[Gm2] A SET error, perhaps?

[John O Goyo]

Greetings:

I believe the following to be correct (and compiles with GPM and XDS). 
I threw in HALT so as to have some sort of conditional without importing 
anything.

=========================================
MODULE bits;

TYPE
  Colour = SET OF (red, green, blue);

VAR
  sky, land :Colour;

BEGIN
  sky := Colour{red, blue};
  land := Colour{green};

  IF land <= sky THEN
     HALT
  END (*IF*)

END bits.
=========================================

Gm2 begs to differ:

% gm2 -c bits.mod
bits.mod:4:symbol (Colour) is already declared in this scope, use a 
different name or remove the declaration
bits.mod:4:and symbol (Colour) is also declared here

Please advise.

Sincerely,
john