entity e1{	
	op op2 ():Number {			 
		var Number n = 1
		n = 1 - 1 //Doesnt work: "Couldn't resolve reference to JvmIdentifiableElement '-'."
        	n = (1 as Double) - 1 // Works, bacause of cast, uses DoubleExtensions				
		return 1 // Works
	}
}

class MyTypeComputer extends XbaseTypeComputer {	
        override void _computeTypes(XNumberLiteral object, ITypeComputationState state) {		
		val LightweightTypeReference result = getTypeForName(typeof(Number), state);
		state.acceptActualType(result);
	}
}

class MyCompiler extends XbaseCompiler {
	override _toJavaExpression(XNumberLiteral expr, ITreeAppendable b) {		
                 b.append(expr.value)
	}
}

class NumberExtensions {
    def public static Number operator_minus(Number x, Number y) {
         return x - y;
     }
    //.....
}

class MyImplicitlyImportedFeatures extends ImplicitlyImportedFeatures {
	override protected getExtensionClasses() {
		(super.getExtensionClasses() + #[NumberExtensions])
			.toList
	}
}