Bug 350748

Description Stephane Barbey 2011-06-29 16:45:10 EDT

Build Identifier:  20110615-0604

The implementation of org.eclipse.xtext.xbase.util.XExpressionHelper.isLiteral(XExpression) is based on the value yielded by expr.eClass().getClassifierID(). 

This value is unique within an EPackage, but not within a language: I have e.g. a language that extends XBase and adds an

XGuardExpression returns xbase::XExpression : ...; 

that gets the classifier ID 13, i.e. the same as XSTRING_LITERAL in Xbase. As a consequence, this rule is considered as being a Literal by XExpressionHelper.

This can have various consequences depending on the usage of this helper function. In my particular case, I have introduced XGuardExpression as part of a XBlockExpression, and thus the validation rule 

	@Check
	public void checkInnerExpressions(XBlockExpression block) {
		for (int i = 0; i < block.getExpressions().size() - 1; ++i) {
			XExpression expr = block.getExpressions().get(i);
			if (expressionHelper.isLiteral(expr)) {
				error("Literals can only appear as the last element of a block expression", expr, null,
						ValidationMessageAcceptor.INSIGNIFICANT_INDEX, INVALID_INNER_EXPRESSION);
			}
		}
	}

fails each time it encounters a XGuardExpression.



Reproducible: Always