fixes

Author: leo-collins

firedrake/assemble.py

@@ -238,7 +238,7 @@ def assemble(self, tensor=None, current_state=None):
             if isinstance(expr, ufl.algebra.Sum):
                 a, b = [assemble(e) for e in expr.ufl_operands]
                 # Only Expr resulting in a Matrix if assembled are BaseFormOperator
-                if not all(isinstance(op, matrix.AssembledMatrix) for op in (a, b)):
+                if not all(isinstance(op, matrix.MatrixBase) for op in (a, b)):
                     raise TypeError('Mismatching Sum shapes')
                 return assemble(ufl.FormSum((a, 1), (b, 1)), tensor=tensor)
             elif isinstance(expr, ufl.algebra.Product):

firedrake/interpolation.py

@@ -307,7 +307,7 @@ def assemble(
         """
         self._check_mat_type(mat_type)
 
-        if mat_type == "matfree":
+        if mat_type == "matfree" and self.rank == 2:
             ctx = ImplicitMatrixContext(
                 self.ufl_interpolate, row_bcs=bcs, col_bcs=bcs,
             )