From 0e2403f2f95a21912972422564de37cbe129c195 Mon Sep 17 00:00:00 2001
From: Guido van Rossum <guido@python.org>
Date: Wed, 20 Feb 2019 18:08:23 -0800
Subject: [PATCH 01/14] Work towards feature_version support

Visible behavior:

- Issue error for `X @ Y` (matrix multiply) if c_feature_version < 5

- Add optional feature_version kw arg to ast.parse() (default -1 which
  implies PY_MINOR_VERSION)

- Add feature_version: int = -1 to compile() (via Argument Clinic);
  this sets cf_feature_version to the given value if >= 0, else
  defaults to PY_MINOR_VERSION

Implementation:

- Add PyAST_obj2mod_ex(): like PyAST_obj2mod() but with feature_version arg;
  the latter calls the former with PY_MINOR_VERSION

- Add cf_feature_version to PyCompilerFlags structure;
  initialized to PY_MINOR_VERSION everywhere

- Add c_feature_version to struct compiling; initialize from
  cf_feature_version

- Add 'c' argument to get_operator()

- In builtin eval() and exec(), default to PY_MINOR_VERSION

TODO:

- Put version-dependent ASYNC/AWAIT keyword scanning back

- Reject async functions, await expressions, and async for/with in minor versions < 5

- Reject async comprehensions in minor versions < 6

- Reject underscores in numeric literals in minor versions < 6

- Reject variable annotations in minor versions < 6

- Reject `X @= Y` in minor versions < 5
---
 Include/Python-ast.h          |  1 +
 Include/compile.h             |  1 +
 Lib/ast.py                    |  9 +++++++--
 Modules/main.c                |  2 +-
 Modules/parsermodule.c        |  5 ++++-
 Parser/asdl_c.py              |  6 ++++++
 Python/Python-ast.c           |  5 +++++
 Python/ast.c                  | 14 +++++++++++---
 Python/bltinmodule.c          | 11 +++++++++--
 Python/clinic/bltinmodule.c.h | 15 ++++++++-------
 Python/compile.c              |  1 +
 Python/pythonrun.c            |  4 ++++
 12 files changed, 58 insertions(+), 16 deletions(-)

diff --git a/Include/Python-ast.h b/Include/Python-ast.h
index 52ba12755ef977..8265bed8d6e95d 100644
--- a/Include/Python-ast.h
+++ b/Include/Python-ast.h
@@ -703,6 +703,7 @@ type_ignore_ty _Py_TypeIgnore(int lineno, PyArena *arena);
 
 PyObject* PyAST_mod2obj(mod_ty t);
 mod_ty PyAST_obj2mod(PyObject* ast, PyArena* arena, int mode);
+mod_ty PyAST_obj2mod_ex(PyObject* ast, PyArena* arena, int mode, int feature_version);
 int PyAST_Check(PyObject* obj);
 
 #ifdef __cplusplus
diff --git a/Include/compile.h b/Include/compile.h
index d0bbed8f558b15..13708678675f7b 100644
--- a/Include/compile.h
+++ b/Include/compile.h
@@ -27,6 +27,7 @@ PyAPI_FUNC(PyCodeObject *) PyNode_Compile(struct _node *, const char *);
 #ifndef Py_LIMITED_API
 typedef struct {
     int cf_flags;  /* bitmask of CO_xxx flags relevant to future */
+    int cf_feature_version;  /* minor Python version (PyCF_ONLY_AST) */
 } PyCompilerFlags;
 #endif
 
diff --git a/Lib/ast.py b/Lib/ast.py
index 470a74b3b5ff79..819be1f4c3cabe 100644
--- a/Lib/ast.py
+++ b/Lib/ast.py
@@ -27,7 +27,8 @@
 from _ast import *
 
 
-def parse(source, filename='<unknown>', mode='exec', *, type_comments=False):
+def parse(source, filename='<unknown>', mode='exec', *,
+          type_comments=False, feature_version=-1):
     """
     Parse the source into an AST node.
     Equivalent to compile(source, filename, mode, PyCF_ONLY_AST).
@@ -36,7 +37,11 @@ def parse(source, filename='<unknown>', mode='exec', *, type_comments=False):
     flags = PyCF_ONLY_AST
     if type_comments:
         flags |= PyCF_TYPE_COMMENTS
-    return compile(source, filename, mode, flags)
+    return compile(source, filename, mode, flags,
+                   dont_inherit=False,
+                   optimize=-1,
+                   feature_version=feature_version,
+                   )
 
 
 def literal_eval(node_or_string):
diff --git a/Modules/main.c b/Modules/main.c
index 34032adca57eed..e30a8bd8d82cd6 100644
--- a/Modules/main.c
+++ b/Modules/main.c
@@ -821,7 +821,7 @@ pymain_run_python(PyInterpreterState *interp, int *exitcode)
         Py_DECREF(path0);
     }
 
-    PyCompilerFlags cf = {.cf_flags = 0};
+    PyCompilerFlags cf = {.cf_flags = 0, .cf_feature_version = PY_MINOR_VERSION};
 
     pymain_header(config);
     pymain_import_readline(config);
diff --git a/Modules/parsermodule.c b/Modules/parsermodule.c
index 87f58d340c2dbe..d4e2be643e7120 100644
--- a/Modules/parsermodule.c
+++ b/Modules/parsermodule.c
@@ -341,6 +341,7 @@ parser_newstobject(node *st, int type)
         o->st_node = st;
         o->st_type = type;
         o->st_flags.cf_flags = 0;
+        o->st_flags.cf_feature_version = PY_MINOR_VERSION;
     }
     else {
         PyNode_Free(st);
@@ -584,8 +585,10 @@ parser_do_parse(PyObject *args, PyObject *kw, const char *argspec, int type)
 
         if (n) {
             res = parser_newstobject(n, type);
-            if (res)
+            if (res) {
                 ((PyST_Object *)res)->st_flags.cf_flags = flags & PyCF_MASK;
+                ((PyST_Object *)res)->st_flags.cf_feature_version = PY_MINOR_VERSION;
+            }
         }
         else {
             PyParser_SetError(&err);
diff --git a/Parser/asdl_c.py b/Parser/asdl_c.py
index 1526995e3f8b55..52247559d1a937 100644
--- a/Parser/asdl_c.py
+++ b/Parser/asdl_c.py
@@ -1188,6 +1188,11 @@ class PartingShots(StaticVisitor):
 
 /* mode is 0 for "exec", 1 for "eval" and 2 for "single" input */
 mod_ty PyAST_obj2mod(PyObject* ast, PyArena* arena, int mode)
+{
+    return PyAST_obj2mod_ex(ast, arena, mode, PY_MINOR_VERSION);
+}
+
+mod_ty PyAST_obj2mod_ex(PyObject* ast, PyArena* arena, int mode, int feature_version)
 {
     mod_ty res;
     PyObject *req_type[3];
@@ -1269,6 +1274,7 @@ def main(srcfile, dump_module=False):
             f.write("\n")
             f.write("PyObject* PyAST_mod2obj(mod_ty t);\n")
             f.write("mod_ty PyAST_obj2mod(PyObject* ast, PyArena* arena, int mode);\n")
+            f.write("mod_ty PyAST_obj2mod_ex(PyObject* ast, PyArena* arena, int mode, int feature_version);\n")
             f.write("int PyAST_Check(PyObject* obj);\n")
             f.write('\n')
             f.write('#ifdef __cplusplus\n')
diff --git a/Python/Python-ast.c b/Python/Python-ast.c
index 92ec1575714485..0411f9f07f27af 100644
--- a/Python/Python-ast.c
+++ b/Python/Python-ast.c
@@ -8899,6 +8899,11 @@ PyObject* PyAST_mod2obj(mod_ty t)
 
 /* mode is 0 for "exec", 1 for "eval" and 2 for "single" input */
 mod_ty PyAST_obj2mod(PyObject* ast, PyArena* arena, int mode)
+{
+    return PyAST_obj2mod_ex(ast, arena, mode, PY_MINOR_VERSION);
+}
+
+mod_ty PyAST_obj2mod_ex(PyObject* ast, PyArena* arena, int mode, int feature_version)
 {
     mod_ty res;
     PyObject *req_type[3];
diff --git a/Python/ast.c b/Python/ast.c
index 2e960485f47c09..276e81e558786e 100644
--- a/Python/ast.c
+++ b/Python/ast.c
@@ -564,6 +564,7 @@ struct compiling {
     PyArena *c_arena; /* Arena for allocating memory. */
     PyObject *c_filename; /* filename */
     PyObject *c_normalize; /* Normalization function from unicodedata. */
+    int c_feature_version; /* Latest minor version of Python for allowed features */
 };
 
 static asdl_seq *seq_for_testlist(struct compiling *, const node *);
@@ -783,6 +784,7 @@ PyAST_FromNodeObject(const node *n, PyCompilerFlags *flags,
     /* borrowed reference */
     c.c_filename = filename;
     c.c_normalize = NULL;
+    c.c_feature_version = flags->cf_feature_version;
 
     if (TYPE(n) == encoding_decl)
         n = CHILD(n, 0);
@@ -955,7 +957,7 @@ PyAST_FromNode(const node *n, PyCompilerFlags *flags, const char *filename_str,
 */
 
 static operator_ty
-get_operator(const node *n)
+get_operator(struct compiling *c, const node *n)
 {
     switch (TYPE(n)) {
         case VBAR:
@@ -975,6 +977,11 @@ get_operator(const node *n)
         case STAR:
             return Mult;
         case AT:
+            if (c->c_feature_version < 5) {
+                ast_error(c, n,
+                        "The '@' operator is only supported in Python 3.5 and greater");
+                return (operator_ty)0;
+            }
             return MatMult;
         case SLASH:
             return Div;
@@ -2524,7 +2531,7 @@ ast_for_binop(struct compiling *c, const node *n)
     if (!expr2)
         return NULL;
 
-    newoperator = get_operator(CHILD(n, 1));
+    newoperator = get_operator(c, CHILD(n, 1));
     if (!newoperator)
         return NULL;
 
@@ -2539,7 +2546,7 @@ ast_for_binop(struct compiling *c, const node *n)
         expr_ty tmp_result, tmp;
         const node* next_oper = CHILD(n, i * 2 + 1);
 
-        newoperator = get_operator(next_oper);
+        newoperator = get_operator(c, next_oper);
         if (!newoperator)
             return NULL;
 
@@ -4768,6 +4775,7 @@ fstring_compile_expr(const char *expr_start, const char *expr_end,
     str[len+2] = 0;
 
     cf.cf_flags = PyCF_ONLY_AST;
+    cf.cf_feature_version = PY_MINOR_VERSION;
     mod_n = PyParser_SimpleParseStringFlagsFilename(str, "<fstring>",
                                                     Py_eval_input, 0);
     if (!mod_n) {
diff --git a/Python/bltinmodule.c b/Python/bltinmodule.c
index a19b8b8ddc86ce..7a2b259cbd89c8 100644
--- a/Python/bltinmodule.c
+++ b/Python/bltinmodule.c
@@ -745,6 +745,7 @@ compile as builtin_compile
     flags: int = 0
     dont_inherit: bool(accept={int}) = False
     optimize: int = -1
+    feature_version: int = -1
 
 Compile source into a code object that can be executed by exec() or eval().
 
