← board

TEnum(intExpr) ordinal→enum typecast fails: "undefined variable"

Repro

program P;
type
  TColor = (cWhite, cBlack);
var
  c: TColor;
  i: Integer;
begin
  i := 1;
  c := TColor(i);           { <-- fails }
  writeln(Ord(c));
end.



pascal26:9: error: undefined variable (TColor)

The reverse direction works fine:

c := cBlack;
i := Integer(c);             { ok, prints 1 }

So enum→ordinal typecasts resolve, but ordinal→enum typecasts (TEnum(expr)) are parsed as if TColor were being looked up as a variable/value identifier rather than recognized as a type name in typecast position — asymmetric handling of the same construct.

Why it matters

Chess-style code commonly derives an enum from an arithmetic index (e.g. pos.sideToMove := TColor(1 - Ord(us)), or table-driven piece-kind lookups cast back to the enum type). examples/chess/chess.pas itself avoids this particular pattern (uses Opp() / direct enum literals instead), so it isn't currently blocking the demo, but it's a basic, commonly-expected cast direction that silently breaks with a confusing error (a Pascal programmer would strongly expect TEnum(ordinalExpr) to be a completely ordinary cast, not suspect "undefined variable" — the message is also misleading, since TColor is a perfectly well-defined type).

Suggested investigation

Likely a gap in wherever the compiler recognizes <ident>(...) as a typecast vs a call/variable reference — probably only checks a small set of built-in target types (Integer/Byte/etc.) and record/class types, missing user-defined enum types in that dispatch.

Acceptance

Log