/**
* Return the greatest lower bound of two types. That is, return the largest type that is a
* subtype of both inputs.
*/
public JReferenceType strongerType(JReferenceType type1, JReferenceType type2) {
if (type1 == type2) {
return type1;
}
if (type1 instanceof JNullType || type2 instanceof JNullType) {
return JNullType.INSTANCE;
}
if (type1 instanceof JNonNullType != type2 instanceof JNonNullType) {
// If either is non-nullable, the result should be non-nullable.
return strongerType(type1.getNonNull(), type2.getNonNull());
}
if (typeOracle.canTriviallyCast(type1, type2)) {
return type1;
}
if (typeOracle.canTriviallyCast(type2, type1)) {
return type2;
}
// cannot determine a strong type, just return the first one (this makes two
// "unrelated" interfaces work correctly in TypeTightener
return type1;
}