@@ -763,8 +764,8 @@ in addition to any features explicitly specified.
 static PyObject *
 builtin_compile_impl(PyObject *module, PyObject *source, PyObject *filename,
                      const char *mode, int flags, int dont_inherit,
-                     int optimize)
-/*[clinic end generated code: output=1fa176e33452bb63 input=0ff726f595eb9fcd]*/
+                     int optimize, int feature_version)
+/*[clinic end generated code: output=b0c09c84f116d3d7 input=5fcc30651a6acaa9]*/
 {
     PyObject *source_copy;
     const char *str;
@@ -775,6 +776,10 @@ builtin_compile_impl(PyObject *module, PyObject *source, PyObject *filename,
     PyObject *result;
 
     cf.cf_flags = flags | PyCF_SOURCE_IS_UTF8;
+    cf.cf_feature_version = PY_MINOR_VERSION;
+    if (feature_version >= 0 && (flags & PyCF_ONLY_AST)) {
+        cf.cf_feature_version = feature_version;
+    }
 
     if (flags &
         ~(PyCF_MASK | PyCF_MASK_OBSOLETE | PyCF_DONT_IMPLY_DEDENT | PyCF_ONLY_AST | PyCF_TYPE_COMMENTS))
@@ -981,6 +986,7 @@ builtin_eval_impl(PyObject *module, PyObject *source, PyObject *globals,
     }
 
     cf.cf_flags = PyCF_SOURCE_IS_UTF8;
+    cf.cf_feature_version = PY_MINOR_VERSION;
     str = source_as_string(source, "eval", "string, bytes or code", &cf, &source_copy);
     if (str == NULL)
         return NULL;
@@ -1068,6 +1074,7 @@ builtin_exec_impl(PyObject *module, PyObject *source, PyObject *globals,
         const char *str;
         PyCompilerFlags cf;
         cf.cf_flags = PyCF_SOURCE_IS_UTF8;
+        cf.cf_feature_version = PY_MINOR_VERSION;
         str = source_as_string(source, "exec",
                                        "string, bytes or code", &cf,
                                        &source_copy);
diff --git a/Python/clinic/bltinmodule.c.h b/Python/clinic/bltinmodule.c.h
index 1b82f773edd8a9..df9970942b7423 100644
--- a/Python/clinic/bltinmodule.c.h
+++ b/Python/clinic/bltinmodule.c.h
@@ -151,7 +151,7 @@ builtin_chr(PyObject *module, PyObject *arg)
 
 PyDoc_STRVAR(builtin_compile__doc__,
 "compile($module, /, source, filename, mode, flags=0,\n"
-"        dont_inherit=False, optimize=-1)\n"
+"        dont_inherit=False, optimize=-1, feature_version=-1)\n"
 "--\n"
 "\n"
 "Compile source into a code object that can be executed by exec() or eval().\n"
@@ -173,26 +173,27 @@ PyDoc_STRVAR(builtin_compile__doc__,
 static PyObject *
 builtin_compile_impl(PyObject *module, PyObject *source, PyObject *filename,
                      const char *mode, int flags, int dont_inherit,
-                     int optimize);
+                     int optimize, int feature_version);
 
 static PyObject *
 builtin_compile(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject *kwnames)
 {
     PyObject *return_value = NULL;
-    static const char * const _keywords[] = {"source", "filename", "mode", "flags", "dont_inherit", "optimize", NULL};
-    static _PyArg_Parser _parser = {"OO&s|iii:compile", _keywords, 0};
+    static const char * const _keywords[] = {"source", "filename", "mode", "flags", "dont_inherit", "optimize", "feature_version", NULL};
+    static _PyArg_Parser _parser = {"OO&s|iiii:compile", _keywords, 0};
     PyObject *source;
     PyObject *filename;
     const char *mode;
     int flags = 0;
     int dont_inherit = 0;
     int optimize = -1;
+    int feature_version = -1;
 
     if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &source, PyUnicode_FSDecoder, &filename, &mode, &flags, &dont_inherit, &optimize)) {
+        &source, PyUnicode_FSDecoder, &filename, &mode, &flags, &dont_inherit, &optimize, &feature_version)) {
         goto exit;
     }
-    return_value = builtin_compile_impl(module, source, filename, mode, flags, dont_inherit, optimize);
+    return_value = builtin_compile_impl(module, source, filename, mode, flags, dont_inherit, optimize, feature_version);
 
 exit:
     return return_value;
@@ -754,4 +755,4 @@ builtin_issubclass(PyObject *module, PyObject *const *args, Py_ssize_t nargs)
 exit:
     return return_value;
 }
-/*[clinic end generated code: output=54e5e33dcc2659e0 input=a9049054013a1b77]*/
+/*[clinic end generated code: output=00b97a48ea49eaf2 input=a9049054013a1b77]*/
diff --git a/Python/compile.c b/Python/compile.c
index c26210675d8713..697833752bb0bd 100644
--- a/Python/compile.c
+++ b/Python/compile.c
@@ -330,6 +330,7 @@ PyAST_CompileObject(mod_ty mod, PyObject *filename, PyCompilerFlags *flags,
         goto finally;
     if (!flags) {
         local_flags.cf_flags = 0;
+        local_flags.cf_feature_version = PY_MINOR_VERSION;
         flags = &local_flags;
     }
     merged = c.c_future->ff_features | flags->cf_flags;
diff --git a/Python/pythonrun.c b/Python/pythonrun.c
index 906877a0a853ca..ae6778d8a58638 100644
--- a/Python/pythonrun.c
+++ b/Python/pythonrun.c
@@ -105,6 +105,7 @@ PyRun_InteractiveLoopFlags(FILE *fp, const char *filename_str, PyCompilerFlags *
     if (flags == NULL) {
         flags = &local_flags;
         local_flags.cf_flags = 0;
+        local_flags.cf_feature_version = PY_MINOR_VERSION;
     }
     v = _PySys_GetObjectId(&PyId_ps1);
     if (v == NULL) {
@@ -1165,6 +1166,7 @@ Py_SymtableStringObject(const char *str, PyObject *filename, int start)
         return NULL;
 
     flags.cf_flags = 0;
+    flags.cf_feature_version = PY_MINOR_VERSION;
     mod = PyParser_ASTFromStringObject(str, filename, start, &flags, arena);
     if (mod == NULL) {
         PyArena_Free(arena);
@@ -1204,6 +1206,7 @@ PyParser_ASTFromStringObject(const char *s, PyObject *filename, int start,
                                          &iflags);
     if (flags == NULL) {
         localflags.cf_flags = 0;
+        localflags.cf_feature_version = PY_MINOR_VERSION;
         flags = &localflags;
     }
     if (n) {
@@ -1249,6 +1252,7 @@ PyParser_ASTFromFileObject(FILE *fp, PyObject *filename, const char* enc,
                                        start, ps1, ps2, &err, &iflags);
     if (flags == NULL) {
         localflags.cf_flags = 0;
+        localflags.cf_feature_version = PY_MINOR_VERSION;
         flags = &localflags;
     }
     if (n) {

From 8caf275763a2c232d81ba0ac1900955215c99bd3 Mon Sep 17 00:00:00 2001
From: Guido van Rossum <guido@python.org>
Date: Wed, 27 Feb 2019 11:58:04 -0800
Subject: [PATCH 02/14] Implement further restrictions on feature_version

This is everything currently in typeshed except await expressions (but
it does reject async functions etc.):

    - Reject async functions and async for/with in minor versions < 5

    - Reject async comprehensions in minor versions < 6

    - Reject underscores in numeric literals in minor versions < 6

    - Reject variable annotations in minor versions < 6

    - Reject `X @= Y` in minor versions < 5
---
 Python/ast.c | 55 +++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 54 insertions(+), 1 deletion(-)

diff --git a/Python/ast.c b/Python/ast.c
index 276e81e558786e..f1b3dccfbeed01 100644
--- a/Python/ast.c
+++ b/Python/ast.c
@@ -1216,6 +1216,11 @@ ast_for_augassign(struct compiling *c, const node *n)
             else
                 return Mult;
         case '@':
+            if (c->c_feature_version < 5) {
+                ast_error(c, n,
+                        "The '@' operator is only supported in Python 3.5 and greater");
+                return (operator_ty)0;
+            }
             return MatMult;
         default:
             PyErr_Format(PyExc_SystemError, "invalid augassign: %s", STR(n));
@@ -1726,6 +1731,12 @@ ast_for_funcdef_impl(struct compiling *c, const node *n0,
     node *tc;
     string type_comment = NULL;
 
+    if (is_async && c->c_feature_version < 5) {
+        ast_error(c, n,
+                  "Async functions are only supported in Python 3.5 and greater");
+        return NULL;
+    }
+
     REQ(n, funcdef);
 
     name = NEW_IDENTIFIER(CHILD(n, name_i));
@@ -2050,6 +2061,13 @@ ast_for_comprehension(struct compiling *c, const node *n)
         }
         REQ(sync_n, sync_comp_for);
 
+        /* Async comprehensions only allowed in Python 3.6 and greater */
+        if (is_async && c->c_feature_version < 6) {
+            ast_error(c, n,
+                    "Async comprehensions are only supported in Python 3.6 and greater");
+            return NULL;
+        }
+
         for_ch = CHILD(sync_n, 1);
         t = ast_for_exprlist(c, for_ch, Store);
         if (!t)
@@ -2344,7 +2362,15 @@ ast_for_atom(struct compiling *c, const node *n)
         return str;
     }
     case NUMBER: {
-        PyObject *pynum = parsenumber(c, STR(ch));
+        PyObject *pynum;
+        /* Underscores in numeric literals are only allowed in Python 3.6 or greater */
+        /* Check for underscores here rather than in parse_number so we can report a line number on error */
+        if (c->c_feature_version < 6 && strchr(STR(ch), '_') != NULL) {
+            ast_error(c, ch,
+                    "Underscores in numeric literals are only supported in Python 3.6 and greater");
+            return NULL;
+        }
+        pynum = parsenumber(c, STR(ch));
         if (!pynum)
             return NULL;
 
@@ -3240,6 +3266,13 @@ ast_for_expr_stmt(struct compiling *c, const node *n)
         node *deep, *ann = CHILD(n, 1);
         int simple = 1;
 
+        /* AnnAssigns are only allowed in Python 3.6 or greater */
+        if (c->c_feature_version < 6) {
+            ast_error(c, ch,
+                    "Variable annotation syntax is only supported in Python 3.6 and greater");
+            return NULL;
+        }
+
         /* we keep track of parens to qualify (x) as expression not name */
         deep = ch;
         while (NCH(deep) == 1) {
@@ -4057,6 +4090,13 @@ ast_for_for_stmt(struct compiling *c, const node *n0, bool is_async)
     int end_lineno, end_col_offset;
     int has_type_comment;
     string type_comment;
+
+    if (is_async && c->c_feature_version < 5) {
+        ast_error(c, n,
+                "Async for loops are only supported in Python 3.5 and greater");
+        return NULL;
+    }
+
     /* for_stmt: 'for' exprlist 'in' testlist ':' [TYPE_COMMENT] suite ['else' ':' suite] */
     REQ(n, for_stmt);
 
