diff --git a/pkg/analyzer/lib/error/error.dart b/pkg/analyzer/lib/error/error.dart
index 56a23d3..cc621a7 100644
--- a/pkg/analyzer/lib/error/error.dart
+++ b/pkg/analyzer/lib/error/error.dart
@@ -1135,8 +1135,7 @@
     return errors.toList();
   }
 
-  static List<Object?>? _translateNamedArguments(
-      Map<String, dynamic> arguments) {
+  static Null _translateNamedArguments(Map<String, dynamic> arguments) {
     // All analyzer errors now use positional arguments, so if this method is
     // being called, either no arguments were provided to the
     // AnalysisError.withNamedArguments constructor, or the client was
diff --git a/pkg/analyzer/lib/src/analysis_options/analysis_options_provider.dart b/pkg/analyzer/lib/src/analysis_options/analysis_options_provider.dart
index efb2263..4269e6b 100644
--- a/pkg/analyzer/lib/src/analysis_options/analysis_options_provider.dart
+++ b/pkg/analyzer/lib/src/analysis_options/analysis_options_provider.dart
@@ -35,7 +35,7 @@
   /// Return the analysis options file from which options should be read, or
   /// `null` if there is no analysis options file for code in the given [root].
   ///
-  /// The given [root] directory will be searched first. If no file is found ,
+  /// The given [root] directory will be searched first. If no file is found,
   /// then enclosing directories will be searched.
   File? getOptionsFile(Folder root) {
     for (var current in root.withAncestors) {
@@ -44,6 +44,7 @@
         return file;
       }
     }
+    return null;
   }
 
   /// Provide the options found in [file].
diff --git a/pkg/analyzer/lib/src/dart/analysis/context_builder.dart b/pkg/analyzer/lib/src/dart/analysis/context_builder.dart
index d8131da..db6b26d 100644
--- a/pkg/analyzer/lib/src/dart/analysis/context_builder.dart
+++ b/pkg/analyzer/lib/src/dart/analysis/context_builder.dart
@@ -198,6 +198,7 @@
         return file;
       }
     }
+    return null;
   }
 
   /// Return the analysis options that should be used to analyze code in the
diff --git a/pkg/analyzer/lib/src/dart/analysis/context_locator.dart b/pkg/analyzer/lib/src/dart/analysis/context_locator.dart
index 38d0316..245db3d 100644
--- a/pkg/analyzer/lib/src/dart/analysis/context_locator.dart
+++ b/pkg/analyzer/lib/src/dart/analysis/context_locator.dart
@@ -420,6 +420,7 @@
         return file;
       }
     }
+    return null;
   }
 
   /// Return the analysis options file to be used to analyze files in the given
@@ -432,6 +433,7 @@
         return file;
       }
     }
+    return null;
   }
 
   /// Return the packages file to be used to analyze files in the given
@@ -444,6 +446,7 @@
         return _PackagesFile(current, file);
       }
     }
+    return null;
   }
 
   /// Return a list containing the glob patterns used to exclude files from the
diff --git a/pkg/analyzer/lib/src/dart/element/inheritance_manager3.dart b/pkg/analyzer/lib/src/dart/element/inheritance_manager3.dart
index cf52a23..168cc9a 100644
--- a/pkg/analyzer/lib/src/dart/element/inheritance_manager3.dart
+++ b/pkg/analyzer/lib/src/dart/element/inheritance_manager3.dart
@@ -401,7 +401,9 @@
       }
     }
 
-    if (getter != null && method != null) {
+    if (getter == null || method == null) {
+      return null;
+    } else {
       return GetterMethodConflict(name: name, getter: getter, method: method);
     }
   }
diff --git a/pkg/analyzer/lib/src/dart/element/type_algebra.dart b/pkg/analyzer/lib/src/dart/element/type_algebra.dart
index 1ffe3d4..5e1389e 100644
--- a/pkg/analyzer/lib/src/dart/element/type_algebra.dart
+++ b/pkg/analyzer/lib/src/dart/element/type_algebra.dart
@@ -567,12 +567,13 @@
   InstantiatedTypeAliasElementImpl? _mapAlias(
     InstantiatedTypeAliasElement? alias,
   ) {
-    if (alias != null) {
-      return InstantiatedTypeAliasElementImpl(
-        element: alias.element,
-        typeArguments: _mapList(alias.typeArguments),
-      );
+    if (alias == null) {
+      return null;
     }
+    return InstantiatedTypeAliasElementImpl(
+      element: alias.element,
+      typeArguments: _mapList(alias.typeArguments),
+    );
   }
 
