Basic Nullness Checker configuration

[wmdietl]

This integrates the Nullness Checker into ./gradlew compileJava.

The line "-AonlyDefs=^org\\.key_project\\.util\\.lookup" says that only elements in the org.key_project.util.lookup package should be checked.
I only did a quick annotation of that file, which might need to change when more sources are checked.

[github-actions]

Thank you for your contribution.

The test artifacts are available on Artiweb.
The newest artifact is here.

[mattulbrich]

It seems that NullMarked sets the default to NonNull.

I think we could need another annotation: If there is no annotation, then the class is excluded from checking, and an annotation like @NonNullChecked activates nullness checking. Is there something like that (sounds like the complement of @SuppressWarning{"nullness"})?

Is it possible to have the checker framework as an extra step outside compileJava?

[wadoon]

Added a system property which enables the nullness checker. See settings.gradle

[wadoon]

@wmdietl Following @NonNull KeYParser.String_valueContext ctx results into an error message:

/home/weigl/work/key/key.core/src/main/java/de/uka/ilkd/key/nparser/builder/ExpressionBuilder.java:1553: error: scoping construct cannot be annotated with type-use annotation: @org.jspecify.annotations.Nullable
    private @Nullable Term[] visitArguments(@Nullable KeYParser.Argument_listContext call) {

Why is there a problem? The inner class is static.

Edit: The correct version is KeYParser. @NonNull String_valueContext ctx

[wadoon]

@flo2702 The flag should work now. I have updated eisop to the latest version which results into one new compile error in key.util.

The two compile errors on ImmutableMap are old.

> Task :key.util:compileJava
Note: Checker Framework 3.42.0-eisop2
/home/weigl/work/key/key.util/src/main/java/org/key_project/util/collection/IdentityHashSet.java:71: error: [override.return.invalid] Incompatible return type.
    public <T1> T1[] toArray(T1[] a) {
                  ^
  found   : T1[ extends @UnknownKeyFor Object super @UnknownKeyFor Void] @UnknownKeyFor []
  required: T[ extends @UnknownKeyFor Object super @KeyForBottom Void] @UnknownKeyFor []
  Consequence: method in IdentityHashSet<T extends Object>
    <T1 extends Object> T1 extends Object [] toArray(IdentityHashSet<T extends Object> this, T1 extends Object [] p0)
  cannot override method in Set<T extends Object>
    <T extends Object> T extends Object [] toArray(Set<T extends Object> this, T extends Object [] p0)
/home/weigl/work/key/key.util/src/main/java/org/key_project/util/collection/ImmutableMap.java:13: error: [type.argument.type.incompatible] incompatible type argument for type parameter S of ImmutableMapEntry.
        extends Iterable<ImmutableMapEntry<S, T>>, java.io.Serializable {
                                           ^
  found   : S[ extends @UnknownKeyFor Object super @KeyForBottom Void]
  required: [extends @UnknownKeyFor Object super @UnknownKeyFor NullType]
/home/weigl/work/key/key.util/src/main/java/org/key_project/util/collection/ImmutableMap.java:13: error: [type.argument.type.incompatible] incompatible type argument for type parameter T of ImmutableMapEntry.
        extends Iterable<ImmutableMapEntry<S, T>>, java.io.Serializable {
                                              ^
  found   : T[ extends @UnknownKeyFor Object super @KeyForBottom Void]
  required: [extends @UnknownKeyFor Object super @UnknownKeyFor NullType]
Note: Some input files use unchecked or unsafe operations.
Note: Recompile with -Xlint:unchecked for details.
3 errors

First one repaired. @SuppresWarning was incorrect

[wadoon]

We have a lot of type errors in the test cases.

This leads to an interesting question:

@mattulbrich @flo2702 Do we start with trusting the type system and get rid of the (now) useless NP checks?

For example, consider CollectionsUtil#searchAll:

public static <T> List<T> searchAll(Iterable<T> iterable, Predicate<T> filter) {
        List<T> result = new ArrayList<>();
        if (iterable != null && filter != null) {
            for (T element : iterable) {
                if (filter.test(element)) {
                    result.add(element);
                }
            }
        }
        return result;
}

Are useless now, as the parameters are non-null by type system. There are test cases which for behavior with null args which currently fail in the type checker.

• Add @Nullable to arguments, or
• cleanup the code and test cases?

Errors:

