Issue #2335: Backport set literals syntax from Python 3.x.

7 files changed, 345 insertions, 184 deletions

diff --git a/Python/Python-ast.c b/Python/Python-ast.c
index 61e7427..4f10aa0 100644
--- a/Python/Python-ast.c
+++ b/Python/Python-ast.c
@@ -188,6 +188,10 @@ static char *Dict_fields[]={
         "keys",
         "values",
 };
+static PyTypeObject *Set_type;
+static char *Set_fields[]={
+        "elts",
+};
 static PyTypeObject *ListComp_type;
 static char *ListComp_fields[]={
         "elt",
@@ -718,6 +722,8 @@ static int init_types(void)
         if (!IfExp_type) return 0;
         Dict_type = make_type("Dict", expr_type, Dict_fields, 2);
         if (!Dict_type) return 0;
+        Set_type = make_type("Set", expr_type, Set_fields, 1);
+        if (!Set_type) return 0;
         ListComp_type = make_type("ListComp", expr_type, ListComp_fields, 2);
         if (!ListComp_type) return 0;
         GeneratorExp_type = make_type("GeneratorExp", expr_type,
@@ -1590,6 +1596,20 @@ Dict(asdl_seq * keys, asdl_seq * values, int lineno, int col_offset, PyArena
 }
 
 expr_ty
+Set(asdl_seq * elts, int lineno, int col_offset, PyArena *arena)
+{
+        expr_ty p;
+        p = (expr_ty)PyArena_Malloc(arena, sizeof(*p));
+        if (!p)
+                return NULL;
+        p->kind = Set_kind;
+        p->v.Set.elts = elts;
+        p->lineno = lineno;
+        p->col_offset = col_offset;
+        return p;
+}
+
+expr_ty
 ListComp(expr_ty elt, asdl_seq * generators, int lineno, int col_offset,
          PyArena *arena)
 {
@@ -2566,6 +2586,15 @@ ast2obj_expr(void* _o)
                         goto failed;
                 Py_DECREF(value);
                 break;
+        case Set_kind:
+                result = PyType_GenericNew(Set_type, NULL, NULL);
+                if (!result) goto failed;
+                value = ast2obj_list(o->v.Set.elts, ast2obj_expr);
+                if (!value) goto failed;
+                if (PyObject_SetAttrString(result, "elts", value) == -1)
+                        goto failed;
+                Py_DECREF(value);
+                break;
         case ListComp_kind:
                 result = PyType_GenericNew(ListComp_type, NULL, NULL);
                 if (!result) goto failed;
@@ -4860,6 +4889,42 @@ obj2ast_expr(PyObject* obj, expr_ty* out, PyArena* arena)
                 if (*out == NULL) goto failed;
                 return 0;
         }
+        isinstance = PyObject_IsInstance(obj, (PyObject*)Set_type);
+        if (isinstance == -1) {
+                return 1;
+        }
+        if (isinstance) {
+                asdl_seq* elts;
+
+                if (PyObject_HasAttrString(obj, "elts")) {
+                        int res;
+                        Py_ssize_t len;
+                        Py_ssize_t i;
+                        tmp = PyObject_GetAttrString(obj, "elts");
+                        if (tmp == NULL) goto failed;
+                        if (!PyList_Check(tmp)) {
+                                PyErr_Format(PyExc_TypeError, "Set field \"elts\" must be a list, not a %.200s", tmp->ob_type->tp_name);
+                                goto failed;