   List<DartType> _mapList(List<DartType> types) {
diff --git a/pkg/analyzer/lib/src/dart/micro/library_graph.dart b/pkg/analyzer/lib/src/dart/micro/library_graph.dart
index d18f5bae..80357fb 100644
--- a/pkg/analyzer/lib/src/dart/micro/library_graph.dart
+++ b/pkg/analyzer/lib/src/dart/micro/library_graph.dart
@@ -749,6 +749,7 @@
         }
       }
     }
+    return null;
   }
 
   _ContentWithDigest _getContent() {
@@ -879,13 +880,14 @@
     }
 
     var libraryUri = unlinked.unit.partOfUri;
-    if (libraryUri != null) {
-      location._fsState.testView.partsDiscoveredLibraries.add(location.path);
-      return _partOfLibrary = location._fileForRelativeUri(
-        relativeUri: libraryUri,
-        performance: performance,
-      );
+    if (libraryUri == null) {
+      return null;
     }
+    location._fsState.testView.partsDiscoveredLibraries.add(location.path);
+    return _partOfLibrary = location._fileForRelativeUri(
+      relativeUri: libraryUri,
+      performance: performance,
+    );
   }
 
   void _prefetchDirectReferences() {
diff --git a/pkg/analyzer/lib/src/dart/micro/resolve_file.dart b/pkg/analyzer/lib/src/dart/micro/resolve_file.dart
index 4fd04f6..e9eec90 100644
--- a/pkg/analyzer/lib/src/dart/micro/resolve_file.dart
+++ b/pkg/analyzer/lib/src/dart/micro/resolve_file.dart
@@ -653,6 +653,7 @@
         return file;
       }
     }
+    return null;
   }
 
   /// Return the analysis options.
diff --git a/pkg/analyzer/lib/src/dart/resolver/invocation_inference_helper.dart b/pkg/analyzer/lib/src/dart/resolver/invocation_inference_helper.dart
index 36357aa..d7a8fd2 100644
--- a/pkg/analyzer/lib/src/dart/resolver/invocation_inference_helper.dart
+++ b/pkg/analyzer/lib/src/dart/resolver/invocation_inference_helper.dart
@@ -129,10 +129,11 @@
       }
     }
 
-    if (typeParameters != null && rawElement != null) {
-      rawElement = _resolver.toLegacyElement(rawElement);
-      return ConstructorElementToInfer(typeParameters, rawElement);
+    if (typeParameters == null || rawElement == null) {
+      return null;
     }
+    rawElement = _resolver.toLegacyElement(rawElement);
+    return ConstructorElementToInfer(typeParameters, rawElement);
   }
 
   FunctionType? inferArgumentTypesForGeneric(AstNode inferenceNode,
diff --git a/pkg/analyzer/lib/src/summary2/bundle_reader.dart b/pkg/analyzer/lib/src/summary2/bundle_reader.dart
index 056696d..e331093 100644
--- a/pkg/analyzer/lib/src/summary2/bundle_reader.dart
+++ b/pkg/analyzer/lib/src/summary2/bundle_reader.dart
@@ -1406,6 +1406,8 @@
   List<DartType>? readOptionalTypeList() {
     if (_reader.readBool()) {
       return _readTypeList();
+    } else {
+      return null;
     }
   }
 
@@ -1695,6 +1697,8 @@
   ExpressionImpl? _readOptionalExpression() {
     if (_reader.readBool()) {
       return _readRequiredNode() as ExpressionImpl;
+    } else {
+      return null;
     }
   }
 
diff --git a/pkg/analyzer/lib/src/summary2/data_reader.dart b/pkg/analyzer/lib/src/summary2/data_reader.dart
index ff6e1b8..e72e947 100644
--- a/pkg/analyzer/lib/src/summary2/data_reader.dart
+++ b/pkg/analyzer/lib/src/summary2/data_reader.dart
@@ -57,18 +57,24 @@
   String? readOptionalStringReference() {
     if (readBool()) {
       return readStringReference();
+    } else {
+      return null;
     }
   }
 
