3.0 deprecations

Author: pq

lib/src/rules/always_require_non_null_named_parameters.dart

@@ -49,6 +49,7 @@ class AlwaysRequireNonNullNamedParameters extends LintRule {
             name: 'always_require_non_null_named_parameters',
             description: _desc,
             details: _details,
+            state: State.deprecated(since: dart3),
             group: Group.style);
 
   @override

lib/src/rules/avoid_returning_null.dart

@@ -59,6 +59,7 @@ class AvoidReturningNull extends LintRule {
             name: 'avoid_returning_null',
             description: _desc,
             details: _details,
+            state: State.deprecated(since: dart3),
             group: Group.style);
 
   @override

lib/src/rules/avoid_returning_null_for_future.dart

@@ -30,6 +30,7 @@ class AvoidReturningNullForFuture extends LintRule {
             name: 'avoid_returning_null_for_future',
             description: _desc,
             details: _details,
+            state: State.deprecated(since: dart3),
             group: Group.errors);
 
   @override

lib/src/rules/prefer_equal_for_default_values.dart

@@ -38,8 +38,7 @@ class PreferEqualForDefaultValues extends LintRule {
             name: 'prefer_equal_for_default_values',
             description: _desc,
             details: _details,
-            // todo(pq): deprecate for 3.0 (https://github.com/dart-lang/linter/issues/3879)
-            state: State.stable(), //State.deprecated(since: dart3),
+            state: State.deprecated(since: dart3),
             group: Group.style);
 
   @override