@@ -4285,6 +4325,12 @@ ast_for_with_stmt(struct compiling *c, const node *n0, bool is_async)
     asdl_seq *items, *body;
     string type_comment;
 
+    if (is_async && c->c_feature_version < 5) {
+        ast_error(c, n,
+                "Async with statements are only supported in Python 3.5 and greater");
+        return NULL;
+    }
+
     REQ(n, with_stmt);
 
     has_type_comment = TYPE(CHILD(n, NCH(n) - 2)) == TYPE_COMMENT;
@@ -5576,6 +5622,13 @@ parsestr(struct compiling *c, const node *n, int *bytesmode, int *rawmode,
             }
         }
     }
+
+    /* fstrings are only allowed in Python 3.6 and greater */
+    if (fmode && c->c_feature_version < 6) {
+        ast_error(c, n, "Format strings are only supported in Python 3.6 and greater");
+        return -1;
+    }
+
     if (fmode && *bytesmode) {
         PyErr_BadInternalCall();
         return -1;

From 713d05089de6554928306378ac95a506472a4a51 Mon Sep 17 00:00:00 2001
From: Guido van Rossum <guido@python.org>
Date: Wed, 27 Feb 2019 15:14:06 -0800
Subject: [PATCH 03/14] Complete feature_version implementation (except loose
 ends)

This adds:
- Add ASYNC/AWAIT tokens back to Grammar and regenerate
- Recognize async/await keywords conditionally if feature_version < 7
- Reject await expressions if feature_version < 5
- Docs for ASYNC/AWAIT tokens and for ast.parse(..., feature_version=N)
---
 Doc/library/ast.rst        |   9 +-
 Doc/library/token-list.inc |   4 +
 Doc/library/token.rst      |   3 +
 Grammar/Grammar            |   8 +-
 Grammar/Tokens             |   2 +
 Include/parsetok.h         |   1 +
 Include/token.h            |  10 +-
 Lib/token.py               |  16 +--
 Parser/parsetok.c          |   2 +
 Parser/token.c             |   2 +
 Parser/tokenizer.c         |  79 ++++++++++++++
 Parser/tokenizer.h         |   7 ++
 Python/ast.c               |  25 ++---
 Python/graminit.c          | 210 ++++++++++++++++++-------------------
 Python/pythonrun.c         |   2 +
 15 files changed, 246 insertions(+), 134 deletions(-)

diff --git a/Doc/library/ast.rst b/Doc/library/ast.rst
index 3df7f9ebc70cc7..742238611628ce 100644
--- a/Doc/library/ast.rst
+++ b/Doc/library/ast.rst
@@ -126,7 +126,7 @@ The abstract grammar is currently defined as follows:
 Apart from the node classes, the :mod:`ast` module defines these utility functions
 and classes for traversing abstract syntax trees:
 
-.. function:: parse(source, filename='<unknown>', mode='exec', *, type_comments=False)
+.. function:: parse(source, filename='<unknown>', mode='exec', *, type_comments=False, feature_version=-1)
 
    Parse the source into an AST node.  Equivalent to ``compile(source,
    filename, mode, ast.PyCF_ONLY_AST)``.
@@ -145,13 +145,18 @@ and classes for traversing abstract syntax trees:
    modified to correspond to :pep:`484` "signature type comments",
    e.g. ``(str, int) -> List[str]``.
 
+   Also, setting ``feature_version`` to the minor version of an
+   earlier Python 3 version will attempt to parse using that version's
+   grammar.  For example, setting ``feature_version=4`` will allow
+   the use of ``async`` and ``await`` as variable names.
+
    .. warning::
       It is possible to crash the Python interpreter with a
       sufficiently large/complex string due to stack depth limitations
       in Python's AST compiler.
 
    .. versionchanged:: 3.8
-      Added ``type_comments=True`` and ``mode='func_type'``.
+      Added ``type_comments``, ``mode='func_type'`` and ``feature_version``.
 
 
 .. function:: literal_eval(node_or_string)
diff --git a/Doc/library/token-list.inc b/Doc/library/token-list.inc
index cb9fcd79effc98..877d39a432ed70 100644
--- a/Doc/library/token-list.inc
+++ b/Doc/library/token-list.inc
@@ -203,6 +203,10 @@
 
 .. data:: OP
 
+.. data:: AWAIT
+
+.. data:: ASYNC
+
 .. data:: TYPE_IGNORE
 
 .. data:: TYPE_COMMENT
diff --git a/Doc/library/token.rst b/Doc/library/token.rst
index 4936e9aa08f43d..5c641ef46d145e 100644
--- a/Doc/library/token.rst
+++ b/Doc/library/token.rst
@@ -88,3 +88,6 @@ the :mod:`tokenize` module.
 
 .. versionchanged:: 3.8
    Added :data:`TYPE_COMMENT`.
+   Added :data:`AWAIT` and :data:`ASYNC` tokens back (they're needed
+   to support parsing older Python versions for :func:`ast.parse` with
+   ``feature_version`` set to 6 or lower).
diff --git a/Grammar/Grammar b/Grammar/Grammar
index a42597805979e9..eaebdc4340f41c 100644
--- a/Grammar/Grammar
+++ b/Grammar/Grammar
@@ -18,7 +18,7 @@ decorator: '@' dotted_name [ '(' [arglist] ')' ] NEWLINE
 decorators: decorator+
 decorated: decorators (classdef | funcdef | async_funcdef)
 
-async_funcdef: 'async' funcdef
+async_funcdef: ASYNC funcdef
 funcdef: 'def' NAME parameters ['->' test] ':' [TYPE_COMMENT] func_body_suite
 
 parameters: '(' [typedargslist] ')'
@@ -70,7 +70,7 @@ nonlocal_stmt: 'nonlocal' NAME (',' NAME)*
 assert_stmt: 'assert' test [',' test]
 
 compound_stmt: if_stmt | while_stmt | for_stmt | try_stmt | with_stmt | funcdef | classdef | decorated | async_stmt
-async_stmt: 'async' (funcdef | with_stmt | for_stmt)
+async_stmt: ASYNC (funcdef | with_stmt | for_stmt)
 if_stmt: 'if' namedexpr_test ':' suite ('elif' namedexpr_test ':' suite)* ['else' ':' suite]
 while_stmt: 'while' namedexpr_test ':' suite ['else' ':' suite]
 for_stmt: 'for' exprlist 'in' testlist ':' [TYPE_COMMENT] suite ['else' ':' suite]
@@ -106,7 +106,7 @@ arith_expr: term (('+'|'-') term)*
 term: factor (('*'|'@'|'/'|'%'|'//') factor)*
 factor: ('+'|'-'|'~') factor | power
 power: atom_expr ['**' factor]
-atom_expr: ['await'] atom trailer*
+atom_expr: [AWAIT] atom trailer*
 atom: ('(' [yield_expr|testlist_comp] ')' |
        '[' [testlist_comp] ']' |
        '{' [dictorsetmaker] '}' |
@@ -144,7 +144,7 @@ argument: ( test [comp_for] |
 
 comp_iter: comp_for | comp_if
 sync_comp_for: 'for' exprlist 'in' or_test [comp_iter]
-comp_for: ['async'] sync_comp_for
+comp_for: [ASYNC] sync_comp_for
 comp_if: 'if' test_nocond [comp_iter]
 
 # not used in grammar, but may appear in "node" passed from Parser to Compiler
diff --git a/Grammar/Tokens b/Grammar/Tokens
index 1d45e05ea21ddb..9de2da5d15fc3b 100644
--- a/Grammar/Tokens
+++ b/Grammar/Tokens
@@ -55,6 +55,8 @@ ELLIPSIS                '...'
 COLONEQUAL              ':='
 
 OP
+AWAIT
+ASYNC
 TYPE_IGNORE
 TYPE_COMMENT
 ERRORTOKEN
diff --git a/Include/parsetok.h b/Include/parsetok.h
index be49f0005ac6c1..935d733e90a5af 100644
--- a/Include/parsetok.h
+++ b/Include/parsetok.h
@@ -35,6 +35,7 @@ typedef struct {
 #define PyPARSE_IGNORE_COOKIE 0x0010
 #define PyPARSE_BARRY_AS_BDFL 0x0020
 #define PyPARSE_TYPE_COMMENTS 0x0040
+#define PyPARSE_ASYNC_HACKS   0x0080
 
 PyAPI_FUNC(node *) PyParser_ParseString(const char *, grammar *, int,
                                               perrdetail *);
diff --git a/Include/token.h b/Include/token.h
index ef6bf969b7c986..e08708baf196e8 100644
--- a/Include/token.h
+++ b/Include/token.h
@@ -65,10 +65,12 @@ extern "C" {
 #define ELLIPSIS        52
 #define COLONEQUAL      53
 #define OP              54
-#define TYPE_IGNORE     55
-#define TYPE_COMMENT    56
-#define ERRORTOKEN      57
-#define N_TOKENS        61
+#define AWAIT           55
+#define ASYNC           56
+#define TYPE_IGNORE     57
+#define TYPE_COMMENT    58
+#define ERRORTOKEN      59
+#define N_TOKENS        63
 #define NT_OFFSET       256
 
 /* Special definitions for cooperation with parser */
diff --git a/Lib/token.py b/Lib/token.py
index 9bf80a5950a2b8..493bf0426508fe 100644
--- a/Lib/token.py
+++ b/Lib/token.py
@@ -58,14 +58,16 @@
 ELLIPSIS = 52
 COLONEQUAL = 53
 OP = 54
-TYPE_IGNORE = 55
-TYPE_COMMENT = 56
+AWAIT = 55
+ASYNC = 56
+TYPE_IGNORE = 57
+TYPE_COMMENT = 58
 # These aren't used by the C tokenizer but are needed for tokenize.py
-ERRORTOKEN = 57
-COMMENT = 58
-NL = 59
-ENCODING = 60
-N_TOKENS = 61
+ERRORTOKEN = 59
+COMMENT = 60
+NL = 61
+ENCODING = 62
+N_TOKENS = 63
 # Special definitions for cooperation with parser
 NT_OFFSET = 256
 
diff --git a/Parser/parsetok.c b/Parser/parsetok.c
index 7a6c8865194335..ba33a9a0586f1a 100644
--- a/Parser/parsetok.c
+++ b/Parser/parsetok.c
@@ -101,6 +101,8 @@ PyParser_ParseStringObject(const char *s, PyObject *filename,
 
     Py_INCREF(err_ret->filename);
     tok->filename = err_ret->filename;
+    if (*flags & PyPARSE_ASYNC_HACKS)
+        tok->async_hacks = 1;
     return parsetok(tok, g, start, err_ret, flags);
 }
 
diff --git a/Parser/token.c b/Parser/token.c
index 228ecffc8415ad..a489668900901d 100644
--- a/Parser/token.c
+++ b/Parser/token.c
@@ -61,6 +61,8 @@ const char * const _PyParser_TokenNames[] = {
     "ELLIPSIS",
     "COLONEQUAL",
     "OP",
+    "AWAIT",
+    "ASYNC",
     "TYPE_IGNORE",
     "TYPE_COMMENT",
     "<ERRORTOKEN>",
diff --git a/Parser/tokenizer.c b/Parser/tokenizer.c
index 44ec41512cb1e6..8f0a9c810053a9 100644
--- a/Parser/tokenizer.c
+++ b/Parser/tokenizer.c
@@ -84,6 +84,11 @@ tok_new(void)
     tok->decoding_buffer = NULL;
     tok->type_comments = 0;
 
