static_cast<UINT>() silently truncates >4GB to UINT32 _MAX

Search for static_cast<UINT and you get several hits, most of which silently truncate size_t to UINT or UINT32. For example

template <>
inline unique_hstring make_unique_string_nothrow<unique_hstring>(
    _When_((source != nullptr) && length != static_cast<size_t>(-1), _In_reads_(length))
        _When_((source != nullptr) && length == static_cast<size_t>(-1), _In_z_) PCWSTR source,
    size_t length) WI_NOEXCEPT
{
    WI_ASSERT(source != nullptr); // the HSTRING version of this function does not support this case
    if (length == static_cast<size_t>(-1))
    {
        length = wcslen(source);
    }

    unique_hstring result;
    ::WindowsCreateString(source, static_cast<UINT32>(length), &result);
    return result;
}

Call will a string >4GB and this succeeds but only copies the first 4GB. This should fail e.g.

...
    unique_hstring result;
    if (length < UINT32_MAX)
    {
        ::WindowsCreateString(source, static_cast<UINT32>(length), &result);
    }
    return result;

I currently see hits in winrt.h, registry_helpers.h, resource.h, and TraceLogging.h. Best to review all instances and very false positives or fix appropriately

Search for static_cast<UINT and review the instances in winrt.h, registry_helpers.h, resource.h, and TraceLogging.h, checking each size_t-to- UINT or UINT32 conversion. Start with the make_unique_string_nothrow example and identify which cases can exceed the target type. Done means every relevant instance either rejects oversized input or is confirmed safe, with false positives handled appropriately.