diff --git a/DEPS b/DEPS
index 665504fa95b..8ec9f700962 100644
--- a/DEPS
+++ b/DEPS
@@ -129,7 +129,7 @@ vars = {
   ### /third_party/pkg dependencies
   # 'tools/rev_sdk_deps.dart' will rev pkg dependencies to their latest; put an
   # EOL comment after a dependency to instead pin at the current revision.
-  "core_rev": "15c7fe9958b95998ba2f5a4ad1beab66b9d815fb",
+  "core_rev": "9f4321008457d16674c0faabfe49327a2bb0cd29",
   "dartdoc_rev": "c41b86b98ca935ec3c29cdb04cb190df30afb242",
   "ecosystem_rev": "a3cc42d999acc95af96a48d155d7749d92cecb92",
   "flute_rev": "e4ea0459a7debae5e9592c85141707b01fac86c9",
diff --git a/pkg/analysis_server/tool/benchmark_tools/language_server_benchmark.dart b/pkg/analysis_server/tool/benchmark_tools/language_server_benchmark.dart
index df0e542cd6e..cd3bc4c995d 100644
--- a/pkg/analysis_server/tool/benchmark_tools/language_server_benchmark.dart
+++ b/pkg/analysis_server/tool/benchmark_tools/language_server_benchmark.dart
@@ -130,7 +130,7 @@ abstract class DartLanguageServerBenchmark {
     }
   }
 
-  void _checkLongRunningRequests(timer) {
+  void _checkLongRunningRequests(Timer timer) {
     bool reportedSomething = false;
     for (MapEntry<int, OutstandingRequest> waitingFor
         in _outstandingRequestsWithId.entries) {
diff --git a/pkg/analyzer/analysis_options.yaml b/pkg/analyzer/analysis_options.yaml
index 886bf7836d9..a9349c65792 100644
--- a/pkg/analyzer/analysis_options.yaml
+++ b/pkg/analyzer/analysis_options.yaml
@@ -35,6 +35,9 @@ analyzer:
     # About 30 violations of this in lib/.
     provide_deprecation_message: ignore
 
+    # ~3,500 violations in test/.
+    strict_top_level_inference: ignore
+
     # Ignoring this for all developers means developers don't need to ignore
     # TODOs in their IDE settings.
     todo: ignore
diff --git a/pkg/analyzer_plugin/test/integration/support/integration_tests.dart b/pkg/analyzer_plugin/test/integration/support/integration_tests.dart
index f6851943ff7..355d90089f7 100644
--- a/pkg/analyzer_plugin/test/integration/support/integration_tests.dart
+++ b/pkg/analyzer_plugin/test/integration/support/integration_tests.dart
@@ -38,7 +38,7 @@ Matcher isMapOf(Matcher keyMatcher, Matcher valueMatcher) =>
 Matcher isOneOf(List<Matcher> choiceMatchers) => _OneOf(choiceMatchers);
 
 /// Assert that [actual] matches [matcher].
-void outOfTestExpect(actual, Matcher matcher,
+void outOfTestExpect(dynamic actual, Matcher matcher,
     {String? reason, skip, bool verbose = false}) {
   var matchState = {};
   try {
@@ -49,8 +49,8 @@ void outOfTestExpect(actual, Matcher matcher,
   fail(_defaultFailFormatter(actual, matcher, reason, matchState, verbose));
 }
 
-String _defaultFailFormatter(
-    actual, Matcher matcher, String? reason, Map matchState, bool verbose) {
+String _defaultFailFormatter(dynamic actual, Matcher matcher, String? reason,
+    Map matchState, bool verbose) {
   var description = StringDescription();
   description.add('Expected: ').addDescriptionOf(matcher).add('\n');
   description.add('  Actual: ').addDescriptionOf(actual).add('\n');
@@ -306,7 +306,7 @@ class MatchesJsonObject extends _RecursiveMatcher {
       description.add(this.description);
 
   @override
-  void populateMismatches(item, List<MismatchDescriber> mismatches) {
+  void populateMismatches(dynamic item, List<MismatchDescriber> mismatches) {
     if (item is! Map) {
       mismatches.add(simpleDescription('is not a map'));
       return;
@@ -344,7 +344,7 @@ class MatchesJsonObject extends _RecursiveMatcher {
   /// Check the type of a field called [key], having value [value], using
   /// [valueMatcher]. If it doesn't match, record a closure in [mismatches]
   /// which can describe the mismatch.
-  void _checkField(String key, value, Matcher valueMatcher,
+  void _checkField(String key, Object? value, Matcher valueMatcher,
       List<MismatchDescriber> mismatches) {
     checkSubstructure(
         value,
@@ -757,7 +757,7 @@ abstract class _RecursiveMatcher extends Matcher {
   /// the mismatch. [describeSubstructure] is used to describe which
   /// substructure did not match.
   void checkSubstructure(
-      item,
+      Object? item,
       Matcher matcher,
       List<MismatchDescriber> mismatches,
       Description Function(Description description) describeSubstructure) {
@@ -806,7 +806,7 @@ abstract class _RecursiveMatcher extends Matcher {
   }
 
   @override
-  bool matches(item, Map matchState) {
+  bool matches(dynamic item, Map matchState) {
     var mismatches = <MismatchDescriber>[];
     populateMismatches(item, mismatches);
     if (mismatches.isEmpty) {
@@ -819,7 +819,7 @@ abstract class _RecursiveMatcher extends Matcher {
 
   /// Populate [mismatches] with descriptions of all the ways in which [item]
   /// does not match.
-  void populateMismatches(item, List<MismatchDescriber> mismatches);
+  void populateMismatches(dynamic item, List<MismatchDescriber> mismatches);
 
   /// Create a [MismatchDescriber] describing a mismatch with a simple string.
   MismatchDescriber simpleDescription(String description) =>
diff --git a/pkg/build_integration/test/file_system/multi_root_test.dart b/pkg/build_integration/test/file_system/multi_root_test.dart
index 3c566193de1..d7dc18b8ba7 100644
--- a/pkg/build_integration/test/file_system/multi_root_test.dart
+++ b/pkg/build_integration/test/file_system/multi_root_test.dart
@@ -14,7 +14,7 @@ import 'package:test/test.dart';
 
 var root = Uri.parse('org-dartlang-test:///');
 
-main() {
+void main() {
   late MemoryFileSystem memoryFs;
   late MultiRootFileSystem multiRoot;
 
diff --git a/pkg/build_integration/test/file_system/single_root_test.dart b/pkg/build_integration/test/file_system/single_root_test.dart
index 08f14d38b1e..c05db725b1b 100644
--- a/pkg/build_integration/test/file_system/single_root_test.dart
+++ b/pkg/build_integration/test/file_system/single_root_test.dart
@@ -9,7 +9,7 @@ import 'package:front_end/src/api_unstable/build_integration.dart';
 import 'package:front_end/src/api_prototype/memory_file_system.dart';
 import 'package:test/test.dart';
 
-main() {
+void main() {
   var root = Uri.parse('org-dartlang-test:///');
   var fileSystem = SingleRootFileSystem(
       'single-root', root.resolve('A/B'), MemoryFileSystem(root));
diff --git a/pkg/dart2bytecode/analysis_options.yaml b/pkg/dart2bytecode/analysis_options.yaml
index be329ed424d..018cb3181c2 100644
--- a/pkg/dart2bytecode/analysis_options.yaml
+++ b/pkg/dart2bytecode/analysis_options.yaml
@@ -3,3 +3,8 @@
 # BSD-style license that can be found in the LICENSE file.
 
