julia

1e45aba0 - Fix indexing triangular matrices with `undef` elements in the parent (#52530)

Fix indexing triangular matrices with `undef` elements in the parent (#52530) I'm not totally sure about specializing`getindex` for numeric arrays, but this lets us display a triangular matrix where the parent is not initialized. ```julia julia> M = Matrix{BigFloat}(undef, 4, 4) 4×4 Matrix{BigFloat}: #undef #undef #undef #undef #undef #undef #undef #undef #undef #undef #undef #undef #undef #undef #undef #undef julia> UpperTriangular(M) 4×4 UpperTriangular{BigFloat, Matrix{BigFloat}}: #undef #undef #undef #undef ⋅ #undef #undef #undef ⋅ ⋅ #undef #undef ⋅ ⋅ ⋅ #undef ```