sample program:

package main

import (
	"fmt"

	"github.com/4kills/go-libdeflate"
)

func main() {
	c, _ := libdeflate.NewCompressor()
	fmt.Print(c)
}

2. go mod init

3. go get

What did you expect to see?

Successfully go-getting the latest version of the repository (v2.0.4)

What did you see instead?

go: finding module for package github.com/4kills/go-libdeflate
go: found github.com/4kills/go-libdeflate in github.com/4kills/go-libdeflate v1.3.0
go: github.com/4kills/hendrikIstdoof imports
        github.com/4kills/go-libdeflate: github.com/4kills/go-libdeflate@v1.3.0: parsing go.mod:
        module declares its path as: github.com/4kills/libdeflate
                but was required as: github.com/4kills/go-libdeflate

Assumption:

See how go get tries to fetch v1.3.0 instead of v2.0.4? I guess this is due to the renaming of the repository as well as it having been a go module and thus being cached in proxy.golang.org with the wrong name!
As stated by https://proxy.golang.org/ the caches of old versions won't ever be removed. Still this is a very annoying issue when renaming repos

Workaround:

This workaround works as it fetches the latest version from the actual source repo instead of the proxy

go get github.com/4kills/go-libdeflate@master