Round of clang compile fixes

Signed-off-by: Nicholas Van Sickle <nvsickle@amazon.com>

Code/Framework/AzCore/AzCore/DOM/DomUtils.cpp

@@ -22,7 +22,7 @@ namespace AZ::Dom::Utils
         return backend.ReadFromBufferInPlace(string.data(), string.size(), visitor);
     }
 
-    AZ::Outcome<Value, AZStd::string> AZ::Dom::Utils::WriteToValue(Backend::WriteCallback writeCallback)
+    AZ::Outcome<Value, AZStd::string> WriteToValue(Backend::WriteCallback writeCallback)
     {
         Value value;
         AZStd::unique_ptr<Visitor> writer = value.GetWriteHandler();

Code/Framework/AzCore/AzCore/DOM/DomValue.cpp

@@ -6,8 +6,6 @@
  *
  */
 
-#pragma once
-
 #include <AzCore/DOM/DomValue.h>
 #include <AzCore/DOM/DomValueWriter.h>
 #include <AzCore/std/smart_ptr/make_shared.h>
@@ -31,11 +29,7 @@ namespace AZ::Dom
     namespace Internal
     {
         template<class TestType>
-        constexpr size_t GetTypeIndexInternal(size_t index = 0)
-        {
-            static_assert(false, "Type not found in ValueType");
-            return index;
-        }
+        constexpr size_t GetTypeIndexInternal(size_t index = 0);
 
         template<class TestType, class FirstType, class... Rest>
         constexpr size_t GetTypeIndexInternal(size_t index = 0)
@@ -143,7 +137,7 @@ namespace AZ::Dom
 
     Value Value::FromOpaqueValue(const AZStd::any& value)
     {
-        return Value(&value);
+        return Value(value);
     }
 
     Value::Value(int8_t value)

Code/Framework/AzCore/AzCore/DOM/DomValueWriter.cpp

@@ -129,7 +129,7 @@ namespace AZ::Dom
                 AZStd::string::format("AZ::Dom::ValueWriter: %s called from within a different container type", endMethodName));
         }
 
-        if (buffer.m_attributes.size() != attributeCount)
+        if (static_cast<AZ::u64>(buffer.m_attributes.size()) != attributeCount)
         {
             return VisitorFailure(
                 VisitorErrorCode::InternalError,
@@ -138,7 +138,7 @@ namespace AZ::Dom
                     buffer.m_attributes.size()));
         }
 
-        if (buffer.m_elements.size() != elementCount)
+        if (static_cast<AZ::u64>(buffer.m_elements.size()) != elementCount)
         {
             return VisitorFailure(
                 VisitorErrorCode::InternalError,
@@ -146,6 +146,7 @@ namespace AZ::Dom
                     "AZ::Dom::ValueWriter: %s expected %llu elements but received %llu elements instead", endMethodName, elementCount,
                     buffer.m_elements.size()));
         }
+
         if (buffer.m_attributes.size() > 0)
         {
             MoveVectorMemory(container.GetMutableObject(), buffer.m_attributes);
@@ -237,8 +238,6 @@ namespace AZ::Dom
         m_entryStack.top().m_value.Swap(value);
         ValueInfo& newEntry = m_entryStack.top();
 
-        constexpr const size_t reserveSize = 8;
-
         if (!newEntry.m_key.IsEmpty())
         {
             GetValueBuffer().m_attributes.emplace_back(AZStd::move(newEntry.m_key), AZStd::move(value));