Cast conflicts with 'instanceof'

Reports type cast expressions that are preceded by an instanceof check for a different type.

Although this might be intended, such a construct is most likely an error, and will result in a java.lang.ClassCastException at runtime.

Example:

  class Main {
    int whenCharSequenceCastToNumber(Object o){
      if (o instanceof CharSequence) {
        return ((Number) o).intValue();
      }
      return 0;
    }

    int earlyReturnWhenNotCharSequence(Object o){
      if (!(o instanceof CharSequence)) return 0;
      return ((Number)o).intValue();
    }
  }

Locating this inspection

By ID

Can be used to locate inspection in e.g. Qodana configuration files, where you can quickly enable or disable it, or adjust its settings.

CastConflictsWithInstanceof

Via Settings dialog

Path to the inspection settings via IntelliJ Platform IDE Settings dialog, when you need to adjust inspection settings directly from your IDE.

Settings or Preferences | Editor | Inspections | Java | Probable bugs

Inspection ID: CastConflictsWithInstanceof

Suppressing Inspection

You can suppress this inspection by placing the following comment marker before the code fragment where you no longer want messages from this inspection to appear:

//noinspection CastConflictsWithInstanceof

More detailed instructions as well as other ways and options that you have can be found in the product documentation:

IntelliJ IDEA 2025.3

Inspection Details
By default bundled with:	IntelliJ IDEA 2025.3, Qodana for JVM 2025.3,

Last modified: 03 December 2025