+                        }
+                        len = PyList_GET_SIZE(tmp);
+                        elts = asdl_seq_new(len, arena);
+                        if (elts == NULL) goto failed;
+                        for (i = 0; i < len; i++) {
+                                expr_ty value;
+                                res = obj2ast_expr(PyList_GET_ITEM(tmp, i), &value, arena);
+                                if (res != 0) goto failed;
+                                asdl_seq_SET(elts, i, value);
+                        }
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        PyErr_SetString(PyExc_TypeError, "required field \"elts\" missing from Set");
+                        return 1;
+                }
+                *out = Set(elts, lineno, col_offset, arena);
+                if (*out == NULL) goto failed;
+                return 0;
+        }
         isinstance = PyObject_IsInstance(obj, (PyObject*)ListComp_type);
         if (isinstance == -1) {
                 return 1;
@@ -6351,6 +6416,7 @@ init_ast(void)
             return;
         if (PyDict_SetItemString(d, "IfExp", (PyObject*)IfExp_type) < 0) return;
         if (PyDict_SetItemString(d, "Dict", (PyObject*)Dict_type) < 0) return;
+        if (PyDict_SetItemString(d, "Set", (PyObject*)Set_type) < 0) return;
         if (PyDict_SetItemString(d, "ListComp", (PyObject*)ListComp_type) < 0)
             return;
         if (PyDict_SetItemString(d, "GeneratorExp",
diff --git a/Python/ast.c b/Python/ast.c
index c8875e0..01d1f7a 100644
--- a/Python/ast.c
+++ b/Python/ast.c
@@ -1383,36 +1383,59 @@ ast_for_atom(struct compiling *c, const node *n)
         else
             return ast_for_listcomp(c, ch);
     case LBRACE: {
-        /* dictmaker: test ':' test (',' test ':' test)* [','] */
+        /* dictorsetmaker: test ':' test (',' test ':' test)* [','] |
+         *                 test (',' test)* [','])
+         */
         int i, size;
         asdl_seq *keys, *values;
-        
+
         ch = CHILD(n, 1);
-        size = (NCH(ch) + 1) / 4; /* +1 in case no trailing comma */
-        keys = asdl_seq_new(size, c->c_arena);
-        if (!keys)
-            return NULL;
-        
-        values = asdl_seq_new(size, c->c_arena);
-        if (!values)
-            return NULL;
-        
-        for (i = 0; i < NCH(ch); i += 4) {
-            expr_ty expression;
+        if (TYPE(ch) == RBRACE) {
+            /* it's an empty dict */
+            return Dict(NULL, NULL, LINENO(n), n->n_col_offset, c->c_arena);
+        } else if (NCH(ch) == 1 || TYPE(CHILD(ch, 1)) == COMMA) {
+            /* it's a simple set */
+            asdl_seq *elts;
+            size = (NCH(ch) + 1) / 2; /* +1 in case no trailing comma */
+            elts = asdl_seq_new(size, c->c_arena);
+            if (!elts)
+                return NULL;
+            for (i = 0; i < NCH(ch); i += 2) {
+                expr_ty expression;
+                expression = ast_for_expr(c, CHILD(ch, i));
+                if (!expression)
+                    return NULL;
+                asdl_seq_SET(elts, i / 2, expression);
+            }
