missing_named_pattern_field_name

The getter name is not specified explicitly, and the pattern is not a variable.

The analyzer produces this diagnostic when, within an object pattern, the specification of a property and the pattern used to match the property's value doesn't have either:

• a getter name before the colon
• a variable pattern from which the getter name can be inferred

The following code produces this diagnostic because there is no getter name before the colon and no variable pattern after the colon in the object pattern (C(:0)):

abstract class C {
  int get f;
}

void f(C c) {
  switch (c) {
    case C(:0):
      break;
  }
}

If you need to use the actual value of the property within the pattern's scope, then add a variable pattern where the name of the variable is the same as the name of the property being matched:

abstract class C {
  int get f;
}

void f(C c) {
  switch (c) {
    case C(:var f) when f == 0:
      print(f);
  }
}

If you don't need to use the actual value of the property within the pattern's scope, then add the name of the property being matched before the colon:

abstract class C {
  int get f;
}

void f(C c) {
  switch (c) {
    case C(f: 0):
      break;
  }
}

Unless stated otherwise, the documentation on this site reflects Dart 3.8.1. Page last updated on 2025-05-08. View source or report an issue.