protected ATNState getReachableTarget(Transition trans, int t) {
		if (trans.matches(t, Lexer.MIN_CHAR_VALUE, Lexer.MAX_CHAR_VALUE)) {
			return trans.target;
		}

		return null;
	}
Given a starting configuration set, figure out all ATN configurations
 we can reach upon input {@code t}. Parameter {@code reach} is a return
 parameter.
runtime/Java/src/org/antlr/v4/runtime/atn/LexerATNSimulator.java