function isIncrementExpression() {
            // This function is called inside parseUnaryExpression to decide
            // whether to call parseSimpleUnaryExpression or call parseIncrmentExpression directly
            switch (token) {
                case 35 /* PlusToken */:
                case 36 /* MinusToken */:
                case 50 /* TildeToken */:
                case 49 /* ExclamationToken */:
                case 78 /* DeleteKeyword */:
                case 101 /* TypeOfKeyword */:
                case 103 /* VoidKeyword */:
                    return false;
                case 25 /* LessThanToken */:
                    // If we are not in JSX context, we are parsing TypeAssertion which is an UnaryExpression
                    if (sourceFile.languageVariant !== 1 /* JSX */) {
                        return false;
                    }
                // We are in JSX context and the token is part of JSXElement.
                // Fall through
                default:
                    return true;
            }
        }
Check if the current token can possibly be an ES7 increment expression.

ES7 IncrementExpression:
     LeftHandSideExpression[?Yield]
     LeftHandSideExpression[?Yield][no LineTerminator here]++
     LeftHandSideExpression[?Yield][no LineTerminator here]--
     ++LeftHandSideExpression[?Yield]
     --LeftHandSideExpression[?Yield]