extension_override_access_to_static_member

An extension override can't be used to access a static member from an extension.

The analyzer produces this diagnostic when an extension override is the receiver of the invocation of a static member. Similar to static members in classes, the static members of an extension should be accessed using the name of the extension, not an extension override.

The following code produces this diagnostic because m is static:

extension E on String {
  static void m() {}
}

void f() {
  E('').m();
}

Replace the extension override with the name of the extension:

extension E on String {
  static void m() {}
}

void f() {
  E.m();
}