'std' panics on lowering

[m-span]

What happened?

trying to compile just std leads to program panic

PRQL input

std

SQL output

The application panicked (crashed).
Message:  called `Option::unwrap()` on a `None` value
Location: prqlc/prqlc/src/semantic/lowering.rs:227

Expected SQL output

n/a

MVCE confirmation

• Minimal example
• New issue

Anything else?

Interestingly enough, if std is later in a pipeline, it errors out appropriately

Error:
   ╭─[:1:10]
   │
 1 │ from a | std
   │          ─┬─
   │           ╰─── expected a function, but found `std`
───╯

[m-span]

This feels similar to #4317 - I'm going to see whats up here

[aljazerzen]

This message should rather say "current implementation of the resolver is half-asses, this should fail earlier, with a better error message".

I'm working on rewriting it all, but I wonder if my new version will cover this case too.

In any case, thanks for the report, this is useful and will be fixed, maybe long time in the future.