[SPIR-V] Partial Template Specializations with non-type parameters crashes DXC with found unregistered decl

[devshgraphicsprogramming]

Description
The following code:

namespace nbl
{
namespace hlsl
{


template<typename MatT>
struct matrix_traits;
// partial spec for matrices
template<typename T, int32_t N, int32_t M>
struct matrix_traits<matrix<T,N,M> >
{
    static const uint32_t RowCount = N;
    static const uint32_t ColumnCount = M;
    static const bool Square = N==M;
};

namespace impl
{
template<typename MatT>
MatT diagonal(float diagonal)
{
    MatT output;
    
    for(int i = 0; i < matrix_traits<MatT>::RowCount; ++i)
    for(int j = 0; j < matrix_traits<MatT>::ColumnCount; ++j)
        output[i][j] = 0;
    
    for(int diag = 0; diag < matrix_traits<MatT>::RowCount; ++diag)
        output[diag][diag] = diagonal;
        
    return output;
}
}
}
}

crashes the compiler when compiling SpirV and not when compiling DXIL

Steps to Reproduce

SPIR-V : https://godbolt.org/z/69KodrMb9
HLSL : https://godbolt.org/z/49YjvYnnh

Actual Behavior

<source>:10:30: fatal error: found unregistered decl N
template<typename T, int32_t N, int32_t M>
                             ^

Environment

• DXC version: trunk
• Host Operating System: Godbolt