Fix missing loop in slice assignment (pyccel#2027)

Fix missing loop in slice assignment by creating missing
`LoopCollection` object. Fixes pyccel#2026 . Modify the existing test so it
would fail on the `devel` branch.

Author: EmilyBourne

CHANGELOG.md

@@ -67,6 +67,7 @@ All notable changes to this project will be documented in this file.
 -   #1930 : Preserve ordering of import targets.
 -   #1892 : Fix implementation of list function when an iterable is passed as parameter.
 -   #1972 : Simplified `printf` statement for Literal String.
+-   #2026 : Fix missing loop in slice assignment.
 
 ### Changed
 

pyccel/ast/utilities.py

@@ -571,13 +571,19 @@ def collect_loops(block, indices, new_index, language_has_vectors = False, resul
             lhs = line.lhs
             rhs = line.rhs
             if lhs.rank > rhs.rank:
-                for index_depth in range(lhs.rank-rhs.rank):
+                loop_len = []
+                n_new_loops = lhs.rank-rhs.rank
+                for index_depth in range(n_new_loops):
+                    loop_len.append(lhs.shape[0])
                     # If an index exists at the same depth, reuse it if not create one
                     if index_depth >= len(indices):
                         indices.append(new_index(PythonNativeInt(), 'i'))
                     index = indices[index_depth]
                     lhs = insert_index(lhs, index_depth, index)
-                collect_loops([Assign(lhs, rhs)], indices, new_index, language_has_vectors, result = result)
+                block = collect_loops([Assign(lhs, rhs)], indices, new_index, language_has_vectors)
+                for s in loop_len:
+                    block = LoopCollection(block, s, set([lhs]))
+                result.append(block)
 
             elif not language_has_vectors:
                 if isinstance(rhs, NumpyArray):

tests/epyccel/modules/arrays.py

@@ -1592,8 +1592,8 @@ def array_2d_C_slice_stride_23(a : 'int[:,:]'):
 
 def copy_to_slice_issue_1218(n : int):
     from numpy import zeros, array
-    x = 1
-    arr = zeros((2, n))
+    x = 2
+    arr = zeros((3, n))
     arr[0:x, 0:6:2] = array([2, 5, 6])
     return arr