fix crash when assigning memoryviews through ternary conditional expressions

CHANGES.rst

@@ -80,6 +80,8 @@ Optimizations
 Bugs fixed
 ----------
 
+* Crash when assigning memory views from ternary conditional expressions.
+
 * Nested C++ templates could lead to unseparated ">>" characters being
   generated into the C++ declarations, which older C++ compilers could
   not parse.

Cython/Compiler/ExprNodes.py

@@ -10156,7 +10156,10 @@ class CondExprNode(ExprNode):
 
     def eval_and_get(self, code, expr):
         expr.generate_evaluation_code(code)
-        expr.make_owned_reference(code)
+        if self.type.is_memoryviewslice:
+            expr.make_owned_memoryviewslice(code)
+        else:
+            expr.make_owned_reference(code)
         code.putln('%s = %s;' % (self.result(), expr.result_as(self.ctype())))
         expr.generate_post_assignment_code(code)
         expr.free_temps(code)

tests/memoryview/memoryview.pyx

@@ -978,3 +978,37 @@ def test_dtype_object_scalar_assignment():
 
     (<object> m)[:] = SingleObject(3)
     assert m[0] == m[4] == m[-1] == 3
+
+
+def test_assignment_in_conditional_expression(bint left):
+    """
+    >>> test_assignment_in_conditional_expression(True)
+    1.0
+    2.0
+    1.0
+    2.0
+    >>> test_assignment_in_conditional_expression(False)
+    3.0
+    4.0
+    3.0
+    4.0
+    """
+    cdef double a[2]
+    cdef double b[2]
+    a[:] = [1, 2]
+    b[:] = [3, 4]
+
+    cdef double[:] A = a
+    cdef double[:] B = b
+    cdef double[:] C, c
+
+    # assign new memoryview references
+    C = A if left else B
+
+    for i in range(C.shape[0]):
+        print C[i]
+
+    # create new memoryviews
+    c = a if left else b
+    for i in range(c.shape[0]):
+        print c[i]