 include: package:lints/core.yaml
+
+analyzer:
+  errors:
+    # ~75 violations in test/.
+    strict_top_level_inference: ignore
diff --git a/pkg/dart2bytecode/bin/dump_bytecode.dart b/pkg/dart2bytecode/bin/dump_bytecode.dart
index dc6b16507e9..bbed10da511 100644
--- a/pkg/dart2bytecode/bin/dump_bytecode.dart
+++ b/pkg/dart2bytecode/bin/dump_bytecode.dart
@@ -13,7 +13,7 @@ Usage: dump_bytecode input.bytecode
 Dumps bytecode file.
 ''';
 
-main(List<String> arguments) async {
+void main(List<String> arguments) async {
   if (arguments.length != 1) {
     print(_usage);
     exit(1);
diff --git a/pkg/dart2bytecode/lib/bytecode_generator.dart b/pkg/dart2bytecode/lib/bytecode_generator.dart
index d2c35c23894..c0d58a50e64 100644
--- a/pkg/dart2bytecode/lib/bytecode_generator.dart
+++ b/pkg/dart2bytecode/lib/bytecode_generator.dart
@@ -3999,7 +3999,7 @@ class BytecodeGenerator extends RecursiveVisitor {
     return locals.tempIndexInFrame(node, tempIndex: 1);
   }
 
-  _saveContextForTryBlock(TreeNode node) {
+  void _saveContextForTryBlock(TreeNode node) {
     if (!locals.hasContextVar) {
       return;
     }
@@ -4007,7 +4007,7 @@ class BytecodeGenerator extends RecursiveVisitor {
     asm.emitPopLocal(_savedContextVar(node));
   }
 
-  _restoreContextForTryBlock(TreeNode node) {
+  void _restoreContextForTryBlock(TreeNode node) {
     if (!locals.hasContextVar) {
       return;
     }
diff --git a/pkg/dart2bytecode/lib/disassembler.dart b/pkg/dart2bytecode/lib/disassembler.dart
index 4aa9b0167aa..1b07fc9a349 100644
--- a/pkg/dart2bytecode/lib/disassembler.dart
+++ b/pkg/dart2bytecode/lib/disassembler.dart
@@ -124,7 +124,7 @@ class BytecodeDisassembler {
     }
   }
 
-  _decodeUint32At(int pos) =>
+  int _decodeUint32At(int pos) =>
       _bytecode[pos] +
       (_bytecode[pos + 1] << 8) +
       (_bytecode[pos + 2] << 16) +
diff --git a/pkg/dart2bytecode/lib/local_vars.dart b/pkg/dart2bytecode/lib/local_vars.dart
index d2cb291f61c..3d2a7951762 100644
--- a/pkg/dart2bytecode/lib/local_vars.dart
+++ b/pkg/dart2bytecode/lib/local_vars.dart
@@ -436,13 +436,13 @@ class _ScopeBuilder extends RecursiveVisitor {
     _loopDepth = saveLoopDepth;
   }
 
-  _enterFrame(TreeNode node) {
+  void _enterFrame(TreeNode node) {
     _currentFrameInternal = new Frame(node, _currentFrameInternal);
     _enterScope(node);
     _currentFrame.topScope = _currentScope;
   }
 
-  _leaveFrame() {
+  void _leaveFrame() {
     _leaveScope();
     _currentFrameInternal = _currentFrame.parent;
   }
diff --git a/pkg/dart2js_info/lib/src/table.dart b/pkg/dart2js_info/lib/src/table.dart
index fac5d97a32e..466036acbc3 100644
--- a/pkg/dart2js_info/lib/src/table.dart
+++ b/pkg/dart2js_info/lib/src/table.dart
@@ -63,7 +63,7 @@ class Table {
 
   /// Add an entry in the table, creating a new row each time [totalColumns]
   /// entries are added.
-  void addEntry(entry) {
+  void addEntry(Object entry) {
     if (_currentRow == null) {
       _sealed = true;
       _currentRow = [];
diff --git a/pkg/dart2js_info/lib/src/util.dart b/pkg/dart2js_info/lib/src/util.dart
index c344d4e3431..ec4968f72cf 100644
--- a/pkg/dart2js_info/lib/src/util.dart
+++ b/pkg/dart2js_info/lib/src/util.dart
@@ -149,7 +149,7 @@ String? libraryGroupName(Info info) {
 }
 
 /// Produce a string containing [value] padded with white space up to [n] chars.
-String pad(value, n, {bool right = false}) {
+String pad(Object value, int n, {bool right = false}) {
   var s = '$value';
   if (s.length >= n) return s;
   // ignore: avoid_dynamic_calls
diff --git a/pkg/dart2js_tools/lib/src/dart2js_mapping.dart b/pkg/dart2js_tools/lib/src/dart2js_mapping.dart
index 8b6611bf344..5e93d91d2b8 100644
--- a/pkg/dart2js_tools/lib/src/dart2js_mapping.dart
+++ b/pkg/dart2js_tools/lib/src/dart2js_mapping.dart
@@ -165,7 +165,7 @@ class _FrameDecoder implements Iterator<String> {
   }
 }
 
-_extractMinifiedNames(
+void _extractMinifiedNames(
   String encodedInput,
   SingleMapping sourceMap,
   Map<String, String> minifiedNames,
diff --git a/pkg/dart2js_tools/lib/src/util.dart b/pkg/dart2js_tools/lib/src/util.dart
index d2c94cd4cd5..5630903771a 100644
--- a/pkg/dart2js_tools/lib/src/util.dart
+++ b/pkg/dart2js_tools/lib/src/util.dart
@@ -56,7 +56,8 @@ class DownloadedFileProvider extends CachingFileProvider {
 
 class Logger {
   final Set<String> _seenMessages = <String>{};
-  log(String message) {
+
+  void log(String message) {
     if (_seenMessages.add(message)) {
       print(message);
     }
diff --git a/pkg/dart2wasm/lib/option.dart b/pkg/dart2wasm/lib/option.dart
index ebbd9fbcd31..b0e8da4c00e 100644
--- a/pkg/dart2wasm/lib/option.dart
+++ b/pkg/dart2wasm/lib/option.dart
@@ -87,24 +87,24 @@ class MultiValueOption<T> extends Option<List<T>> {
 }
 
 class IntMultiOption extends MultiValueOption<int> {
-  IntMultiOption(
-      name, void Function(WasmCompilerOptions o, List<int> v) applyToOptions,
+  IntMultiOption(String name,
+      void Function(WasmCompilerOptions o, List<int> v) applyToOptions,
       {Iterable<String>? defaultsTo})
       : super(name, applyToOptions, (v) => int.parse(v),
             defaultsTo: defaultsTo);
 }
 
 class StringMultiOption extends MultiValueOption<String> {
-  StringMultiOption(
-      name, void Function(WasmCompilerOptions o, List<String> v) applyToOptions,
+  StringMultiOption(String name,
+      void Function(WasmCompilerOptions o, List<String> v) applyToOptions,
       {String? abbr, Iterable<String>? defaultsTo})
       : super(name, applyToOptions, (v) => v,
             abbr: abbr, defaultsTo: defaultsTo);
 }
 
 class UriMultiOption extends MultiValueOption<Uri> {
-  UriMultiOption(
-      name, void Function(WasmCompilerOptions o, List<Uri> v) applyToOptions,
+  UriMultiOption(String name,
+      void Function(WasmCompilerOptions o, List<Uri> v) applyToOptions,
       {Iterable<String>? defaultsTo})
       : super(name, applyToOptions, (v) => Uri.file(Directory(v).absolute.path),
             defaultsTo: defaultsTo);
diff --git a/pkg/dds/analysis_options.yaml b/pkg/dds/analysis_options.yaml
index 7386f12d2e5..c9da9825c63 100644
--- a/pkg/dds/analysis_options.yaml
+++ b/pkg/dds/analysis_options.yaml
@@ -1,5 +1,10 @@
 include: package:lints/recommended.yaml
 
