unnecessary_cast_pattern

Unnecessary cast pattern.

The analyzer produces this diagnostic when a cast pattern is used on a value that is known to be of the specified type.

The following code produces this diagnostic because the cast as num is known to always succeed because the type of z is int:

void f(int x) {
  if (x case var z as num) {
    print(z);
  }
}

Remove the cast pattern:

void f(int x) {
  if (x case var z) {
    print(z);
  }
}