Terminal rule ID not matching valid values for ID

Question

I'm trying to define a rule where one element is the perfect candidate for the common terminal rule ID. When I launch the editor to test with sample code, the ID rule is not matched for the string "ABC":

Define : ABC : Holder_1 

I get "mismatched input 'ABC' expecting RULE_ID".

Is there something in my grammar conflicting with the ID rule to cause this error?

This is my grammar file:

grammar com.testco.Test with org.eclipse.xtext.common.Terminals 
import "http://www.eclipse.org/emf/2002/Ecore" as ecore
generate defwiz "http://www.testco.com/Test"

Define_Holder:
  'Definition' ':' holder_name=ID ':' holder_number=HOLDER_NUMBER (':' attribute=define_attr)? (':' pad=holder_pad)?
;

holder_pad:
  HEX
;

Type:
  TYPE_TERM ':' type_value=TYPE_VAL
;


//***************** TERMINALS *****************
terminal TYPE_TERM:
 'Type_' INT+
;  

terminal PROFILE:
  (PROFILE_ID)(PROFILE_ID)'.'(PROFILE_ID)(PROFILE_ID)
;

terminal HOLDER_NUMBER returns ecore:: EString:
  'Holder_' INT+; 

terminal HEX returns ecore:: EString :
  ('0'..'9'|'A'..'F')
;

terminal PROFILE_ID  : '^'?('a'..'z'|'A'..'Z') ('a'..'z'|'A'..'Z'|'0'..'9')*;


//***************** ENUMS *****************
enum define_attr:
  BINARY='Binary' |
  SCRAMBLE='Scramble' |
  FORCESIZE='ForceSize' |
  FIXEDSIZE='FixedSize'
;

Answer 1

Your rule PROFILE_ID shadows the ID rule for almost every case (except for the underscore).

Answer 2

Yes, it's likely that lexer scans ABC as HEX terminal. Try to define the latter, for example, as follows:

terminal HEX returns ecore:: EString :
 '0x' ('0'..'9'|'A'..'F')
;