analyzer: Deprecate the avoid_null_checks_in_equality_operators lint rule

Work towards https://github.com/dart-lang/sdk/issues/59514

We introduced a new Warning called NON_NULLABLE_EQUALS_PARAMETER a few releases ago. It warns when the parameter of an `operator ==` override has a nullable type:

> The parameter type of '==' operators should be non-nullable.

I didn't realize it at the time, but that new warning, plus null safety, basically replace the `avoid_null_checks_in_equality_operators` lint rule. This rule reports doing any null-check work on a nullable parameter of an `operator ==` override.

Change-Id: Ibd8139cd5804a9ccb6cc07d2187c9305a336c7cd
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/467922
Reviewed-by: Brian Wilkerson <brianwilkerson@google.com>
Commit-Queue: Samuel Rawlins <srawlins@google.com>

CHANGELOG.md

@@ -50,6 +50,9 @@
 - Fixes to the 'Extract Widget' refactoring.
 - (Thanks [@FMorschel](https://github.com/FMorschel) and
   [@DanTup](https://github.com/DanTup) for many of the above enhancements!)
+- The `avoid_null_checks_in_equality_operators` lint rule is now deprecated.
+- The `prefer_final_parameters` lint rule is now deprecated.
+- The `use_if_null_to_convert_nulls_to_bools` lint rule is now deprecated.
 
 #### Pub
 

pkg/linter/example/all.yaml

@@ -27,7 +27,6 @@ linter:
     - avoid_init_to_null
     - avoid_js_rounded_ints
     - avoid_multiple_declarations_per_line
-    - avoid_null_checks_in_equality_operators
     - avoid_positional_boolean_parameters
     - avoid_print
     - avoid_private_typedef_functions

pkg/linter/lib/src/rules/avoid_null_checks_in_equality_operators.dart

@@ -4,6 +4,7 @@
 
 import 'package:analyzer/analysis_rule/analysis_rule.dart';
 import 'package:analyzer/analysis_rule/rule_context.dart';
+import 'package:analyzer/analysis_rule/rule_state.dart';
 import 'package:analyzer/analysis_rule/rule_visitor_registry.dart';
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/ast/token.dart';
@@ -11,6 +12,7 @@ import 'package:analyzer/dart/ast/visitor.dart';
 import 'package:analyzer/dart/element/element.dart';
 import 'package:analyzer/dart/element/nullability_suffix.dart';
 import 'package:analyzer/error/error.dart';
+import 'package:pub_semver/pub_semver.dart';
 
 import '../analyzer.dart';
 import '../diagnostic.dart' as diag;
@@ -43,6 +45,7 @@ class AvoidNullChecksInEqualityOperators extends AnalysisRule {
     : super(
         name: LintNames.avoid_null_checks_in_equality_operators,
         description: _desc,
+        state: RuleState.deprecated(since: Version(3, 11, 0)),
       );
 
   @override

pkg/linter/messages.yaml

@@ -1728,6 +1728,7 @@ LinterLintCode:
     correctionMessage: "Try removing the comparison."
     state:
       stable: "2.0"
+      deprecated: "3.11"
     categories: [style]
     hasPublishedDocs: false
     deprecatedDetails: |-