Index: src/Parser/parser.yy
===================================================================
--- src/Parser/parser.yy	(revision d3aa55e994d9978b6eeed324d12124cd1e92a452)
+++ src/Parser/parser.yy	(revision 7552fdeef475fdf78568b8832b5d1ae15b0f249a)
@@ -10,6 +10,6 @@
 // Created On       : Sat Sep  1 20:22:55 2001
 // Last Modified By : Peter A. Buhr
-// Last Modified On : Tue Jun 25 18:44:14 2024
-// Update Count     : 6692
+// Last Modified On : Wed Jun 26 09:37:28 2024
+// Update Count     : 6700
 //
 
@@ -1607,11 +1607,12 @@
 	| comma_expression ';' enum_key						// CFA, enum type
 		{
-			$$ = enumRangeCtrl( $1, OperKinds::LThan, new ExpressionNode( new ast::TypeExpr( yylloc, $3->buildType() ) ) );
+			$$ = enumRangeCtrl( $1, OperKinds::LEThan, new ExpressionNode( new ast::TypeExpr( yylloc, $3->buildType() ) ) );
 		}
 	| comma_expression ';' downupdowneq enum_key		// CFA, enum type, reverse direction
 		{
-			if ( $3 == OperKinds::LEThan || $3 == OperKinds::GEThan ) {
-				SemanticError( yylloc, "illegal syntax, all enumeration ranges are equal (all values). Remove \"=~\"." ); $$ = nullptr;
-			}
+			if ( $3 == OperKinds::GThan ) {
+				SemanticError( yylloc, "all enumeration ranges are equal (all values). Add an equal, e.g., ~=, -~=." ); $$ = nullptr;
+				$3 = OperKinds::GEThan;
+			} // if
 			$$ = enumRangeCtrl( $1, $3, new ExpressionNode( new ast::TypeExpr( yylloc, $4->buildType() ) ) );
 		}
@@ -1627,4 +1628,7 @@
 	;
 
+// This rule exists to handle the ambiguity with unary operator '~'. The rule is the same as updowneq minus the '~'.
+// Specifically, "for ( ~5 )" means the complement of 5, not loop 0..4. Hence, in this case "for ( ~= 5 )", i.e., 0..5,
+// it is not possible to just remove the '='. The entire '~=' must be removed.
 downupdowneq:
 	ErangeDown