Improve error message when extension file does not contain module #51626
Description
I just tried to create a package extension, but forgot to wrap the code in the extension file in its own module. I got an error saying:
[ Info: Precompiling TestExt [29286dec-c893-52d1-88fe-e07e79eb4405]
ERROR: LoadError: ArgumentError: Package Base does not have Test in its dependencies:
- You may have a partially installed environment. Try `Pkg.instantiate()`
to ensure all packages in the environment are installed.
- Or, if you have Base checked out for development and have
added Test as a dependency but haven't updated your primary
environment's manifest file, try `Pkg.resolve()`.
- Otherwise you may need to report an issue with Base
Stacktrace:
[1] macro expansion
@ Base ./loading.jl:1770 [inlined]
[2] macro expansion
@ Base ./lock.jl:267 [inlined]
[3] __require(into::Module, mod::Symbol)
@ Base ./loading.jl:1747
IMO this error is pretty confusing because it claimed I was trying to load Test from Base, whereas in fact, I tried loading it in my extension module.