Suppress special casing of attribute names in closure classes since they are...

Suppress special casing of attribute names in closure classes since they are not user defined and any local variable name is allowed without being special.

Closes #1797.

Cython/Compiler/ModuleNode.py

@@ -1334,11 +1334,11 @@ class ModuleNode(Nodes.Node, Nodes.BlockNode):
         is_final_type = scope.parent_type.is_final_type
         needs_gc = scope.needs_gc()
 
-        weakref_slot = scope.lookup_here("__weakref__")
+        weakref_slot = scope.lookup_here("__weakref__") if not scope.is_closure_class_scope else None
         if weakref_slot not in scope.var_entries:
             weakref_slot = None
 
-        dict_slot = scope.lookup_here("__dict__")
+        dict_slot = scope.lookup_here("__dict__") if not scope.is_closure_class_scope else None
         if dict_slot not in scope.var_entries:
             dict_slot = None
 
@@ -2800,7 +2800,7 @@ class ModuleNode(Nodes.Node, Nodes.BlockNode):
                             scope.class_name,
                             typeobj_cname,
                             code.error_goto(entry.pos)))
-                weakref_entry = scope.lookup_here("__weakref__")
+                weakref_entry = scope.lookup_here("__weakref__") if not scope.is_closure_class_scope else None
                 if weakref_entry:
                     if weakref_entry.type is py_object_type:
                         tp_weaklistoffset = "%s.tp_weaklistoffset" % typeobj_cname
@@ -2815,7 +2815,7 @@ class ModuleNode(Nodes.Node, Nodes.BlockNode):
                             weakref_entry.cname))
                     else:
                         error(weakref_entry.pos, "__weakref__ slot must be of type 'object'")
-                if scope.lookup_here("__reduce_cython__"):
+                if scope.lookup_here("__reduce_cython__") if not scope.is_closure_class_scope else None:
                     # Unfortunately, we cannot reliably detect whether a
                     # superclass defined __reduce__ at compile time, so we must
                     # do so at runtime.

Cython/Compiler/ParseTreeTransforms.py

@@ -2632,6 +2632,7 @@ class CreateClosureClasses(CythonTransform):
         func_scope.scope_class = entry
         class_scope = entry.type.scope
         class_scope.is_internal = True
+        class_scope.is_closure_class_scope = True
         if Options.closure_freelist_size:
             class_scope.directives['freelist'] = Options.closure_freelist_size
 

Cython/Compiler/Symtab.py

@@ -1917,6 +1917,7 @@ class CClassScope(ClassScope):
     #  inherited_var_entries [Entry]  Adapted var entries from base class
 
     is_c_class_scope = 1
+    is_closure_class_scope = False
 
     has_pyobject_attrs = False
     has_memoryview_attrs = False
@@ -1960,7 +1961,7 @@ class CClassScope(ClassScope):
 
         for entry in self.var_entries:
             if entry.type.is_pyobject:
-                if include_weakref or entry.name != "__weakref__":
+                if include_weakref or (self.is_closure_class_scope or entry.name != "__weakref__"):
                     if include_gc_simple or not entry.type.is_gc_simple:
                         py_attrs.append(entry)
             elif entry.type == PyrexTypes.c_py_buffer_type:
@@ -1980,7 +1981,7 @@ class CClassScope(ClassScope):
                 error(pos,
                     "C attributes cannot be added in implementation part of"
                     " extension type defined in a pxd")
-            if get_special_method_signature(name):
+            if not self.is_closure_class_scope and get_special_method_signature(name):
                 error(pos,
                     "The name '%s' is reserved for a special method."
                         % name)
@@ -1998,7 +1999,7 @@ class CClassScope(ClassScope):
                 self.has_memoryview_attrs = True
             elif type.is_cpp_class:
                 self.has_cpp_class_attrs = True
-            elif type.is_pyobject and name != '__weakref__':
+            elif type.is_pyobject and (self.is_closure_class_scope or name != '__weakref__'):
                 self.has_pyobject_attrs = True
                 if (not type.is_builtin_type
                         or not type.scope or type.scope.needs_gc()):
@@ -2011,7 +2012,7 @@ class CClassScope(ClassScope):
                 # so do conversion ourself rather than rely on the CPython mechanism (through
                 # a property; made in AnalyseDeclarationsTransform).
                 entry.needs_property = True
-                if name == "__weakref__":
+                if not self.is_closure_class_scope and name == "__weakref__":
                     error(pos, "Special attribute __weakref__ cannot be exposed to Python")
                 if not (type.is_pyobject or type.can_coerce_to_pyobject(self)):
                     # we're not testing for coercion *from* Python here - that would fail later
@@ -2056,7 +2057,7 @@ class CClassScope(ClassScope):
         return entry
 
     def lookup_here(self, name):
-        if name == "__new__":
+        if not self.is_closure_class_scope and name == "__new__":
             name = EncodedString("__cinit__")
         entry = ClassScope.lookup_here(self, name)
         if entry and entry.is_builtin_cmethod:

Cython/Compiler/TypeSlots.py

@@ -519,7 +519,7 @@ class DictOffsetSlot(SlotDescriptor):
     #  Slot descriptor for a class' dict offset, for dynamic attributes.
 
     def slot_code(self, scope):
-        dict_entry = scope.lookup_here("__dict__")
+        dict_entry = scope.lookup_here("__dict__") if not scope.is_closure_class_scope else None
         if dict_entry and dict_entry.is_variable:
             if getattr(dict_entry.type, 'cname', None) != 'PyDict_Type':
                 error(dict_entry.pos, "__dict__ slot must be of type 'dict'")

tests/run/closure_names.pyx

+# mode: run
+# tag: closures
+# ticket: gh-1797
+
+
+def func():
+    """
+    >>> funcs = func()
+    >>> [f(1) for f in funcs]
+    ['eq', 'str', 'weakref', 'new', 'dict']
+    """
+    def __eq__(a):
+        return 'eq'
+
+    def __str__(a):
+        return 'str'
+
+    def __weakref__(a):
+        return 'weakref'
+
+    def __new__(a):
+        return 'new'
+
+    def __dict__(a):
+        return 'dict'
+
+    def list_from_gen(g):
+        return list(g)
+
+    # move into closure by using inside of generator expression
+    return list_from_gen([__eq__, __str__, __weakref__, __new__, __dict__][i] for i in range(5))