+    tok->async_hacks = 0;
+    tok->async_def = 0;
+    tok->async_def_indent = 0;
+    tok->async_def_nl = 0;
+
     return tok;
 }
 
@@ -1196,6 +1201,31 @@ tok_get(struct tok_state *tok, char **p_start, char **p_end)
         }
     }
 
+    /* Peek ahead at the next character */
+    c = tok_nextc(tok);
+    tok_backup(tok, c);
+    /* Check if we are closing an async function */
+    if (tok->async_def
+        && !blankline
+        /* Due to some implementation artifacts of type comments,
+         * a TYPE_COMMENT at the start of a function won't set an
+         * indentation level and it will produce a NEWLINE after it.
+         * To avoid spuriously ending an async function due to this,
+         * wait until we have some non-newline char in front of us. */
+        && c != '\n'
+        && tok->level == 0
+        /* There was a NEWLINE after ASYNC DEF,
+           so we're past the signature. */
+        && tok->async_def_nl
+        /* Current indentation level is less than where
+           the async function was defined */
+        && tok->async_def_indent >= tok->indent)
+    {
+        tok->async_def = 0;
+        tok->async_def_indent = 0;
+        tok->async_def_nl = 0;
+    }
+
  again:
     tok->start = NULL;
     /* Skip spaces */
@@ -1310,6 +1340,50 @@ tok_get(struct tok_state *tok, char **p_start, char **p_end)
         *p_start = tok->start;
         *p_end = tok->cur;
 
+        /* async/await parsing block. */
+        if (tok->cur - tok->start == 5 && tok->start[0] == 'a') {
+            /* May be an 'async' or 'await' token.  For Python 3.7 or
+               later we recognize them unconditionally.  For Python
+               3.5 or 3.6 we recognize 'async' in front of 'def', and
+               either one inside of 'async def'.  (Technically we
+               shouldn't recognize these at all for 3.4 or earlier,
+               but there's no *valid* Python 3.4 code that would be
+               rejected, and async functions will be rejected in a
+               later phase.) */
+            if (!tok->async_hacks || tok->async_def) {
+                /* Always recognize the keywords. */
+                if (memcmp(tok->start, "async", 5) == 0) {
+                    return ASYNC;
+                }
+                if (memcmp(tok->start, "await", 5) == 0) {
+                    return AWAIT;
+                }
+            }
+            else if (memcmp(tok->start, "async", 5) == 0) {
+                /* The current token is 'async'.
+                   Look ahead one token to see if that is 'def'. */
+
+                struct tok_state ahead_tok;
+                char *ahead_tok_start = NULL, *ahead_tok_end = NULL;
+                int ahead_tok_kind;
+
+                memcpy(&ahead_tok, tok, sizeof(ahead_tok));
+                ahead_tok_kind = tok_get(&ahead_tok, &ahead_tok_start,
+                                         &ahead_tok_end);
+
+                if (ahead_tok_kind == NAME
+                    && ahead_tok.cur - ahead_tok.start == 3
+                    && memcmp(ahead_tok.start, "def", 3) == 0)
+                {
+                    /* The next token is going to be 'def', so instead of
+                       returning a plain NAME token, return ASYNC. */
+                    tok->async_def_indent = tok->indent;
+                    tok->async_def = 1;
+                    return ASYNC;
+                }
+            }
+        }
+
         return NAME;
     }
 
@@ -1322,6 +1396,11 @@ tok_get(struct tok_state *tok, char **p_start, char **p_end)
         *p_start = tok->start;
         *p_end = tok->cur - 1; /* Leave '\n' out of the string */
         tok->cont_line = 0;
+        if (tok->async_def) {
+            /* We're somewhere inside an 'async def' function, and
+               we've encountered a NEWLINE after its signature. */
+            tok->async_def_nl = 1;
+        }
         return NEWLINE;
     }
 
diff --git a/Parser/tokenizer.h b/Parser/tokenizer.h
index 22e91f7dca7624..06c7a14b70b061 100644
--- a/Parser/tokenizer.h
+++ b/Parser/tokenizer.h
@@ -64,6 +64,13 @@ struct tok_state {
     const char* input; /* Tokenizer's newline translated copy of the string. */
 
     int type_comments;      /* Whether to look for type comments */
+
+    /* async/await related fields (still needed depending on feature_version) */
+    int async_hacks;     /* =1 if async/await aren't always keywords */
+    int async_def;        /* =1 if tokens are inside an 'async def' body. */
+    int async_def_indent; /* Indentation level of the outermost 'async def'. */
+    int async_def_nl;     /* =1 if the outermost 'async def' had at least one
+                             NEWLINE token after it. */
 };
 
 extern struct tok_state *PyTokenizer_FromString(const char *, int);
diff --git a/Python/ast.c b/Python/ast.c
index f1b3dccfbeed01..2741926d67a78b 100644
--- a/Python/ast.c
+++ b/Python/ast.c
@@ -1790,10 +1790,9 @@ ast_for_funcdef_impl(struct compiling *c, const node *n0,
 static stmt_ty
 ast_for_async_funcdef(struct compiling *c, const node *n, asdl_seq *decorator_seq)
 {
-    /* async_funcdef: 'async' funcdef */
+    /* async_funcdef: ASYNC funcdef */
     REQ(n, async_funcdef);
-    REQ(CHILD(n, 0), NAME);
-    assert(strcmp(STR(CHILD(n, 0)), "async") == 0);
+    REQ(CHILD(n, 0), ASYNC);
     REQ(CHILD(n, 1), funcdef);
 
     return ast_for_funcdef_impl(c, n, decorator_seq,
@@ -1812,10 +1811,9 @@ ast_for_funcdef(struct compiling *c, const node *n, asdl_seq *decorator_seq)
 static stmt_ty
 ast_for_async_stmt(struct compiling *c, const node *n)
 {
-    /* async_stmt: 'async' (funcdef | with_stmt | for_stmt) */
+    /* async_stmt: ASYNC (funcdef | with_stmt | for_stmt) */
     REQ(n, async_stmt);
-    REQ(CHILD(n, 0), NAME);
-    assert(strcmp(STR(CHILD(n, 0)), "async") == 0);
+    REQ(CHILD(n, 0), ASYNC);
 
     switch (TYPE(CHILD(n, 1))) {
         case funcdef:
@@ -1966,8 +1964,7 @@ count_comp_fors(struct compiling *c, const node *n)
     n_fors++;
     REQ(n, comp_for);
     if (NCH(n) == 2) {
-        REQ(CHILD(n, 0), NAME);
-        assert(strcmp(STR(CHILD(n, 0)), "async") == 0);
+        REQ(CHILD(n, 0), ASYNC);
         n = CHILD(n, 1);
     }
     else if (NCH(n) == 1) {
@@ -2052,8 +2049,7 @@ ast_for_comprehension(struct compiling *c, const node *n)
 
         if (NCH(n) == 2) {
             is_async = 1;
-            REQ(CHILD(n, 0), NAME);
-            assert(strcmp(STR(CHILD(n, 0)), "async") == 0);
+            REQ(CHILD(n, 0), ASYNC);
             sync_n = CHILD(n, 1);
         }
         else {
@@ -2711,7 +2707,12 @@ ast_for_atom_expr(struct compiling *c, const node *n)
     REQ(n, atom_expr);
     nch = NCH(n);
 
-    if (TYPE(CHILD(n, 0)) == NAME && strcmp(STR(CHILD(n, 0)), "await") == 0) {
+    if (TYPE(CHILD(n, 0)) == AWAIT) {
+        if (c->c_feature_version < 5) {
+            ast_error(c, n,
+                    "Await expressions are only supported in Python 3.5 and greater");
+            return NULL;
+        }
         start = 1;
         assert(nch > 1);
     }
@@ -2808,7 +2809,7 @@ ast_for_expr(struct compiling *c, const node *n)
        term: factor (('*'|'@'|'/'|'%'|'//') factor)*
        factor: ('+'|'-'|'~') factor | power
        power: atom_expr ['**' factor]
-       atom_expr: ['await'] atom trailer*
+       atom_expr: [AWAIT] atom trailer*
        yield_expr: 'yield' [yield_arg]
     */
 
