Inspectopedia 2025.2 Help

Impossible interface type assertion

Reports impossible interface-to-interface type assertions.

Checks for type assertions v.(T) and corresponding type-switch cases in which the static type V of v is the interface that cannot possibly implement the target interface T. This occurs when V and T contain methods with the same name but different signatures.

Example:

var v interface { Read() } _ = v.(io.Reader)

The Read method in v has a different signature than the Read method in io.Reader, so this assertion cannot succeed.

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.

GoVetImpossibleInterfaceToInterfaceAssertion
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 | Go | Probable bugs

This inspection only reports if the language version is 1.15 or higher.

Inspection ID: GoVetImpossibleInterfaceToInterfaceAssertion

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 GoVetImpossibleInterfaceToInterfaceAssertion

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

Inspection Details

By default bundled with:

GoLand 2025.2, Qodana for Go 2025.2,

Can be installed with plugin:

Go, 252.26654.0

Last modified: 18 September 2025