Array constructor `[...]` as open-array arg fails at a statement-level call

Type: bug (parser / call lowering — correctness) — Track A
Status: done — fixed 2026-07-01, pin v127
Opened: 2026-06-30 (Track B latent-bug sweep, against stable v97)
Relates: regresses part of [[feature-open-array-constructor-arg]] (done 2026-06-23)

Resolution

Confirmed exactly the predicted cause: compiler/parser.inc's statement-level call-arg by-ref check (~line 8755) excluded AN_VARREC_ARRAY from the "must be a variable" gate but never added AN_ARRAY_CTOR alongside it, unlike the expression-level check (~line 5248) which already allowed both. One-line fix: and (ASTKind[exprNode] <> AN_ARRAY_CTOR) added to the same gate. Regression test test/test_open_array_ctor_stmt.pas (procedure + function statement-call with a [...] literal, plus an empty-[] statement call), wired into make test. Front-end only — self-host byte-identical (gen1==gen2, no lag), full make test green, make stabilize green.

Symptom

Passing an inline array constructor [...] to an array of T parameter works when the call is an expression but is rejected when the same call is a statement (procedure call, or function call with the result discarded):

function f(const a: array of integer): integer; begin f := length(a); end;
var r: integer;
begin
  r := f([1,2,3]);   { OK  -> 3 }
  f([4,5]);          { ERROR }
end.

pascal26: error: by-reference argument must be a variable ()

Procedures (which can only be called as statements) therefore can never take an inline constructor:

procedure p(const a: array of integer); begin writeln(length(a)); end;
begin p([1,2,3]); end.    { ERROR — same message }

Isolation

Call site	result
`writeln(f([1,2,3]))` (expression)	OK
`r := f([1,2,3])` (expression, assignment RHS)	OK
`f([4,5]);` (statement, result discarded)	FAIL
`p([1,2,3]);` (procedure, statement)	FAIL

Element type (integer / string) and body (length-only vs indexing) do not matter — the only axis is expression-context vs statement-context call.

Likely cause

feature-open-array-constructor-arg (done 2026-06-23) added AN_ARRAY_CTOR and wired it into both the expression-level (parser ~4243) and statement-level (~7494) call-arg loops, including a bypass of the by-ref "must be a variable" check. The expression path still works; the statement-level path no longer applies the AN_ARRAY_CTOR handling / by-ref bypass (regressed or never fully landed). Re-check the statement-call-arg loop against the expression one and restore the ParamIsOpenArrayScalar → ParseArrayCtorAST → bypass branch.

Acceptance