+analyzer:
+  errors:
+    # ~40 violations in test/.
+    strict_top_level_inference: ignore
+
 linter:
   rules:
     - directives_ordering
diff --git a/pkg/dds/lib/src/dap/adapters/dart.dart b/pkg/dds/lib/src/dap/adapters/dart.dart
index 1e8c4d0600a..542234de15e 100644
--- a/pkg/dds/lib/src/dap/adapters/dart.dart
+++ b/pkg/dds/lib/src/dap/adapters/dart.dart
@@ -3046,7 +3046,7 @@ class _DdsCapabilities {
   /// `postEvent`.
   bool get supportsCustomStreams => _isAtLeast(major: 1, minor: 4);
 
-  bool _isAtLeast({required major, required minor}) {
+  bool _isAtLeast({required int major, required int minor}) {
     if (this.major > major) {
       return true;
     } else if (this.major == major && this.minor >= minor) {
diff --git a/pkg/dds/lib/src/dap_handler.dart b/pkg/dds/lib/src/dap_handler.dart
index 32ce9e9e95b..4c184a16dc3 100644
--- a/pkg/dds/lib/src/dap_handler.dart
+++ b/pkg/dds/lib/src/dap_handler.dart
@@ -45,7 +45,7 @@ class DapHandler {
     };
   }
 
-  _handleEvent(Event event) {
+  void _handleEvent(Event event) {
     if (event.event == 'initialized') {
       _initializedCompleter.complete();
     }
diff --git a/pkg/dev_compiler/analysis_options.yaml b/pkg/dev_compiler/analysis_options.yaml
index 6c680e028e3..88f9011991d 100644
--- a/pkg/dev_compiler/analysis_options.yaml
+++ b/pkg/dev_compiler/analysis_options.yaml
@@ -10,6 +10,8 @@ analyzer:
     constant_identifier_names: ignore
     implementation_imports: ignore
     prefer_void_to_null: ignore
+    # ~5 violations in test/sourcemap.
+    strict_top_level_inference: ignore
   exclude:
     - doc/api/**
     - gen/**
diff --git a/pkg/dev_compiler/lib/src/js_ast/nodes.dart b/pkg/dev_compiler/lib/src/js_ast/nodes.dart
index e0a6e6ef5e0..0b359251d78 100644
--- a/pkg/dev_compiler/lib/src/js_ast/nodes.dart
+++ b/pkg/dev_compiler/lib/src/js_ast/nodes.dart
@@ -323,7 +323,7 @@ abstract class Node {
   /// Returns a node equivalent to [this], but with new source position and end
   /// source position.
   T _withSourceInformation<T extends Node>(
-      sourceInformation, T Function() cloneFunc) {
+      Object? sourceInformation, T Function() cloneFunc) {
     if (sourceInformation == this.sourceInformation) {
       return this as T;
     }
@@ -334,7 +334,7 @@ abstract class Node {
     return clone;
   }
 
-  Node withSourceInformation(sourceInformation) =>
+  Node withSourceInformation(Object? sourceInformation) =>
       _withSourceInformation(sourceInformation, _clone);
 
   bool get isCommaOperator => false;
diff --git a/pkg/dev_compiler/lib/src/js_ast/template.dart b/pkg/dev_compiler/lib/src/js_ast/template.dart
index 72429ec8af7..663130a5ae2 100644
--- a/pkg/dev_compiler/lib/src/js_ast/template.dart
+++ b/pkg/dev_compiler/lib/src/js_ast/template.dart
@@ -158,7 +158,7 @@ class InstantiatorGeneratorVisitor implements NodeVisitor<Instantiator> {
   }
 
   static Instantiator<T> same<T extends Node>(T node) => (arguments) => node;
-  static Null makeNull(arguments) => null;
+  static Null makeNull(dynamic arguments) => null;
 
   Instantiator visit<T extends Node>(T node) {
     if (forceCopy || analysis.containsInterpolatedNodes(node)) {
diff --git a/pkg/dynamic_modules/bin/dynamic_module_runner.dart b/pkg/dynamic_modules/bin/dynamic_module_runner.dart
index bde4f95862f..0514f89e6bc 100644
--- a/pkg/dynamic_modules/bin/dynamic_module_runner.dart
+++ b/pkg/dynamic_modules/bin/dynamic_module_runner.dart
@@ -6,7 +6,7 @@ import 'dart:io';
 
 import 'package:dynamic_modules/dynamic_modules.dart' show loadModuleFromBytes;
 
-main(List<String> args) {
+Future<void> main(List<String> args) {
   final bytes = File(args[0]).readAsBytesSync();
   return loadModuleFromBytes(bytes);
 }
diff --git a/pkg/dynamic_modules/test/data/apply_mixin/main.dart b/pkg/dynamic_modules/test/data/apply_mixin/main.dart
index 405b2ec71ef..0a34e1ba637 100644
--- a/pkg/dynamic_modules/test/data/apply_mixin/main.dart
+++ b/pkg/dynamic_modules/test/data/apply_mixin/main.dart
@@ -8,7 +8,7 @@ import 'package:expect/expect.dart';
 import 'shared/shared.dart' show M;
 
 /// A dynamic module can apply an exposed mixin.
-main() async {
+void main() async {
   final o = (await helper.load('entry1.dart')) as M;
   Expect.equals(3, o.method1());
   Expect.equals('*3 2', o.method2());
diff --git a/pkg/dynamic_modules/test/data/closure_invocation/main.dart b/pkg/dynamic_modules/test/data/closure_invocation/main.dart
index fa56d261b94..360180efed9 100644
--- a/pkg/dynamic_modules/test/data/closure_invocation/main.dart
+++ b/pkg/dynamic_modules/test/data/closure_invocation/main.dart
@@ -7,7 +7,7 @@ import 'package:expect/expect.dart';
 
 import 'shared/shared.dart' as shared;
 
-main() async {
+void main() async {
   await helper.load('entry1.dart');
   Expect.equals('dynamic module 1: hello', shared.topLevelClosure!('hello'));
   helper.done();
diff --git a/pkg/dynamic_modules/test/data/core_api/main.dart b/pkg/dynamic_modules/test/data/core_api/main.dart
index ef53d5444ac..0baee72e7c0 100644
--- a/pkg/dynamic_modules/test/data/core_api/main.dart
+++ b/pkg/dynamic_modules/test/data/core_api/main.dart
@@ -6,7 +6,7 @@ import '../../common/testing.dart' as helper;
 import 'package:expect/expect.dart';
 
 /// A dynamic module can use core libraries and language features.
-main() async {
+void main() async {
   final result = await helper.load('entry1.dart');
   Expect.isTrue(result);
   helper.done();
diff --git a/pkg/dynamic_modules/test/data/duplicate_library/main.dart b/pkg/dynamic_modules/test/data/duplicate_library/main.dart
index 179a1fac643..24f6436deb1 100644
--- a/pkg/dynamic_modules/test/data/duplicate_library/main.dart
+++ b/pkg/dynamic_modules/test/data/duplicate_library/main.dart
@@ -7,7 +7,7 @@ import 'package:expect/async_helper.dart' show asyncExpectThrows;
 
