mypy error reporting should include column position

[zen0wu]

Currently it seems that only line number is included, and confusion will be introduced when there's multiple errors in the same line. Is there any plans to improve this?

typecheck_error.py: note: In function "f":
typecheck_error.py:2: error: Unsupported operand types for * ("str" and "complex")
typecheck_error.py:2: error: Incompatible return value type: expected builtins.int, got builtins.complex

[JukkaL]

It would be nice to have the column numbers as well. We are planning a parser rewrite and that might make this easy enough to implement.

[ddfisher]

Yeah, the parser rewrite should make this info easily available.

[bavardage]

was there any progress here? pretty interested in this too

[gvanrossum]

I apologize, we have been occupied with higher priority projects. Thanks for showing your interest though -- we'll be sure to bump the priority eventually. (We also accept PRs of course.)

[bavardage]

happy to attempt a PR at some point, not super familiar with the code yet

thoughts:

• add column info to node @ https://github.com/python/mypy/blob/master/mypy/nodes.py#L91
  • potentially also add start column, end column, start line, end line (?)
• modify the parser to add on this info (where it's available)

for the parser, this would mean modifying both fastparse, fastparse2 and parse?

[gvanrossum]

We're phasing out parse.py, but yes, both fastparse{,2}.py would need to be updated. The big question is whether typed_ast, which we use for the actual parser, is collecting this info. If not, we have to modify typed_ast first.

[gvanrossum]

This was done. Thanks to Ben Duffield! Note that you need to use --show-column-numbers.

[zen0wu]

Thank you so much guys! This is amazing!