in javac-ast-extension/src/org/jetbrains/jps/javac/ast/api/JavacRef.java [283:290]
public boolean equals(Object o) {
if (this == o) return true;
if (o == null || getClass() != o.getClass()) return false;
JavacElementRefBase base = (JavacElementRefBase)o;
return myOriginalElement == base.myOriginalElement && myQualifier == base.myQualifier;
}