 // It is an error to load a module that provides a second definition for
 // a library that already exists in the application.
-main() async {
+void main() async {
   await helper.load('entry1.dart');
   await asyncExpectThrows(helper.load('entry2.dart'));
   helper.done();
diff --git a/pkg/dynamic_modules/test/data/dyn_module_type_checks/main.dart b/pkg/dynamic_modules/test/data/dyn_module_type_checks/main.dart
index d94d6dbee06..499b42a4351 100644
--- a/pkg/dynamic_modules/test/data/dyn_module_type_checks/main.dart
+++ b/pkg/dynamic_modules/test/data/dyn_module_type_checks/main.dart
@@ -9,7 +9,7 @@ import 'shared/shared.dart' show Base;
 
 /// A dynamic module is allowed to extend a class in the dynamic interface and
 /// override its members.
-main() async {
+void main() async {
   Expect.equals(100, Base().method1(0));
   final o1 = (await helper.load('entry1.dart'));
   final o2 = (await helper.load('entry2.dart'));
diff --git a/pkg/dynamic_modules/test/data/extend_class/main.dart b/pkg/dynamic_modules/test/data/extend_class/main.dart
index ac94bdd1d70..0a70c6111f0 100644
--- a/pkg/dynamic_modules/test/data/extend_class/main.dart
+++ b/pkg/dynamic_modules/test/data/extend_class/main.dart
@@ -9,7 +9,7 @@ import 'shared/shared.dart' show Base;
 
 /// A dynamic module is allowed to extend a class in the dynamic interface and
 /// override its members.
-main() async {
+void main() async {
   final o = (await helper.load('entry1.dart')) as Base;
   Expect.equals(1, o.method1());
   Expect.equals(2, o.method2());
diff --git a/pkg/dynamic_modules/test/data/extend_class2/main.dart b/pkg/dynamic_modules/test/data/extend_class2/main.dart
index da9c1d610e5..1079922e7ba 100644
--- a/pkg/dynamic_modules/test/data/extend_class2/main.dart
+++ b/pkg/dynamic_modules/test/data/extend_class2/main.dart
@@ -18,7 +18,7 @@ class Child extends Base {
 /// This is similar to the `extend_class` test case, but includes more nuance,
 /// like extending a non-leaf class that already was used in the program, since
 /// that may affect dispatch logic based on some backends.
-main() async {
+void main() async {
   Base o = Child1();
   Expect.equals(1, o.method1());
   Expect.equals(3, o.method2());
diff --git a/pkg/dynamic_modules/test/data/extend_class_dyn_only/main.dart b/pkg/dynamic_modules/test/data/extend_class_dyn_only/main.dart
index 90c80c5d4db..b601c70c92b 100644
--- a/pkg/dynamic_modules/test/data/extend_class_dyn_only/main.dart
+++ b/pkg/dynamic_modules/test/data/extend_class_dyn_only/main.dart
@@ -7,7 +7,7 @@ import 'package:expect/expect.dart';
 
 /// A dynamic module is allowed to extend a class in the dynamic interface and
 /// override its members.
-main() async {
+void main() async {
   final o = (await helper.load('entry1.dart')) as int;
   Expect.equals(1, o);
   helper.done();
diff --git a/pkg/dynamic_modules/test/data/extend_class_generics/main.dart b/pkg/dynamic_modules/test/data/extend_class_generics/main.dart
index 35f0e21f8eb..57125bad858 100644
--- a/pkg/dynamic_modules/test/data/extend_class_generics/main.dart
+++ b/pkg/dynamic_modules/test/data/extend_class_generics/main.dart
@@ -9,7 +9,7 @@ import 'shared/shared.dart' show Base, SuperBase;
 
 /// A dynamic module is allowed to extend a class in the dynamic interface and
 /// override its members.
-main() async {
+void main() async {
   final o = (await helper.load('entry1.dart')) as Base;
   if (o is SuperBase<num, String>) {
     Expect.equals(3, o.method1());
diff --git a/pkg/dynamic_modules/test/data/implement_interface/main.dart b/pkg/dynamic_modules/test/data/implement_interface/main.dart
index e8728aae390..c6fdd87f514 100644
--- a/pkg/dynamic_modules/test/data/implement_interface/main.dart
+++ b/pkg/dynamic_modules/test/data/implement_interface/main.dart
@@ -8,7 +8,7 @@ import 'package:expect/expect.dart';
 import 'shared/shared.dart' show Base;
 
 /// A dynamic module can implement an exposed class.
-main() async {
+void main() async {
   final o = (await helper.load('entry1.dart')) as Base;
   Expect.equals(3, o.method1());
   Expect.equals(4, o.method2());
diff --git a/pkg/dynamic_modules/test/data/implicitly_extendable/main.dart b/pkg/dynamic_modules/test/data/implicitly_extendable/main.dart
index 3d96bb6e6a5..72193e963ac 100644
--- a/pkg/dynamic_modules/test/data/implicitly_extendable/main.dart
+++ b/pkg/dynamic_modules/test/data/implicitly_extendable/main.dart
@@ -8,7 +8,7 @@ import 'package:expect/expect.dart';
 import 'shared/shared.dart' show Base;
 
 /// A dynamic module can implement an exposed class.
-main() async {
+void main() async {
   final o = (await helper.load('entry1.dart')) as Base;
   Expect.equals(5, o.method1());
   Expect.equals(6, o.method2());
diff --git a/pkg/dynamic_modules/test/data/indirect_expose/main.dart b/pkg/dynamic_modules/test/data/indirect_expose/main.dart
index 88e721f486f..538d063594b 100644
--- a/pkg/dynamic_modules/test/data/indirect_expose/main.dart
+++ b/pkg/dynamic_modules/test/data/indirect_expose/main.dart
@@ -8,7 +8,7 @@ import 'package:expect/expect.dart';
 import 'shared/shared.dart';
 
 /// A dynamic module can implement an exposed class.
-main() async {
+void main() async {
   final o = await helper.load('entry1.dart') as Triple;
   Expect.equals(3, o.e.method3());
   Expect.equals(2, o.i1.method1());
diff --git a/pkg/dynamic_modules/test/data/load_twice/main.dart b/pkg/dynamic_modules/test/data/load_twice/main.dart
index 61cdcaa57e6..6b49ff45094 100644
--- a/pkg/dynamic_modules/test/data/load_twice/main.dart
+++ b/pkg/dynamic_modules/test/data/load_twice/main.dart
@@ -7,7 +7,7 @@ import 'package:expect/async_helper.dart' show asyncExpectThrows;
 
 /// For the same reasons as the `duplicate_library` test, it is an error to load
 /// the same module twice.
-main() async {
+void main() async {
   await helper.load('entry1.dart');
   await asyncExpectThrows(helper.load('entry1.dart'));
   helper.done();
diff --git a/pkg/dynamic_modules/test/data/load_unmodifiable_view/main.dart b/pkg/dynamic_modules/test/data/load_unmodifiable_view/main.dart
index a2fc344ff51..eb51b619525 100644
--- a/pkg/dynamic_modules/test/data/load_unmodifiable_view/main.dart
+++ b/pkg/dynamic_modules/test/data/load_unmodifiable_view/main.dart
@@ -8,7 +8,7 @@ import '../../common/testing.dart' as helper;
 import 'package:expect/expect.dart';
 
 /// Dynamic module can be loaded from unmodifiable view.
-main() async {
+void main() async {
   final result = await helper.load('entry1.dart',
       transformBytes: (Uint8List bytes) => bytes.buffer
           .asUint8List(0, bytes.lengthInBytes)
diff --git a/pkg/dynamic_modules/test/data/multiple_classes/main.dart b/pkg/dynamic_modules/test/data/multiple_classes/main.dart
index c2fe2505085..c8915871960 100644
--- a/pkg/dynamic_modules/test/data/multiple_classes/main.dart
+++ b/pkg/dynamic_modules/test/data/multiple_classes/main.dart
@@ -7,7 +7,7 @@ import 'package:expect/expect.dart';
 import '../../common/testing.dart' as helper;
 import 'modules/common.dart';
 