   String? readOptionalStringUtf8() {
     if (readBool()) {
       return readStringUtf8();
+    } else {
+      return null;
     }
   }
 
   int? readOptionalUInt30() {
     if (readBool()) {
       return readUInt30();
+    } else {
+      return null;
     }
   }
 
diff --git a/pkg/analyzer/lib/src/summary2/element_builder.dart b/pkg/analyzer/lib/src/summary2/element_builder.dart
index 794ef17..8d6599b 100644
--- a/pkg/analyzer/lib/src/summary2/element_builder.dart
+++ b/pkg/analyzer/lib/src/summary2/element_builder.dart
@@ -1014,7 +1014,9 @@
 
   LibraryElement? _selectLibrary(NamespaceDirective node) {
     var uri = _selectAbsoluteUri(node);
-    if (uri != null) {
+    if (uri == null) {
+      return null;
+    } else {
       return _linker.elementFactory.libraryOfUri('$uri');
     }
   }
@@ -1270,7 +1272,9 @@
 
   Reference? addParameter(String? name, ParameterElementImpl element) {
     parameters.add(element);
-    if (name != null) {
+    if (name == null) {
+      return null;
+    } else {
       return _bindReference('@parameter', name, element);
     }
   }
diff --git a/pkg/analyzer/lib/src/workspace/bazel.dart b/pkg/analyzer/lib/src/workspace/bazel.dart
index c8d032c..13f0edb 100644
--- a/pkg/analyzer/lib/src/workspace/bazel.dart
+++ b/pkg/analyzer/lib/src/workspace/bazel.dart
@@ -358,6 +358,8 @@
         return packageRootedAt(folder);
       }
     }
+
+    return null;
   }
 
   /// In some distributed build environments, BUILD files are not preserved.
@@ -497,10 +499,9 @@
             context.join(root, '$symlinkPrefix-genfiles'),
             lookForBuildFileSubstitutes: lookForBuildFileSubstitutes);
       }
-
-      // // Go up the folder.
-      // folder = parent;
     }
+
+    return null;
   }
 
   /// Find the "bin" folder path, by searching for it.
@@ -587,6 +588,8 @@
     for (var match in pattern.allMatches(content)) {
       return Version.parse('${match.group(1)}.0');
     }
+
+    return null;
   }
 }
 
diff --git a/pkg/analyzer/lib/src/workspace/bazel_watcher.dart b/pkg/analyzer/lib/src/workspace/bazel_watcher.dart
index b3f09ec..54b96a0 100644
--- a/pkg/analyzer/lib/src/workspace/bazel_watcher.dart
+++ b/pkg/analyzer/lib/src/workspace/bazel_watcher.dart
@@ -123,6 +123,8 @@
         // folder, so we use a dummy value here. But this shouldn't really
         // matter, since the `symlinkTarget` should detect any modifications.
         return _ModifiedInfo(0, 0, symlinkTarget);
+      } else {
+        return null;
       }
     } on FileSystemException catch (_) {
       // File doesn't exist, so return null.
diff --git a/pkg/analyzer/lib/src/workspace/gn.dart b/pkg/analyzer/lib/src/workspace/gn.dart
index e22ce32..8ebed62 100644
--- a/pkg/analyzer/lib/src/workspace/gn.dart
+++ b/pkg/analyzer/lib/src/workspace/gn.dart
@@ -88,6 +88,7 @@
         return GnWorkspacePackage(folder.path, this);
       }
     }
+    return null;
   }
 
   /// Find the GN workspace that contains the given [filePath].
@@ -123,6 +124,7 @@
         return GnWorkspace._(provider, root, packageMap);
       }
     }
+    return null;
   }
 
   /// For a source at `$root/foo/bar`, the packages files are generated in
diff --git a/pkg/analyzer/lib/src/workspace/package_build.dart b/pkg/analyzer/lib/src/workspace/package_build.dart
index 53a293f..4e06f04 100644
--- a/pkg/analyzer/lib/src/workspace/package_build.dart
+++ b/pkg/analyzer/lib/src/workspace/package_build.dart
@@ -328,13 +328,16 @@
         return null;
       }
     }
+    return null;
   }
 
