invalid_deprecated_optional_annotation

The annotation '@Deprecated.optional' can only be applied to optional parameters.

The analyzer produces this diagnostic when the @Deprecated.optional annotation is applied to a parameter that isn't an optional parameter. The annotation must not be used on a parameter in a local function, an anonymous function, a function-typed parameter, or a typedef. It is only valid on optional parameters in a top-level function, a method, or a constructor.

The following code produces this diagnostic because the annotation is on a required parameter:

void f(@Deprecated.optional() int p) {}

Remove the annotation:

void f(int p) {}