wrong_number_of_type_arguments_method

The method '{0}' is declared with {1} type parameters, but {2} type arguments are given.

The analyzer produces this diagnostic when a method or function is invoked with a different number of type arguments than the number of type parameters specified in its declaration. There must either be no type arguments or the number of arguments must match the number of parameters.

The following code produces this diagnostic because the invocation of the method m has two type arguments, but the declaration of m only has one type parameter:

class C {
  int m<A>(A a) => 0;
}

int f(C c) => c.m<int, int>(2);

If the type arguments are necessary, then make them match the number of type parameters by either adding or removing type arguments:

class C {
  int m<A>(A a) => 0;
}

int f(C c) => c.m<int>(2);

If the type arguments aren't necessary, then remove them:

class C {
  int m<A>(A a) => 0;
}

int f(C c) => c.m(2);

Unless stated otherwise, the documentation on this site reflects Dart 3.8.0. Page last updated on 2025-05-08. View source or report an issue.