unnecessary_null_aware_assignments

Unnecessary assignment of 'null'.

The analyzer produces this diagnostic when the right-hand side of a null-aware assignment is the null literal.

The following code produces this diagnostic because the null aware operator is being used to assign null to s when s is already null:

void f(String? s) {
  s ??= null;
}

If a non-null value should be assigned to the left-hand operand, then change the right-hand side:

void f(String? s) {
  s ??= '';
}

If there is no non-null value to assign to the left-hand operand, then remove the assignment:

void f(String? s) {
}