1 files changed, 28 insertions, 21 deletions

diff --git a/Python/ceval.c b/Python/ceval.c
index 032bc0c..a8abead 100644
--- a/Python/ceval.c
+++ b/Python/ceval.c
@@ -3076,6 +3076,34 @@ _PyEval_EvalFrameDefault(PyThreadState *tstate, PyFrameObject *f, int throwflag)
             goto error;
         }
 
+        case TARGET(MAKE_CELL): {
+            PyObject *initial = GETLOCAL(oparg);
+            // Normally initial would be NULL.  However, it
+            // might have been set to an initial value during
+            // a call to PyFrame_LocalsToFast().
+            PyObject *cell = PyCell_New(initial);
+            if (cell == NULL) {
+                goto error;
+            }
+            /* If it is an arg then copy the arg into the cell. */
+            if (initial == NULL && co->co_cell2arg != NULL) {
+                int argoffset = co->co_cell2arg[oparg - co->co_nlocals];
+                if (argoffset != CO_CELL_NOT_AN_ARG) {
+                    PyObject *arg = GETLOCAL(argoffset);
+                    // It will have been set in initialize_locals() but
+                    // may have been deleted PyFrame_LocalsToFast().
+                    if (arg != NULL) {;
+                        Py_INCREF(arg);
+                        PyCell_SET(cell, arg);
+                        /* Clear the local copy. */
+                        SETLOCAL(argoffset, NULL);
+                    }
+                }
+            }
+            SETLOCAL(oparg, cell);
+            DISPATCH();
+        }
+
         case TARGET(DELETE_DEREF): {
             PyObject *cell = GETLOCAL(oparg);
             PyObject *oldobj = PyCell_GET(cell);
@@ -5067,27 +5095,6 @@ initialize_locals(PyThreadState *tstate, PyFrameConstructor *con,
         }
     }
 
-
-    /* Allocate and initialize storage for cell vars, and copy free
-       vars into frame. */
-    for (i = 0; i < co->co_ncellvars; ++i) {
-        PyObject *c;
-        Py_ssize_t arg;
-        /* Possibly account for the cell variable being an argument. */
-        if (co->co_cell2arg != NULL &&
-            (arg = co->co_cell2arg[i]) != CO_CELL_NOT_AN_ARG) {
-            c = PyCell_New(GETLOCAL(arg));
-            /* Clear the local copy. */
-            SETLOCAL(arg, NULL);
-        }
-        else {
-            c = PyCell_New(NULL);
-        }
-        if (c == NULL)
-            goto fail;
-        SETLOCAL(co->co_nlocals + i, c);
-    }
-
     /* Copy closure variables to free variables */
     for (i = 0; i < co->co_nfreevars; ++i) {
         PyObject *o = PyTuple_GET_ITEM(con->fc_closure, i);