Track access paths of the form Foo.this.bar

[msridhar]

Fixes #936

We add limited tracking of such access paths, to handle null checks on fields from an enclosing class of a nested class.

[msridhar]

/benchmark

[codecov]

Codecov Report

Attention: Patch coverage is 85.71429% with 1 lines in your changes are missing coverage. Please review.

Project coverage is 87.04%. Comparing base (3bde26c) to head (3c8ff10).

Files	Patch %	Lines
...in/java/com/uber/nullaway/dataflow/AccessPath.java	85.71%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##             master     #937      +/-   ##
============================================
- Coverage     87.04%   87.04%   -0.01%     
- Complexity     1993     1995       +2     
============================================
  Files            77       77              
  Lines          6440     6447       +7     
  Branches       1249     1252       +3     
============================================
+ Hits           5606     5612       +6     
  Misses          422      422              
- Partials        412      413       +1     

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[yuxincs]

LGTM!

[github-actions]

Main Branch:

Benchmark                          Mode  Cnt   Score   Error  Units
AutodisposeBenchmark.compile      thrpt   25   9.212 ± 0.074  ops/s
CaffeineBenchmark.compile         thrpt   25   2.122 ± 0.023  ops/s
DFlowMicroBenchmark.compile       thrpt   25  25.144 ± 0.348  ops/s
NullawayReleaseBenchmark.compile  thrpt   25   1.283 ± 0.020  ops/s

With This PR:

Benchmark                          Mode  Cnt   Score   Error  Units
AutodisposeBenchmark.compile      thrpt   25   9.264 ± 0.093  ops/s
CaffeineBenchmark.compile         thrpt   25   2.120 ± 0.025  ops/s
DFlowMicroBenchmark.compile       thrpt   25  24.611 ± 0.319  ops/s
NullawayReleaseBenchmark.compile  thrpt   25   1.271 ± 0.018  ops/s