   /// Return the content of the [file], `null` if cannot be read.
   static String? _fileContentOrNull(File file) {
     try {
       return file.readAsStringSync();
-    } catch (_) {}
+    } catch (_) {
+      return null;
+    }
   }
 }
 
diff --git a/pkg/analyzer/lib/src/workspace/pub.dart b/pkg/analyzer/lib/src/workspace/pub.dart
index e5059d7..1d83253 100644
--- a/pkg/analyzer/lib/src/workspace/pub.dart
+++ b/pkg/analyzer/lib/src/workspace/pub.dart
@@ -74,13 +74,16 @@
         return PubWorkspace._(provider, packageMap, root, pubspec);
       }
     }
+    return null;
   }
 
   /// Return the content of the [file], `null` if cannot be read.
   static String? _fileContentOrNull(File file) {
     try {
       return file.readAsStringSync();
-    } catch (_) {}
+    } catch (_) {
+      return null;
+    }
   }
 }
 
diff --git a/runtime/vm/compiler/jit/jit_call_specializer.cc b/runtime/vm/compiler/jit/jit_call_specializer.cc
index 191e6bb..3afc611 100644
--- a/runtime/vm/compiler/jit/jit_call_specializer.cc
+++ b/runtime/vm/compiler/jit/jit_call_specializer.cc
@@ -162,57 +162,6 @@
   }
 }
 
-void JitCallSpecializer::VisitStoreInstanceField(
-    StoreInstanceFieldInstr* instr) {
-  if (instr->IsUnboxedDartFieldStore()) {
-    // Determine if this field should be unboxed based on the usage of getter
-    // and setter functions: The heuristic requires that the setter has a
-    // usage count of at least 1/kGetterSetterRatio of the getter usage count.
-    // This is to avoid unboxing fields where the setter is never or rarely
-    // executed.
-    const Field& field = instr->slot().field();
-    const String& field_name = String::Handle(Z, field.name());
-    const Class& owner = Class::Handle(Z, field.Owner());
-    const Function& getter =
-        Function::Handle(Z, owner.LookupGetterFunction(field_name));
-    const Function& setter =
-        Function::Handle(Z, owner.LookupSetterFunction(field_name));
-    bool unboxed_field = false;
-    if (!getter.IsNull() && !setter.IsNull()) {
-      if (field.is_double_initialized()) {
-        unboxed_field = true;
-      } else if ((setter.usage_counter() > 0) &&
-                 ((FLAG_getter_setter_ratio * setter.usage_counter()) >=
-                  getter.usage_counter())) {
-        unboxed_field = true;
-      }
-    }
-    if (!unboxed_field) {
-      if (FLAG_trace_optimization || FLAG_trace_field_guards) {
-        THR_Print("Disabling unboxing of %s\n", field.ToCString());
-        if (!setter.IsNull()) {
-          THR_Print("  setter usage count: %" Pd "\n", setter.usage_counter());
-        }
-        if (!getter.IsNull()) {
-          THR_Print("  getter usage count: %" Pd "\n", getter.usage_counter());
-        }
-      }
-      // We determined it's not beneficial for performance to unbox the
-      // field, therefore we mark it as boxed here.
-      //
-      // Calling `DisableFieldUnboxing` will cause transition the field to
-      // boxed and deoptimize dependent code.
-      //
-      // NOTE: It will also, as a side-effect, change our field clone's
-      // `is_unboxing_candidate()` bit. So we assume the compiler has so far
-      // not relied on this bit.
-      field.DisableFieldUnboxing();
-    } else {
-      flow_graph()->parsed_function().AddToGuardedFields(&field);
-    }
-  }
-}
-
 // Replace generic context allocation or cloning with a sequence of inlined
 // allocation and explicit initializing stores.
 // If context_value is not NULL then newly allocated context is a populated
diff --git a/runtime/vm/compiler/jit/jit_call_specializer.h b/runtime/vm/compiler/jit/jit_call_specializer.h
index 8c743ed..ecbee73 100644
--- a/runtime/vm/compiler/jit/jit_call_specializer.h
+++ b/runtime/vm/compiler/jit/jit_call_specializer.h
@@ -27,7 +27,6 @@
   // Find a better place for them.
   virtual void VisitAllocateContext(AllocateContextInstr* instr);
   virtual void VisitCloneContext(CloneContextInstr* instr);
-  virtual void VisitStoreInstanceField(StoreInstanceFieldInstr* instr);
 
