nonecheck directive works for memoryviewslices.

Cython/Compiler/ExprNodes.py

@@ -3929,7 +3929,7 @@ class AttributeNode(ExprNode):
                 self.obj.result_as(self.obj.type),
                 rhs.result_as(self.ctype())))
         else:
-            if (self.obj.type.is_extension_type
+            if (self.obj.type.needs_nonecheck()
                   and self.needs_none_check
                   and code.globalstate.directives['nonecheck']):
                 self.put_nonecheck(code)
@@ -3978,7 +3978,13 @@ class AttributeNode(ExprNode):
 
     def put_nonecheck(self, code):
         code.globalstate.use_utility_code(raise_noneattr_error_utility_code)
-        code.putln("if (%s) {" % code.unlikely("%s == Py_None") % self.obj.result_as(PyrexTypes.py_object_type))
+        if self.obj.type.is_extension_type:
+            test = "%s == Py_None" % self.obj.result_as(PyrexTypes.py_object_type)
+        elif self.obj.type.is_memoryviewslice:
+            test = "!%s.memview" % self.obj.result()
+        else:
+            assert False
+        code.putln("if (%s) {" % code.unlikely(test))
         code.putln("__Pyx_RaiseNoneAttributeError(\"%s\");" % self.attribute)
         code.putln(code.error_goto(self.pos))
         code.putln("}")

Cython/Compiler/MemoryView.py

@@ -218,6 +218,14 @@ static int %s(const __Pyx_memviewslice mvs) {
 
     return decl, impl
 
+copy_to_template = '''
+static int %(copy_to_name)s(const __Pyx_memviewslice from_mvs, __Pyx_memviewslice to_mvs) {
+
+    /* ensure from_mvs & to_mvs have the same shape & dtype */
+
+}
+'''
+
 copy_template = '''
 static __Pyx_memviewslice %(copy_name)s(const __Pyx_memviewslice from_mvs) {
 

Cython/Compiler/PyrexTypes.py

@@ -174,6 +174,9 @@ class PyrexType(BaseType):
         # abstract
         pass
 
+    def needs_nonecheck(self):
+        return 0
+
         
 def public_decl(base_code, dll_linkage):
     if dll_linkage:
@@ -362,6 +365,9 @@ class MemoryViewSliceType(PyrexType):
         self.is_c_contig, self.is_f_contig = MemoryView.is_cf_contig(self.axes)
         assert not (self.is_c_contig and self.is_f_contig)
 
+    def needs_nonecheck(self):
+        return True
+
     def is_complete(self):
         # incomplete since the underlying struct doesn't have a cython.memoryview object.
         return 0
@@ -671,6 +677,9 @@ class PyExtensionType(PyObjectType):
     is_extension_type = 1
     has_attributes = 1
 
+    def needs_nonecheck(self):
+        return True
+
     objtypedef_cname = None
 
     def __init__(self, name, typedef_flag, base_type, is_external=0):