diff --git a/ipc/mscom/ActivationContext.h b/ipc/mscom/ActivationContext.h
index 2368027841d4..2365c5e49628 100644
--- a/ipc/mscom/ActivationContext.h
+++ b/ipc/mscom/ActivationContext.h
@@ -23,15 +23,10 @@ namespace mscom {
 
 class ActivationContext final {
  public:
-  // This is the default resource ID that the Windows dynamic linker searches
-  // for when seeking a manifest while loading a DLL.
-  static constexpr WORD kDllManifestDefaultResourceId = 2;
-
   ActivationContext() : mActCtx(INVALID_HANDLE_VALUE) {}
 
   explicit ActivationContext(WORD aResourceId);
-  explicit ActivationContext(HMODULE aLoadFromModule,
-                             WORD aResourceId = kDllManifestDefaultResourceId);
+  explicit ActivationContext(HMODULE aLoadFromModule, WORD aResourceId = 2);
 
   ActivationContext(ActivationContext&& aOther);
   ActivationContext& operator=(ActivationContext&& aOther);
diff --git a/ipc/mscom/ApartmentRegion.h b/ipc/mscom/ApartmentRegion.h
index aa4d3e6d418f..dc56e3fc9676 100644
--- a/ipc/mscom/ApartmentRegion.h
+++ b/ipc/mscom/ApartmentRegion.h
@@ -15,14 +15,14 @@
 namespace mozilla {
 namespace mscom {
 
-class MOZ_NON_TEMPORARY_CLASS ApartmentRegion final {
+class MOZ_NON_TEMPORARY_CLASS ApartmentRegion {
  public:
   /**
    * This constructor is to be used when we want to instantiate the object but
    * we do not yet know which type of apartment we want. Call Init() to
    * complete initialization.
    */
-  constexpr ApartmentRegion() : mInitResult(CO_E_NOTINITIALIZED) {}
+  ApartmentRegion() : mInitResult(CO_E_NOTINITIALIZED) {}
 
   explicit ApartmentRegion(COINIT aAptType)
       : mInitResult(::CoInitializeEx(nullptr, aAptType)) {
@@ -62,7 +62,7 @@ class MOZ_NON_TEMPORARY_CLASS ApartmentRegion final {
 };
 
 template <COINIT T>
-class MOZ_NON_TEMPORARY_CLASS ApartmentRegionT final {
+class MOZ_NON_TEMPORARY_CLASS ApartmentRegionT {
  public:
   ApartmentRegionT() : mAptRgn(T) {}
 
diff --git a/ipc/mscom/Objref.cpp b/ipc/mscom/Objref.cpp
index 37108c71ac1f..c0e8e98b162d 100644
--- a/ipc/mscom/Objref.cpp
+++ b/ipc/mscom/Objref.cpp
@@ -262,7 +262,8 @@ bool StripHandlerFromOBJREF(NotNull<IStream*> aStream, const uint64_t aStartPos,
 
   // The difference between a OBJREF_STANDARD and an OBJREF_HANDLER is
   // sizeof(CLSID), so we'll zero out the remaining bytes.
-  hr = aStream->Write(&CLSID_NULL, sizeof(CLSID), &bytesWritten);
+  CLSID zeroClsid = {0};
+  hr = aStream->Write(&zeroClsid, sizeof(CLSID), &bytesWritten);
   if (FAILED(hr) || bytesWritten != sizeof(CLSID)) {
     return false;
   }
diff --git a/ipc/mscom/Ptr.h b/ipc/mscom/Ptr.h
index e800d4f568bf..fd4bd9c91ffc 100644
--- a/ipc/mscom/Ptr.h
+++ b/ipc/mscom/Ptr.h
@@ -37,7 +37,6 @@ struct MainThreadRelease {
     if (!aPtr) {
       return;
     }
-
     if (NS_IsMainThread()) {
       aPtr->Release();
       return;
@@ -57,8 +56,7 @@ struct MTADelete {
       return;
     }
 
-    EnsureMTA::AsyncOperation(
-        [ptr = std::move(aPtr)]() -> void { delete ptr; });
+    EnsureMTA::AsyncOperation([aPtr]() -> void { delete aPtr; });
   }
 };
 
@@ -69,8 +67,11 @@ struct MTARelease {
       return;
     }
 
+    // Static analysis doesn't recognize that, even though aPtr escapes the
+    // current scope, we are in effect moving our strong ref into the lambda.
+    void* ptr = aPtr;
     EnsureMTA::AsyncOperation(
-        [ptr = std::move(aPtr)]() -> void { ptr->Release(); });
+        [ptr]() -> void { reinterpret_cast<T*>(ptr)->Release(); });
   }
 };
 
@@ -87,8 +88,11 @@ struct MTAReleaseInChildProcess {
       return;
     }
 
+    // Static analysis doesn't recognize that, even though aPtr escapes the
+    // current scope, we are in effect moving our strong ref into the lambda.
+    void* ptr = aPtr;
     EnsureMTA::AsyncOperation(
-        [ptr = std::move(aPtr)]() -> void { ptr->Release(); });
+        [ptr]() -> void { reinterpret_cast<T*>(ptr)->Release(); });
   }
 };
 