diff --git a/Python/graminit.c b/Python/graminit.c
index 6cb7bbc9f76ff3..24f6f6c72a6b07 100644
--- a/Python/graminit.c
+++ b/Python/graminit.c
@@ -106,7 +106,7 @@ static state states_5[3] = {
     {1, arcs_5_2},
 };
 static arc arcs_6_0[1] = {
-    {16, 1},
+    {38, 1},
 };
 static arc arcs_6_1[1] = {
     {56, 2},
@@ -120,7 +120,7 @@ static state states_6[3] = {
     {1, arcs_6_2},
 };
 static arc arcs_7_0[1] = {
-    {21, 1},
+    {19, 1},
 };
 static arc arcs_7_1[1] = {
     {40, 2},
@@ -583,7 +583,7 @@ static state states_19[2] = {
     {1, arcs_19_1},
 };
 static arc arcs_20_0[1] = {
-    {22, 1},
+    {20, 1},
 };
 static arc arcs_20_1[1] = {
     {98, 2},
@@ -597,7 +597,7 @@ static state states_20[3] = {
     {1, arcs_20_2},
 };
 static arc arcs_21_0[1] = {
-    {31, 1},
+    {29, 1},
 };
 static arc arcs_21_1[1] = {
     {0, 1},
@@ -621,7 +621,7 @@ static state states_22[2] = {
     {1, arcs_22_1},
 };
 static arc arcs_23_0[1] = {
-    {18, 1},
+    {16, 1},
 };
 static arc arcs_23_1[1] = {
     {0, 1},
@@ -631,7 +631,7 @@ static state states_23[2] = {
     {1, arcs_23_1},
 };
 static arc arcs_24_0[1] = {
-    {20, 1},
+    {18, 1},
 };
 static arc arcs_24_1[1] = {
     {0, 1},
@@ -641,7 +641,7 @@ static state states_24[2] = {
     {1, arcs_24_1},
 };
 static arc arcs_25_0[1] = {
-    {33, 1},
+    {31, 1},
 };
 static arc arcs_25_1[2] = {
     {80, 2},
@@ -666,14 +666,14 @@ static state states_26[2] = {
     {1, arcs_26_1},
 };
 static arc arcs_27_0[1] = {
-    {32, 1},
+    {30, 1},
 };
 static arc arcs_27_1[2] = {
     {60, 2},
     {0, 1},
 };
 static arc arcs_27_2[2] = {
-    {24, 3},
+    {22, 3},
     {0, 2},
 };
 static arc arcs_27_3[1] = {
@@ -701,7 +701,7 @@ static state states_28[2] = {
     {1, arcs_28_1},
 };
 static arc arcs_29_0[1] = {
-    {27, 1},
+    {25, 1},
 };
 static arc arcs_29_1[1] = {
     {106, 2},
@@ -715,7 +715,7 @@ static state states_29[3] = {
     {1, arcs_29_2},
 };
 static arc arcs_30_0[1] = {
-    {24, 1},
+    {22, 1},
 };
 static arc arcs_30_1[3] = {
     {107, 2},
@@ -725,11 +725,11 @@ static arc arcs_30_1[3] = {
 static arc arcs_30_2[4] = {
     {107, 2},
     {9, 2},
-    {27, 4},
+    {25, 4},
     {49, 3},
 };
 static arc arcs_30_3[1] = {
-    {27, 4},
+    {25, 4},
 };
 static arc arcs_30_4[3] = {
     {5, 5},
@@ -832,7 +832,7 @@ static state states_35[2] = {
     {2, arcs_35_1},
 };
 static arc arcs_36_0[1] = {
-    {25, 1},
+    {23, 1},
 };
 static arc arcs_36_1[1] = {
     {40, 2},
@@ -847,7 +847,7 @@ static state states_36[3] = {
     {2, arcs_36_2},
 };
 static arc arcs_37_0[1] = {
-    {29, 1},
+    {27, 1},
 };
 static arc arcs_37_1[1] = {
     {40, 2},
@@ -903,7 +903,7 @@ static state states_39[2] = {
     {1, arcs_39_1},
 };
 static arc arcs_40_0[1] = {
-    {16, 1},
+    {38, 1},
 };
 static arc arcs_40_1[3] = {
     {113, 2},
@@ -919,7 +919,7 @@ static state states_40[3] = {
     {1, arcs_40_2},
 };
 static arc arcs_41_0[1] = {
-    {26, 1},
+    {24, 1},
 };
 static arc arcs_41_1[1] = {
     {118, 2},
@@ -955,7 +955,7 @@ static state states_41[8] = {
     {1, arcs_41_7},
 };
 static arc arcs_42_0[1] = {
-    {35, 1},
+    {33, 1},
 };
 static arc arcs_42_1[1] = {
     {118, 2},
@@ -990,7 +990,7 @@ static state states_42[8] = {
     {1, arcs_42_7},
 };
 static arc arcs_43_0[1] = {
-    {23, 1},
+    {21, 1},
 };
 static arc arcs_43_1[1] = {
     {98, 2},
@@ -1038,7 +1038,7 @@ static state states_43[11] = {
     {1, arcs_43_10},
 };
 static arc arcs_44_0[1] = {
-    {34, 1},
+    {32, 1},
 };
 static arc arcs_44_1[1] = {
     {59, 2},
@@ -1097,7 +1097,7 @@ static state states_44[13] = {
     {2, arcs_44_12},
 };
 static arc arcs_45_0[1] = {
-    {36, 1},
+    {34, 1},
 };
 static arc arcs_45_1[1] = {
     {125, 2},
@@ -1218,7 +1218,7 @@ static arc arcs_50_1[1] = {
     {0, 1},
 };
 static arc arcs_50_2[2] = {
-    {26, 3},
+    {24, 3},
     {0, 2},
 };
 static arc arcs_50_3[1] = {
@@ -1250,7 +1250,7 @@ static state states_51[2] = {
     {1, arcs_51_1},
 };
 static arc arcs_52_0[1] = {
-    {28, 1},
+    {26, 1},
 };
 static arc arcs_52_1[2] = {
     {59, 2},
@@ -1273,7 +1273,7 @@ static state states_52[5] = {
     {1, arcs_52_4},
 };
 static arc arcs_53_0[1] = {
-    {28, 1},
+    {26, 1},
 };
 static arc arcs_53_1[2] = {
     {59, 2},
@@ -1318,7 +1318,7 @@ static state states_55[2] = {
     {2, arcs_55_1},
 };
 static arc arcs_56_0[2] = {
-    {30, 1},
+    {28, 1},
     {139, 2},
 };
 static arc arcs_56_1[1] = {
@@ -1353,13 +1353,13 @@ static arc arcs_58_0[10] = {
     {146, 1},
     {122, 1},
     {147, 2},
-    {30, 3},
+    {28, 3},
 };
 static arc arcs_58_1[1] = {
     {0, 1},
 };
 static arc arcs_58_2[2] = {
-    {30, 1},
+    {28, 1},
     {0, 2},
 };
 static arc arcs_58_3[1] = {
@@ -1460,7 +1460,7 @@ static state states_65[2] = {
 static arc arcs_66_0[4] = {
     {7, 1},
     {8, 1},
-    {39, 1},
+    {37, 1},
     {162, 2},
 };
 static arc arcs_66_1[1] = {
@@ -1494,7 +1494,7 @@ static state states_67[4] = {
     {1, arcs_67_3},
 };
 static arc arcs_68_0[2] = {
-    {17, 1},
+    {39, 1},
     {164, 2},
 };
 static arc arcs_68_1[1] = {
@@ -1516,7 +1516,7 @@ static arc arcs_69_0[10] = {
     {12, 2},
     {13, 2},
     {14, 3},
-    {38, 4},
+    {36, 4},
     {40, 2},
     {41, 2},
     {42, 5},
@@ -1788,7 +1788,7 @@ static state states_77[14] = {
     {1, arcs_77_13},
 };
 static arc arcs_78_0[1] = {
-    {19, 1},
+    {17, 1},
 };
 static arc arcs_78_1[1] = {
     {40, 2},
@@ -1874,7 +1874,7 @@ static state states_81[2] = {
     {1, arcs_81_1},
 };
 static arc arcs_82_0[1] = {
-    {23, 1},
+    {21, 1},
 };
 static arc arcs_82_1[1] = {
     {98, 2},
@@ -1901,7 +1901,7 @@ static state states_82[6] = {
     {1, arcs_82_5},
 };
 static arc arcs_83_0[2] = {
-    {16, 1},
+    {38, 1},
     {177, 2},
 };
 static arc arcs_83_1[1] = {
@@ -1916,7 +1916,7 @@ static state states_83[3] = {
     {1, arcs_83_2},
 };
 static arc arcs_84_0[1] = {
-    {26, 1},
+    {24, 1},
 };
 static arc arcs_84_1[1] = {
     {133, 2},
@@ -1945,7 +1945,7 @@ static state states_85[2] = {
     {1, arcs_85_1},
 };
 static arc arcs_86_0[1] = {
-    {37, 1},
+    {35, 1},
 };
 static arc arcs_86_1[2] = {
     {179, 2},
@@ -1960,7 +1960,7 @@ static state states_86[3] = {
     {1, arcs_86_2},
 };
 static arc arcs_87_0[2] = {
-    {24, 1},
+    {22, 1},
     {80, 2},
 };
 static arc arcs_87_1[1] = {
@@ -2115,7 +2115,7 @@ static dfa dfas[92] = {
     {257, "file_input", 0, 2, states_1,
      "\344\377\377\377\377\027\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
     {258, "eval_input", 0, 3, states_2,
-     "\240\173\002\120\300\007\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
+     "\240\173\000\024\260\007\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
     {259, "decorator", 0, 7, states_3,
      "\000\004\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
     {260, "decorators", 0, 2, states_4,
@@ -2123,9 +2123,9 @@ static dfa dfas[92] = {
     {261, "decorated", 0, 3, states_5,
      "\000\004\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
     {262, "async_funcdef", 0, 3, states_6,
-     "\000\000\001\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
+     "\000\000\000\000\100\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
     {263, "funcdef", 0, 9, states_7,
-     "\000\000\040\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
+     "\000\000\010\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
     {264, "parameters", 0, 4, states_8,
      "\040\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
     {265, "typedargslist", 0, 22, states_9,
@@ -2139,39 +2139,39 @@ static dfa dfas[92] = {
     {269, "stmt", 0, 2, states_13,
      "\340\377\377\377\377\007\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
     {270, "simple_stmt", 0, 4, states_14,
-     "\340\373\126\373\343\007\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
+     "\340\373\325\376\270\007\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
     {271, "small_stmt", 0, 2, states_15,
-     "\340\373\126\373\343\007\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
+     "\340\373\325\376\270\007\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
     {272, "expr_stmt", 0, 6, states_16,
-     "\340\173\002\120\300\007\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
+     "\340\173\000\024\260\007\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
     {273, "annassign", 0, 5, states_17,
      "\000\000\000\000\000\000\000\010\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
     {274, "testlist_star_expr", 0, 3, states_18,
-     "\340\173\002\120\300\007\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
+     "\340\173\000\024\260\007\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
     {275, "augassign", 0, 2, states_19,
      "\000\000\000\000\000\000\000\000\000\000\340\377\003\000\000\000\000\000\000\000\000\000\000"},
     {276, "del_stmt", 0, 3, states_20,
-     "\000\000\100\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
+     "\000\000\020\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
     {277, "pass_stmt", 0, 2, states_21,
-     "\000\000\000\200\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
+     "\000\000\000\040\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
     {278, "flow_stmt", 0, 2, states_22,
-     "\000\000\024\000\043\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
+     "\000\000\005\300\010\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
     {279, "break_stmt", 0, 2, states_23,
-     "\000\000\004\000\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"},
     {280, "continue_stmt", 0, 2, states_24,
-     "\000\000\020\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
+     "\000\000\004\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
     {281, "return_stmt", 0, 3, states_25,
-     "\000\000\000\000\002\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
+     "\000\000\000\200\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
     {282, "yield_stmt", 0, 2, states_26,
-     "\000\000\000\000\040\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
+     "\000\000\000\000\010\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
     {283, "raise_stmt", 0, 5, states_27,
-     "\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\100\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
     {284, "import_stmt", 0, 2, states_28,
-     "\000\000\000\011\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
+     "\000\000\100\002\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
     {285, "import_name", 0, 3, states_29,
-     "\000\000\000\010\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
+     "\000\000\000\002\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
     {286, "import_from", 0, 8, states_30,
-     "\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\100\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
     {287, "import_as_name", 0, 4, states_31,
      "\000\000\000\000\000\001\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
     {288, "dotted_as_name", 0, 4, states_32,
@@ -2183,117 +2183,117 @@ static dfa dfas[92] = {
     {291, "dotted_name", 0, 2, states_35,
      "\000\000\000\000\000\001\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
     {292, "global_stmt", 0, 3, states_36,
-     "\000\000\000\002\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
+     "\000\000\200\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
     {293, "nonlocal_stmt", 0, 3, states_37,
-     "\000\000\000\040\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
+     "\000\000\000\010\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
     {294, "assert_stmt", 0, 5, states_38,
      "\000\200\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
     {295, "compound_stmt", 0, 2, states_39,
-     "\000\004\251\004\034\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
+     "\000\004\052\001\107\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
     {296, "async_stmt", 0, 3, states_40,
-     "\000\000\001\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
+     "\000\000\000\000\100\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
     {297, "if_stmt", 0, 8, states_41,
-     "\000\000\000\004\000\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"},
     {298, "while_stmt", 0, 8, states_42,
-     "\000\000\000\000\010\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
+     "\000\000\000\000\002\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
     {299, "for_stmt", 0, 11, states_43,
-     "\000\000\200\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
+     "\000\000\040\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
     {300, "try_stmt", 0, 13, states_44,
-     "\000\000\000\000\004\000\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"},
     {301, "with_stmt", 0, 6, states_45,
-     "\000\000\000\000\020\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
+     "\000\000\000\000\004\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
     {302, "with_item", 0, 4, states_46,
-     "\240\173\002\120\300\007\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
+     "\240\173\000\024\260\007\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
     {303, "except_clause", 0, 5, states_47,
      "\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\200\000\000\000\000\000\000\000"},
     {304, "suite", 0, 5, states_48,
-     "\344\373\126\373\343\007\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
+     "\344\373\325\376\270\007\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
     {305, "namedexpr_test", 0, 4, states_49,
-     "\240\173\002\120\300\007\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
+     "\240\173\000\024\260\007\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
     {306, "test", 0, 6, states_50,
-     "\240\173\002\120\300\007\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
+     "\240\173\000\024\260\007\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
     {307, "test_nocond", 0, 2, states_51,
-     "\240\173\002\120\300\007\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
+     "\240\173\000\024\260\007\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
     {308, "lambdef", 0, 5, states_52,
-     "\000\000\000\020\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
+     "\000\000\000\004\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
     {309, "lambdef_nocond", 0, 5, states_53,
-     "\000\000\000\020\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
+     "\000\000\000\004\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
     {310, "or_test", 0, 2, states_54,
-     "\240\173\002\100\300\007\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
+     "\240\173\000\020\260\007\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
     {311, "and_test", 0, 2, states_55,
-     "\240\173\002\100\300\007\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
+     "\240\173\000\020\260\007\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
     {312, "not_test", 0, 3, states_56,
-     "\240\173\002\100\300\007\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
+     "\240\173\000\020\260\007\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
     {313, "comparison", 0, 2, states_57,
-     "\240\173\002\000\300\007\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
+     "\240\173\000\000\260\007\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
     {314, "comp_op", 0, 4, states_58,
-     "\000\000\000\100\000\000\000\000\000\000\000\000\000\000\000\004\000\340\017\000\000\000\000"},
+     "\000\000\000\020\000\000\000\000\000\000\000\000\000\000\000\004\000\340\017\000\000\000\000"},
     {315, "star_expr", 0, 3, states_59,
      "\100\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
     {316, "expr", 0, 2, states_60,
-     "\240\173\002\000\300\007\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
+     "\240\173\000\000\260\007\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
     {317, "xor_expr", 0, 2, states_61,
-     "\240\173\002\000\300\007\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
+     "\240\173\000\000\260\007\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
     {318, "and_expr", 0, 2, states_62,
-     "\240\173\002\000\300\007\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
+     "\240\173\000\000\260\007\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
     {319, "shift_expr", 0, 2, states_63,
-     "\240\173\002\000\300\007\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
+     "\240\173\000\000\260\007\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
     {320, "arith_expr", 0, 2, states_64,
-     "\240\173\002\000\300\007\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
+     "\240\173\000\000\260\007\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
     {321, "term", 0, 2, states_65,
-     "\240\173\002\000\300\007\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
+     "\240\173\000\000\260\007\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
     {322, "factor", 0, 3, states_66,
-     "\240\173\002\000\300\007\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
+     "\240\173\000\000\260\007\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
     {323, "power", 0, 4, states_67,
-     "\040\172\002\000\100\007\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
+     "\040\172\000\000\220\007\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
     {324, "atom_expr", 0, 3, states_68,
-     "\040\172\002\000\100\007\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
+     "\040\172\000\000\220\007\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
     {325, "atom", 0, 9, states_69,
-     "\040\172\000\000\100\007\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
+     "\040\172\000\000\020\007\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
     {326, "testlist_comp", 0, 5, states_70,
-     "\340\173\002\120\300\007\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
+     "\340\173\000\024\260\007\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
     {327, "trailer", 0, 7, states_71,
      "\040\100\000\000\000\000\000\000\000\000\000\000\000\010\000\000\000\000\000\000\000\000\000"},
     {328, "subscriptlist", 0, 3, states_72,
-     "\240\173\002\120\300\007\000\010\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
+     "\240\173\000\024\260\007\000\010\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
     {329, "subscript", 0, 5, states_73,
-     "\240\173\002\120\300\007\000\010\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
+     "\240\173\000\024\260\007\000\010\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
     {330, "sliceop", 0, 3, states_74,
      "\000\000\000\000\000\000\000\010\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
     {331, "exprlist", 0, 3, states_75,
-     "\340\173\002\000\300\007\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
+     "\340\173\000\000\260\007\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
     {332, "testlist", 0, 3, states_76,
-     "\240\173\002\120\300\007\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
+     "\240\173\000\024\260\007\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
     {333, "dictorsetmaker", 0, 14, states_77,
-     "\340\173\002\120\300\007\000\000\001\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
+     "\340\173\000\024\260\007\000\000\001\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
     {334, "classdef", 0, 8, states_78,
-     "\000\000\010\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
+     "\000\000\002\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
     {335, "arglist", 0, 3, states_79,
-     "\340\173\002\120\300\007\000\000\001\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
+     "\340\173\000\024\260\007\000\000\001\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
     {336, "argument", 0, 4, states_80,
-     "\340\173\002\120\300\007\000\000\001\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
+     "\340\173\000\024\260\007\000\000\001\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
     {337, "comp_iter", 0, 2, states_81,
-     "\000\000\201\004\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
+     "\000\000\040\001\100\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
     {338, "sync_comp_for", 0, 6, states_82,
-     "\000\000\200\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
+     "\000\000\040\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
     {339, "comp_for", 0, 3, states_83,
-     "\000\000\201\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
+     "\000\000\040\000\100\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
     {340, "comp_if", 0, 4, states_84,
-     "\000\000\000\004\000\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"},
     {341, "encoding_decl", 0, 2, states_85,
      "\000\000\000\000\000\001\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
     {342, "yield_expr", 0, 3, states_86,
-     "\000\000\000\000\040\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
+     "\000\000\000\000\010\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
     {343, "yield_arg", 0, 3, states_87,
-     "\340\173\002\121\300\007\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
+     "\340\173\100\024\260\007\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
     {344, "func_body_suite", 0, 7, states_88,
-     "\344\373\126\373\343\007\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
+     "\344\373\325\376\270\007\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
     {345, "func_type_input", 0, 3, states_89,
      "\040\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
     {346, "func_type", 0, 6, states_90,
      "\040\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
     {347, "typelist", 0, 11, states_91,
-     "\340\173\002\120\300\007\000\000\001\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
+     "\340\173\000\024\260\007\000\000\001\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
 };
 static label labels[183] = {
     {0, "EMPTY"},
@@ -2312,8 +2312,6 @@ static label labels[183] = {
     {1, "True"},
     {9, 0},
     {1, "assert"},
-    {1, "async"},
-    {1, "await"},
     {1, "break"},
     {1, "class"},
     {1, "continue"},
@@ -2336,6 +2334,8 @@ static label labels[183] = {
     {1, "yield"},
     {25, 0},
     {31, 0},
+    {56, 0},
+    {55, 0},
     {1, 0},
     {2, 0},
     {3, 0},
@@ -2357,7 +2357,7 @@ static label labels[183] = {
     {51, 0},
     {11, 0},
     {306, 0},
-    {56, 0},
+    {58, 0},
     {344, 0},
     {265, 0},
     {35, 0},
diff --git a/Python/pythonrun.c b/Python/pythonrun.c
index ae6778d8a58638..b763c99da01378 100644
--- a/Python/pythonrun.c
+++ b/Python/pythonrun.c
@@ -1200,6 +1200,8 @@ PyParser_ASTFromStringObject(const char *s, PyObject *filename, int start,
     PyCompilerFlags localflags;
     perrdetail err;
     int iflags = PARSER_FLAGS(flags);
+    if (flags->cf_feature_version < 7)
+        iflags |= PyPARSE_ASYNC_HACKS;
 
