[dartdevc] Apply lints and cleanup violations

- always_require_non_null_named_parameters
- prefer_final_fields

Change-Id: I21dc5a9514fe2a7bb09c91fe28b2d4b79d7991e2
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/133840
Auto-Submit: Nicholas Shahan <nshahan@google.com>
Reviewed-by: Nate Bosch <nbosch@google.com>
Commit-Queue: Nate Bosch <nbosch@google.com>

pkg/dev_compiler/analysis_options.yaml

@@ -17,12 +17,14 @@ linter:
   rules:
     # Enforced by pedantic v1.9.0.
     - always_declare_return_types
+    - always_require_non_null_named_parameters
     - annotate_overrides
     - avoid_null_checks_in_equality_operators
     - camel_case_extensions
     - prefer_adjacent_string_concatenation
     - prefer_collection_literals
     - prefer_conditional_assignment
+    - prefer_final_fields
     - prefer_for_elements_to_map_fromIterable
     - prefer_if_null_operators
     - prefer_single_quotes
@@ -30,4 +32,4 @@ linter:
     # Not enforced by pedantic at any version.
     - directives_ordering
     - prefer_null_aware_operators
-    - prefer_typing_uninitialized_variables
+    - prefer_typing_uninitialized_variables

pkg/dev_compiler/lib/src/js_ast/nodes.dart

@@ -3,7 +3,8 @@
 // BSD-style license that can be found in the LICENSE file.
 
 // ignore_for_file: slash_for_doc_comments, prefer_single_quotes
-// ignore_for_file: always_declare_return_types
+// ignore_for_file: always_declare_return_types, prefer_final_fields
+// ignore_for_file: always_require_non_null_named_parameters
 
 part of js_ast;
 

pkg/dev_compiler/lib/src/js_ast/printer.dart

@@ -4,7 +4,7 @@
 
 // ignore_for_file: slash_for_doc_comments, unnecessary_const
 // ignore_for_file: always_declare_return_types, prefer_single_quotes
-// ignore_for_file: prefer_collection_literals
+// ignore_for_file: prefer_collection_literals, prefer_final_fields
 
 part of js_ast;
 

pkg/dev_compiler/lib/src/kernel/compiler.dart

@@ -2298,7 +2298,7 @@ class ProgramCompiler extends ComputeOnceConstantVisitor<js_ast.Expression>
     return _extensionTypes.isNativeInterface(c);
   }
 
-  var _forwardingCache = HashMap<Class, Map<String, Member>>();
+  final _forwardingCache = HashMap<Class, Map<String, Member>>();
 
   Member _lookupForwardedMember(Class c, String name) {
     // We only care about public methods.

pkg/dev_compiler/lib/src/kernel/target.dart

@@ -22,8 +22,8 @@ import 'kernel_helpers.dart';
 class DevCompilerTarget extends Target {
   // TODO(39698) Turn these back into const lists returned from the getters
   // once we don't have to exclude libraries from the forked NNBD sdk.
-  List<String> _extraRequiredLibraries;
-  List<String> _extraIndexedLibraries;
+  final List<String> _extraRequiredLibraries;
+  final List<String> _extraIndexedLibraries;
 
   DevCompilerTarget(this.flags)
       : _extraRequiredLibraries = [

pkg/dev_compiler/web/stack_trace_mapper.dart

@@ -60,8 +60,8 @@ external String _stringify(dynamic json);
 /// The unparsed data for the source maps must still be loaded before
 /// LazyMapping is used.
 class LazyMapping extends Mapping {
-  MappingBundle _bundle = MappingBundle();
-  SourceMapProvider _provider;
+  final MappingBundle _bundle = MappingBundle();
+  final SourceMapProvider _provider;
 
   LazyMapping(this._provider);