Empty class descendant shorthand

• Type: feature
• Track: A
• Status: done
• Owner: —
• Opened: 2026-06-20
• Relation: surfaced by examples/chess after SysUtils.Exception landed.

Problem

FPC accepts an empty descendant declaration with a parent and no explicit end:

EChess = class(Exception);

PXX currently treats this as the start of a class body, consumes following type declarations, and eventually fails later in the type section.

Scope

• In type parsing, accept T = class(TBase); as a complete empty class declaration.
• Keep the existing full form working:

T = class(TBase)
end;

Acceptance

• A focused test can declare E = class(Exception); from uses sysutils.
• examples/chess/chess.pas gets past the EChess declaration.
• Existing class/inheritance tests still pass.

Log

• 2026-06-20 - Opened after adding the Track B Exception base class to lib/rtl/sysutils.pas. The chess discovery gap moved from missing base class to this syntax form.
• 2026-06-20 - DONE (Track A). parser.inc: if CurTok.Kind <> tkSemicolon guard wraps the class body while-loop + Expect(tkEnd). Semicolon seen after class(TBase) → skip body entirely, UClsSize still set from curFieldOff. make test green, byte-identical self-host. chess.pas now past EChess line (next gap: UpCase RTL). test/test_empty_class_shorthand.pas added.

Resolved-in: 1dd9873 (finalizing commit)