+            return Set(elts, LINENO(n), n->n_col_offset, c->c_arena);
+        } else {
+            /* it's a dict */
+            size = (NCH(ch) + 1) / 4; /* +1 in case no trailing comma */
+            keys = asdl_seq_new(size, c->c_arena);
+            if (!keys)
+                return NULL;
             
-            expression = ast_for_expr(c, CHILD(ch, i));
-            if (!expression)
+            values = asdl_seq_new(size, c->c_arena);
+            if (!values)
                 return NULL;
+            
+            for (i = 0; i < NCH(ch); i += 4) {
+                expr_ty expression;
+                
+                expression = ast_for_expr(c, CHILD(ch, i));
+                if (!expression)
+                    return NULL;
 
-            asdl_seq_SET(keys, i / 4, expression);
+                asdl_seq_SET(keys, i / 4, expression);
 
-            expression = ast_for_expr(c, CHILD(ch, i + 2));
-            if (!expression)
-                return NULL;
+                expression = ast_for_expr(c, CHILD(ch, i + 2));
+                if (!expression)
+                    return NULL;
 
-            asdl_seq_SET(values, i / 4, expression);
+                asdl_seq_SET(values, i / 4, expression);
+            }
+            return Dict(keys, values, LINENO(n), n->n_col_offset, c->c_arena);
         }
-        return Dict(keys, values, LINENO(n), n->n_col_offset, c->c_arena);
     }
     case BACKQUOTE: { /* repr */
         expr_ty expression;
diff --git a/Python/ceval.c b/Python/ceval.c
index e5e7046..3221ab1 100644
--- a/Python/ceval.c
+++ b/Python/ceval.c
@@ -2186,6 +2186,25 @@ PyEval_EvalFrameEx(PyFrameObject *f, int throwflag)
 			}
 			break;
 
+		case BUILD_SET:
+			x = PySet_New(NULL);
+			if (x != NULL) {
+				for (; --oparg >= 0;) {
+					w = POP();
+					if (err == 0)
+						err = PySet_Add(x, w);
+					Py_DECREF(w);
+				}
+				if (err != 0) {
+					Py_DECREF(x);
+					break;
+				}
+				PUSH(x);
+				continue;
+			}
+			break;
+
+
 		case BUILD_MAP:
 			x = _PyDict_NewPresized((Py_ssize_t)oparg);
 			PUSH(x);
diff --git a/Python/compile.c b/Python/compile.c
index 03875a5..c8cab1c 100644
--- a/Python/compile.c
+++ b/Python/compile.c
@@ -808,6 +808,7 @@ opcode_stack_effect(int opcode, int oparg)
 			return 1;
 		case BUILD_TUPLE:
 		case BUILD_LIST:
+		case BUILD_SET:
 			return 1-oparg;
 		case BUILD_MAP:
 			return 1;
@@ -2894,6 +2895,11 @@ compiler_visit_expr(struct compiler *c, expr_ty e)
 			ADDOP(c, STORE_MAP);
 		}
 		break;
+	case Set_kind:
+		n = asdl_seq_LEN(e->v.Set.elts);
+		VISIT_SEQ(c, expr, e->v.Set.elts);
+		ADDOP_I(c, BUILD_SET, n);
+		break;
 	case ListComp_kind:
 		return compiler_listcomp(c, e);
 	case GeneratorExp_kind:
diff --git a/Python/graminit.c b/Python/graminit.c
index 2e3e9e8..8c8fa38 100644
--- a/Python/graminit.c
+++ b/Python/graminit.c
@@ -1548,258 +1548,298 @@ static state states_72[5] = {
 	{2, arcs_72_4},
 };
 static arc arcs_73_0[1] = {
-	{161, 1},
+	{28, 1},
+};
+static arc arcs_73_1[3] = {
+	{23, 2},
+	{29, 3},
+	{0, 1},
+};
+static arc arcs_73_2[1] = {
+	{28, 4},
+};
+static arc arcs_73_3[2] = {
+	{28, 5},
