[dart2js] Add lints

Add `unneccessary_statements`.

Add `unneccesary_ignore` so we can better maintain the ignores.

Change-Id: I50303be70fd6dbc14bdf0c5f0af9e58a1c6ec042
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/420464
Commit-Queue: Stephen Adams <[email protected]>
Reviewed-by: Nate Biggs <[email protected]>

Author: rakudrama

pkg/compiler/analysis_options.yaml

@@ -19,3 +19,5 @@ linter:
     - always_declare_return_types
     - avoid_dynamic_calls
     - no_default_cases
+    - unnecessary_ignore
+    - unnecessary_statements

pkg/compiler/lib/src/constants/values.dart

@@ -815,7 +815,7 @@ class JsNameConstantValue extends ConstantValue {
 
   @override
   String toDartText(DartTypes? dartTypes) {
-    if (name.isFinalized) 'js_name($name)';
+    if (name.isFinalized) return 'js_name($name)';
     return 'js_name(name.nonfinalizedDebugText())';
   }
 

pkg/compiler/lib/src/io/mapped_file.dart

@@ -4,7 +4,6 @@
 
 // File is compiled with checked in SDK, update [FfiNative]s to [Native] when
 // SDK is rolled.
-// ignore_for_file: deprecated_member_use
 
 import 'dart:typed_data';
 

pkg/compiler/lib/src/io/position_information.dart

@@ -1173,7 +1173,6 @@ class OnlineJavaScriptTracer extends js.BaseVisitor1Void<int>
   }
 
   @override
-  // ignore: avoid_renaming_method_parameters
   void visitNode(js.Node node, _) {}
 
   void _handleFunction(_PositionInfoNode node, js.Node body, int start) {
@@ -1267,7 +1266,6 @@ class OnlineJavaScriptTracer extends js.BaseVisitor1Void<int>
   }
 
   @override
-  // ignore: avoid_renaming_method_parameters
   void visitCall(js.Call node, _) {
     _visit(
       node.target,
@@ -1298,7 +1296,6 @@ class OnlineJavaScriptTracer extends js.BaseVisitor1Void<int>
   }
 
   @override
-  // ignore: avoid_renaming_method_parameters
   void visitNew(js.New node, _) {
     _visit(
       node.target,
@@ -1312,7 +1309,6 @@ class OnlineJavaScriptTracer extends js.BaseVisitor1Void<int>
   }
 
   @override
-  // ignore: avoid_renaming_method_parameters
   void visitAccess(js.PropertyAccess node, _) {
     final receiverNode = _visit(node.receiver);
     // Technically we'd like to use the offset of the `.` in the property
@@ -1446,27 +1442,23 @@ class OnlineJavaScriptTracer extends js.BaseVisitor1Void<int>
   }
 
   @override
-  // ignore: avoid_renaming_method_parameters
   void visitContinue(js.Continue node, _) {
     _currentNode.addNotifyStep(StepKind.continue_);
   }
 
   @override
-  // ignore: avoid_renaming_method_parameters
   void visitBreak(js.Break node, _) {
     _currentNode.addNotifyStep(StepKind.break_);
   }
 
   @override
-  // ignore: avoid_renaming_method_parameters
   void visitTry(js.Try node, _) {
     _visit(node.body);
     _visit(node.catchPart, branchKind: BranchKind.catch_);
     _visit(node.finallyPart, branchKind: BranchKind.finally_);
   }
 
   @override
-  // ignore: avoid_renaming_method_parameters
   void visitConditional(js.Conditional node, _) {
     _visit(node.condition);
     _visit(node.then, branchKind: BranchKind.condition, branchToken: 1);
@@ -1495,7 +1487,6 @@ class OnlineJavaScriptTracer extends js.BaseVisitor1Void<int>
   }
 
   @override
-  // ignore: avoid_renaming_method_parameters
   void visitDeferredExpression(js.DeferredExpression node, _) {
     _visit(node.value);
   }

pkg/compiler/lib/src/js_model/records.dart

@@ -274,9 +274,9 @@ class RecordRepresentation {
 
 /// Conversion of records to classes.
 class RecordDataBuilder {
-  final DiagnosticReporter _reporter;
+  final DiagnosticReporter _reporter; // ignore: unused_field
   final JsToElementMap _elementMap;
-  final AnnotationsData _annotationsData;
+  final AnnotationsData _annotationsData; // ignore: unused_field
   final Map<RecordShape, List<MemberEntity>> _gettersByShape = {};
 
   RecordDataBuilder(this._reporter, this._elementMap, this._annotationsData);
@@ -285,9 +285,6 @@ class RecordDataBuilder {
     JClosedWorldBuilder closedWorldBuilder,
     Iterable<RecordType> recordTypes,
   ) {
-    _reporter;
-    _annotationsData;
-
     // Sorted shapes lead to a more consistent class ordering in the generated
     // code.
     final shapes =