Better import error message for named imports

[Per Östlund]

If a named import uses a name that does not exist, e.g.

model M
  import B = A;
end M;

you get an error message:

Import A not found in scope .

This could be improved by:

• Use the full import, import B = A, in the error message.
• Either print out the correct scope, or no scope at all.

[Francesco Casella]

I just tried this with v1.13.0-dev-798-g1c8bb86de, both old and new FE, and I got them both to compile.

Honestly, I don't see a problem with this as long as the imported name B is not used...

[Per Östlund]

Replying to casella:

Honestly, I don't see a problem with this as long as the imported name B is not used...

Yeah, the NF only resolves imported names the first time they're used. And if the import isn't used it doesn't matter what it points to.

And for the record, if the import is used the NF will now print an error message with the correct scope. It just so happens that the scope is always <top> since imports are always looked up in the top scope, so it's kind of redundant but still correct.