Error when adding Dirichlet on nodes for MixedDofHandler

[fredrikekre]

Error happens here:

Ferrite.jl/src/Dofs/ConstraintHandler.jl

Line 911 in 9de9677

for (cellid, _) in dbc.faces

because dbc.faces is just Set{Int} and not Set{Tuple{Int,Int}} then.

Repro:

grid = generate_grid(Line, (2,))
dh = MixedDofHandler(grid)
push!(dh, :u, 2)
close!(dh)
ch = ConstraintHandler(dh)
add!(ch, Dirichlet(:u, Set(1), x -> 0))