avoid-unused-after-null-check

added in: 1.13.0

warning

Pro+

Warns when a variable is checked for non-nullable value, but is not used within the condition or then branch.

info

This rule triggers only for cases when there is a potential place for an unused variable (e.g. matching type or invocation target).

Example

❌ Bad:

void fn(String value) {
  final String? myNullableValue = 'hello';
  // LINT: This variable is checked for non-nullable value, but is not used within the condition or then branch. Try referencing it or removing the check.
  if (myNullableValue != null) {
    print(value);
  }
}

✅ Good:

void fn(String value) {
  final String? myNullableValue = 'hello';
  if (myNullableValue != null) {
    print(myNullableValue); // Correct, replaced with 'myNullableValue'
  }
}