+	{0, 3},
+};
+static arc arcs_73_4[2] = {
+	{29, 6},
+	{0, 4},
+};
+static arc arcs_73_5[2] = {
+	{29, 3},
+	{0, 5},
+};
+static arc arcs_73_6[2] = {
+	{28, 7},
+	{0, 6},
+};
+static arc arcs_73_7[1] = {
+	{23, 2},
+};
+static state states_73[8] = {
+	{1, arcs_73_0},
+	{3, arcs_73_1},
+	{1, arcs_73_2},
+	{2, arcs_73_3},
+	{2, arcs_73_4},
+	{2, arcs_73_5},
+	{2, arcs_73_6},
+	{1, arcs_73_7},
 };
-static arc arcs_73_1[1] = {
+static arc arcs_74_0[1] = {
+	{162, 1},
+};
+static arc arcs_74_1[1] = {
 	{21, 2},
 };
-static arc arcs_73_2[2] = {
+static arc arcs_74_2[2] = {
 	{13, 3},
 	{23, 4},
 };
-static arc arcs_73_3[2] = {
+static arc arcs_74_3[2] = {
 	{9, 5},
 	{15, 6},
 };
-static arc arcs_73_4[1] = {
+static arc arcs_74_4[1] = {
 	{24, 7},
 };
-static arc arcs_73_5[1] = {
+static arc arcs_74_5[1] = {
 	{15, 6},
 };
-static arc arcs_73_6[1] = {
+static arc arcs_74_6[1] = {
 	{23, 4},
 };
-static arc arcs_73_7[1] = {
+static arc arcs_74_7[1] = {
 	{0, 7},
 };
-static state states_73[8] = {
-	{1, arcs_73_0},
-	{1, arcs_73_1},
-	{2, arcs_73_2},
-	{2, arcs_73_3},
-	{1, arcs_73_4},
-	{1, arcs_73_5},
-	{1, arcs_73_6},
-	{1, arcs_73_7},
+static state states_74[8] = {
+	{1, arcs_74_0},
+	{1, arcs_74_1},
+	{2, arcs_74_2},
+	{2, arcs_74_3},
+	{1, arcs_74_4},
+	{1, arcs_74_5},
+	{1, arcs_74_6},
+	{1, arcs_74_7},
 };
-static arc arcs_74_0[3] = {
-	{162, 1},
+static arc arcs_75_0[3] = {
+	{163, 1},
 	{30, 2},
 	{31, 3},
 };
-static arc arcs_74_1[2] = {
+static arc arcs_75_1[2] = {
 	{29, 4},
 	{0, 1},
 };
-static arc arcs_74_2[1] = {
+static arc arcs_75_2[1] = {
 	{28, 5},
 };
-static arc arcs_74_3[1] = {
+static arc arcs_75_3[1] = {
 	{28, 6},
 };
-static arc arcs_74_4[4] = {
-	{162, 1},
+static arc arcs_75_4[4] = {
+	{163, 1},
 	{30, 2},
 	{31, 3},
 	{0, 4},
 };
-static arc arcs_74_5[2] = {
+static arc arcs_75_5[2] = {
 	{29, 7},
 	{0, 5},
 };
-static arc arcs_74_6[1] = {
+static arc arcs_75_6[1] = {
 	{0, 6},
 };
-static arc arcs_74_7[2] = {
-	{162, 5},
+static arc arcs_75_7[2] = {
+	{163, 5},
 	{31, 3},
 };
-static state states_74[8] = {
-	{3, arcs_74_0},
-	{2, arcs_74_1},
-	{1, arcs_74_2},
-	{1, arcs_74_3},
-	{4, arcs_74_4},
-	{2, arcs_74_5},
-	{1, arcs_74_6},
-	{2, arcs_74_7},
+static state states_75[8] = {
+	{3, arcs_75_0},
+	{2, arcs_75_1},
+	{1, arcs_75_2},
+	{1, arcs_75_3},
+	{4, arcs_75_4},
+	{2, arcs_75_5},
+	{1, arcs_75_6},
+	{2, arcs_75_7},
 };
-static arc arcs_75_0[1] = {
+static arc arcs_76_0[1] = {
 	{28, 1},
 };
-static arc arcs_75_1[3] = {
+static arc arcs_76_1[3] = {
 	{157, 2},
 	{27, 3},
 	{0, 1},
 };
-static arc arcs_75_2[1] = {
+static arc arcs_76_2[1] = {
 	{0, 2},
 };
-static arc arcs_75_3[1] = {
+static arc arcs_76_3[1] = {
 	{28, 2},
 };
-static state states_75[4] = {
-	{1, arcs_75_0},
-	{3, arcs_75_1},
-	{1, arcs_75_2},
-	{1, arcs_75_3},
+static state states_76[4] = {
+	{1, arcs_76_0},
+	{3, arcs_76_1},
+	{1, arcs_76_2},
+	{1, arcs_76_3},
 };
-static arc arcs_76_0[2] = {
+static arc arcs_77_0[2] = {
 	{156, 1},
-	{164, 1},
+	{165, 1},
 };
-static arc arcs_76_1[1] = {
+static arc arcs_77_1[1] = {
 	{0, 1},
 };
-static state states_76[2] = {
-	{2, arcs_76_0},
