{$mode delphi} — remaining @-relax edge slices

• Type: feature (dialect mode, follow-up)
• Status: rainy-day (low priority)
• Owner: — (Track A)
• Opened: 2026-06-22
• Follows: [[feature-mode-delphi]] (core slices DONE — done/)
• Driver: [[feature-mimic-fpc]] / [[feature-networking]] — a proper Synapse library compile is the real test. Pull a slice in here only when a concrete Synapse (or other real {$mode delphi} source) unit actually trips on it; file the offending construct as the trigger. Do not speculatively build these out — they are edge bind sites the headline deltas already cover for the common cases.

Why low priority

The two FPC-verified behavioural deltas and the bind sites that carry real library weight are already done and oracle-matched against FPC -Mdelphi:

• @-optional procedural value at the assignment site (p := F).
• @-optional procedural value at the call-argument site (g(F)).
• @-optional method pointer at the assignment site (p := obj.M).
• bare own-name read is never the result var in delphi (paramless → recursive call; with-params → function value).

What remains are narrower constructs. They mostly parse to a wrong-but-rare shape rather than mis-compile silently, so they surface loudly when hit. Hold until Synapse (or similar) demands them.

Remaining slices

1. Proc-value comparison if p = F / if p <> F (and @F on either side of a relational op). A bare routine name compared to a proc-typed expression should take its address. Weaker footing than the bind sites: needs the LHS proc-type known at the point the RHS is parsed (ParseExpr, the tkEq/tkNeq/... branch ~parser.inc 4304), and there is no overload-retry harness there as there is for call args — so the paramless-function ambiguity (call-first vs address) has to be resolved differently (likely: only relax when one side is unambiguously proc-typed and the other is a bare routine name that cannot be a value-call here — procedure / with-params fn, the TryDelphiBareProcArg rule). FPC -Mdelphi is the oracle.

2. Proc-typed / method-pointer record & array fields as the bind target: rec.cb := F, arr[i] := obj.M. The current assignment-site relax keys off a simple lvalue var symbol (idx with SymProcSig[idx] >= 0, TypeKind = tyRecord for method ptr). A field/element lvalue goes through a different node (AN_FIELD/AN_INDEX) and is not covered. Need to detect the target's element/field proc-sig and reuse the same AN_PROCADDR / AN_METHODREF emission.

3. Method pointer at the call-arg site g(obj.M) — only the assignment site does method pointers today. Mirror the TryDelphiBareProcArg peek for the obj.method shape (emit AN_METHODREF), gated on the formal being a method-pointer parameter.

4. Per-unit / per-section {$mode} reset. DelphiMode is currently a whole-compile flag (set by the lexer directive, never restored). Fine for a single delphi program, but in a multi-unit compile a non-delphi unit pulled after a delphi one would inherit delphi semantics. Needs save/restore of DelphiMode around ParseUsesUnit / unit boundaries (same shape the [[feature-mimic-fpc]] v2 per-unit define scoping will want — coordinate). This is the one that bites silently in a real multi-unit Synapse build, so it is the most likely first trigger.

Implementation pointers (already in tree)

• Assignment-site relax + method-ptr branch: compiler/parser.inc, search "Delphi-mode @-optional procedural value".
• Call-arg relax: TryDelphiBareProcArg + MatchCallDelphiProcAddr (same file).
• Method-pointer infra: AN_METHODREF, EnsureMethodPtrRec, of object types, target-aware TMethod Data offset in AN_ASSIGN (compiler/ir.inc).
• Distinguisher: a method-pointer var/field is TypeKind = tyRecord (16-byte Code+Data); a plain proc-ptr is tyPointer. SymProcSig >= 0 = proc-typed.
• Oracle: fpc -Mdelphi. Gate any change: make test (self-host byte-identical)
  • make cross-bootstrap.

Gate / landmines

• } inside a { } comment closes it early (cost a test once — use Code+Data, not {Code,Data}).
• Never default DelphiMode on; lib/rtl must stay {$ifdef FPC}-clean.