In type/Metamodel/Primitives§

See primary documentation in context for method configure type checking

method configure_type_checking( Mu $type, @cache, :$authoritative = True, :$call_accepts = False )

Configures the type checking for $type. @cache is a list of known types against which $type checks positively (so in a classical class-based system, the type itself and all recursive superclasses). If :authoritative is missing or True, this type will fail checks against all types not in @cache. If :call_accepts is True, the method ACCEPTS will be called for type checks against this type.