-	{1, arcs_76_1},
+static state states_77[2] = {
+	{2, arcs_77_0},
+	{1, arcs_77_1},
 };
-static arc arcs_77_0[1] = {
+static arc arcs_78_0[1] = {
 	{96, 1},
 };
-static arc arcs_77_1[1] = {
+static arc arcs_78_1[1] = {
 	{61, 2},
 };
-static arc arcs_77_2[1] = {
+static arc arcs_78_2[1] = {
 	{85, 3},
 };
-static arc arcs_77_3[1] = {
+static arc arcs_78_3[1] = {
 	{105, 4},
 };
-static arc arcs_77_4[2] = {
-	{163, 5},
+static arc arcs_78_4[2] = {
+	{164, 5},
 	{0, 4},
 };
-static arc arcs_77_5[1] = {
+static arc arcs_78_5[1] = {
 	{0, 5},
 };
-static state states_77[6] = {
-	{1, arcs_77_0},
-	{1, arcs_77_1},
-	{1, arcs_77_2},
-	{1, arcs_77_3},
-	{2, arcs_77_4},
-	{1, arcs_77_5},
+static state states_78[6] = {
+	{1, arcs_78_0},
+	{1, arcs_78_1},
+	{1, arcs_78_2},
+	{1, arcs_78_3},
+	{2, arcs_78_4},
+	{1, arcs_78_5},
 };
-static arc arcs_78_0[1] = {
+static arc arcs_79_0[1] = {
 	{92, 1},
 };
-static arc arcs_78_1[1] = {
+static arc arcs_79_1[1] = {
 	{106, 2},
 };
-static arc arcs_78_2[2] = {
-	{163, 3},
+static arc arcs_79_2[2] = {
+	{164, 3},
 	{0, 2},
 };
-static arc arcs_78_3[1] = {
+static arc arcs_79_3[1] = {
 	{0, 3},
 };
-static state states_78[4] = {
-	{1, arcs_78_0},
-	{1, arcs_78_1},
-	{2, arcs_78_2},
-	{1, arcs_78_3},
+static state states_79[4] = {
+	{1, arcs_79_0},
+	{1, arcs_79_1},
+	{2, arcs_79_2},
+	{1, arcs_79_3},
 };
-static arc arcs_79_0[2] = {
+static arc arcs_80_0[2] = {
 	{157, 1},
-	{166, 1},
+	{167, 1},
 };
-static arc arcs_79_1[1] = {
+static arc arcs_80_1[1] = {
 	{0, 1},
 };
-static state states_79[2] = {
-	{2, arcs_79_0},
-	{1, arcs_79_1},
+static state states_80[2] = {
+	{2, arcs_80_0},
+	{1, arcs_80_1},
 };
-static arc arcs_80_0[1] = {
+static arc arcs_81_0[1] = {
 	{96, 1},
 };
-static arc arcs_80_1[1] = {
+static arc arcs_81_1[1] = {
 	{61, 2},
 };
-static arc arcs_80_2[1] = {
+static arc arcs_81_2[1] = {
 	{85, 3},
 };
-static arc arcs_80_3[1] = {
+static arc arcs_81_3[1] = {
 	{107, 4},
 };
-static arc arcs_80_4[2] = {
-	{165, 5},
+static arc arcs_81_4[2] = {
+	{166, 5},
 	{0, 4},
 };
-static arc arcs_80_5[1] = {
+static arc arcs_81_5[1] = {
 	{0, 5},
 };
-static state states_80[6] = {
-	{1, arcs_80_0},
-	{1, arcs_80_1},
-	{1, arcs_80_2},
-	{1, arcs_80_3},
-	{2, arcs_80_4},
-	{1, arcs_80_5},
+static state states_81[6] = {
+	{1, arcs_81_0},
+	{1, arcs_81_1},
+	{1, arcs_81_2},
+	{1, arcs_81_3},
+	{2, arcs_81_4},
+	{1, arcs_81_5},
 };
-static arc arcs_81_0[1] = {
+static arc arcs_82_0[1] = {
 	{92, 1},
 };
-static arc arcs_81_1[1] = {
+static arc arcs_82_1[1] = {
 	{106, 2},
 };
-static arc arcs_81_2[2] = {
-	{165, 3},
+static arc arcs_82_2[2] = {
+	{166, 3},
 	{0, 2},
 };
-static arc arcs_81_3[1] = {
+static arc arcs_82_3[1] = {
 	{0, 3},
 };
-static state states_81[4] = {
-	{1, arcs_81_0},
-	{1, arcs_81_1},
-	{2, arcs_81_2},
-	{1, arcs_81_3},
+static state states_82[4] = {
+	{1, arcs_82_0},
+	{1, arcs_82_1},
+	{2, arcs_82_2},
+	{1, arcs_82_3},
 };
-static arc arcs_82_0[1] = {
+static arc arcs_83_0[1] = {
 	{28, 1},
 };
-static arc arcs_82_1[2] = {
+static arc arcs_83_1[2] = {
 	{29, 0},
 	{0, 1},
 };
-static state states_82[2] = {
-	{1, arcs_82_0},