Note: Checker Framework 3.42.0-eisop2
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/collection/TestSLListOfString.java:27: error: [initialization.field.uninitialized] the default constructor does not initialize field a
    ImmutableList<String> a; // "A" "B" "C"
                          ^
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/collection/TestSLListOfString.java:28: error: [initialization.field.uninitialized] the default constructor does not initialize field a1
    ImmutableList<String> a1; // "A" "B" "C"
                          ^
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/collection/TestSLListOfString.java:29: error: [initialization.field.uninitialized] the default constructor does not initialize field b
    ImmutableList<String> b; // "A" "B"
                          ^
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/collection/TestSLListOfString.java:30: error: [initialization.field.uninitialized] the default constructor does not initialize field c
    ImmutableList<String> c; // "A" "B" "C" "D"
                          ^
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/collection/TestSLListOfString.java:31: error: [initialization.field.uninitialized] the default constructor does not initialize field d
    ImmutableList<String> d; // "A" "B" "A"
                          ^
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/collection/TestSLListOfString.java:32: error: [initialization.field.uninitialized] the default constructor does not initialize field e
    ImmutableList<String> e; // "A" "B" null
                          ^
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/collection/TestSLListOfString.java:33: error: [initialization.field.uninitialized] the default constructor does not initialize field e1
    ImmutableList<String> e1; // "A" "B" null
                          ^
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/collection/TestSLListOfString.java:43: error: [argument.type.incompatible] incompatible argument for parameter arg0 of ImmutableList.prepend.
        e = ImmutableSLList.<String>nil().prepend((String) null).prepend("B").prepend("A");
                                                  ^
  found   : @Nullable String
  required: @NonNull String
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/collection/TestSLListOfString.java:44: error: [argument.type.incompatible] incompatible argument for parameter arg0 of ImmutableList.prepend.
        e1 = ImmutableSLList.<String>nil().prepend((String) null).prepend("B").prepend("A");
                                                   ^
  found   : @Nullable String
  required: @NonNull String
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/collection/TestMapAsListFromIntegerToString.java:21: error: [initialization.field.uninitialized] the default constructor does not initialize field entryStr
    private String[] entryStr;
                     ^
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/collection/TestMapAsListFromIntegerToString.java:22: error: [initialization.field.uninitialized] the default constructor does not initialize field entryInt
    private Integer[] entryInt;
                      ^
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/collection/TestLeftistHeapOfInteger.java:24: error: [initialization.field.uninitialized] the default constructor does not initialize field a
    ImmutableList<Integer> a;
                           ^
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/collection/TestLeftistHeapOfInteger.java:25: error: [initialization.field.uninitialized] the default constructor does not initialize field b
    ImmutableList<Integer> b;
                           ^
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/XMLUtilTest.java:35: error: [argument.type.incompatible] incompatible argument for parameter fixedReplacement of XMLUtilTest.assertReplaceTags.
        assertReplaceTags("Hello World", "Hello World", null);
                                                        ^
  found   : null (NullType)
  required: @NonNull String
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/XMLUtilTest.java:36: error: [argument.type.incompatible] incompatible argument for parameter fixedReplacement of XMLUtilTest.assertReplaceTags.
        assertReplaceTags("<html>Hello<br> World</html>", "Hello World", null, "<html>", "<br>",
                                                                         ^
  found   : null (NullType)
  required: @NonNull String
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/ArrayUtilTest.java:30: error: [argument.type.incompatible] incompatible argument for parameter array of ArrayUtil.insert.
        assertArray(ArrayUtil.insert(null, "X", 0), "X");
                                     ^
  found   : null (NullType)
  required: /*INFERENCE FAILED for:*/ ? extends @NonNull Object @NonNull []
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/ArrayUtilTest.java:35: error: [type.argument.type.incompatible] incompatible type argument for type parameter T extends @NonNull Object of ArrayUtil.insert.
            ArrayUtil.insert(null, null, 0);
                            ^
  found   : @Nullable Object
  required: @NonNull Object
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/ArrayUtilTest.java:35: error: [argument.type.incompatible] incompatible argument for parameter array of ArrayUtil.insert.
            ArrayUtil.insert(null, null, 0);
                             ^
  found   : null (NullType)
  required: @Nullable Object @NonNull []
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/ArrayUtilTest.java:74: error: [argument.type.incompatible] incompatible argument for parameter filter of ArrayUtil.search.
        assertNull(ArrayUtil.search(array, null));
                                           ^
  found   : null (NullType)
  required: @NonNull Predicate<@NonNull String>
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/ArrayUtilTest.java:75: error: [argument.type.incompatible] incompatible argument for parameter array of ArrayUtil.search.
        assertNull(ArrayUtil.search(null, "E"::equals));
                                    ^
  found   : null (NullType)
  required: @NonNull Object @NonNull []
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/ArrayUtilTest.java:83: error: [argument.type.incompatible] incompatible argument for parameter array of ArrayUtil.isEmpty.
        assertTrue(ArrayUtil.isEmpty(null));
                                     ^
  found   : null (NullType)
  required: @NonNull Object @NonNull []
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/ArrayUtilTest.java:86: error: [type.argument.type.incompatible] incompatible type argument for type parameter T extends @NonNull Object of ArrayUtil.isEmpty.
        assertFalse(ArrayUtil.isEmpty(new String[] { null }));
                                     ^
  found   : @Nullable String
  required: @NonNull Object
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/ArrayUtilTest.java:95: error: [argument.type.incompatible] incompatible argument for parameter array of ArrayUtil.toString.
        assertEquals(StringUtil.EMPTY_STRING, ArrayUtil.toString((int[]) null, ";"));
                                                                 ^
  found   : @NonNull int @Nullable []
  required: @NonNull int @NonNull []
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/ArrayUtilTest.java:100: error: [argument.type.incompatible] incompatible argument for parameter separator of ArrayUtil.toString.
        assertEquals("1null2null3", ArrayUtil.toString(new int[] { 1, 2, 3 }, null));
                                                                              ^
  found   : null (NullType)
  required: @NonNull String
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/ArrayUtilTest.java:108: error: [argument.type.incompatible] incompatible argument for parameter array of ArrayUtil.toString.
        assertEquals(StringUtil.EMPTY_STRING, ArrayUtil.toString((int[]) null));
                                                                 ^
  found   : @NonNull int @Nullable []
  required: @NonNull int @NonNull []
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/ArrayUtilTest.java:120: error: [argument.type.incompatible] incompatible argument for parameter array of ArrayUtil.toString.
        assertEquals(StringUtil.EMPTY_STRING, ArrayUtil.toString((String[]) null, ";"));
                                                                 ^
  found   : @NonNull String @Nullable []
  required: @NonNull String @NonNull []
