gh-138857: Improve error message for case outside of match

[sobolevn]

Preview:

What do you think? :)

• Issue: Improve syntax error message for case 1: statement #138857

[pablogsal]

I am fine with this but I wonder how often people may fall into this... I don't think is a bad idea I cannot see anything wrong with the grammar since the short circuit is NAME + NAME. Does this trigger for case match: (afk atm so I cannot check myselef) ?

[sobolevn]

@pablogsal here's the result :)

[sobolevn]

I am fine with this but I wonder how often people may fall into this

I always try to report parsing problems from errors that I make myself that make me scratch my head. Today I wrote this code while reviewing this PR: wemake-services/wemake-python-styleguide#3526

case some:  # <- should be `match`
    case other: ...

and I was like: what's wrong? Why is there a syntax error?

It was not easy to mention, especially given that some languages like gleam do start pattern matching with case, not match :)

[pablogsal]

I am fine with this but I wonder how often people may fall into this

I always try to report parsing problems from errors that I make myself that make me scratch my head. Today I wrote this code while reviewing this PR: wemake-services/wemake-python-styleguide#3526

case some:  # <- should be match
    case other: ...

and I was like: what's wrong? Why is there a syntax error?

It was not easy to mention, especially given that some languages like gleam do start pattern matching with case, not match :)

Sold! Ok, let's get it in I think is a good idea. I was tempted to suggest getting:

case some:  # <- should be match
    case other: ...

as "maybe you mean match" but that's going to be a can of worms