-main() async {
+void main() async {
   final a1 = await helper.load('entry1.dart') as A;
   final a2 = await helper.load('entry2.dart') as A;
   Expect.equals(a1.getString(), 'B');
diff --git a/pkg/dynamic_modules/test/data/override_extra_params/main.dart b/pkg/dynamic_modules/test/data/override_extra_params/main.dart
index 8d0c2cfbf23..0459ee6f680 100644
--- a/pkg/dynamic_modules/test/data/override_extra_params/main.dart
+++ b/pkg/dynamic_modules/test/data/override_extra_params/main.dart
@@ -9,7 +9,7 @@ import 'shared/shared.dart' show Base;
 
 /// A dynamic module is allowed to extend a class in the dynamic interface and
 /// override its members.
-main() async {
+void main() async {
   final o = (await helper.load('entry1.dart')) as Base;
   Expect.equals(1, o.method1(1));
   helper.done();
diff --git a/pkg/dynamic_modules/test/data/reshape_selectors/main.dart b/pkg/dynamic_modules/test/data/reshape_selectors/main.dart
index fbb2754d695..c896d69d75f 100644
--- a/pkg/dynamic_modules/test/data/reshape_selectors/main.dart
+++ b/pkg/dynamic_modules/test/data/reshape_selectors/main.dart
@@ -6,7 +6,7 @@ import '../../common/testing.dart' as helper;
 
 import 'shared/shared.dart' show A, B;
 
-main() async {
+void main() async {
   final o = (await helper.load('entry1.dart')) as A;
   final l = <dynamic>[A(), B()];
   for (final entry in l) {
diff --git a/pkg/dynamic_modules/test/data/same_record_shape/main.dart b/pkg/dynamic_modules/test/data/same_record_shape/main.dart
index a87980b2fa8..5a99c6ffcf9 100644
--- a/pkg/dynamic_modules/test/data/same_record_shape/main.dart
+++ b/pkg/dynamic_modules/test/data/same_record_shape/main.dart
@@ -8,7 +8,7 @@ import 'package:expect/expect.dart';
 // Similar to `isolated_shared`, constant canonicalization distinguishes
 // two constnats, even if they are created from a common library that was
 // not part of the original application.
-main() async {
+void main() async {
   final c1 = (await helper.load('entry1.dart'));
   final c2 = (await helper.load('entry2.dart'));
 
diff --git a/pkg/dynamic_modules/test/data/shared_const/main.dart b/pkg/dynamic_modules/test/data/shared_const/main.dart
index 812e8e46e85..3a2a9384cd9 100644
--- a/pkg/dynamic_modules/test/data/shared_const/main.dart
+++ b/pkg/dynamic_modules/test/data/shared_const/main.dart
@@ -13,7 +13,7 @@ class B {
 // Similar to `isolated_shared`, constant canonicalization distinguishes
 // two constnats, even if they are created from a common library that was
 // not part of the original application.
-main() async {
+void main() async {
   final c1 = (await helper.load('entry1.dart'));
   final c2 = (await helper.load('entry2.dart'));
 
diff --git a/pkg/dynamic_modules/test/data/tearoff_no_concrete_impl/main.dart b/pkg/dynamic_modules/test/data/tearoff_no_concrete_impl/main.dart
index d1db943c6d0..9dc5c1c57b1 100644
--- a/pkg/dynamic_modules/test/data/tearoff_no_concrete_impl/main.dart
+++ b/pkg/dynamic_modules/test/data/tearoff_no_concrete_impl/main.dart
@@ -6,7 +6,7 @@ import '../../common/testing.dart' as helper;
 
 import 'shared/shared.dart' show A, B, C;
 
-main() async {
+void main() async {
   final c = await helper.load('entry1.dart') as C?;
   if (c != null) {
     A(B(c).c.foo);
diff --git a/pkg/dynamic_modules/test/data/top_level/main.dart b/pkg/dynamic_modules/test/data/top_level/main.dart
index cbc9da4e8ca..0af2def5de1 100644
--- a/pkg/dynamic_modules/test/data/top_level/main.dart
+++ b/pkg/dynamic_modules/test/data/top_level/main.dart
@@ -8,7 +8,7 @@ import 'package:expect/expect.dart';
 import 'shared/shared.dart' as shared;
 
 /// A top-level setter can be invoked from a dynamic module.
-main() async {
+void main() async {
   Expect.equals('original', shared.topLevelField);
   Expect.equals(0, shared.topLevelGetterInternal);
   Expect.equals(0, shared.topLevelSetterInternal);
diff --git a/pkg/expect/test/identical_distinct_test.dart b/pkg/expect/test/identical_distinct_test.dart
index 3545ab10357..9fa55bb363a 100644
--- a/pkg/expect/test/identical_distinct_test.dart
+++ b/pkg/expect/test/identical_distinct_test.dart
@@ -4,7 +4,7 @@
 
 import "package:expect/expect.dart";
 
-main() {
+void main() {
   var o1 = Object();
   var o2 = Object();
   var o3 = Object();
diff --git a/pkg/heap_snapshot/test/int_set_benchmark.dart b/pkg/heap_snapshot/test/int_set_benchmark.dart
index 7a35122bef0..e93d0e410ae 100644
--- a/pkg/heap_snapshot/test/int_set_benchmark.dart
+++ b/pkg/heap_snapshot/test/int_set_benchmark.dart
@@ -4,7 +4,7 @@
 
 import 'package:heap_snapshot/intset.dart';
 
-main() {
+void main() {
   for (int every in [16, 8, 4, 3, 2, 1]) {
     iterationBenchmark(every, 1);
     iterationBenchmark(every, 0.5);
diff --git a/pkg/heap_snapshot/test/int_set_test.dart b/pkg/heap_snapshot/test/int_set_test.dart
index 02354b14e3c..bdac7c1db2e 100644
--- a/pkg/heap_snapshot/test/int_set_test.dart
+++ b/pkg/heap_snapshot/test/int_set_test.dart
@@ -6,7 +6,7 @@ import 'dart:math';
 
 import 'package:heap_snapshot/intset.dart';
 
-main() {
+void main() {
   checkDump();
   checkBounds();
   handCodedTests();
@@ -15,7 +15,7 @@ main() {
   print("OK");
 }
 
-void addExpectRangeError(set, int value) {
+void addExpectRangeError(Set set, int value) {
   try {
     set.add(value);
     throw "Expected RangeError";
diff --git a/pkg/js_ast/lib/src/template.dart b/pkg/js_ast/lib/src/template.dart
index 4c4e926fe8f..56fcbdd64f5 100644
--- a/pkg/js_ast/lib/src/template.dart
+++ b/pkg/js_ast/lib/src/template.dart
@@ -197,7 +197,7 @@ class InstantiatorGeneratorVisitor implements NodeVisitor<Instantiator> {
   }
 
   static Instantiator same(Node node) => (arguments) => node;
-  static Null makeNull(arguments) => null;
+  static Null makeNull(dynamic arguments) => null;
 
   Instantiator visit(Node node) {
     if (forceCopy || analysis.containsInterpolatedNodes(node)) {
diff --git a/pkg/modular_test/lib/src/loader.dart b/pkg/modular_test/lib/src/loader.dart
index 61fa60ea913..3f0b30ff140 100644
--- a/pkg/modular_test/lib/src/loader.dart
+++ b/pkg/modular_test/lib/src/loader.dart
@@ -209,7 +209,8 @@ Future<Module> _createSdkModule(Uri root) async {
 }
 
