@Override
	public boolean equals(Object obj) {
		if ( this==obj ) return true;
		// A() and label A are different
		if ( !(obj instanceof ContextGetterDecl) ) return false;
		return name.equals(((Decl) obj).name) &&
				getArgType().equals(((ContextGetterDecl) obj).getArgType());
	}
Make sure that a getter does not equal a label. X() and X are ok.
 OTOH, treat X() with two diff return values as the same.  Treat
 two X() with diff args as different.
tool/src/org/antlr/v4/codegen/model/decl/ContextGetterDecl.java