Unnecessary 'def'

Reports unnecessary def modifiers when used with explicit type declaration.

Example:

  def boolean foo() {} // modifier is unnecessary
  def Object bar // modifier is unnecessary

  // modifier is required and therefore not highlighted
  def (int a, String b) = []

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.

GrUnnecessaryDefModifier

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 | Groovy | Style

Inspection ID: GrUnnecessaryDefModifier

Inspection options

Here you can find the description of settings available for the Unnecessary 'def' inspection, and the reference of their default values.

Only report in explicitly typed declarations

Option ID:

reportExplicitTypeOnly

Default value:

Selected

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 GrUnnecessaryDefModifier

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