 /// Trim the set of modules, and detect cycles while we are at it.
-_detectCyclesAndRemoveUnreachable(Map<String, Module> modules, Module main) {
+void _detectCyclesAndRemoveUnreachable(
+    Map<String, Module> modules, Module main) {
   Set<Module> visiting = {};
   Set<Module> visited = {};
 
@@ -249,7 +250,7 @@ packages:
 ''';
 
 /// Report an conflict error.
-_moduleConflict(String name, Module existing, Uri root) {
+Never _moduleConflict(String name, Module existing, Uri root) {
   var isFile = name.endsWith('.dart');
   var entryType = isFile ? 'file' : 'folder';
 
diff --git a/pkg/modular_test/test/find_sdk_root1_test.dart b/pkg/modular_test/test/find_sdk_root1_test.dart
index dbbf8b63408..bac9d1416d3 100644
--- a/pkg/modular_test/test/find_sdk_root1_test.dart
+++ b/pkg/modular_test/test/find_sdk_root1_test.dart
@@ -10,7 +10,7 @@ import 'package:modular_test/src/find_sdk_root.dart';
 
 // This and the 'src/find_sdk_root2_test.dart' check that we can locate
 // the SDK root properly regardless of the location of the `Platform.script`.
-main() {
+void main() {
   asyncTest(() async {
     Expect.equals(Platform.script.resolve("../../../"), await findRoot());
   });
diff --git a/pkg/modular_test/test/io_pipeline_test.dart b/pkg/modular_test/test/io_pipeline_test.dart
index aa4e818f06e..e9e89221dd0 100644
--- a/pkg/modular_test/test/io_pipeline_test.dart
+++ b/pkg/modular_test/test/io_pipeline_test.dart
@@ -11,7 +11,7 @@ import 'package:modular_test/src/io_pipeline.dart';
 
 import 'pipeline_common.dart';
 
-main() async {
+void main() async {
   var uri = Directory.systemTemp.uri.resolve("io_modular_test_root/");
   int i = 0;
   while (await Directory.fromUri(uri).exists()) {
diff --git a/pkg/modular_test/test/loader/loader_test.dart b/pkg/modular_test/test/loader/loader_test.dart
index cf7de5c7b7e..8b8ceebc10e 100644
--- a/pkg/modular_test/test/loader/loader_test.dart
+++ b/pkg/modular_test/test/loader/loader_test.dart
@@ -13,7 +13,7 @@ import 'package:modular_test/src/suite.dart';
 
 import 'package:args/args.dart';
 
-main(List<String> args) async {
+void main(List<String> args) async {
   var options = _Options.parse(args);
   var baseUri = Platform.script.resolve('./');
   var baseDir = Directory.fromUri(baseUri);
diff --git a/pkg/modular_test/test/memory_pipeline_test.dart b/pkg/modular_test/test/memory_pipeline_test.dart
index 98c1d006101..28a6343d363 100644
--- a/pkg/modular_test/test/memory_pipeline_test.dart
+++ b/pkg/modular_test/test/memory_pipeline_test.dart
@@ -11,7 +11,7 @@ import 'package:modular_test/src/memory_pipeline.dart';
 
 import 'pipeline_common.dart';
 
-main() {
+void main() {
   runPipelineTest(MemoryPipelineTestStrategy());
 }
 
diff --git a/pkg/modular_test/test/pipeline_common.dart b/pkg/modular_test/test/pipeline_common.dart
index 7cef7e3eff5..ceaecd0eaee 100644
--- a/pkg/modular_test/test/pipeline_common.dart
+++ b/pkg/modular_test/test/pipeline_common.dart
@@ -91,7 +91,8 @@ abstract class PipelineTestStrategy<S extends ModularStep> {
   FutureOr<void> cleanup(Pipeline<S> pipeline);
 }
 
-runPipelineTest<S extends ModularStep>(PipelineTestStrategy<S> testStrategy) {
+void runPipelineTest<S extends ModularStep>(
+    PipelineTestStrategy<S> testStrategy) {
   var sources = {
     testStrategy.testRootUri.resolve("a1.dart"): 'A1',
     testStrategy.testRootUri.resolve("a2.dart"): 'A2',
diff --git a/pkg/modular_test/test/specification_parser_test.dart b/pkg/modular_test/test/specification_parser_test.dart
index 6940d5e93ec..b1432ffa470 100644
--- a/pkg/modular_test/test/specification_parser_test.dart
+++ b/pkg/modular_test/test/specification_parser_test.dart
@@ -5,7 +5,7 @@
 import 'package:test/test.dart';
 import 'package:modular_test/src/test_specification_parser.dart';
 
-main() {
+void main() {
   test('require dependencies section', () {
     expect(() => parseTestSpecification(""),
         throwsA(TypeMatcher<InvalidSpecificationError>()));
diff --git a/pkg/modular_test/test/src/find_sdk_root2_test.dart b/pkg/modular_test/test/src/find_sdk_root2_test.dart
index 05dba888959..a4202e4f93a 100644
--- a/pkg/modular_test/test/src/find_sdk_root2_test.dart
+++ b/pkg/modular_test/test/src/find_sdk_root2_test.dart
@@ -10,7 +10,7 @@ import 'package:modular_test/src/find_sdk_root.dart';
 
 // This and the '../find_sdk_root1_test.dart' check that we can locate
 // the SDK root properly regardless of the location of the `Platform.script`.
-main() {
+void main() {
   asyncTest(() async {
     Expect.equals(Platform.script.resolve("../../../../"), await findRoot());
   });
diff --git a/pkg/modular_test/test/validate_pipeline_test.dart b/pkg/modular_test/test/validate_pipeline_test.dart
index 1e5135b76ed..e0dc309daf4 100644
--- a/pkg/modular_test/test/validate_pipeline_test.dart
+++ b/pkg/modular_test/test/validate_pipeline_test.dart
@@ -9,7 +9,7 @@ import 'package:test/test.dart';
 import 'package:modular_test/src/suite.dart';
 import 'package:modular_test/src/pipeline.dart';
 
-main() {
+void main() {
   test('no steps is OK', () {
     validateSteps([]);
   });
@@ -73,7 +73,7 @@ main() {
   });
 }
 
-validateSteps(List<ModularStep> steps) {
+void validateSteps(List<ModularStep> steps) {
   _NoopPipeline(steps);
 }
 
diff --git a/pkg/modular_test/test/validate_suite_test.dart b/pkg/modular_test/test/validate_suite_test.dart
index 742a9ef4f3b..d78356facd7 100644
--- a/pkg/modular_test/test/validate_suite_test.dart
+++ b/pkg/modular_test/test/validate_suite_test.dart
@@ -8,7 +8,7 @@ library;
 import 'package:test/test.dart';
 import 'package:modular_test/src/suite.dart';
 
-main() {
+void main() {
   test('module test is not empty', () {
     var m = Module("a", [], Uri.parse("app:/"), []);
     expect(() => ModularTest([], m, []), throwsA(TypeMatcher<ArgumentError>()));
diff --git a/pkg/status_file/bin/lint.dart b/pkg/status_file/bin/lint.dart
index 23cd03cc23c..1bb91e3aae4 100644
--- a/pkg/status_file/bin/lint.dart
+++ b/pkg/status_file/bin/lint.dart
@@ -80,7 +80,7 @@ void lintStdIn(
   }
 }
 