     node *n = PyParser_ParseStringObject(s, filename,
                                          &_PyParser_Grammar, start, &err,

From 1851eafa63415e8dd19dc2cf78d0cac84f2fd55e Mon Sep 17 00:00:00 2001
From: Guido van Rossum <guido@python.org>
Date: Wed, 27 Feb 2019 16:49:30 -0800
Subject: [PATCH 04/14] Add blurb

---
 .../2019-02-27-16-49-08.bpo-35975.IescLY.rst               | 7 +++++++
 1 file changed, 7 insertions(+)
 create mode 100644 Misc/NEWS.d/next/Core and Builtins/2019-02-27-16-49-08.bpo-35975.IescLY.rst

diff --git a/Misc/NEWS.d/next/Core and Builtins/2019-02-27-16-49-08.bpo-35975.IescLY.rst b/Misc/NEWS.d/next/Core and Builtins/2019-02-27-16-49-08.bpo-35975.IescLY.rst
new file mode 100644
index 00000000000000..3bbfc74469c902
--- /dev/null
+++ b/Misc/NEWS.d/next/Core and Builtins/2019-02-27-16-49-08.bpo-35975.IescLY.rst	
@@ -0,0 +1,7 @@
+Add a ``feature_version`` flag to ``ast.parse()`` (documented) and
+``compile()`` (hidden) that allows tweaking the parser to support older
+versions of the grammar. In particular, if ``feature_version`` is 5 or 6,
+the hacks for the ``async`` and ``await`` keyword from PEP 492 are
+reinstated. (For 7 or higher, these are unconditionally treated as keywords,
+but they are still special tokens rather than ``NAME`` tokens that the
+parser driver recognizes.)

