compiler: Fix/test 1D array construction from generic iterables

artiq/compiler/transforms/inferencer.py

@@ -740,6 +740,10 @@ class Inferencer(algorithm.Visitor):
                     # KLUDGE: Support multidimensional arary creation if lexically
                     # specified as a rectangular array of lists.
                     elt, num_dims = match_rectangular_list([arg])
+                    if num_dims == 0:
+                        # Not given as a list, so just default to 1 dimension.
+                        elt = builtins.get_iterable_elt(arg.type)
+                        num_dims = 1
                     self._unify(node.type,
                                 builtins.TArray(elt, types.TValue(num_dims)),
                                 node.loc, arg.loc)

artiq/test/lit/integration/array.py

@@ -13,6 +13,14 @@ assert len(empty_array) == 0
 assert empty_array.shape == (0,)
 assert [x * x for x in empty_array] == []
 
+# Creating a list from a generic iterable always generates an 1D array, as we can't
+# check for rectangularity at compile time. (This could be changed to *assume*
+# rectangularity and insert runtime checks instead.)
+list_of_lists = [[1, 2], [3, 4]]
+array_of_lists = array(list_of_lists)
+assert array_of_lists.shape == (2,)
+assert [x for x in array_of_lists] == list_of_lists
+
 matrix = array([[1.0, 2.0, 3.0], [4.0, 5.0, 6.0]])
 assert len(matrix) == 2
 assert matrix.shape == (2, 3)