Indexed / element proc-value call: arr[i](args)

• Type: feature (Track A — parser + element proc-sig tracking)
• Track: A — compiler/**
• Status: done
• Owner: Track A
• Closed: 2026-06-25
• Opened: 2026-06-25
• Split-from: [[bug-proc-typed-call-const-record-arg]] (its array-element symptom; the scalar/const-record half is fixed).
• Found-by: [[feature-demo-chess]] — Evaluate calls eval terms through a procedural-typed table EvalTerms[i](pos).

Symptom

Calling a proc-typed value held in an ARRAY ELEMENT is not parsed as an indirect call at all:

type TFn = function(x: Integer): Integer;
function Dbl(x: Integer): Integer; begin Dbl := x*2; end;
var arr: array[0..0] of TFn;
begin arr[0] := @Dbl; writeln(arr[0](21)); end.   { error: unexpected token () }

A scalar proc var (fn(args)) and a record FIELD proc value (rec.fn(args), via UFldProcSig) both work; only the array-element form is missing.

Why

ParseProcVarCallAST and its callers only special-case a simple identifier callee (fires when ( immediately follows the name). For arr[i] the callee is an AN_INDEX, and the array's element proc signature is not tracked (there is SymProcSig for a var and UFldProcSig for a field, but no element equivalent), so the postfix (args) after an indexed proc value has nowhere to bind. arr[0] yields the pointer and the (...) is dropped / mis-parsed.

Fix sketch

1. Record an element proc signature for array of <proctype> — a new SymElemProcSig (mirroring UFldProcSig), captured from LastTypeProcSig at the array declaration. NB: every symtab Alloc* must reset it to -1 (the parallel-array landmine), and that reseeds once.
2. In the ParseFactor postfix loop, after building an AN_INDEX whose base array has an element proc sig and ( follows, build AN_CALL_IND (mirror the field path at parser.inc ~1882), method-pointer flag when the element is of object.

Done when

• arr[i](args) (and EvalTerms[i](pos) with a const record param) compiles and calls correctly; the chess eval no longer saturates to ±INF.
• Regression test under make test; self-host fixedpoint byte-identical.

Resolution (2026-06-25)

• New SymElemProcSig parallel array (defs.inc) tracks an array's ELEMENT proc signature; reset to -1 at all four symtab Alloc* sites (parallel-array landmine). Captured in ParseVarSection from LastTypeProcSig after the element ParseTypeKind (plain proc => tyPointer, method ptr => tyRecord).
• ParseFactor postfix loop: after building an AN_INDEX whose base is an AN_IDENT with a non-negative SymElemProcSig and ( follows, splice an AN_CALL_IND (callee = the index node), mirroring the record-field path.
• No reseed needed — make bootstrap byte-identical first pass. make test green. Chess compiles + runs: startpos bestmove e2e4 score 10 (sane, no ±INF saturation). Regression: test/test_indexed_proc_call.pas.