From 00fdd08bc1160510d8ed3d7a2d82bdd88e148a47 Mon Sep 17 00:00:00 2001
From: Guido van Rossum <guido@python.org>
Date: Wed, 27 Feb 2019 17:04:28 -0800
Subject: [PATCH 05/14] Check flags isn't NULL before dereferencing (this broke
 regen-importlib)

---
 Python/pythonrun.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Python/pythonrun.c b/Python/pythonrun.c
index b763c99da01378..199ea82434e9e7 100644
--- a/Python/pythonrun.c
+++ b/Python/pythonrun.c
@@ -1200,7 +1200,7 @@ PyParser_ASTFromStringObject(const char *s, PyObject *filename, int start,
     PyCompilerFlags localflags;
     perrdetail err;
     int iflags = PARSER_FLAGS(flags);
-    if (flags->cf_feature_version < 7)
+    if (flags && flags->cf_feature_version < 7)
         iflags |= PyPARSE_ASYNC_HACKS;
 
     node *n = PyParser_ParseStringObject(s, filename,

From 543ab7597db93cdbf3e347552675df0e3c54e9dd Mon Sep 17 00:00:00 2001
From: Guido van Rossum <guido@python.org>
Date: Wed, 27 Feb 2019 20:07:02 -0800
Subject: [PATCH 06/14] 'async' and 'await' are no longer plain keywords -- fix
 test_keyword.py

---
 Lib/keyword.py | 2 --
 1 file changed, 2 deletions(-)

diff --git a/Lib/keyword.py b/Lib/keyword.py
index 431991dcf4ace6..6e1e882a91e700 100755
--- a/Lib/keyword.py
+++ b/Lib/keyword.py
@@ -20,8 +20,6 @@
         'and',
         'as',
         'assert',
-        'async',
-        'await',
         'break',
         'class',
         'continue',

From 9f4cb2392439243c94caa76614b1330ed2357334 Mon Sep 17 00:00:00 2001
From: Guido van Rossum <guido@python.org>
Date: Wed, 27 Feb 2019 22:06:18 -0800
Subject: [PATCH 07/14] Fix test_parser.py

The PyST_Object header in parsermodule.c became one int larger
because it contains a PyCompilerFlags struct, which grew extra
space for the st_feature_version field.  Took me long enough!
---
 Lib/test/test_parser.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Lib/test/test_parser.py b/Lib/test/test_parser.py
index 0afeb322e9b511..5548a871c0244f 100644
--- a/Lib/test/test_parser.py
+++ b/Lib/test/test_parser.py
@@ -916,7 +916,7 @@ def XXXROUNDUP(n):
                 return (n + 3) & ~3
             return 1 << (n - 1).bit_length()
 
-        basesize = support.calcobjsize('Pii')
+        basesize = support.calcobjsize('Piii')
         nodesize = struct.calcsize('hP3iP0h2i')
         def sizeofchildren(node):
             if node is None:

From 855e07bc6624ee75132edac153da3912220e88fe Mon Sep 17 00:00:00 2001
From: Guido van Rossum <guido@python.org>
Date: Thu, 28 Feb 2019 07:46:22 -0800
Subject: [PATCH 08/14] Manually add async and await to kwlist in keywords.py,
 since they are not regular keywords

---
 Lib/keyword.py | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/Lib/keyword.py b/Lib/keyword.py
index 6e1e882a91e700..150c2bc46d229c 100755
--- a/Lib/keyword.py
+++ b/Lib/keyword.py
@@ -50,6 +50,10 @@
 #--end keywords--
         ]
 
+kwlist.append('async')
+kwlist.append('await')
+kwlist.sort()
+
 iskeyword = frozenset(kwlist).__contains__
 
 def main():

From ee95fef4b76a1d088cc717673130d992344282bf Mon Sep 17 00:00:00 2001
From: Guido van Rossum <guido@python.org>
Date: Tue, 5 Mar 2019 11:31:52 -0800
Subject: [PATCH 09/14] Simplify compile() call in ast.parse()

---
 Lib/ast.py | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/Lib/ast.py b/Lib/ast.py
index 819be1f4c3cabe..64e7a2551fb1aa 100644
--- a/Lib/ast.py
+++ b/Lib/ast.py
@@ -38,10 +38,7 @@ def parse(source, filename='<unknown>', mode='exec', *,
     if type_comments:
         flags |= PyCF_TYPE_COMMENTS
     return compile(source, filename, mode, flags,
-                   dont_inherit=False,
-                   optimize=-1,
-                   feature_version=feature_version,
-                   )
+                   feature_version=feature_version)
 
 
 def literal_eval(node_or_string):

From ae36b7b34f8f672fc5f06e60930cf199584b18ff Mon Sep 17 00:00:00 2001
From: Guido van Rossum <guido@python.org>
Date: Tue, 5 Mar 2019 11:35:21 -0800
Subject: [PATCH 10/14] Fix indentation of many ast_error() calls

---
 Python/ast.c | 22 +++++++++++-----------
 1 file changed, 11 insertions(+), 11 deletions(-)

diff --git a/Python/ast.c b/Python/ast.c
index 2741926d67a78b..d4ee1b351fe16f 100644
--- a/Python/ast.c
+++ b/Python/ast.c
@@ -979,7 +979,7 @@ get_operator(struct compiling *c, const node *n)
         case AT:
             if (c->c_feature_version < 5) {
                 ast_error(c, n,
-                        "The '@' operator is only supported in Python 3.5 and greater");
+                          "The '@' operator is only supported in Python 3.5 and greater");
                 return (operator_ty)0;
             }
             return MatMult;
@@ -1218,7 +1218,7 @@ ast_for_augassign(struct compiling *c, const node *n)
         case '@':
             if (c->c_feature_version < 5) {
                 ast_error(c, n,
-                        "The '@' operator is only supported in Python 3.5 and greater");
+                          "The '@' operator is only supported in Python 3.5 and greater");
                 return (operator_ty)0;
             }
             return MatMult;
@@ -1530,7 +1530,7 @@ ast_for_arguments(struct compiling *c, const node *n)
                 }
                 else if (found_default) {
                     ast_error(c, n,
-                             "non-default argument follows default argument");
+                              "non-default argument follows default argument");
                     return NULL;
                 }
                 arg = ast_for_arg(c, ch);
@@ -2060,7 +2060,7 @@ ast_for_comprehension(struct compiling *c, const node *n)
         /* Async comprehensions only allowed in Python 3.6 and greater */
         if (is_async && c->c_feature_version < 6) {
             ast_error(c, n,
-                    "Async comprehensions are only supported in Python 3.6 and greater");
+                      "Async comprehensions are only supported in Python 3.6 and greater");
             return NULL;
         }
 
@@ -2363,7 +2363,7 @@ ast_for_atom(struct compiling *c, const node *n)
         /* Check for underscores here rather than in parse_number so we can report a line number on error */
         if (c->c_feature_version < 6 && strchr(STR(ch), '_') != NULL) {
             ast_error(c, ch,
-                    "Underscores in numeric literals are only supported in Python 3.6 and greater");
+                      "Underscores in numeric literals are only supported in Python 3.6 and greater");
             return NULL;
         }
         pynum = parsenumber(c, STR(ch));
@@ -2449,8 +2449,8 @@ ast_for_atom(struct compiling *c, const node *n)
                     TYPE(CHILD(ch, 3 - is_dict)) == comp_for) {
                 /* It's a dictionary comprehension. */
                 if (is_dict) {
-                    ast_error(c, n, "dict unpacking cannot be used in "
-                              "dict comprehension");
+                    ast_error(c, n,
+                              "dict unpacking cannot be used in dict comprehension");
                     return NULL;
                 }
                 res = ast_for_dictcomp(c, ch);
@@ -2710,7 +2710,7 @@ ast_for_atom_expr(struct compiling *c, const node *n)
     if (TYPE(CHILD(n, 0)) == AWAIT) {
         if (c->c_feature_version < 5) {
             ast_error(c, n,
-                    "Await expressions are only supported in Python 3.5 and greater");
+                      "Await expressions are only supported in Python 3.5 and greater");
             return NULL;
         }
         start = 1;
@@ -3270,7 +3270,7 @@ ast_for_expr_stmt(struct compiling *c, const node *n)
         /* AnnAssigns are only allowed in Python 3.6 or greater */
         if (c->c_feature_version < 6) {
             ast_error(c, ch,
-                    "Variable annotation syntax is only supported in Python 3.6 and greater");
+                      "Variable annotation syntax is only supported in Python 3.6 and greater");
             return NULL;
         }
 
@@ -4094,7 +4094,7 @@ ast_for_for_stmt(struct compiling *c, const node *n0, bool is_async)
 
     if (is_async && c->c_feature_version < 5) {
         ast_error(c, n,
-                "Async for loops are only supported in Python 3.5 and greater");
+                  "Async for loops are only supported in Python 3.5 and greater");
         return NULL;
     }
 
@@ -4328,7 +4328,7 @@ ast_for_with_stmt(struct compiling *c, const node *n0, bool is_async)
 
     if (is_async && c->c_feature_version < 5) {
         ast_error(c, n,
-                "Async with statements are only supported in Python 3.5 and greater");
+                  "Async with statements are only supported in Python 3.5 and greater");
         return NULL;
     }
 

From bae211cdf25930afa729c75e679a996053ed0105 Mon Sep 17 00:00:00 2001
From: Guido van Rossum <guido@python.org>
Date: Tue, 5 Mar 2019 15:19:28 -0800
Subject: [PATCH 11/14] Add tests for feature_version

---
 Lib/test/test_type_comments.py | 135 +++++++++++++++++++++++----------
 1 file changed, 94 insertions(+), 41 deletions(-)

diff --git a/Lib/test/test_type_comments.py b/Lib/test/test_type_comments.py
index 3065ddca2d9ab2..f0ae4ff9d9c3a6 100644
--- a/Lib/test/test_type_comments.py
+++ b/Lib/test/test_type_comments.py
@@ -1,4 +1,5 @@
 import ast
+import sys
 import unittest
 
 
@@ -20,6 +21,25 @@ async def bar():  # type: () -> int
     return await bar()
 """
 
+asyncvar = """\
+async = 12
+await = 13
+"""
+
+asynccomp = """\
+async def foo(xs):
+    [x async for x in xs]
+"""
+
+matmul = """\
+a = b @ c
+"""
+
+fstring = """\
+a = 42
+f"{a}"
+"""
+
 redundantdef = """\
 def foo():  # type: () -> int
     # type: () -> str
@@ -155,80 +175,113 @@ def favk(
 
 class TypeCommentTests(unittest.TestCase):
 
-    def parse(self, source):
-        return ast.parse(source, type_comments=True)
+    lowest = 4  # Lowest minor version supported
+    highest = sys.version_info[1]  # Highest minor version
+
+    def parse(self, source, feature_version=highest):
+        return ast.parse(source, type_comments=True,
+                         feature_version=feature_version)
+
+    def parses(self, source, minver=lowest, maxver=highest, expected_regex=""):
+        for feature_version in range(self.lowest, self.highest + 1):
+            if minver <= feature_version <= maxver:
+                try:
+                    yield self.parse(source, feature_version)
+                except SyntaxError as err:
+                    raise SyntaxError(str(err) + f" feature_version={feature_version}")
+            else:
+                with self.assertRaisesRegex(SyntaxError, expected_regex,
+                                            msg=f"feature_version={feature_version}"):
+                    self.parse(source, feature_version)
 
     def classic_parse(self, source):
         return ast.parse(source)
 
     def test_funcdef(self):
-        tree = self.parse(funcdef)
-        self.assertEqual(tree.body[0].type_comment, "() -> int")
-        self.assertEqual(tree.body[1].type_comment, "() -> None")
+        for tree in self.parses(funcdef):
+            self.assertEqual(tree.body[0].type_comment, "() -> int")
+            self.assertEqual(tree.body[1].type_comment, "() -> None")
         tree = self.classic_parse(funcdef)
         self.assertEqual(tree.body[0].type_comment, None)
         self.assertEqual(tree.body[1].type_comment, None)
 
     def test_asyncdef(self):
-        tree = self.parse(asyncdef)
-        self.assertEqual(tree.body[0].type_comment, "() -> int")
-        self.assertEqual(tree.body[1].type_comment, "() -> int")
+        for tree in self.parses(asyncdef, minver=5):
+            self.assertEqual(tree.body[0].type_comment, "() -> int")
+            self.assertEqual(tree.body[1].type_comment, "() -> int")
         tree = self.classic_parse(asyncdef)
         self.assertEqual(tree.body[0].type_comment, None)
         self.assertEqual(tree.body[1].type_comment, None)
 