@@ -104,10 +108,14 @@ struct PreservedStreamDeleter {
       return;
     }
 
-    auto cleanup = [ptr = std::move(aPtr)]() -> void {
-      DebugOnly<HRESULT> hr = ::CoReleaseMarshalData(ptr);
+    // Static analysis doesn't recognize that, even though aPtr escapes the
+    // current scope, we are in effect moving our strong ref into the lambda.
+    void* ptr = aPtr;
+    auto cleanup = [ptr]() -> void {
+      DebugOnly<HRESULT> hr =
+          ::CoReleaseMarshalData(reinterpret_cast<LPSTREAM>(ptr));
       MOZ_ASSERT(SUCCEEDED(hr));
-      ptr->Release();
+      reinterpret_cast<LPSTREAM>(ptr)->Release();
     };
 
     if (XRE_IsParentProcess()) {
@@ -116,7 +124,7 @@ struct PreservedStreamDeleter {
       return;
     }
 
-    EnsureMTA::AsyncOperation(std::move(cleanup));
+    EnsureMTA::AsyncOperation(cleanup);
   }
 };
 
@@ -184,7 +192,6 @@ inline STAUniquePtr<T> ToSTAUniquePtr(T* aRawPtr) {
   if (aRawPtr) {
     aRawPtr->AddRef();
   }
-
   return STAUniquePtr<T>(aRawPtr);
 }
 
@@ -212,7 +219,6 @@ inline MTAUniquePtr<T> ToMTAUniquePtr(T* aRawPtr) {
   if (aRawPtr) {
     aRawPtr->AddRef();
   }
-
   return MTAUniquePtr<T>(aRawPtr);
 }
 
@@ -239,7 +245,6 @@ inline ProxyUniquePtr<T> ToProxyUniquePtr(T* aRawPtr) {
   if (aRawPtr) {
     aRawPtr->AddRef();
   }
-
   return ProxyUniquePtr<T>(aRawPtr);
 }
 
diff --git a/ipc/mscom/Utils.cpp b/ipc/mscom/Utils.cpp
index e87b35c45c7c..ab6ac719696b 100644
--- a/ipc/mscom/Utils.cpp
+++ b/ipc/mscom/Utils.cpp
@@ -5,7 +5,6 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 #if defined(MOZILLA_INTERNAL_API)
-#  include "MainThreadUtils.h"
 #  include "mozilla/dom/ContentChild.h"
 #endif
 
@@ -75,16 +74,6 @@ bool IsCurrentThreadImplicitMTA() {
          aptTypeQualifier == APTTYPEQUALIFIER_IMPLICIT_MTA;
 }
 
-#if defined(MOZILLA_INTERNAL_API)
-bool IsCurrentThreadNonMainMTA() {
-  if (NS_IsMainThread()) {
-    return false;
-  }
-
-  return IsCurrentThreadMTA();
-}
-#endif  // defined(MOZILLA_INTERNAL_API)
-
 bool IsProxy(IUnknown* aUnknown) {
   if (!aUnknown) {
     return false;
@@ -139,8 +128,8 @@ uintptr_t GetContainingModuleHandle() {
   return reinterpret_cast<uintptr_t>(thisModule);
 }
 
-long CreateStream(const uint8_t* aInitBuf, const uint32_t aInitBufSize,
-                  IStream** aOutStream) {
+uint32_t CreateStream(const uint8_t* aInitBuf, const uint32_t aInitBufSize,
+                      IStream** aOutStream) {
   if (!aInitBufSize || !aOutStream) {
     return E_INVALIDARG;
   }
@@ -219,7 +208,7 @@ long CreateStream(const uint8_t* aInitBuf, const uint32_t aInitBufSize,
   return S_OK;
 }
 
-long CopySerializedProxy(IStream* aInStream, IStream** aOutStream) {
+uint32_t CopySerializedProxy(IStream* aInStream, IStream** aOutStream) {
   if (!aInStream || !aOutStream) {
     return E_INVALIDARG;
   }
diff --git a/ipc/mscom/Utils.h b/ipc/mscom/Utils.h
index ddc9979b8146..d93740fe7425 100644
--- a/ipc/mscom/Utils.h
+++ b/ipc/mscom/Utils.h
@@ -24,9 +24,6 @@ bool IsCOMInitializedOnCurrentThread();
 bool IsCurrentThreadMTA();
 bool IsCurrentThreadExplicitMTA();
 bool IsCurrentThreadImplicitMTA();
-#if defined(MOZILLA_INTERNAL_API)
-bool IsCurrentThreadNonMainMTA();
-#endif  // defined(MOZILLA_INTERNAL_API)
 bool IsProxy(IUnknown* aUnknown);
 bool IsValidGUID(REFGUID aCheckGuid);
 uintptr_t GetContainingModuleHandle();
@@ -41,8 +38,8 @@ uintptr_t GetContainingModuleHandle();
  * @param aOutStream Outparam to receive the newly created stream.
  * @return HRESULT error code.
  */
-long CreateStream(const uint8_t* aBuf, const uint32_t aBufLen,
-                  IStream** aOutStream);
+uint32_t CreateStream(const uint8_t* aBuf, const uint32_t aBufLen,
+                      IStream** aOutStream);
 
 /**
  * Creates a deep copy of a proxy contained in a stream.
@@ -51,7 +48,7 @@ long CreateStream(const uint8_t* aBuf, const uint32_t aBufLen,
  * @param aOutStream Outparam to receive the newly created stream.
  * @return HRESULT error code.
  */
-long CopySerializedProxy(IStream* aInStream, IStream** aOutStream);
+uint32_t CopySerializedProxy(IStream* aInStream, IStream** aOutStream);
 
 #if defined(MOZILLA_INTERNAL_API)
 /**