Avoid going through an attribute assignment for an intermediate node result...

Avoid going through an attribute assignment for an intermediate node result since it may not be the end result.

Cython/Compiler/Nodes.py

@@ -5842,8 +5842,8 @@ class SingleAssignmentNode(AssignmentNode):
         elif self.lhs.type.is_array:
             if not isinstance(self.lhs, ExprNodes.SliceIndexNode):
                 # cannot assign to C array, only to its full slice
-                self.lhs = ExprNodes.SliceIndexNode(self.lhs.pos, base=self.lhs, start=None, stop=None)
-                self.lhs = self.lhs.analyse_target_types(env)
+                lhs = ExprNodes.SliceIndexNode(self.lhs.pos, base=self.lhs, start=None, stop=None)
+                self.lhs = lhs.analyse_target_types(env)
 
         if self.lhs.type.is_cpp_class:
             op = env.lookup_operator_for_types(self.pos, '=', [self.lhs.type, self.rhs.type])