WildcardType your = canonicalizeWildcardType(declaration, (WildcardType) formalType);
      // if "formalType" is <? extends Foo>, "this" can be:
      // Foo, SubFoo, <? extends Foo>, <? extends SubFoo>, <T extends Foo> or
      // <T extends SubFoo>.
      // if "formalType" is <? super Foo>, "this" can be:
      // Foo, SuperFoo, <? super Foo> or <? super SuperFoo>.