RFR: 8253584: Redunant errors for partial member selects [v2]

[Jan Lahoda]

> For code like:
> package t;
> 
> class Test {
> 
>     void t() {
>         if (true) {
>             s().
>         } else {
>         }
>     }
> 
>     String s() {
>         return null;
>     }
> }
> 
> (note the missing member name after `s().`), javac will produce a number of compile-time errors:
> $ javac /tmp/Test.java
> 
>             s().
>                 ^
> 
>             s().
>                ^
> 
>         } else {
>          ^
> 
>         } else {
>           ^
> 
>     String s() {
>             ^
> 
> }
>  ^
> 6 errors
> 
> The reason is that after not seeing an identifier after the `.` javac will skip the token that follows the dot. This
> was done to improve errors in https://bugs.openjdk.java.net/browse/JDK-8081769 . But here, reading the next token will
> skip the closing `}`, and the parser will de-synchronize with the braces, leading to the follow-up errors.  The
> proposal here is to handle incorrect `.class` specially, and avoid reading the next token when an identifier is no
> specified in a member select, except when the next token is `class`.  The errors with this patch are:
> $ javac /tmp/Test.java
> 
>             s().
>                 ^
> 
>             s().
>                ^
> 2 errors
> 
> This seems much better.

Jan Lahoda has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev
excludes the unrelated changes brought in by the merge/rebase. The pull request contains two additional commits since
the last revision:

 - Merge branch 'master' into JDK-8253584
 - 8253584: Redunant errors for partial member selects

-------------

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/333/files
  - new: https://git.openjdk.java.net/jdk/pull/333/files/914c9fde..9bc235ad

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=333&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=333&range=00-01

  Stats: 28156 lines in 596 files changed: 4818 ins; 21874 del; 1464 mod
  Patch: https://git.openjdk.java.net/jdk/pull/333.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/333/head:pull/333

PR: https://git.openjdk.java.net/jdk/pull/333