  private:
   virtual bool IsAllowedForInlining(intptr_t deopt_id) const;
diff --git a/runtime/vm/flag_list.h b/runtime/vm/flag_list.h
index 679bf26..edf42f7 100644
--- a/runtime/vm/flag_list.h
+++ b/runtime/vm/flag_list.h
@@ -125,8 +125,6 @@
   P(enable_ffi, bool, true, "Disable to make importing dart:ffi an error.")    \
   P(force_clone_compiler_objects, bool, false,                                 \
     "Force cloning of objects needed in compiler (ICData and Field).")         \
-  P(getter_setter_ratio, int, 13,                                              \
-    "Ratio of getter/setter usage used for double field unboxing heuristics")  \
   P(guess_icdata_cid, bool, true,                                              \
     "Artificially create type feedback for arithmetic etc. operations")        \
   P(huge_method_cutoff_in_tokens, int, 20000,                                  \
diff --git a/tests/lib/js/external_extension_members_test.dart b/tests/lib/js/external_extension_members_test.dart
index 823861c..7f98c7d 100644
--- a/tests/lib/js/external_extension_members_test.dart
+++ b/tests/lib/js/external_extension_members_test.dart
@@ -35,6 +35,7 @@
   external set annotatedSetter(_);
 
   external num getField();
+  external void setField10([optionalArgument = 10]);
   @JS('toString')
   external String extToString();
   external dynamic getFirstEl(list);
@@ -72,6 +73,10 @@
       return this.field;
     }
 
+    Foo.prototype.setField10 = function(optionalArgument) {
+      this.field = optionalArgument;
+    }
+
     Foo.prototype.getFirstEl = function(list) {
       return list[0];
     }
@@ -128,6 +133,24 @@
     expect(foo.otherSumFn(10, 5), equals(15));
   });
 
+  // TODO(41375): Remove if JS interop default value arguments are disallowed.
+  test('optional arguments', () {
+    var foo = Foo(42);
+    expect(foo.field, equals(42));
+
+    foo.setField10();
+    expect(foo.field, equals(10));
+    foo.setField10(6);
+    expect(foo.field, equals(6));
+
+    // Test using tearoffs
+    var setF = foo.setField10;
+    setF();
+    expect(foo.field, equals(10));
+    setF(6);
+    expect(foo.field, equals(6));
+  });
+
   test('module class', () {
     var bar = Bar(5);
     expect(js_util.getProperty(bar, 'fieldAnnotation'), equals(5));
diff --git a/tests/lib_2/js/external_extension_members_test.dart b/tests/lib_2/js/external_extension_members_test.dart
index b1b0cfe..34cc509 100644
--- a/tests/lib_2/js/external_extension_members_test.dart
+++ b/tests/lib_2/js/external_extension_members_test.dart
@@ -32,6 +32,7 @@
   external set annotatedSetter(_);
 
   external num getField();
+  external void setField10([optionalArgument = 10]);
   @JS('toString')
   external String extToString();
   external dynamic getFirstEl(list);
@@ -71,6 +72,10 @@
       return this.field;
     }
 
+    Foo.prototype.setField10 = function(optionalArgument) {
+      this.field = optionalArgument;
+    }
+
     Foo.prototype.getFirstEl = function(list) {
       return list[0];
     }
@@ -110,6 +115,24 @@
     expect(foo.otherSumFn(10, 5), equals(15));
   });
 
+  // TODO(41375): Remove if JS interop default value arguments are disallowed.
+  test('optional arguments', () {
+    var foo = Foo(42);
+    expect(foo.getField(), equals(42));
+
+    foo.setField10();
+    expect(foo.getField(), equals(10));
+    foo.setField10(6);
+    expect(foo.getField(), equals(6));
+
+    // Test using tearoffs
+    var setF = foo.setField10;
+    setF();
+    expect(foo.getField(), equals(10));
+    setF(6);
+    expect(foo.getField(), equals(6));
+  });
+
   test('module class', () {
     var bar = Bar(5);
     expect(js_util.getProperty(bar, 'fieldAnnotation'), equals(5));
diff --git a/tools/VERSION b/tools/VERSION
index 30279d0..7b40e22 100644
--- a/tools/VERSION
+++ b/tools/VERSION
@@ -27,5 +27,5 @@
 MAJOR 2
 MINOR 16
 PATCH 0
-PRERELEASE 60
+PRERELEASE 61
 PRERELEASE_PATCH 0
\ No newline at end of file