There are two different bugs here, but I decided to include them in one issue/PR since the fix for both is quite simple and they are related.

Problem 1

In Java < 1.4, assert is not yet a keyword and can therefore be used as a regular identifier. There is an ambiguity in the grammar that causes a parse error when attempting to parse the statement:

assert++;

The parser currently tries to parse this as an assert statement followed by a PREFIX_INCREMENT UnaryExpr. Parsing the UnaryExpr then fails since there is no expression following the ++.

Problem 2

module is a conditional keyword that can still be used as a package name. #4910 introduced a new grammar ambiguity causing a parse error when attempting to parse an import statement for a package starting with module:

import module.Foo

The parser attempts to parse this as a module import import module .Foo and crashes when attempting to parse the name since a name cannot start with ..