Captured Boolean loses its type inside a parallel-for body (overload resolution fails)

• Type: bug — Track A (parallel-for capture lowering; parser.inc capture-frame path).
• Status: done
• Found by: Track E, building examples/mandelbrot/mandelzoom.pas ([[feature-demo-mandelbrot-asm-autozoom]]).

Repro

program Cap2;
uses palparallel;
procedure Sink(i: Integer; flag: Boolean);
begin if flag then ; end;
procedure Run;
var i: Integer; lflag: Boolean;
begin
  lflag := True;
  parallel for i := 0 to 99 do Sink(i, lflag);
  writeln('ok');
end;
begin Run; end.

    param[0] = 1
    param[1] = 2
pascal26:9: error: no overload of Sink matches these arguments ()
  near:  i  lflag   >>>

The diagnostic's own dump gives it away: the callee's parameter 1 is kind 2 (Boolean) but the argument arrives as kind 1 (Integer). lflag is a plain Boolean local — the supported Phase-A scalar-capture shape — and reading it in the body (if lflag then ...) works; only passing it to a Boolean parameter fails. So the capture rewrite is dropping the declared type and re-materialising the slot as an Integer.

Presumably every non-Integer scalar (Char, enums, subranges, Byte…) is worth checking at the same time — Boolean is just the one this hit first.

Secondary: the error message is unhelpful

no overload of Sink matches these arguments () — the parenthesis is empty where the argument types should be, and the numeric param[n] = k dump above it is internal type-kind numbering with no legend. For a non-overloaded procedure the message should say which argument mismatched and in what way. Worth fixing alongside; it cost more time here than the bug itself.

Acceptance

• The repro prints ok.
• A regression test extending test/test_parallel_for_capture.pas to cover a captured Boolean (and Char / enum) both read in the body and passed as an argument.
• Track A gate: make test + self-host byte-identical.

Links

[[bug-parallel-for-captured-dynarray-var-arg-segfault]] (same session, same capture path, worse failure mode) · [[feature-demo-mandelbrot-asm-autozoom]] · test/test_parallel_for_capture.pas.

Log

• 2026-07-20 — Filed from Track E. Demo works around it by reading the flag from a global instead of a captured local.
• 2026-07-22 — resolved, commit 49f4eb55.