Read / Write can't be used as method names (reserved)

• Type: bug (lexer/parser) — language
• Status: urgent (Track A)
• Owner: — (Track A — compiler/**)
• Opened: 2026-06-24
• Found-by: Classes / TStream ([[feature-own-net-http-lib]]) — TStream.Read / TStream.Write.

Symptom

Declaring a method named Read or Write fails, even with ordinary typed parameters:

type TC = class
  function Read(p: Pointer; Count: Integer): Integer;   { ERROR }
  function Write(p: Pointer; Count: Integer): Integer;
end;

→ error: expected method name at the Read line.

Read/Write are lexed as reserved tokens (for the Read/Readln/Write/ Writeln console/file intrinsics) and so are not accepted as identifiers in a method-name position.

Impact

TStream.Read / TStream.Write are the canonical FPC/Delphi stream method names — synapse and all stream code call stream.Read(buf, n) / stream.Write(buf, n). Without these names the standard TStream/TMemoryStream cannot be expressed (renaming them breaks compatibility). Together with [[bug-untyped-params-in-methods]] this blocks the stream surface.

Fix

Read/Write (and Readln/Writeln) are intrinsics resolved at the call site by context, not true reserved words — allow them as identifiers in a declaration/member-name position (method names, and ideally fields/locals). FPC treats them as system identifiers that user declarations can shadow. The call stream.Read(...) already has a receiver, so it should resolve to the method, not the console intrinsic.

Done when

• A class may declare Read/Write methods; obj.Read(...) calls the method while bare Read(...)/Write(...) still reach the console/file intrinsics.
• TStream/TMemoryStream compile (with [[bug-untyped-params-in-methods]]).
• Regression test under make test; self-host fixedpoint byte-identical.

Log

• 2026-06-24 — FIXED (Track A). Read/Write/Readln/Writeln carry their text in SVal, so they are accepted as method NAMES via a new IsMemberNameTok helper at the method-declaration and implementation-header name positions (parser.inc). Member CALL sites (stream.Read(...)) already accepted them. Verified: a class with virtual Read/Write declares, implements, and dispatches. RESIDUAL (separate, filed bug-virtual-keyword-name-result): assigning such a method's result by its OWN name (Read := x) inside a VIRTUAL method miscompiled the return value; that form is now a clear compile error directing to Result := ... (which is correct in all cases) instead of silently mis-storing. Regression test/test_stream_methods.pas in make test.