JetBrains/intellij-community · error · SliceFilterParseException

slice.filter.parse.error.not.null.filter.not.applicable.for.primitive.type

slice.filter.parse.error.not.null.filter.not.applicable.for.primitive.type

Error message

'!null' filter is not applicable to primitive type {0}

What it means

Thrown by JavaSliceProvider.parseFilter when the user types a '!null' filter in the Java Slice (dataflow) tool window for a value whose static type is a primitive (int, boolean, etc.). Primitives can never be null in Java, so a NOT_NULL dataflow value filter is meaningless and the parser rejects it with SliceFilterParseException. The message interpolates the presentable text of the primitive type.

Solutions

1. Remove the '!null' filter when slicing a value of primitive type — primitives are never null by language rules.
2. If you expected a reference type, check that you are slicing the right expression (e.g. the boxed Integer, not the unboxed int).
3. Use a value filter appropriate to primitives, such as a relational filter (e.g. '>=5') or a plain constant like '5'.
4. If you are a plugin author calling this API programmatically, guard with 'type instanceof PsiPrimitiveType' before requesting '!null'.

Example fix

// before (Slice filter on int x):
filter = "!null"

// after:
filter = ">=0"   // relational constant filter valid for int

PsiType type = JavaSliceProvider.getType(expression); // or resolve the sliced value's type yourself
boolean primitive = type instanceof PsiPrimitiveType;
// only offer '!null' filter when !primitive

try { provider.parseFilter(expression, filter); } catch (SliceFilterParseException e) { /* show e.getMessage() in the filter UI */ }

When it happens

Trigger: Opening the Slice tool window on a variable/parameter of primitive type (e.g. int x) and entering '!null' in the filter field; parseFilter resolves the type via getType(), sees type instanceof PsiPrimitiveType for the '!null' branch, and throws.

Common situations: Users exploring data flow for an int/long/boolean value and reflexively applying the same '!null' filter they use for reference types; plugin code calling SliceLanguageSupportProvider.parseFilter or JavaSliceProvider directly with a hardcoded '!null' filter; analyzing auto-unboxed values where the declared type is still primitive.

Related errors

• slice.filter.parse.error.enum.constant.not.found
• slice.filter.parse.error.expression.must.evaluate.to.constant
• slice.filter.parse.error.incorrect.constant.expected.number
• slice.filter.parse.error.incorrect.constant.type
• slice.filter.parse.error.incorrect.expression

AI-assisted analysis of JetBrains/intellij-community@be881553f2 (2026-08-14). Data as JSON: /api/errors/ca9ff12885ba234d. Report an issue: GitHub.

Appendix: source

Thrown at java/java-impl/src/com/intellij/slicer/JavaSliceProvider.java:129

    return type != null && !PsiTypes.voidType().equals(type) && !PsiTypes.nullType().equals(type);
  }

  @Override
  public @NotNull SliceValueFilter parseFilter(@NotNull PsiElement expression, @NotNull String filter) throws SliceFilterParseException {
    PsiType type = getType(expression);
    if (type == null) {
      return SliceLanguageSupportProvider.super.parseFilter(expression, filter);
    }
    if (filter.equals("null")) {
      if (type instanceof PsiPrimitiveType) {
        throw new SliceFilterParseException(
          JavaBundle.message("slice.filter.parse.error.null.filter.not.applicable.for.primitive.type", type.getPresentableText()));
      }
      return new JavaValueFilter(DfTypes.NULL);
    }
    if (filter.equals("!null")) {
      if (type instanceof PsiPrimitiveType) {
        throw new SliceFilterParseException(
          JavaBundle.message("slice.filter.parse.error.not.null.filter.not.applicable.for.primitive.type", type.getPresentableText()));
      }
      return new JavaValueFilter(DfTypes.NOT_NULL_OBJECT);
    }
    RelationType relationType = RelationType.EQ;
    if (PsiTypes.byteType().equals(type) ||
        PsiTypes.charType().equals(type) ||
        PsiTypes.shortType().equals(type) ||
        PsiTypes.intType().equals(type) ||
        PsiTypes.longType().equals(type)) {
      for (RelationType relType : RelationType.values()) {
        if (filter.startsWith(relType.toString())) {
          relationType = relType;
          filter = filter.substring(relType.toString().length()).trim();
          break;
        }
      }
    }

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