@Override
			public void IOError(STMessage msg) {
				reportError(msg);
			}
How many bits should be used to do inline token type tests? Java assumes
 a 64-bit word for bitsets.  Must be a valid wordsize for your target like
 8, 16, 32, 64, etc...

 @since 4.5
tool/src/org/antlr/v4/codegen/Target.java