pp_line: do not swallow #line with negative deltas - #49
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The short-newline path used `d < 8`, which also matches negative deltas. The inner `while (d > 0)` is then a no-op, so a user #line that resumes an earlier line after a large injection is dropped and diagnostics drift. Restrict the swallow to `d >= 0 && d < 8`.
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Summary
pp_linetakes the short-newline swallow path whenlevel == 0 && f->line_ref && d < 8.d(a#linethat resumes an earlier line after a large synthetic injection) still matchesd < 8, butwhile (d > 0)is a no-op, so the directive is silently dropped and line tracking drifts.d >= 0 && d < 8so negative deltas fall through to the normal#line/# Nemission.Context
Hit this while preserving user-source line numbers after prepending generated declarations (Concurrent-C). Reproducible with any preprocess (
-E/LINE_MACRO_OUTPUT) flow that emits#line NwithNsmaller than the current physical line by 8+.Test plan
tcc -Ea file that does a large injection then#lineback to a small line number; confirm the#line(or# N) appears in the outputMade with Cursor