Infer type of var variable from right-hand-side of assignment

[xenoterracide]

  Map<String, @Nullable Object> getContext( Map<String, String> context ) {
    var map = new HashMap<String, @Nullable Object>();
    map.putAll( context );
    map.putAll( mapper.convertValue( cliConfiguration, Map.class ) );
    map.put( "configDir", configDir.getParent() );
    return Collections.unmodifiableMap( map );
  }

fails to compile with 2 errors

home/xeno/IdeaProjects/brix/config-loader/spi/src/main/java/com/xenoterracide/brix/configloader/spi/ConfigValueProcessor.java:75: error: [assignment.type.incompatible] incompatible types in assignment.
    var map = new HashMap<String, @Nullable Object>();
              ^
  found   : @Initialized @NonNull HashMap<@Initialized @NonNull String, @Initialized @Nullable Object>
  required: @UnknownInitialization @Nullable HashMap<@Initialized @NonNull String, @Initialized @NonNull Object>
/home/xeno/IdeaProjects/brix/config-loader/spi/src/main/java/com/xenoterracide/brix/configloader/spi/ConfigValueProcessor.java:78: error: [argument.type.incompatible] incompatible argument for parameter value of put.
    map.put( "configDir", configDir.getParent() );
                                             ^
  found   : @Initialized @Nullable Path
  required: @Initialized @NonNull Object

but this code has no errors

  Map<String, @Nullable Object> getContext( Map<String, String> context ) {
    Map<String, @Nullable Object> map = new HashMap<>();
    map.putAll( context );
    map.putAll( mapper.convertValue( cliConfiguration, Map.class ) );
    map.put( "configDir", configDir.getParent() );
    return Collections.unmodifiableMap( map );
  }

the only difference is that I'm not using var (I believe var uses left hand side inference as opposed to this being right hand side, but I may have them inverted)

related to #4587 (comment) but that's a request for better documentation, this is for an actual compiler improvement.

[mernst]

I added a simplified test case as Issue4593.java.

[spacether]

The var feature JEP286 was released in Java 10, which was released in 2018.
So this feature has been around for 6 years.
I am still seeing this issue in the checker framework v3.34.0
Any chance that fixing this can be prioritized? Thank you for all of your hard work!

[msridhar]

@spacether I believe this was fixed by #5770, which was included in v3.35.0. There have been further fixes since then, so I suggest you give things a try with the latest Checker Framework release.

I'm going to go ahead and close this issue (sorry we missed closing it before), but if you notice a problem with var support please file a new issue.

[spacether]

Upgrading fixed it, thanks!