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/ArrayUtilTest.java:124: error: [type.argument.type.incompatible] incompatible type argument for type parameter T extends @NonNull Object of ArrayUtil.toString.
        assertEquals("A;B;null", ArrayUtil.toString(new String[] { "A", "B", null }, ";"));
                                                   ^
  found   : @Nullable String
  required: @NonNull Object
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/ArrayUtilTest.java:125: error: [type.argument.type.incompatible] incompatible type argument for type parameter T extends @NonNull Object of ArrayUtil.toString.
        assertEquals("A;B;null;D", ArrayUtil.toString(new String[] { "A", "B", null, "D" }, ";"));
                                                     ^
  found   : @Nullable String
  required: @NonNull Object
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/ArrayUtilTest.java:127: error: [type.argument.type.incompatible] incompatible type argument for type parameter T extends @NonNull Object of ArrayUtil.toString.
            ArrayUtil.toString(new String[] { "A", "B", null, "D" }, null));
                              ^
  found   : @Nullable String
  required: @NonNull Object
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/ArrayUtilTest.java:127: error: [argument.type.incompatible] incompatible argument for parameter separator of ArrayUtil.toString.
            ArrayUtil.toString(new String[] { "A", "B", null, "D" }, null));
                                                                     ^
  found   : null (NullType)
  required: @NonNull String
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/ArrayUtilTest.java:135: error: [argument.type.incompatible] incompatible argument for parameter array of ArrayUtil.toString.
        assertEquals(StringUtil.EMPTY_STRING, ArrayUtil.toString((String[]) null));
                                                                 ^
  found   : @NonNull String @Nullable []
  required: @NonNull String @NonNull []
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/ArrayUtilTest.java:139: error: [type.argument.type.incompatible] incompatible type argument for type parameter T extends @NonNull Object of ArrayUtil.toString.
        assertEquals("A, B, null", ArrayUtil.toString(new String[] { "A", "B", null }));
                                                     ^
  found   : @Nullable String
  required: @NonNull Object
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/ArrayUtilTest.java:140: error: [type.argument.type.incompatible] incompatible type argument for type parameter T extends @NonNull Object of ArrayUtil.toString.
        assertEquals("A, B, null, D", ArrayUtil.toString(new String[] { "A", "B", null, "D" }));
                                                        ^
  found   : @Nullable String
  required: @NonNull Object
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/ArrayUtilTest.java:149: error: [assignment.type.incompatible] incompatible types in assignment.
        String[] array = new String[] { "A", "B", "C", null, "D", null, null, "C", "A" };
                         ^
  found   : @Nullable String @NonNull []
  required: @NonNull String @Nullable []
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/ArrayUtilTest.java:151: error: [argument.type.incompatible] incompatible argument for parameter array of ArrayUtilTest.assertArrayEquals.
        assertArrayEquals(array, "A", "C", null, "D", null, null, "C", "A");
                          ^
  found   : @NonNull String @Nullable []
  required: @Nullable String @NonNull []
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/ArrayUtilTest.java:153: error: [argument.type.incompatible] incompatible argument for parameter array of ArrayUtilTest.assertArrayEquals.
        assertArrayEquals(array, "A", "C", null, "D", null, null, "C", "A");
                          ^
  found   : @NonNull String @Nullable []
  required: @Nullable String @NonNull []
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/ArrayUtilTest.java:155: error: [argument.type.incompatible] incompatible argument for parameter array of ArrayUtilTest.assertArrayEquals.
        assertArrayEquals(array, "A", "C", null, null, null, "C", "A");
                          ^
  found   : @NonNull String @Nullable []
  required: @Nullable String @NonNull []
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/ArrayUtilTest.java:157: error: [argument.type.incompatible] incompatible argument for parameter array of ArrayUtilTest.assertArrayEquals.
        assertArrayEquals(array, "A", null, null, null, "A");
                          ^
  found   : @NonNull String @Nullable []
  required: @Nullable String @NonNull []
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/ArrayUtilTest.java:159: error: [argument.type.incompatible] incompatible argument for parameter array of ArrayUtilTest.assertArrayEquals.
        assertArrayEquals(array, "A", "A");
                          ^
  found   : @NonNull String @Nullable []
  required: @NonNull String @NonNull []
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/ArrayUtilTest.java:161: error: [argument.type.incompatible] incompatible argument for parameter array of ArrayUtilTest.assertArrayEquals.
        assertArrayEquals(array, "A", "A");
                          ^
  found   : @NonNull String @Nullable []
  required: @NonNull String @NonNull []
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/ArrayUtilTest.java:163: error: [argument.type.incompatible] incompatible argument for parameter array of ArrayUtilTest.assertArrayEquals.
        assertArrayEquals(array);
                          ^
  found   : @NonNull String @Nullable []
  required: @NonNull String @NonNull []
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/ArrayUtilTest.java:165: error: [argument.type.incompatible] incompatible argument for parameter array of ArrayUtilTest.assertArrayEquals.
        assertArrayEquals(array);
                          ^
  found   : @NonNull String @Nullable []
  required: @NonNull String @NonNull []
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/ArrayUtilTest.java:262: error: [argument.type.incompatible] incompatible argument for parameter array of ArrayUtil.add.
        int[] result = ArrayUtil.add(null, 1);
                                     ^
  found   : null (NullType)
  required: @NonNull int @NonNull []
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/ArrayUtilTest.java:304: error: [assignment.type.incompatible] incompatible types in assignment.
        String[] result = ArrayUtil.add(null, "A");
                                       ^
  found   : @Nullable String @NonNull []
  required: @NonNull String @Nullable []
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/ArrayUtilTest.java:310: error: [assignment.type.incompatible] incompatible types in assignment.
        result = ArrayUtil.add(array, "A");
                              ^
  found   : @Nullable String @NonNull []
  required: @NonNull String @Nullable []
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/ArrayUtilTest.java:316: error: [assignment.type.incompatible] incompatible types in assignment.
        result = ArrayUtil.add(array, "B");
                              ^
  found   : @Nullable String @NonNull []
  required: @NonNull String @Nullable []
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/ArrayUtilTest.java:323: error: [assignment.type.incompatible] incompatible types in assignment.
        result = ArrayUtil.add(array, "C");
                              ^
  found   : @Nullable String @NonNull []
  required: @NonNull String @Nullable []
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/ArrayUtilTest.java:331: error: [assignment.type.incompatible] incompatible types in assignment.
        result = ArrayUtil.add(array, "D");
                              ^
  found   : @Nullable String @NonNull []
  required: @NonNull String @Nullable []
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/ArrayUtilTest.java:340: error: [assignment.type.incompatible] incompatible types in assignment.
        result = ArrayUtil.add(array, null);
                              ^
  found   : @Nullable String @NonNull []
  required: @NonNull String @Nullable []
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/ArrayUtilTest.java:362: error: [type.argument.type.incompatible] incompatible type argument for type parameter T extends @NonNull Object of ArrayUtil.contains.
        assertFalse(ArrayUtil.contains(array, null));
                                      ^
  found   : @Nullable String
