Permission denied when running go from Makefile - go

Question

I'm experiencing some weird permission denied errors that I have no idea where could be coming from.
$ go run .
Hello from go
$ make run
go run .
make: go: Permission denied
make: *** [Makefile:2: run] Error 127
$ make run2
echo "Make says hello" ; go run .
Make says hello
Hello from go
$ cat Makefile
run:
go run .
run2:
echo "Make says hello" ; go run .
$ cat main.go
package main
import "fmt"
func main() {
fmt.Println("Hello from go")
}
My terminal is bash running on Ubuntu 22.04.
What is the difference between my run target and running go directly that can cause a permission denied error?
What's the difference between run and run2 that allow it to work in one but not in the other?
EDIT: Running make with -d / --trace
$ make -d run
<...snip...>
No need to remake target 'Makefile'.
Updating goal targets....
Considering target file 'run'.
File 'run' does not exist.
Finished prerequisites of target file 'run'.
Must remake target 'run'.
go run .
make: go: Permission denied
make: *** [Makefile:2: run] Error 127
$ make --trace run
Makefile:2: target 'run' does not exist
go run .
make: go: Permission denied
make: *** [Makefile:2: run] Error 127
$ make --trace run2
Makefile:5: target 'run2' does not exist
echo "Make says hello"; go run .
Make says hello
Hello from go

Answer 1

This is due to a bug in GNU make (actually it's a bug in gnulib). It means that you have a directory named go, in some directory on your PATH (before the actual directory containing the go executable).
So if you have a directory /usr/bin/go/. and you have /usr/bin on your PATH, you'll see this issue.
You should check your PATH and make sure to remove any directories that contain such subdirectories. If you can't remove that directory from your PATH (it's unusual to need directories containing subdirectories on your PATH but I guess it's possible) and you can't rename the go directory to something else, you'll have to ensure that GNU make invokes a shell, by adding a special character. Just ; is good enough:
run:
go run . ;

Answer 2

The issue you're experiencing is likely due to different environment between your shell and shell executed by Makefile. If for example you have a shell alias for go this alias is not visible to Makefile or if you have a custom path in you're shell rc file it's not visible to Makefile. It's hard to guess where the difference might be.
You might want to try debug the issue by trying following in your Makefile:
echo $(PATH)
command -v go
and run the same commands in your shell and compare results.
Note that the default shell for Makefile is /bin/sh whereas you probably have bash or zsh.
Here's some handy defaults to configure your Makefile build:
LANG=en_US.UTF-8
SHELL=/bin/bash
.SHELLFLAGS=--norc --noprofile -e -u -o pipefail -c