-void lintPath(path,
+void lintPath(String path,
     {bool checkForDisjunctions = false, required bool checkForNonExisting}) {
   var filesWithErrors = <String>[];
   if (FileSystemEntity.isFileSync(path)) {
diff --git a/pkg/status_file/bin/remove_non_essential_entries.dart b/pkg/status_file/bin/remove_non_essential_entries.dart
index a7c1f5d7b57..ceaa3b233c4 100644
--- a/pkg/status_file/bin/remove_non_essential_entries.dart
+++ b/pkg/status_file/bin/remove_non_essential_entries.dart
@@ -224,7 +224,7 @@ String formatComments(List<String> comments) {
   return sb.toString();
 }
 
-main(List<String> arguments) async {
+void main(List<String> arguments) async {
   var parser = buildParser();
   var results = parser.parse(arguments);
   if (results["help"] || results.rest.isEmpty) {
diff --git a/pkg/status_file/lib/src/disjunctive.dart b/pkg/status_file/lib/src/disjunctive.dart
index 6bac6f7778f..e3d74d2702b 100644
--- a/pkg/status_file/lib/src/disjunctive.dart
+++ b/pkg/status_file/lib/src/disjunctive.dart
@@ -334,11 +334,13 @@ List<Expression> _difference(List<Expression> aList, List<Expression> bList) {
 
 /// Finds the first occurrence of [expressionToFind] in [expressions] or
 /// returns null.
-TExpression? _findFirst<TExpression>(
-    expressionToFind, List<TExpression> expressions) {
-  return expressions.cast<TExpression?>().firstWhere(
-      (otherExpression) => expressionToFind.compareTo(otherExpression) == 0,
-      orElse: () => null);
+T? _findFirst<T extends Expression>(T expressionToFind, List<T> expressions) {
+  for (var expr in expressions) {
+    if (expressionToFind.compareTo(expr) == 0) {
+      return expr;
+    }
+  }
+  return null;
 }
 
 /// Adds [expressionToAdd] to [expressions] if is not present.
diff --git a/pkg/status_file/test/linter_test.dart b/pkg/status_file/test/linter_test.dart
index c84375517b4..6cb55111b8c 100644
--- a/pkg/status_file/test/linter_test.dart
+++ b/pkg/status_file/test/linter_test.dart
@@ -41,7 +41,8 @@ StatusFile createFromString(String text) {
   return StatusFile.parse("test", text.split('\n'));
 }
 
-expectError(String text, String expectedError, {bool disjunctions = false}) {
+void expectError(String text, String expectedError,
+    {bool disjunctions = false}) {
   var statusFile = createFromString(text);
   var errors = lint(statusFile,
           checkForDisjunctions: disjunctions, checkForNonExisting: false)
@@ -49,7 +50,7 @@ expectError(String text, String expectedError, {bool disjunctions = false}) {
   Expect.equals(expectedError, errors.first.toString());
 }
 
-expectNoError(String text, {bool disjunctions = true}) {
+void expectNoError(String text, {bool disjunctions = true}) {
   var errors = lint(createFromString(text),
           checkForDisjunctions: disjunctions, checkForNonExisting: false)
       .toList();
diff --git a/pkg/status_file/test/normalize_test.dart b/pkg/status_file/test/normalize_test.dart
index 52ceceaac90..890c11b70ce 100644
--- a/pkg/status_file/test/normalize_test.dart
+++ b/pkg/status_file/test/normalize_test.dart
@@ -16,7 +16,7 @@ import 'package:status_file/status_file_normalizer.dart';
 
 final Uri statusFilePath = Platform.script.resolve("data/");
 
-main() {
+void main() {
   sanityCheck();
   normalizeCheck();
 }
diff --git a/pkg/status_file/test/status_expression_dnf_test.dart b/pkg/status_file/test/status_expression_dnf_test.dart
index 546395a7907..958387155ac 100644
--- a/pkg/status_file/test/status_expression_dnf_test.dart
+++ b/pkg/status_file/test/status_expression_dnf_test.dart
@@ -6,7 +6,7 @@ import "package:expect/expect.dart";
 import "package:status_file/src/expression.dart";
 import 'package:status_file/src/disjunctive.dart';
 
-main() {
+void main() {
   testDnf();
 }
 
diff --git a/pkg/status_file/test/status_expression_test.dart b/pkg/status_file/test/status_expression_test.dart
index 279f9207a3a..064a18261a3 100644
--- a/pkg/status_file/test/status_expression_test.dart
+++ b/pkg/status_file/test/status_expression_test.dart
@@ -21,10 +21,10 @@ class TestEnvironment implements Environment {
   @override
   String? lookUp(String name) => _values[name];
 
-  operator []=(String key, String value) => _values[key] = value;
+  void operator []=(String key, String value) => _values[key] = value;
 }
 
-main() {
+void main() {
   testExpression();
   testSyntaxError();
   testBoolean();
diff --git a/pkg/test_runner/lib/src/browser_controller.dart b/pkg/test_runner/lib/src/browser_controller.dart
index 91a63b85593..6dca53fc14b 100644
--- a/pkg/test_runner/lib/src/browser_controller.dart
+++ b/pkg/test_runner/lib/src/browser_controller.dart
@@ -1146,7 +1146,7 @@ class BrowserTestingServer {
     errorReportingServer.listen(errorReportingHandler, onError: errorHandler);
   }
 
-  void setupDispatchingServer(_) {
+  void setupDispatchingServer(HttpServer _) {
     var server = configuration.servers.server!;
     void noCache(HttpRequest request) {
       request.response.headers
diff --git a/pkg/test_runner/lib/src/testing_servers.dart b/pkg/test_runner/lib/src/testing_servers.dart
index fcdf199d983..3ece9dbd2b9 100644
--- a/pkg/test_runner/lib/src/testing_servers.dart
+++ b/pkg/test_runner/lib/src/testing_servers.dart
@@ -152,7 +152,7 @@ class TestingServers {
     }
   }
 
-  void _onError(e) {
+  void _onError(Object? e) {
     DebugLogger.error('HttpServer: an error occurred', e);
   }
 
diff --git a/pkg/test_runner/test/dependency_graph_test.dart b/pkg/test_runner/test/dependency_graph_test.dart
index 86c89668922..db79fb99345 100644
--- a/pkg/test_runner/test/dependency_graph_test.dart
+++ b/pkg/test_runner/test/dependency_graph_test.dart
@@ -6,7 +6,7 @@ import 'package:expect/expect.dart';
 
 import 'package:test_runner/src/dependency_graph.dart';
 
-main() {
+void main() {
   var graph = Graph<int>();
   var numberOfEvents = 0;
   var addEventAssertions = [];
diff --git a/pkg/test_runner/test/experiment_test.dart b/pkg/test_runner/test/experiment_test.dart
index 1dffb4affec..19526d57aec 100644
--- a/pkg/test_runner/test/experiment_test.dart
+++ b/pkg/test_runner/test/experiment_test.dart
@@ -10,7 +10,7 @@ import 'dart:io';
 import 'package:expect/expect.dart';
 
 // SharedOptions=--enable-experiment=test-experiment
-main() {
+void main() {
   Expect.isTrue(Platform.executableArguments
       .contains("--enable-experiment=test-experiment"));
 }
diff --git a/pkg/test_runner/test/skipping_dart2js_compilations_helper.dart b/pkg/test_runner/test/skipping_dart2js_compilations_helper.dart
index 74fc9916ba3..48fbe367128 100644
--- a/pkg/test_runner/test/skipping_dart2js_compilations_helper.dart
+++ b/pkg/test_runner/test/skipping_dart2js_compilations_helper.dart
@@ -4,7 +4,7 @@
 
 import 'dart:io';
 
