Do not cast structures, memoryview slices or complex numbers

Cython/Compiler/Nodes.py

@@ -3306,7 +3306,9 @@ class DefNodeWrapper(FuncDefNode):
         if self.signature.has_dummy_arg:
             args.append(Naming.self_cname)
         for arg in self.args:
-            if arg.hdr_type and not (arg.type.is_memoryviewslice or arg.type.is_struct):
+            if arg.hdr_type and not (arg.type.is_memoryviewslice or
+                                     arg.type.is_struct or
+                                     arg.type.is_complex):
                 args.append(arg.type.cast_code(arg.entry.cname))
             else:
                 args.append(arg.entry.cname)

Cython/Compiler/PyrexTypes.py

@@ -732,6 +732,8 @@ class MemoryViewSliceType(PyrexType):
         if dtype is not self.dtype:
             return MemoryViewSliceType(dtype, self.axes)
 
+    def cast_code(self, expr_code):
+        return expr_code
 
 
 class BufferType(BaseType):
@@ -1822,6 +1824,9 @@ class CComplexType(CNumericType):
     def py_type_name(self):
         return "complex"
 
+    def cast_code(self, expr_code):
+        return expr_code
+
 complex_ops = {
     (1, '-'): 'neg',
     (1, 'zero'): 'is_zero',
@@ -2860,6 +2865,11 @@ class CStructOrUnionType(CType):
                         for x in self.scope.var_entries]
         return max(child_depths) + 1
 
+    def cast_code(self, expr_code):
+        if self.is_struct:
+            return expr_code
+        return super(CStructOrUnionType, self).cast_code(expr_code)
+
 class CppClassType(CType):
     #  name          string
     #  cname         string