Error recognizing Class.isInstance filters out null

[jpschewe]

Checker version 3.52.0.
Java version: 21.0.8

To reproduce:

1. mkdir -p net/mtu/eggplant/checker/
2. cd net/mtu/eggplant/checker/ tar -xzf isinstance_null.tar.gz
3. Build this with checker. Result is

/home/jpschewe/projects/checker-bugs/src/main/java/net/mtu/eggplant/checker/isinstance_null/Test.java:21: error: [argument] incompatible argument for parameter goal of Test.findRangeShortDescriptionWithTitle.
                        .map(g -> findRangeShortDescriptionWithTitle(title, g))//
                                                                            ^
  found   : @Initialized @PolyNull Goal
  required: @Initialized @NonNull Goal
1 error

[jpschewe]

Alternative to test

1. git clone https://github.com/jpschewe/checker-bugs.git
2. git checkout isinstance-null
3. ./gradlew classes