-main(List<String> arguments) {
+void main(List<String> arguments) {
   var outputFile = arguments[0];
   var file = File(outputFile);
   file.createSync();
diff --git a/pkg/test_runner/test/test_runner_test.dart b/pkg/test_runner/test/test_runner_test.dart
index 7fe3422dd89..3c6332488d6 100644
--- a/pkg/test_runner/test/test_runner_test.dart
+++ b/pkg/test_runner/test/test_runner_test.dart
@@ -23,7 +23,7 @@ class TestController {
   static int numCompletedTests = 0;
 
   // Used as TestCase.completedCallback.
-  static processCompletedTest(TestCase testCase) {
+  static void processCompletedTest(TestCase testCase) {
     final passed = testCase.result.canBeOutcomeOf(testCase.realExpected);
     numCompletedTests++;
 
diff --git a/pkg/testing/lib/src/chain.dart b/pkg/testing/lib/src/chain.dart
index eac11745bc1..59a285d314d 100644
--- a/pkg/testing/lib/src/chain.dart
+++ b/pkg/testing/lib/src/chain.dart
@@ -347,13 +347,14 @@ abstract class Step<I, O, C extends ChainContext> {
 
   Future<Result<O>> run(I input, C context);
 
-  Result<O> unhandledError(error, StackTrace trace) {
+  Result<O> unhandledError(Object? error, StackTrace trace) {
     return Result<O>.crash(error, trace);
   }
 
   Result<O> pass(O output) => Result<O>.pass(output);
 
-  Result<O> crash(error, StackTrace trace) => Result<O>.crash(error, trace);
+  Result<O> crash(Object? error, StackTrace trace) =>
+      Result<O>.crash(error, trace);
 
   Result<O> fail(O output, [error, StackTrace? trace]) {
     return Result<O>.fail(output, error, trace);
@@ -392,7 +393,7 @@ class Result<O> {
 
   Result.pass(O output) : this(output, Expectation.pass, null);
 
-  Result.crash(error, StackTrace trace)
+  Result.crash(Object? error, StackTrace trace)
       : this(null, Expectation.crash, error, trace: trace);
 
   Result.fail(O output, [error, StackTrace? trace])
diff --git a/pkg/testing/lib/src/log.dart b/pkg/testing/lib/src/log.dart
index f85dd3c01c9..d4eb3fe11d7 100644
--- a/pkg/testing/lib/src/log.dart
+++ b/pkg/testing/lib/src/log.dart
@@ -67,12 +67,12 @@ abstract class Logger {
 
   void logSuiteComplete(Suite suite);
 
-  void logUncaughtError(error, StackTrace stackTrace);
+  void logUncaughtError(Object error, StackTrace stackTrace);
 
   /// Issued when there's been a crash caught by the framework.
   /// Notice that the exit-code has already been set and that the error has
   /// been printed to stderr.
-  void noticeFrameworkCatchError(error, StackTrace stackTrace);
+  void noticeFrameworkCatchError(Object? error, StackTrace stackTrace);
 }
 
 class StdoutLogger implements Logger {
@@ -196,7 +196,7 @@ class StdoutLogger implements Logger {
   }
 
   @override
-  void logUncaughtError(error, StackTrace stackTrace) {
+  void logUncaughtError(Object error, StackTrace stackTrace) {
     logMessage(error);
     logMessage(stackTrace);
   }
diff --git a/pkg/vm/analysis_options.yaml b/pkg/vm/analysis_options.yaml
index 6d3c44727b3..ba0281ea043 100644
--- a/pkg/vm/analysis_options.yaml
+++ b/pkg/vm/analysis_options.yaml
@@ -3,3 +3,8 @@
 # BSD-style license that can be found in the LICENSE file.
 
 include: package:lints/core.yaml
+
+analyzer:
+  errors:
+    # ~50 violations in bin, lib, and test.
+    strict_top_level_inference: ignore
diff --git a/pkg/vm/bin/list_libraries.dart b/pkg/vm/bin/list_libraries.dart
index fe400c79757..a1a4257d25a 100644
--- a/pkg/vm/bin/list_libraries.dart
+++ b/pkg/vm/bin/list_libraries.dart
@@ -13,7 +13,7 @@ Usage: list_libraries input.dill
 Lists libraries included in a kernel binary file.
 ''';
 
-main(List<String> arguments) async {
+void main(List<String> arguments) async {
   if (arguments.length != 1) {
     print(_usage);
     exit(1);
diff --git a/pkg/vm_service/analysis_options.yaml b/pkg/vm_service/analysis_options.yaml
index dc7825c45de..6601c71c077 100644
--- a/pkg/vm_service/analysis_options.yaml
+++ b/pkg/vm_service/analysis_options.yaml
@@ -3,6 +3,8 @@ include: package:lints/recommended.yaml
 analyzer:
   errors:
     unnecessary_library_name: ignore
+    # ~300 violations in test/.
+    strict_top_level_inference: ignore
 
 linter:
   rules:
diff --git a/third_party/pkg/dap/lib/src/protocol_special.dart b/third_party/pkg/dap/lib/src/protocol_special.dart
index 5105ca17363..70f398d49b6 100644
--- a/third_party/pkg/dap/lib/src/protocol_special.dart
+++ b/third_party/pkg/dap/lib/src/protocol_special.dart
@@ -47,7 +47,7 @@ class Either2<T1, T2> extends ToJsonable {
   String toString() => map((t) => t.toString(), (t) => t.toString());
 
   /// Checks whether the value of the union equals the supplied value.
-  bool valueEquals(o) => map((t) => t == o, (t) => t == o);
+  bool valueEquals(Object o) => map((t) => t == o, (t) => t == o);
 }
 
 /// An object from the LSP/DAP specs that can be converted to JSON.
diff --git a/third_party/pkg/language_server_protocol/lib/protocol_special.dart b/third_party/pkg/language_server_protocol/lib/protocol_special.dart
index a4f634892ec..502b5deb877 100644
--- a/third_party/pkg/language_server_protocol/lib/protocol_special.dart
+++ b/third_party/pkg/language_server_protocol/lib/protocol_special.dart
@@ -31,9 +31,9 @@ Object? specToJson(Object? obj) {
   }
 }
 
-void _alwaysNull(_, [__]) {}
+void _alwaysNull(dynamic _, [dynamic __]) {}
 
-bool _alwaysTrue(_, [__]) => true;
+bool _alwaysTrue(dynamic _, [dynamic __]) => true;
 
 typedef DocumentChanges
     = List<Either4<CreateFile, DeleteFile, RenameFile, TextDocumentEdit>>;
@@ -71,7 +71,7 @@ class Either2<T1, T2> implements ToJsonable {
   String toString() => map((t) => t.toString(), (t) => t.toString());
 
   /// Checks whether the value of the union equals the supplied value.
-  bool valueEquals(o) => map((t) => t == o, (t) => t == o);
+  bool valueEquals(Object o) => map((t) => t == o, (t) => t == o);
 }
 
 class Either3<T1, T2, T3> implements ToJsonable {
@@ -125,7 +125,8 @@ class Either3<T1, T2, T3> implements ToJsonable {
       );
 
   /// Checks whether the value of the union equals the supplied value.
-  bool valueEquals(o) => map((t) => t == o, (t) => t == o, (t) => t == o);
+  bool valueEquals(Object o) =>
+      map((t) => t == o, (t) => t == o, (t) => t == o);
 }
 
 class Either4<T1, T2, T3, T4> implements ToJsonable {
@@ -193,7 +194,7 @@ class Either4<T1, T2, T3, T4> implements ToJsonable {
       );
 
   /// Checks whether the value of the union equals the supplied value.
-  bool valueEquals(o) =>
+  bool valueEquals(Object o) =>
       map((t) => t == o, (t) => t == o, (t) => t == o, (t) => t == o);
 }