protected void reportNoViableAlternative(Parser recognizer,
											 NoViableAltException e)
	{
		TokenStream tokens = recognizer.getInputStream();
		String input;
		if ( tokens!=null ) {
			if ( e.getStartToken().getType()==Token.EOF ) input = "<EOF>";
			else input = tokens.getText(e.getStartToken(), e.getOffendingToken());
		}
		else {
			input = "<unknown input>";
		}
		String msg = "no viable alternative at input "+escapeWSAndQuote(input);
		recognizer.notifyErrorListeners(e.getOffendingToken(), msg, e);
	}
This is called by {@link #reportError} when the exception is a
{@link NoViableAltException}.

@see #reportError

@param recognizer the parser instance
@param e the recognition exception
runtime/Java/src/org/antlr/v4/runtime/DefaultErrorStrategy.java