  required: @NonNull Object
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/ArrayUtilTest.java:363: error: [argument.type.incompatible] incompatible argument for parameter array of ArrayUtil.contains.
        assertFalse(ArrayUtil.contains(null, "A"));
                                       ^
  found   : null (NullType)
  required: @NonNull String @NonNull []
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/ArrayUtilTest.java:368: error: [assignment.type.incompatible] incompatible types in assignment.
        String[] arrayWithNull = { "A", "B", null, "D" };
                                 ^
  found   : @Nullable String @NonNull []
  required: @NonNull String @Nullable []
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/ArrayUtilTest.java:368: error: [array.initializer.type.incompatible] incompatible types in array initializer.
        String[] arrayWithNull = { "A", "B", null, "D" };
                                             ^
  found   : null (NullType)
  required: @NonNull String
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/ArrayUtilTest.java:369: error: [type.argument.type.incompatible] incompatible type argument for type parameter T extends @NonNull Object of ArrayUtil.contains.
        assertTrue(ArrayUtil.contains(arrayWithNull, null));
                                     ^
  found   : @Nullable String
  required: @NonNull Object
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/ArrayUtilTest.java:370: error: [argument.type.incompatible] incompatible argument for parameter array of ArrayUtil.contains.
        assertFalse(ArrayUtil.contains(null, "A"));
                                       ^
  found   : null (NullType)
  required: @NonNull String @NonNull []
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/ArrayUtilTest.java:377: error: [type.argument.type.incompatible] incompatible type argument for type parameter T extends @NonNull Object of ArrayUtil.contains.
        assertFalse(ArrayUtil.contains(arrayWithDoubleElements, null));
                                      ^
  found   : @Nullable String
  required: @NonNull Object
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/ArrayUtilTest.java:378: error: [argument.type.incompatible] incompatible argument for parameter array of ArrayUtil.contains.
        assertFalse(ArrayUtil.contains(null, "A"));
                                       ^
  found   : null (NullType)
  required: @NonNull String @NonNull []
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/ArrayUtilTest.java:391: error: [type.argument.type.incompatible] incompatible type argument for type parameter T extends @NonNull Object of ArrayUtil.indexOf.
        assertEquals(-1, ArrayUtil.indexOf(array, null));
                                          ^
  found   : @Nullable String
  required: @NonNull Object
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/ArrayUtilTest.java:392: error: [argument.type.incompatible] incompatible argument for parameter array of ArrayUtil.indexOf.
        assertEquals(-1, ArrayUtil.indexOf(null, "A"));
                                           ^
  found   : null (NullType)
  required: @NonNull String @NonNull []
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/ArrayUtilTest.java:397: error: [assignment.type.incompatible] incompatible types in assignment.
        String[] arrayWithNull = { "A", "B", null, "D" };
                                 ^
  found   : @Nullable String @NonNull []
  required: @NonNull String @Nullable []
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/ArrayUtilTest.java:397: error: [array.initializer.type.incompatible] incompatible types in array initializer.
        String[] arrayWithNull = { "A", "B", null, "D" };
                                             ^
  found   : null (NullType)
  required: @NonNull String
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/ArrayUtilTest.java:398: error: [type.argument.type.incompatible] incompatible type argument for type parameter T extends @NonNull Object of ArrayUtil.indexOf.
        assertEquals(2, ArrayUtil.indexOf(arrayWithNull, null));
                                         ^
  found   : @Nullable String
  required: @NonNull Object
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/ArrayUtilTest.java:399: error: [argument.type.incompatible] incompatible argument for parameter array of ArrayUtil.indexOf.
        assertEquals(-1, ArrayUtil.indexOf(null, "A"));
                                           ^
  found   : null (NullType)
  required: @NonNull String @NonNull []
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/ArrayUtilTest.java:406: error: [type.argument.type.incompatible] incompatible type argument for type parameter T extends @NonNull Object of ArrayUtil.indexOf.
        assertEquals(-1, ArrayUtil.indexOf(arrayWithDoubleElements, null));
                                          ^
  found   : @Nullable String
  required: @NonNull Object
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/ArrayUtilTest.java:407: error: [argument.type.incompatible] incompatible argument for parameter array of ArrayUtil.indexOf.
        assertEquals(-1, ArrayUtil.indexOf(null, "A"));
                                           ^
  found   : null (NullType)
  required: @NonNull String @NonNull []
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/StringUtilTest.java:166: error: [argument.type.incompatible] incompatible argument for parameter toSearch of StringUtil.replaceAll.
        assertEquals(text, StringUtil.replaceAll(text, null, 'X'));
                                                       ^
  found   : null (NullType)
  required: @NonNull char @NonNull []
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/StringUtilTest.java:215: error: [argument.type.incompatible] incompatible argument for parameter text of StringUtil.repeat.
            assertEquals("nullnullnullnull", StringUtil.repeat(null, 4));
                                                               ^
  found   : null (NullType)
  required: @NonNull String
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/StringUtilTest.java:234: error: [argument.type.incompatible] incompatible argument for parameter arg1 of Comparator.compare.
        assertNotSame(0, c.compare("A", null));
                                        ^
  found   : null (NullType)
  required: @NonNull String
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/StringUtilTest.java:235: error: [argument.type.incompatible] incompatible argument for parameter arg0 of Comparator.compare.
        assertNotSame(0, c.compare(null, "A"));
                                   ^
  found   : null (NullType)
  required: @NonNull String
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/StringUtilTest.java:236: error: [argument.type.incompatible] incompatible argument for parameter arg0 of Comparator.compare.
        assertSame(0, c.compare(null, null));
                                ^
  found   : null (NullType)
  required: @NonNull String
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/StringUtilTest.java:236: error: [argument.type.incompatible] incompatible argument for parameter arg1 of Comparator.compare.
        assertSame(0, c.compare(null, null));
                                      ^
  found   : null (NullType)
  required: @NonNull String
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/CollectionUtilTest.java:41: error: [argument.type.incompatible] incompatible argument for parameter filter of CollectionUtil.searchAll.
        found = CollectionUtil.searchAll(collection, null);
                                                     ^
  found   : null (NullType)
  required: @NonNull Predicate<@NonNull String>
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/CollectionUtilTest.java:43: error: [argument.type.incompatible] incompatible argument for parameter iterable of CollectionUtil.searchAll.
        found = CollectionUtil.searchAll(null, "E"::equals);
                                         ^
  found   : null (NullType)
  required: @NonNull Iterable<@NonNull String>
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/CollectionUtilTest.java:104: error: [argument.type.incompatible] incompatible argument for parameter iter of CollectionUtil.indexOf.
        assertEquals(-1, CollectionUtil.indexOf((Iterator<?>) null, null));
                                                ^
  found   : @Nullable Iterator<? extends @Nullable Object>
  required: @NonNull Iterator<capture#01 extends @NonNull Object>