-	{2, arcs_82_1},
+static state states_83[2] = {
+	{1, arcs_83_0},
+	{2, arcs_83_1},
 };
-static arc arcs_83_0[1] = {
+static arc arcs_84_0[1] = {
 	{21, 1},
 };
-static arc arcs_83_1[1] = {
+static arc arcs_84_1[1] = {
 	{0, 1},
 };
-static state states_83[2] = {
-	{1, arcs_83_0},
-	{1, arcs_83_1},
+static state states_84[2] = {
+	{1, arcs_84_0},
+	{1, arcs_84_1},
 };
-static arc arcs_84_0[1] = {
-	{168, 1},
+static arc arcs_85_0[1] = {
+	{169, 1},
 };
-static arc arcs_84_1[2] = {
+static arc arcs_85_1[2] = {
 	{9, 2},
 	{0, 1},
 };
-static arc arcs_84_2[1] = {
+static arc arcs_85_2[1] = {
 	{0, 2},
 };
-static state states_84[3] = {
-	{1, arcs_84_0},
-	{2, arcs_84_1},
-	{1, arcs_84_2},
+static state states_85[3] = {
+	{1, arcs_85_0},
+	{2, arcs_85_1},
+	{1, arcs_85_2},
 };
-static dfa dfas[85] = {
+static dfa dfas[86] = {
 	{256, "single_input", 0, 3, states_0,
-	 "\004\050\060\000\000\000\000\124\360\024\114\220\023\040\010\000\200\041\044\015\002\001"},
+	 "\004\050\060\000\000\000\000\124\360\024\114\220\023\040\010\000\200\041\044\015\004\002"},
 	{257, "file_input", 0, 2, states_1,
-	 "\204\050\060\000\000\000\000\124\360\024\114\220\023\040\010\000\200\041\044\015\002\001"},
+	 "\204\050\060\000\000\000\000\124\360\024\114\220\023\040\010\000\200\041\044\015\004\002"},
 	{258, "eval_input", 0, 3, states_2,
 	 "\000\040\040\000\000\000\000\000\000\000\000\000\000\040\010\000\200\041\044\015\000\000"},
 	{259, "decorator", 0, 7, states_3,
@@ -1819,11 +1859,11 @@ static dfa dfas[85] = {
 	{266, "fplist", 0, 3, states_10,
 	 "\000\040\040\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
 	{267, "stmt", 0, 2, states_11,
-	 "\000\050\060\000\000\000\000\124\360\024\114\220\023\040\010\000\200\041\044\015\002\001"},
+	 "\000\050\060\000\000\000\000\124\360\024\114\220\023\040\010\000\200\041\044\015\004\002"},
 	{268, "simple_stmt", 0, 4, states_12,
-	 "\000\040\040\000\000\000\000\124\360\024\114\000\000\040\010\000\200\041\044\015\000\001"},
+	 "\000\040\040\000\000\000\000\124\360\024\114\000\000\040\010\000\200\041\044\015\000\002"},
 	{269, "small_stmt", 0, 2, states_13,
-	 "\000\040\040\000\000\000\000\124\360\024\114\000\000\040\010\000\200\041\044\015\000\001"},
+	 "\000\040\040\000\000\000\000\124\360\024\114\000\000\040\010\000\200\041\044\015\000\002"},
 	{270, "expr_stmt", 0, 6, states_14,
 	 "\000\040\040\000\000\000\000\000\000\000\000\000\000\040\010\000\200\041\044\015\000\000"},
 	{271, "augassign", 0, 2, states_15,
@@ -1835,7 +1875,7 @@ static dfa dfas[85] = {
 	{274, "pass_stmt", 0, 2, states_18,
 	 "\000\000\000\000\000\000\000\100\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
 	{275, "flow_stmt", 0, 2, states_19,
-	 "\000\000\000\000\000\000\000\000\360\000\000\000\000\000\000\000\000\000\000\000\000\001"},
+	 "\000\000\000\000\000\000\000\000\360\000\000\000\000\000\000\000\000\000\000\000\000\002"},
 	{276, "break_stmt", 0, 2, states_20,
 	 "\000\000\000\000\000\000\000\000\020\000\000\000\000\000\000\000\000\000\000\000\000\000"},
 	{277, "continue_stmt", 0, 2, states_21,
@@ -1843,7 +1883,7 @@ static dfa dfas[85] = {
 	{278, "return_stmt", 0, 3, states_22,
