@Override
	public void blockOption(GrammarAST ID, GrammarAST valueAST) {
		checkOptions((GrammarAST)ID.getAncestor(BLOCK), ID.token, valueAST);
	}
Value of caseInsensitive option (false if not defined)
tool/src/org/antlr/v4/semantics/BasicSemanticChecks.java