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/CollectionUtilTest.java:104: error: [argument.type.incompatible] incompatible argument for parameter toSearch of CollectionUtil.indexOf.
        assertEquals(-1, CollectionUtil.indexOf((Iterator<?>) null, null));
                                                                    ^
  found   : null (NullType)
  required: capture#01 extends @NonNull Object
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/CollectionUtilTest.java:105: error: [argument.type.incompatible] incompatible argument for parameter toSearch of CollectionUtil.indexOf.
        assertEquals(-1, CollectionUtil.indexOf(list.iterator(), null));
                                                                 ^
  found   : null (NullType)
  required: @NonNull String
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/CollectionUtilTest.java:106: error: [argument.type.incompatible] incompatible argument for parameter iter of CollectionUtil.indexOf.
        assertEquals(-1, CollectionUtil.indexOf(null, "A"));
                                                ^
  found   : null (NullType)
  required: @NonNull Iterator<@NonNull String>
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/CollectionUtilTest.java:156: error: [argument.type.incompatible] incompatible argument for parameter filter of CollectionUtil.searchAndRemoveWithException.
        assertNull(CollectionUtil.searchAndRemoveWithException(collection, null));
                                                                           ^
  found   : null (NullType)
  required: @NonNull IFilterWithException<@NonNull String, @NonNull Throwable>
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/CollectionUtilTest.java:157: error: [argument.type.incompatible] incompatible argument for parameter iterable of CollectionUtil.searchAndRemoveWithException.
        assertNull(CollectionUtil.searchAndRemoveWithException(null,
                                                               ^
  found   : null (NullType)
  required: @NonNull Iterable<@NonNull String>
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/CollectionUtilTest.java:[186](https://github.com/KeYProject/key/actions/runs/8859550688/job/24329433919?pr=3183#step:4:188): error: [argument.type.incompatible] incompatible argument for parameter filter of CollectionUtil.searchAndRemove.
        assertNull(CollectionUtil.searchAndRemove(collection, null));
                                                              ^
  found   : null (NullType)
  required: @NonNull Predicate<@NonNull String>
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/CollectionUtilTest.java:[187](https://github.com/KeYProject/key/actions/runs/8859550688/job/24329433919?pr=3183#step:4:189): error: [argument.type.incompatible] incompatible argument for parameter iterable of CollectionUtil.searchAndRemove.
        assertNull(CollectionUtil.searchAndRemove(null, "E"::equals));
                                                  ^
  found   : null (NullType)
  required: @NonNull Iterable<@NonNull Object>
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/CollectionUtilTest.java:197: error: [argument.type.incompatible] incompatible argument for parameter iterable of CollectionUtil.removeFirst.
        assertNull(CollectionUtil.removeFirst(null));
                                              ^
  found   : null (NullType)
  required: @NonNull Iterable<@NonNull Object>
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/CollectionUtilTest.java:238: error: [assignment.type.incompatible] incompatible types in assignment.
        List<String> four = Arrays.asList("A", "B", null, "A");
                                         ^
  found   : @NonNull List<@Nullable String>
  required: @Nullable List<@NonNull String>
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/CollectionUtilTest.java:239: error: [assignment.type.incompatible] incompatible types in assignment.
        List<String> fourCopy = Arrays.asList("A", "B", null, "A");
                                             ^
  found   : @NonNull List<@Nullable String>
  required: @Nullable List<@NonNull String>
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/CollectionUtilTest.java:240: error: [assignment.type.incompatible] incompatible types in assignment.
        List<String> fourDifferent = Arrays.asList("A", null, null, "B");
                                                  ^
  found   : @NonNull List<@Nullable String>
  required: @Nullable List<@NonNull String>
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/CollectionUtilTest.java:241: error: [assignment.type.incompatible] incompatible types in assignment.
        List<String> fourChangedOrder = Arrays.asList(null, "A", "A", "B");
                                                     ^
  found   : @NonNull List<@Nullable String>
  required: @Nullable List<@NonNull String>
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/CollectionUtilTest.java:243: error: [argument.type.incompatible] incompatible argument for parameter first of CollectionUtil.containsSame.
        assertTrue(CollectionUtil.containsSame(null, null));
                                               ^
  found   : null (NullType)
  required: @NonNull Collection<@NonNull Object>
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/CollectionUtilTest.java:243: error: [argument.type.incompatible] incompatible argument for parameter second of CollectionUtil.containsSame.
        assertTrue(CollectionUtil.containsSame(null, null));
                                                     ^
  found   : null (NullType)
  required: @NonNull Collection<@NonNull Object>
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/CollectionUtilTest.java:244: error: [argument.type.incompatible] incompatible argument for parameter second of CollectionUtil.containsSame.
        assertTrue(CollectionUtil.containsSame(empty, null));
                                                      ^
  found   : null (NullType)
  required: @NonNull Collection<@NonNull String>
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/CollectionUtilTest.java:245: error: [argument.type.incompatible] incompatible argument for parameter first of CollectionUtil.containsSame.
        assertTrue(CollectionUtil.containsSame(null, empty));
                                               ^
  found   : null (NullType)
  required: @NonNull Collection<@NonNull String>
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/CollectionUtilTest.java:246: error: [argument.type.incompatible] incompatible argument for parameter first of CollectionUtil.containsSame.
        assertFalse(CollectionUtil.containsSame(null, one));
                                                ^
  found   : null (NullType)
  required: @NonNull Collection<@NonNull String>
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/CollectionUtilTest.java:247: error: [argument.type.incompatible] incompatible argument for parameter second of CollectionUtil.containsSame.
        assertFalse(CollectionUtil.containsSame(one, null));
                                                     ^
  found   : null (NullType)
  required: @NonNull Collection<@NonNull String>
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/CollectionUtilTest.java:326: error: [argument.type.incompatible] incompatible argument for parameter first of CollectionUtil.containsSame.
        assertTrue(CollectionUtil.containsSame(null, null));
                                               ^
  found   : null (NullType)
  required: @NonNull Collection<@NonNull Object>
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/CollectionUtilTest.java:326: error: [argument.type.incompatible] incompatible argument for parameter second of CollectionUtil.containsSame.
        assertTrue(CollectionUtil.containsSame(null, null));
                                                     ^
  found   : null (NullType)
  required: @NonNull Collection<@NonNull Object>
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/CollectionUtilTest.java:327: error: [argument.type.incompatible] incompatible argument for parameter second of CollectionUtil.containsSame.
        assertTrue(CollectionUtil.containsSame(empty, null));
                                                      ^
  found   : null (NullType)
  required: @NonNull Collection<@NonNull String>
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/CollectionUtilTest.java:328: error: [argument.type.incompatible] incompatible argument for parameter first of CollectionUtil.containsSame.
        assertTrue(CollectionUtil.containsSame(null, empty));
                                               ^