 	 "\000\000\000\000\000\000\000\000\100\000\000\000\000\000\000\000\000\000\000\000\000\000"},
 	{279, "yield_stmt", 0, 2, states_23,
-	 "\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\001"},
+	 "\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\002"},
 	{280, "raise_stmt", 0, 7, states_24,
 	 "\000\000\000\000\000\000\000\000\200\000\000\000\000\000\000\000\000\000\000\000\000\000"},
 	{281, "import_stmt", 0, 2, states_25,
@@ -1869,7 +1909,7 @@ static dfa dfas[85] = {
 	{291, "assert_stmt", 0, 5, states_35,
 	 "\000\000\000\000\000\000\000\000\000\000\100\000\000\000\000\000\000\000\000\000\000\000"},
 	{292, "compound_stmt", 0, 2, states_36,
-	 "\000\010\020\000\000\000\000\000\000\000\000\220\023\000\000\000\000\000\000\000\002\000"},
+	 "\000\010\020\000\000\000\000\000\000\000\000\220\023\000\000\000\000\000\000\000\004\000"},
 	{293, "if_stmt", 0, 8, states_37,
 	 "\000\000\000\000\000\000\000\000\000\000\000\020\000\000\000\000\000\000\000\000\000\000"},
 	{294, "while_stmt", 0, 8, states_38,
@@ -1885,7 +1925,7 @@ static dfa dfas[85] = {
 	{299, "except_clause", 0, 5, states_43,
 	 "\000\000\000\000\000\000\000\000\000\000\000\000\100\000\000\000\000\000\000\000\000\000"},
 	{300, "suite", 0, 5, states_44,
-	 "\004\040\040\000\000\000\000\124\360\024\114\000\000\040\010\000\200\041\044\015\000\001"},
+	 "\004\040\040\000\000\000\000\124\360\024\114\000\000\040\010\000\200\041\044\015\000\002"},
 	{301, "testlist_safe", 0, 5, states_45,
 	 "\000\040\040\000\000\000\000\000\000\000\000\000\000\040\010\000\200\041\044\015\000\000"},
 	{302, "old_test", 0, 2, states_46,
@@ -1942,32 +1982,34 @@ static dfa dfas[85] = {
 	 "\000\040\040\000\000\000\000\000\000\000\000\000\000\040\010\000\200\041\044\015\000\000"},
 	{328, "dictmaker", 0, 5, states_72,
 	 "\000\040\040\000\000\000\000\000\000\000\000\000\000\040\010\000\200\041\044\015\000\000"},
-	{329, "classdef", 0, 8, states_73,
-	 "\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\002\000"},
-	{330, "arglist", 0, 8, states_74,
+	{329, "dictorsetmaker", 0, 8, states_73,
+	 "\000\040\040\000\000\000\000\000\000\000\000\000\000\040\010\000\200\041\044\015\000\000"},
+	{330, "classdef", 0, 8, states_74,
+	 "\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\004\000"},
+	{331, "arglist", 0, 8, states_75,
 	 "\000\040\040\300\000\000\000\000\000\000\000\000\000\040\010\000\200\041\044\015\000\000"},
-	{331, "argument", 0, 4, states_75,
+	{332, "argument", 0, 4, states_76,
 	 "\000\040\040\000\000\000\000\000\000\000\000\000\000\040\010\000\200\041\044\015\000\000"},
-	{332, "list_iter", 0, 2, states_76,
+	{333, "list_iter", 0, 2, states_77,
 	 "\000\000\000\000\000\000\000\000\000\000\000\020\001\000\000\000\000\000\000\000\000\000"},
-	{333, "list_for", 0, 6, states_77,
+	{334, "list_for", 0, 6, states_78,
 	 "\000\000\000\000\000\000\000\000\000\000\000\000\001\000\000\000\000\000\000\000\000\000"},
-	{334, "list_if", 0, 4, states_78,
+	{335, "list_if", 0, 4, states_79,
 	 "\000\000\000\000\000\000\000\000\000\000\000\020\000\000\000\000\000\000\000\000\000\000"},
-	{335, "gen_iter", 0, 2, states_79,
