Fix infinite loop when slices are found in array call (#1615)

Remove wrong assumption that elements of a list passed to a call
to `array` are always scalars, which resulted in an infinite loop when
a slice was encountered. To this end handle a multi-dimensional
`IndexedElement` in the same way as a `Variable`. This fixes #1613.

Add a condition to ensure that an error is raised if this problem
re-arises, rather than entering an infinite loop.

CHANGELOG.md

@@ -20,6 +20,7 @@ All notable changes to this project will be documented in this file.
 -   #1582 : Allow homogeneous tuples in classes.
 -   #1619 : Give priority to imported functions over builtin functions.
 -   #1614 : Allow relative paths for custom compilation file.
+-   #1615 : Fixed infinite loop when passing slices while copying arrays.
 
 ### Changed
 

pyccel/codegen/printing/ccode.py

@@ -434,7 +434,7 @@ def copy_NumpyArray_Data(self, expr):
         while i < num_elements:
             current_element = flattened_list[i]
             # Copy an array element
-            if isinstance(current_element, Variable) and current_element.rank >= 1:
+            if isinstance(current_element, (Variable, IndexedElement)) and current_element.rank >= 1:
                 elem_name = self._print(current_element)
                 target = self._print(ObjectAddress(copy_to))
                 operations += f"array_copy_data({target}, {elem_name}, {offset_str});\n"
@@ -447,6 +447,9 @@ def copy_NumpyArray_Data(self, expr):
                 self.add_import(c_imports['string'])
                 remaining_elements = flattened_list[i:]
                 lenSubset = next((i for i,v in enumerate(remaining_elements) if v.rank != 0), len(remaining_elements))
+                if lenSubset == 0:
+                    errors.report(f"Can't copy {rhs} into {lhs}", symbol=expr,
+                            severity='fatal')
                 subset = remaining_elements[:lenSubset]
 
                 # Declare list of consecutive elements

pyccel/parser/semantic.py

@@ -2165,7 +2165,7 @@ def _visit_IndexedElement(self, expr):
         elif any(isinstance(getattr(a, 'class_type', None), NativeTuple) for a in args):
             n_exprs = None
             for a in args:
-                if a.shape and isinstance(a.shape[0], LiteralInteger):
+                if getattr(a, 'shape', None) and isinstance(a.shape[0], LiteralInteger):
                     a_len = a.shape[0]
                     if n_exprs:
                         assert n_exprs == a_len

tests/epyccel/modules/arrays.py

@@ -1674,6 +1674,10 @@ def arrs_2d_negative_index():
     b = a[1:-1, :-1] + a[2:, -9:]
     return np.shape(b)[0], np.shape(b)[1], np.sum(b)
 
+def arr_tuple_slice_index(a : 'int[:,:]'):
+    r = a[(0,1,3),1:]
+    return r
+
 #==============================================================================
 # NUMPY ARANGE
 #==============================================================================

tests/epyccel/test_arrays.py

@@ -3549,6 +3549,15 @@ def test_arrs_1d_int64_index(language):
     f2 = epyccel(f1, language = language)
     assert f1() == f2()
 
+def test_arr_tuple_slice_index(language):
+    f1 = arrays.arr_tuple_slice_index
+    f2 = epyccel(f1, language = language)
+
+    r_python = f1(arrays.a_2d_c)
+    r_pyccel = f2(arrays.a_2d_c)
+
+    check_array_equal(r_python, r_pyccel)
+
 @pytest.mark.parametrize( 'language', [
         pytest.param("c", marks = [
             pytest.mark.skip(reason="negative step does not work in c. See #1311"),