  found   : null (NullType)
  required: @NonNull Collection<@NonNull String>
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/CollectionUtilTest.java:329: error: [argument.type.incompatible] incompatible argument for parameter first of CollectionUtil.containsSame.
        assertFalse(CollectionUtil.containsSame(null, one));
                                                ^
  found   : null (NullType)
  required: @NonNull Collection<@NonNull String>
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/CollectionUtilTest.java:330: error: [argument.type.incompatible] incompatible argument for parameter second of CollectionUtil.containsSame.
        assertFalse(CollectionUtil.containsSame(one, null));
                                                     ^
  found   : null (NullType)
  required: @NonNull Collection<@NonNull String>
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/CollectionUtilTest.java:363: error: [argument.type.incompatible] incompatible argument for parameter iterable of CollectionUtil.count.
        assertEquals(0, CollectionUtil.count(null, null));
                                             ^
  found   : null (NullType)
  required: @NonNull Iterable<@NonNull Object>
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/CollectionUtilTest.java:363: error: [argument.type.incompatible] incompatible argument for parameter filter of CollectionUtil.count.
        assertEquals(0, CollectionUtil.count(null, null));
                                                   ^
  found   : null (NullType)
  required: @NonNull Predicate<@NonNull Object>
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/CollectionUtilTest.java:364: error: [argument.type.incompatible] incompatible argument for parameter filter of CollectionUtil.count.
        assertEquals(0, CollectionUtil.count(list, null));
                                                   ^
  found   : null (NullType)
  required: @NonNull Predicate<@NonNull String>
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/CollectionUtilTest.java:365: error: [argument.type.incompatible] incompatible argument for parameter iterable of CollectionUtil.count.
        assertEquals(0, CollectionUtil.count(null, element -> false));
                                             ^
  found   : null (NullType)
  required: @NonNull Iterable<@NonNull Object>
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/CollectionUtilTest.java:384: error: [argument.type.incompatible] incompatible argument for parameter iterable of CollectionUtil.contains.
        assertFalse(CollectionUtil.contains(null, "A"));
                                            ^
  found   : null (NullType)
  required: @NonNull Iterable<@NonNull String>
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/CollectionUtilTest.java:385: error: [argument.type.incompatible] incompatible argument for parameter element of CollectionUtil.contains.
        assertFalse(CollectionUtil.contains(list, null));
                                                  ^
  found   : null (NullType)
  required: @NonNull String
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/CollectionUtilTest.java:386: error: [type.argument.type.incompatible] incompatible type argument for type parameter T extends @NonNull Object of CollectionUtil.contains.
        assertFalse(CollectionUtil.contains(null, null));
                                           ^
  found   : @Nullable Object
  required: @NonNull Object
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/CollectionUtilTest.java:386: error: [argument.type.incompatible] incompatible argument for parameter iterable of CollectionUtil.contains.
        assertFalse(CollectionUtil.contains(null, null));
                                            ^
  found   : null (NullType)
  required: @NonNull Iterable<@Nullable Object>
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/CollectionUtilTest.java:394: error: [argument.type.incompatible] incompatible argument for parameter arg0 of List.add.
        list.add(null);
                 ^
  found   : null (NullType)
  required: @NonNull String
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/CollectionUtilTest.java:395: error: [argument.type.incompatible] incompatible argument for parameter element of CollectionUtil.contains.
        assertTrue(CollectionUtil.contains(list, null));
                                                 ^
  found   : null (NullType)
  required: @NonNull String
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/CollectionUtilTest.java:409: error: [argument.type.incompatible] incompatible argument for parameter filter of CollectionUtil.search.
        assertNull(CollectionUtil.search(collection, null));
                                                     ^
  found   : null (NullType)
  required: @NonNull Predicate<@NonNull String>
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/CollectionUtilTest.java:410: error: [argument.type.incompatible] incompatible argument for parameter iterable of CollectionUtil.search.
        assertNull(CollectionUtil.search(null, "E"::equals));
                                         ^
  found   : null (NullType)
  required: @NonNull Iterable<@NonNull Object>
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/CollectionUtilTest.java:420: error: [argument.type.incompatible] incompatible argument for parameter toRemove of CollectionUtil.removeComplete.
        assertFalse(CollectionUtil.removeComplete(collection, null));
                                                              ^
  found   : null (NullType)
  required: @NonNull String
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/CollectionUtilTest.java:429: error: [argument.type.incompatible] incompatible argument for parameter collection of CollectionUtil.removeComplete.
        assertFalse(CollectionUtil.removeComplete(null, "A"));
                                                  ^
  found   : null (NullType)
  required: @NonNull Collection<@NonNull String>
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/CollectionUtilTest.java:471: error: [argument.type.incompatible] incompatible argument for parameter collection of CollectionUtil.addAll.
        CollectionUtil.addAll(null, List.of("A"));
                              ^
  found   : null (NullType)
  required: @NonNull Collection</*INFERENCE FAILED for:*/ ? extends @NonNull Object>
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/CollectionUtilTest.java:473: error: [argument.type.incompatible] incompatible argument for parameter iterable of CollectionUtil.addAll.
        CollectionUtil.addAll(collection, null);
                                          ^
  found   : null (NullType)
  required: @NonNull Iterable<@NonNull String>
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/CollectionUtilTest.java:511: error: [argument.type.incompatible] incompatible argument for parameter collection of CollectionUtil.isEmpty.
        assertTrue(CollectionUtil.isEmpty((Collection<?>) null));
                                          ^
  found   : @Nullable Collection<? extends @Nullable Object>
  required: @NonNull Collection<? extends @Nullable Object>
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/CollectionUtilTest.java:527: error: [argument.type.incompatible] incompatible argument for parameter map of CollectionUtil.isEmpty.
        assertTrue(CollectionUtil.isEmpty((Map<?, ?>) null));
                                          ^
  found   : @Nullable Map<? extends @Nullable Object, ? extends @Nullable Object>
  required: @NonNull Map<? extends @Nullable Object, ? extends @Nullable Object>
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/CollectionUtilTest.java:543: error: [argument.type.incompatible] incompatible argument for parameter collection of CollectionUtil.toString.
        assertEquals("", CollectionUtil.toString(null, " | "));
                                                 ^
  found   : null (NullType)
  required: @NonNull Collection<? extends @Nullable Object>
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/CollectionUtilTest.java:554: error: [argument.type.incompatible] incompatible argument for parameter separator of CollectionUtil.toString.
        assertEquals("ABCD", CollectionUtil.toString(collection, null));
                                                                 ^
  found   : null (NullType)
  required: @NonNull String
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/CollectionUtilTest.java:562: error: [argument.type.incompatible] incompatible argument for parameter collection of CollectionUtil.toString.
