Fix unused argument bug

[kimdv]

While running develop branch (dc580e8) on out code base, we see this

        for item in items { <--- Before formatting
        for _ in items { <--- After formatting
            guard let item = try? await storage.record(
                matching: item.id
            ) else {
                return
            }

            storage.save(item)
        }

I added a test case to reproduce the error.

I will try to solve it, with Cursor, and maybe also I need to ask some stupid questions 😅

[kimdv]

Analysis from Cursor:

Root cause: In isStartOfStatement (ParsingHelpers.swift), the .keyword("await") case checks if the previous token is a postfix operator and returns true (is a start of statement) if so. When parsing try? await, the ? after try is a postfix operator, so await was incorrectly treated as a new statement.

This caused removeUsed to call pushLocals() prematurely, moving the guard let binding (item) from tempLocals into locals. When the actual usage of item (in item.id) was later encountered, it was already in locals and skipped -- so the for-loop variable was never recognized as "used" and got replaced with _.

Fix: Added a new case in the switch inside isStartOfStatement for .operator("?", .postfix) and .operator("!", .postfix) that checks if the token before the operator is try or as. If so, the current token is a continuation of the expression, not a new statement, and false is returned. This mirrors an identical check that already existed for .identifier tokens (line 1159-1172) but was missing for .keyword("await").

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 95.29%. Comparing base (dc580e8) to head (2b79fa3).
⚠️ Report is 1 commits behind head on develop.

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #2421      +/-   ##
===========================================
- Coverage    95.30%   95.29%   -0.01%     
===========================================
  Files          164      164              
  Lines        25080    25090      +10     
===========================================
+ Hits         23902    23910       +8     
- Misses        1178     1180       +2     

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[calda]

Thanks!