Template function TSparseArray::PointerToIndex does not compile

Error:  C:\Program Files\Epic Games\UE_4.25\Engine\Source\Runtime\Core\Public\Containers/SparseArray.h(778): error C2440: '-': cannot convert from 'const TSparseArrayElementOrFreeListLink<TAlignedBytes<4,4>> *' to 'const int *'
> C:\Program Files\Epic Games\UE_4.25\Engine\Source\Runtime\Core\Public\Containers/SparseArray.h(776): note: while compiling class template member function 'int32 TSparseArray<int,FDefaultSparseArrayAllocator>::PointerToIndex(const int *) const'

Note from user: 

we are using a workaround "int index = ptrToElement - &sparseArray[0];" but it is only valid code because in TSparseArray::operator[] a essential check has been commented out with the note "Disabled to improve loading times -BZ". The workaround would become a bug if that check would be enabled again.

The engine code line "int32 Index = Ptr - &GetData(0);" should be "int32 Index = Ptr - (ElementType*)&GetData(Index).ElementData;"

1. Add the following code into a new class: TSparseArray<int> sparseArray;
   sparseArray.Add(1);
   int* ptrToElement = &sparseArray[0];
   int index = sparseArray.PointerToIndex(ptrToElement);
2. Compile the project

Result: Compiler Error

Expected: No compiler error