        assertEquals("", CollectionUtil.toString(null));
                                                 ^
  found   : null (NullType)
  required: @NonNull Collection<? extends @Nullable Object>
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/NumberUtilTest.java:36: error: [argument.type.incompatible] incompatible argument for parameter text of NumberUtil.parseFullInt.
            NumberUtil.parseFullInt(null);
                                    ^
  found   : null (NullType)
  required: @NonNull String
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/NumberUtilTest.java:60: error: [argument.type.incompatible] incompatible argument for parameter text of NumberUtil.parseFullInt.
            NumberUtil.parseFullInt(null);
                                    ^
  found   : null (NullType)
  required: @NonNull String
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/IOUtilTest.java:50: error: [argument.type.incompatible] incompatible argument for parameter file of IOUtil.exists.
        assertFalse(IOUtil.exists(null));
                                  ^
  found   : null (NullType)
  required: @NonNull File
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/IOUtilTest.java:87: error: [argument.type.incompatible] incompatible argument for parameter parents of IOUtil.contains.
            assertFalse(IOUtil.contains((Iterable<File>) null, yesFile));
                                        ^
  found   : @Nullable Iterable<@NonNull File>
  required: @NonNull Iterable<@NonNull File>
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/IOUtilTest.java:88: error: [argument.type.incompatible] incompatible argument for parameter child of IOUtil.contains.
            assertFalse(IOUtil.contains(parents, null));
                                                 ^
  found   : null (NullType)
  required: @NonNull File
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/IOUtilTest.java:89: error: [argument.type.incompatible] incompatible argument for parameter parents of IOUtil.contains.
            assertFalse(IOUtil.contains((Iterable<File>) null, null));
                                        ^
  found   : @Nullable Iterable<@NonNull File>
  required: @NonNull Iterable<@NonNull File>
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/IOUtilTest.java:89: error: [argument.type.incompatible] incompatible argument for parameter child of IOUtil.contains.
            assertFalse(IOUtil.contains((Iterable<File>) null, null));
                                                               ^
  found   : null (NullType)
  required: @NonNull File
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/IOUtilTest.java:90: error: [argument.type.incompatible] incompatible argument for parameter child of IOUtil.contains.
            assertFalse(IOUtil.contains(parents, yesDir.getParentFile()));
                                                                     ^
  found   : @Nullable File
  required: @NonNull File
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/IOUtilTest.java:151: error: [argument.type.incompatible] incompatible argument for parameter toTest of IOUtilTest.doTestUnifyLineBreaks.
        doTestUnifyLineBreaks(null, null);
                              ^
  found   : null (NullType)
  required: @NonNull String
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/IOUtilTest.java:151: error: [argument.type.incompatible] incompatible argument for parameter expected of IOUtilTest.doTestUnifyLineBreaks.
        doTestUnifyLineBreaks(null, null);
                                    ^
  found   : null (NullType)
  required: @NonNull String
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/IOUtilTest.java:[235](https://github.com/KeYProject/key/actions/runs/8859550688/job/24329433919?pr=3183#step:4:237): error: [argument.type.incompatible] incompatible argument for parameter file of IOUtil.visit.
            IOUtil.visit(null, visitor);
                         ^
  found   : null (NullType)
  required: @NonNull File
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/IOUtilTest.java:309: error: [argument.type.incompatible] incompatible argument for parameter file of IOUtil.search.
            List<File> result = IOUtil.search(null, filter);
                                              ^
  found   : null (NullType)
  required: @NonNull File
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/IOUtilTest.java:312: error: [argument.type.incompatible] incompatible argument for parameter filter of IOUtil.search.
            result = IOUtil.search(tempDir, null);
                                            ^
  found   : null (NullType)
  required: @NonNull Predicate<@NonNull File>
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/IOUtilTest.java:363: error: [argument.type.incompatible] incompatible argument for parameter actual of Assertions.assertNotNull.
        assertNotNull(home);
                      ^
  found   : @Nullable File
  required: @NonNull Object
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/IOUtilTest.java:394: error: [argument.type.incompatible] incompatible argument for parameter file of IOUtil.delete.
            IOUtil.delete(tempDir);
                          ^
  found   : @Nullable File
  required: @NonNull File
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/IOUtilTest.java:465: error: [argument.type.incompatible] incompatible argument for parameter file of IOUtilTest.assertLineInformation.
        assertLineInformation((File) null);
                              ^
  found   : @Nullable File
  required: @NonNull File
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/IOUtilTest.java:616: error: [argument.type.incompatible] incompatible argument for parameter text of IOUtilTest.assertLineInformation.
            assertLineInformation(sb.length() >= 1 ? sb.toString() : null, expectedInfos);
                                                   ^
  found   : @Nullable String
  required: @NonNull String
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/IOUtilTest.java:618: error: [argument.type.incompatible] incompatible argument for parameter text of IOUtilTest.assertLineInformation.
            assertLineInformation(null, new LineInformation[0]);
                                  ^
  found   : null (NullType)
  required: @NonNull String
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/IOUtilTest.java:657: error: [argument.type.incompatible] incompatible argument for parameter out of IOUtil.writeTo.
            IOUtil.writeTo(null, content);
                           ^
  found   : null (NullType)
  required: @NonNull OutputStream
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/IOUtilTest.java:660: error: [argument.type.incompatible] incompatible argument for parameter content of IOUtil.writeTo.
            IOUtil.writeTo(out, null);
                                ^
  found   : null (NullType)
  required: @NonNull String
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/IOUtilTest.java:700: error: [argument.type.incompatible] incompatible argument for parameter encoding of XMLUtil.appendXmlHeader.
        XMLUtil.appendXmlHeader(encoding != null ? encoding.displayName() : null, sb);
                                                 ^
  found   : @Nullable String
  required: @NonNull String
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/IOUtilTest.java:702: error: [argument.type.incompatible] incompatible argument for parameter arg1 of Map.put.
        attributes.put("text", XMLUtil.encodeText(text));
                                                 ^
  found   : @Nullable String
  required: @NonNull String
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/IOUtilTest.java:727: error: [initialization.field.uninitialized] the default constructor does not initialize field text
        private String text;
                       ^
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/IOUtilTest.java:783: error: [argument.type.incompatible] incompatible argument for parameter text of IOUtilTest.doTestReadFrom.
            doTestReadFrom(null);
                           ^
  found   : null (NullType)
  required: @NonNull String
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/IOUtilTest.java:811: error: [argument.type.incompatible] incompatible argument for parameter file of IOUtil.delete.
        IOUtil.delete(null); // No exception expected
                      ^
  found   : null (NullType)
  required: @NonNull File
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/IOUtilTest.java:847: error: [argument.type.incompatible] incompatible argument for parameter text of IOUtilTest.doTestCopy.
