Issue #16546: merge fix from 3.3

4 files changed, 25 insertions, 23 deletions

diff --git a/Python/Python-ast.c b/Python/Python-ast.c
index 805f2b8..e6f1e58 100644
--- a/Python/Python-ast.c
+++ b/Python/Python-ast.c
@@ -1802,6 +1802,11 @@ expr_ty
 YieldFrom(expr_ty value, int lineno, int col_offset, PyArena *arena)
 {
         expr_ty p;
+        if (!value) {
+                PyErr_SetString(PyExc_ValueError,
+                                "field value is required for YieldFrom");
+                return NULL;
+        }
         p = (expr_ty)PyArena_Malloc(arena, sizeof(*p));
         if (!p)
                 return NULL;
@@ -5431,7 +5436,8 @@ obj2ast_expr(PyObject* obj, expr_ty* out, PyArena* arena)
                         Py_XDECREF(tmp);
                         tmp = NULL;
                 } else {
-                        value = NULL;
+                        PyErr_SetString(PyExc_TypeError, "required field \"value\" missing from YieldFrom");
+                        return 1;
                 }
                 *out = YieldFrom(value, lineno, col_offset, arena);
                 if (*out == NULL) goto failed;
diff --git a/Python/ast.c b/Python/ast.c
index 0c0c1a6..7657b22 100644
--- a/Python/ast.c
+++ b/Python/ast.c
@@ -224,8 +224,7 @@ validate_expr(expr_ty exp, expr_context_ty ctx)
     case Yield_kind:
         return !exp->v.Yield.value || validate_expr(exp->v.Yield.value, Load);
     case YieldFrom_kind:
-        return !exp->v.YieldFrom.value ||
-            validate_expr(exp->v.YieldFrom.value, Load);
+        return validate_expr(exp->v.YieldFrom.value, Load);
     case Compare_kind:
         if (!asdl_seq_LEN(exp->v.Compare.comparators)) {
             PyErr_SetString(PyExc_ValueError, "Compare with no comparators");
diff --git a/Python/compile.c b/Python/compile.c
index 5016f99..3cf71ef 100644
--- a/Python/compile.c
+++ b/Python/compile.c
@@ -3341,27 +3341,24 @@ compiler_visit_expr(struct compiler *c, expr_ty e)
     case DictComp_kind:
         return compiler_dictcomp(c, e);
     case Yield_kind:
-    case YieldFrom_kind: {
-        expr_ty value;
         if (c->u->u_ste->ste_type != FunctionBlock)
             return compiler_error(c, "'yield' outside function");
-        value = (e->kind == YieldFrom_kind) ? e->v.YieldFrom.value : e->v.Yield.value;
-        if (value) {
-            VISIT(c, expr, value);
+        if (e->v.Yield.value) {
+            VISIT(c, expr, e->v.Yield.value);
         }
         else {
             ADDOP_O(c, LOAD_CONST, Py_None, consts);
         }
-        if (e->kind == YieldFrom_kind) {
-            ADDOP(c, GET_ITER);
-            ADDOP_O(c, LOAD_CONST, Py_None, consts);
-            ADDOP(c, YIELD_FROM);
-        }
-        else {
-            ADDOP(c, YIELD_VALUE);
-        }
+        ADDOP(c, YIELD_VALUE);
+        break;
+    case YieldFrom_kind:
+        if (c->u->u_ste->ste_type != FunctionBlock)
+            return compiler_error(c, "'yield' outside function");
+        VISIT(c, expr, e->v.YieldFrom.value);
+        ADDOP(c, GET_ITER);
+        ADDOP_O(c, LOAD_CONST, Py_None, consts);
+        ADDOP(c, YIELD_FROM);
         break;
-    }
     case Compare_kind:
         return compiler_compare(c, e);
     case Call_kind:
diff --git a/Python/symtable.c b/Python/symtable.c
index da2c1e3..8d941f0 100644
--- a/Python/symtable.c
+++ b/Python/symtable.c
@@ -1412,14 +1412,14 @@ symtable_visit_expr(struct symtable *st, expr_ty e)
             VISIT_QUIT(st, 0);
         break;
     case Yield_kind:
-    case YieldFrom_kind: {
-        expr_ty value;
-        value = (e->kind == YieldFrom_kind) ? e->v.YieldFrom.value : e->v.Yield.value;
-        if (value)
-            VISIT(st, expr, value);
+        if (e->v.Yield.value)
+            VISIT(st, expr, e->v.Yield.value);
+        st->st_cur->ste_generator = 1;
+        break;
+    case YieldFrom_kind:
+        VISIT(st, expr, e->v.YieldFrom.value);
         st->st_cur->ste_generator = 1;
         break;
-    }
     case Compare_kind:
         VISIT(st, expr, e->v.Compare.left);
         VISIT_SEQ(st, expr, e->v.Compare.comparators);