Add feedback from PVS (static code analyzer)

https://pvs-studio.com/en/blog/posts/cpp/1153/

Source/Engine/Content/Storage/FlaxStorage.cpp

@@ -662,13 +662,13 @@ bool FlaxStorage::LoadAssetChunk(FlaxChunk* chunk)
                 if (!failed)
                 {
                     stream->SetPosition(chunk->LocationInFile.Address);
+                    if (!stream->HasError())
+                        break;
                 }
-                if (!stream->HasError())
-                    break;
             }
         }
 
-        if (stream->HasError())
+        if (!stream || stream->HasError())
         {
             failed = true;
             UnlockChunks();

Source/Engine/Core/Math/Matrix2x2.cs

@@ -94,8 +94,8 @@ namespace FlaxEngine
                 throw new ArgumentOutOfRangeException(nameof(values), "There must be sixteen and only four input values for Matrix2x2.");
             M11 = values[0];
             M12 = values[1];
-            M21 = values[3];
-            M22 = values[4];
+            M21 = values[2];
+            M22 = values[3];
         }
 
         /// <summary>

Source/Engine/Core/Types/DataContainer.h

@@ -324,15 +324,14 @@ public:
     {
         if (length <= 0)
             return;
-        if (Base::Length() == 0)
+        auto prev = Base::_data;
+        const auto prevLength = Base::_length;
+        if (prevLength == 0 || prev == nullptr)
         {
             Copy(data, length);
             return;
         }
 
-        auto prev = Base::_data;
-        const auto prevLength = Base::_length;
-
         Base::_length = prevLength + length;
         Base::_data = (T*)Allocator::Allocate(Base::_length * sizeof(T));
 

Source/Engine/Core/Types/Variant.cpp

@@ -2702,8 +2702,8 @@ void Variant::SetAsset(Asset* asset)
         SetType(VariantType(VariantType::Asset));
     if (AsAsset)
     {
-        asset->OnUnloaded.Unbind<Variant, &Variant::OnAssetUnloaded>(this);
-        asset->RemoveReference();
+        AsAsset->OnUnloaded.Unbind<Variant, &Variant::OnAssetUnloaded>(this);
+        AsAsset->RemoveReference();
     }
     AsAsset = asset;
     if (asset)

Source/Engine/UI/GUI/WindowRootControl.cs

@@ -77,7 +77,7 @@ namespace FlaxEngine.GUI
         /// </summary>
         public void Hide()
         {
-            _window.Show();
+            _window.Hide();
         }
 
         /// <summary>