Specify all discrete FEM spaces when discretizing bilinear forms

[yguclu]

domain = Square('Omega')
S = ScalarFunctionSpace('S', domain)
V = VectorFunctionSpace('V', domain)

u, v = elements_of(V, names='u, v')
w = element_of(S, name='h')

a = BilinearForm((u, v),  integral(domain, dot(curl(u), curl(v)) * w))
l = LinearForm(v, integral(domain, dot(f, v * w)))  # f is some analytical expression

l2norm = Norm(u - f, domain, kind='l2')

domain_h1 = discretize(domain, ncells=nc)
domain_h2 = discretize(domain, ncells=nc*2)

V_h1 = discretize(V, domain_h1, degree=p)
V_h2 = discretize(V, domain_h2, degree=p)

S_h1 = discretize(S, domain_h1, degree=p+1)
S_h2 = discretize(S, domain_h2, degree=p+1)

# Dictionary of spaces which maps SymPDE analytical spaces to Psydac discrete spaces
spaces_h1 = {V: V_h1, S: S_h1}

# Old vs. new interface
# a_h1 = discretize(a, domain_h1, (V_h1, V_h1), nquads=p+1)
a_h1 = discretize(a, domain_h1, spaces_h1, nquads=p+1) # Check: all spaces have the same domain

# l_h1 = discretize(a, domain_h1, V_h1, nquads=p+2)
l_h1 = discretize(l, domain_h1, spaces_h1, nquads=p+2)

# l2norm_h1 = discretize(l2norm, domain_h1, V_h1, nquads=p+1)  #-- but why?
l2norm_h1 = discretize(l2norm, domain_h1, spaces_h1, nquads=p+1)