        doTestCopy(null);
                   ^
  found   : null (NullType)
  required: @NonNull String
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/IOUtilTest.java:848: error: [argument.type.incompatible] incompatible argument for parameter source of IOUtil.copy.
        assertFalse(IOUtil.copy((InputStream) null, null));
                                ^
  found   : @Nullable InputStream
  required: @NonNull InputStream
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/IOUtilTest.java:848: error: [argument.type.incompatible] incompatible argument for parameter target of IOUtil.copy.
        assertFalse(IOUtil.copy((InputStream) null, null));
                                                    ^
  found   : null (NullType)
  required: @NonNull OutputStream
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/IOUtilTest.java:850: error: [argument.type.incompatible] incompatible argument for parameter target of IOUtil.copy.
            new ByteArrayInputStream("NotCopied".getBytes(StandardCharsets.UTF_8)), null));
                                                                                    ^
  found   : null (NullType)
  required: @NonNull OutputStream
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/IOUtilTest.java:878: error: [argument.type.incompatible] incompatible argument for parameter source of IOUtil.copy.
            assertFalse(IOUtil.copy(null, new ByteArrayOutputStream()));
                                    ^
  found   : null (NullType)
  required: @NonNull InputStream
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/IOUtilTest.java:888: error: [argument.type.incompatible] incompatible argument for parameter actual of Assertions.assertNotNull.
        assertNotNull(IOUtil.getClassLocation(getClass()));
                                             ^
  found   : @Nullable File
  required: @NonNull Object
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/IOUtilTest.java:896: error: [argument.type.incompatible] incompatible argument for parameter classInstance of IOUtil.getProjectRoot.
        assertNull(IOUtil.getProjectRoot(null));
                                         ^
  found   : null (NullType)
  required: @NonNull Class<? extends @Nullable Object>
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/IOUtilTest.java:897: error: [argument.type.incompatible] incompatible argument for parameter actual of Assertions.assertNotNull.
        assertNotNull(IOUtil.getProjectRoot(getClass()));
                                           ^
  found   : @Nullable File
  required: @NonNull Object
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/IOUtilTest.java:913: error: [argument.type.incompatible] incompatible argument for parameter actual of Assertions.assertNotNull.
        assertNotNull(uri);
                      ^
  found   : @Nullable URI
  required: @NonNull Object
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/IOUtilTest.java:919: error: [argument.type.incompatible] incompatible argument for parameter actual of Assertions.assertNotNull.
        assertNotNull(uri);
                      ^
  found   : @Nullable URI
  required: @NonNull Object
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/testcase/java/IOUtilTest.java:925: error: [argument.type.incompatible] incompatible argument for parameter actual of Assertions.assertNotNull.
        assertNotNull(uri);
                      ^
  found   : @Nullable URI
  required: @NonNull Object
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/collection/TestImmutables.java:37: error: [array.initializer.type.incompatible] incompatible types in array initializer.
        String[][] a = { { "a", "b", "a", "c", "d", "d", "a", "e" }, { null, "a", null },
                                                                     ^
  found   : @Nullable String @NonNull []
  required: @NonNull String @NonNull []
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/collection/TestImmutables.java:37: error: [array.initializer.type.incompatible] incompatible types in array initializer.
        String[][] a = { { "a", "b", "a", "c", "d", "d", "a", "e" }, { null, "a", null },
                                                                       ^
  found   : null (NullType)
  required: @NonNull String
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/collection/TestImmutables.java:37: error: [array.initializer.type.incompatible] incompatible types in array initializer.
        String[][] a = { { "a", "b", "a", "c", "d", "d", "a", "e" }, { null, "a", null },
                                                                                  ^
  found   : null (NullType)
  required: @NonNull String
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/collection/TestImmutables.java:40: error: [array.initializer.type.incompatible] incompatible types in array initializer.
        String[][] expected = { { "a", "b", "c", "d", "e" }, { null, "a" }, { "1" } };
                                                             ^
  found   : @Nullable String @NonNull []
  required: @NonNull String @NonNull []
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/collection/TestImmutables.java:40: error: [array.initializer.type.incompatible] incompatible types in array initializer.
        String[][] expected = { { "a", "b", "c", "d", "e" }, { null, "a" }, { "1" } };
                                                               ^
  found   : null (NullType)
  required: @NonNull String
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/collection/TestImmutables.java:68: error: [array.initializer.type.incompatible] incompatible types in array initializer.
        String[][] a = { { "a", "b", "c", "d", "e" }, {}, { "a" }, { null }, { null, "a" } };
                                                                   ^
  found   : @Nullable String @NonNull []
  required: @NonNull String @NonNull []
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/collection/TestImmutables.java:68: error: [array.initializer.type.incompatible] incompatible types in array initializer.
        String[][] a = { { "a", "b", "c", "d", "e" }, {}, { "a" }, { null }, { null, "a" } };
                                                                     ^
  found   : null (NullType)
  required: @NonNull String
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/collection/TestImmutables.java:68: error: [array.initializer.type.incompatible] incompatible types in array initializer.
        String[][] a = { { "a", "b", "c", "d", "e" }, {}, { "a" }, { null }, { null, "a" } };
                                                                             ^
  found   : @Nullable String @NonNull []
  required: @NonNull String @NonNull []
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/collection/TestImmutables.java:68: error: [array.initializer.type.incompatible] incompatible types in array initializer.
        String[][] a = { { "a", "b", "c", "d", "e" }, {}, { "a" }, { null }, { null, "a" } };
                                                                               ^
  found   : null (NullType)
  required: @NonNull String
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/collection/TestImmutables.java:76: error: [array.initializer.type.incompatible] incompatible types in array initializer.
            { "a", "b", "d", "d", "e" }, { "a", "b", "c", "d", "d" }, { null, "a", null } };
                                                                      ^
  found   : @Nullable String @NonNull []
  required: @NonNull String @NonNull []
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/collection/TestImmutables.java:76: error: [array.initializer.type.incompatible] incompatible types in array initializer.
            { "a", "b", "d", "d", "e" }, { "a", "b", "c", "d", "d" }, { null, "a", null } };
                                                                        ^
  found   : null (NullType)
  required: @NonNull String
/home/runner/work/key/key/key.util/src/test/java/org/key_project/util/collection/TestImmutables.java:76: error: [array.initializer.type.incompatible] incompatible types in array initializer.
            { "a", "b", "d", "d", "e" }, { "a", "b", "c", "d", "d" }, { null, "a", null } };
                                                                                   ^
  found   : null (NullType)
  required: @NonNull String

[wadoon]

Is there a plan for the other modules? Next would be key.core, but I think we should do this incrementally each package/cluster at once