+	{336, "gen_iter", 0, 2, states_80,
 	 "\000\000\000\000\000\000\000\000\000\000\000\020\001\000\000\000\000\000\000\000\000\000"},
-	{336, "gen_for", 0, 6, states_80,
+	{337, "gen_for", 0, 6, states_81,
 	 "\000\000\000\000\000\000\000\000\000\000\000\000\001\000\000\000\000\000\000\000\000\000"},
-	{337, "gen_if", 0, 4, states_81,
+	{338, "gen_if", 0, 4, states_82,
 	 "\000\000\000\000\000\000\000\000\000\000\000\020\000\000\000\000\000\000\000\000\000\000"},
-	{338, "testlist1", 0, 2, states_82,
+	{339, "testlist1", 0, 2, states_83,
 	 "\000\040\040\000\000\000\000\000\000\000\000\000\000\040\010\000\200\041\044\015\000\000"},
-	{339, "encoding_decl", 0, 2, states_83,
+	{340, "encoding_decl", 0, 2, states_84,
 	 "\000\000\040\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
-	{340, "yield_expr", 0, 3, states_84,
-	 "\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\001"},
+	{341, "yield_expr", 0, 3, states_85,
+	 "\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\002"},
 };
-static label labels[169] = {
+static label labels[170] = {
 	{0, "EMPTY"},
 	{256, 0},
 	{4, 0},
@@ -1982,11 +2024,11 @@ static label labels[169] = {
 	{50, 0},
 	{288, 0},
 	{7, 0},
-	{330, 0},
+	{331, 0},
 	{8, 0},
 	{260, 0},
 	{261, 0},
-	{329, 0},
+	{330, 0},
 	{262, 0},
 	{1, "def"},
 	{1, 0},
@@ -2013,7 +2055,7 @@ static label labels[169] = {
 	{290, 0},
 	{291, 0},
 	{271, 0},
-	{340, 0},
+	{341, 0},
 	{37, 0},
 	{38, 0},
 	{39, 0},
@@ -2118,29 +2160,30 @@ static label labels[169] = {
 	{319, 0},
 	{10, 0},
 	{26, 0},
-	{328, 0},
+	{329, 0},
 	{27, 0},
 	{25, 0},
-	{338, 0},
+	{339, 0},
 	{2, 0},
 	{3, 0},
-	{333, 0},
-	{336, 0},
+	{334, 0},
+	{337, 0},
 	{323, 0},
 	{324, 0},
 	{325, 0},
+	{328, 0},
 	{1, "class"},
-	{331, 0},
 	{332, 0},
-	{334, 0},
+	{333, 0},
 	{335, 0},
-	{337, 0},
-	{339, 0},
+	{336, 0},
+	{338, 0},
+	{340, 0},
 	{1, "yield"},
 };
 grammar _PyParser_Grammar = {
-	85,
+	86,
 	dfas,
-	{169, labels},
+	{170, labels},
 	256
 };
diff --git a/Python/import.c b/Python/import.c
index 3ca452a..3df70a8 100644
--- a/Python/import.c
+++ b/Python/import.c
@@ -75,9 +75,10 @@ typedef unsigned short mode_t;
        Python 2.7a0: 62181 (optimize conditional branches:
 			    introduce POP_JUMP_IF_FALSE and POP_JUMP_IF_TRUE)
        Python 2.7a0  62191 (introduce SETUP_WITH)
+       Python 2.7a0  62201 (introduce BUILD_SET)
 .
 */
-#define MAGIC (62191 | ((long)'\r'<<16) | ((long)'\n'<<24))
+#define MAGIC (62201 | ((long)'\r'<<16) | ((long)'\n'<<24))
 
 /* Magic word as global; note that _PyImport_Init() can change the
    value of this global to accommodate for alterations of how the
diff --git a/Python/symtable.c b/Python/symtable.c
index d782a19..5e735cc 100644
--- a/Python/symtable.c
+++ b/Python/symtable.c
@@ -1211,6 +1211,9 @@ symtable_visit_expr(struct symtable *st, expr_ty e)
 		VISIT_SEQ(st, expr, e->v.Dict.keys);
 		VISIT_SEQ(st, expr, e->v.Dict.values);
 		break;
+        case Set_kind:
+		VISIT_SEQ(st, expr, e->v.Set.elts);
+		break;
         case ListComp_kind:
 		VISIT(st, expr, e->v.ListComp.elt);
 		VISIT_SEQ(st, comprehension, e->v.ListComp.generators);