/**
* Check that t1 :> t2 or, equivalently, that t2 is a subtype of t1. A type
* <code>t1</code> is said to be a subtype of another type <code>t2</code>
* iff the semantic set described by <code>t1</code> contains that described
* by <code>t2</code>.
*
* @param t1
* --- Semantic type that should contain <code>t2</code>.
* @param t2
* --- Semantic type that shold be contained by <code>t1/code>.
* @param element
* --- Syntax error is reported against this element if
* <code>t1</code> does not contain <code>t2</code>.
*/
private void checkIsSubtype(SemanticType t1, SemanticType t2, SyntacticElement element) {
if (!SemanticType.isSubtype(t1, t2)) {
syntaxError("expected type " + t1 + ", got type " + t2, filename, element);
}
}