+    def test_asyncvar(self):
+        for tree in self.parses(asyncvar, maxver=6):
+            pass
+
+    def test_asynccomp(self):
+        for tree in self.parses(asynccomp, minver=6):
+            pass
+
+    def test_matmul(self):
+        for tree in self.parses(matmul, minver=5):
+            pass
+
+    def test_fstring(self):
+        for tree in self.parses(fstring, minver=6):
+            pass
+
     def test_redundantdef(self):
-        with self.assertRaisesRegex(SyntaxError, "^Cannot have two type comments on def"):
-            tree = self.parse(redundantdef)
+        for tree in self.parses(redundantdef, maxver=0,
+                                expected_regex="^Cannot have two type comments on def"):
+            pass
 
     def test_nonasciidef(self):
-        tree = self.parse(nonasciidef)
-        self.assertEqual(tree.body[0].type_comment, "() -> àçčéñt")
+        for tree in self.parses(nonasciidef):
+            self.assertEqual(tree.body[0].type_comment, "() -> àçčéñt")
 
     def test_forstmt(self):
-        tree = self.parse(forstmt)
-        self.assertEqual(tree.body[0].type_comment, "int")
+        for tree in self.parses(forstmt):
+            self.assertEqual(tree.body[0].type_comment, "int")
         tree = self.classic_parse(forstmt)
         self.assertEqual(tree.body[0].type_comment, None)
 
     def test_withstmt(self):
-        tree = self.parse(withstmt)
-        self.assertEqual(tree.body[0].type_comment, "int")
+        for tree in self.parses(withstmt):
+            self.assertEqual(tree.body[0].type_comment, "int")
         tree = self.classic_parse(withstmt)
         self.assertEqual(tree.body[0].type_comment, None)
 
     def test_vardecl(self):
-        tree = self.parse(vardecl)
-        self.assertEqual(tree.body[0].type_comment, "int")
+        for tree in self.parses(vardecl):
+            self.assertEqual(tree.body[0].type_comment, "int")
         tree = self.classic_parse(vardecl)
         self.assertEqual(tree.body[0].type_comment, None)
 
     def test_ignores(self):
-        tree = self.parse(ignores)
-        self.assertEqual([ti.lineno for ti in tree.type_ignores], [2, 5])
+        for tree in self.parses(ignores):
+            self.assertEqual([ti.lineno for ti in tree.type_ignores], [2, 5])
         tree = self.classic_parse(ignores)
         self.assertEqual(tree.type_ignores, [])
 
     def test_longargs(self):
-        tree = self.parse(longargs)
-        for t in tree.body:
-            # The expected args are encoded in the function name
-            todo = set(t.name[1:])
-            self.assertEqual(len(t.args.args),
-                             len(todo) - bool(t.args.vararg) - bool(t.args.kwarg))
-            self.assertTrue(t.name.startswith('f'), t.name)
-            for c in t.name[1:]:
-                todo.remove(c)
-                if c == 'v':
-                    arg = t.args.vararg
-                elif c == 'k':
-                    arg = t.args.kwarg
-                else:
-                    assert 0 <= ord(c) - ord('a') < len(t.args.args)
-                    arg = t.args.args[ord(c) - ord('a')]
-                self.assertEqual(arg.arg, c)  # That's the argument name
-                self.assertEqual(arg.type_comment, arg.arg.upper())
-            assert not todo
+        for tree in self.parses(longargs):
+            for t in tree.body:
+                # The expected args are encoded in the function name
+                todo = set(t.name[1:])
+                self.assertEqual(len(t.args.args),
+                                 len(todo) - bool(t.args.vararg) - bool(t.args.kwarg))
+                self.assertTrue(t.name.startswith('f'), t.name)
+                for c in t.name[1:]:
+                    todo.remove(c)
+                    if c == 'v':
+                        arg = t.args.vararg
+                    elif c == 'k':
+                        arg = t.args.kwarg
+                    else:
+                        assert 0 <= ord(c) - ord('a') < len(t.args.args)
+                        arg = t.args.args[ord(c) - ord('a')]
+                    self.assertEqual(arg.arg, c)  # That's the argument name
+                    self.assertEqual(arg.type_comment, arg.arg.upper())
+                assert not todo
         tree = self.classic_parse(longargs)
         for t in tree.body:
             for arg in t.args.args + [t.args.vararg, t.args.kwarg]:
@@ -247,8 +300,8 @@ def test_inappropriate_type_comments(self):
 
         def check_both_ways(source):
             ast.parse(source, type_comments=False)
-            with self.assertRaises(SyntaxError):
-                ast.parse(source, type_comments=True)
+            for tree in self.parses(source, maxver=0):
+                pass
 
         check_both_ways("pass  # type: int\n")
         check_both_ways("foo()  # type: int\n")

From dbb08ccc4bc34618a49582d7247ee4b75c5cccd2 Mon Sep 17 00:00:00 2001
From: Guido van Rossum <guido@python.org>
Date: Thu, 7 Mar 2019 12:06:36 -0800
Subject: [PATCH 12/14] Clarify range of feature_version in docs.

---
 Doc/library/ast.rst | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/Doc/library/ast.rst b/Doc/library/ast.rst
index 742238611628ce..1884bea80e8047 100644
--- a/Doc/library/ast.rst
+++ b/Doc/library/ast.rst
@@ -148,7 +148,8 @@ and classes for traversing abstract syntax trees:
    Also, setting ``feature_version`` to the minor version of an
    earlier Python 3 version will attempt to parse using that version's
    grammar.  For example, setting ``feature_version=4`` will allow
-   the use of ``async`` and ``await`` as variable names.
+   the use of ``async`` and ``await`` as variable names.  The lowest
+   supported value is 4; the highest is ``sys.version_info[1]``.
 
    .. warning::
       It is possible to crash the Python interpreter with a

From c8c84f44b66b087eadde48f9b2e033bf289cf353 Mon Sep 17 00:00:00 2001
From: Guido van Rossum <guido@python.org>
Date: Thu, 7 Mar 2019 12:08:15 -0800
Subject: [PATCH 13/14] Rename parses() to parse_all()

---
 Lib/test/test_type_comments.py | 30 +++++++++++++++---------------
 1 file changed, 15 insertions(+), 15 deletions(-)

diff --git a/Lib/test/test_type_comments.py b/Lib/test/test_type_comments.py
index f0ae4ff9d9c3a6..7f71ee851d408b 100644
--- a/Lib/test/test_type_comments.py
+++ b/Lib/test/test_type_comments.py
@@ -182,7 +182,7 @@ def parse(self, source, feature_version=highest):
         return ast.parse(source, type_comments=True,
                          feature_version=feature_version)
 
-    def parses(self, source, minver=lowest, maxver=highest, expected_regex=""):
+    def parse_all(self, source, minver=lowest, maxver=highest, expected_regex=""):
         for feature_version in range(self.lowest, self.highest + 1):
             if minver <= feature_version <= maxver:
                 try:
@@ -198,7 +198,7 @@ def classic_parse(self, source):
         return ast.parse(source)
 
     def test_funcdef(self):
-        for tree in self.parses(funcdef):
+        for tree in self.parse_all(funcdef):
             self.assertEqual(tree.body[0].type_comment, "() -> int")
             self.assertEqual(tree.body[1].type_comment, "() -> None")
         tree = self.classic_parse(funcdef)
@@ -206,7 +206,7 @@ def test_funcdef(self):
         self.assertEqual(tree.body[1].type_comment, None)
 
     def test_asyncdef(self):
-        for tree in self.parses(asyncdef, minver=5):
+        for tree in self.parse_all(asyncdef, minver=5):
             self.assertEqual(tree.body[0].type_comment, "() -> int")
             self.assertEqual(tree.body[1].type_comment, "() -> int")
         tree = self.classic_parse(asyncdef)
@@ -214,56 +214,56 @@ def test_asyncdef(self):
         self.assertEqual(tree.body[1].type_comment, None)
 
     def test_asyncvar(self):
-        for tree in self.parses(asyncvar, maxver=6):
+        for tree in self.parse_all(asyncvar, maxver=6):
             pass
 
     def test_asynccomp(self):
-        for tree in self.parses(asynccomp, minver=6):
+        for tree in self.parse_all(asynccomp, minver=6):
             pass
 
     def test_matmul(self):
-        for tree in self.parses(matmul, minver=5):
+        for tree in self.parse_all(matmul, minver=5):
             pass
 
     def test_fstring(self):
-        for tree in self.parses(fstring, minver=6):
+        for tree in self.parse_all(fstring, minver=6):
             pass
 
     def test_redundantdef(self):
-        for tree in self.parses(redundantdef, maxver=0,
+        for tree in self.parse_all(redundantdef, maxver=0,
                                 expected_regex="^Cannot have two type comments on def"):
             pass
 
     def test_nonasciidef(self):
-        for tree in self.parses(nonasciidef):
+        for tree in self.parse_all(nonasciidef):
             self.assertEqual(tree.body[0].type_comment, "() -> àçčéñt")
 
     def test_forstmt(self):
-        for tree in self.parses(forstmt):
+        for tree in self.parse_all(forstmt):
             self.assertEqual(tree.body[0].type_comment, "int")
         tree = self.classic_parse(forstmt)
         self.assertEqual(tree.body[0].type_comment, None)
 
     def test_withstmt(self):
-        for tree in self.parses(withstmt):
+        for tree in self.parse_all(withstmt):
             self.assertEqual(tree.body[0].type_comment, "int")
         tree = self.classic_parse(withstmt)
         self.assertEqual(tree.body[0].type_comment, None)
 
     def test_vardecl(self):
-        for tree in self.parses(vardecl):
+        for tree in self.parse_all(vardecl):
             self.assertEqual(tree.body[0].type_comment, "int")
         tree = self.classic_parse(vardecl)
         self.assertEqual(tree.body[0].type_comment, None)
 
     def test_ignores(self):
-        for tree in self.parses(ignores):
+        for tree in self.parse_all(ignores):
             self.assertEqual([ti.lineno for ti in tree.type_ignores], [2, 5])
         tree = self.classic_parse(ignores)
         self.assertEqual(tree.type_ignores, [])
 
     def test_longargs(self):
-        for tree in self.parses(longargs):
+        for tree in self.parse_all(longargs):
             for t in tree.body:
                 # The expected args are encoded in the function name
                 todo = set(t.name[1:])
@@ -300,7 +300,7 @@ def test_inappropriate_type_comments(self):
 
         def check_both_ways(source):
             ast.parse(source, type_comments=False)
-            for tree in self.parses(source, maxver=0):
+            for tree in self.parse_all(source, maxver=0):
                 pass
 
         check_both_ways("pass  # type: int\n")

From e925175040f0f55b6fadf7cd03bd77fb17650b39 Mon Sep 17 00:00:00 2001
From: Guido van Rossum <guido@python.org>
Date: Thu, 7 Mar 2019 12:13:15 -0800
Subject: [PATCH 14/14] Add test for underscore in number

---
 Lib/test/test_type_comments.py | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/Lib/test/test_type_comments.py b/Lib/test/test_type_comments.py
index 7f71ee851d408b..cac6e8b25d21af 100644
--- a/Lib/test/test_type_comments.py
+++ b/Lib/test/test_type_comments.py
@@ -40,6 +40,10 @@ async def foo(xs):
 f"{a}"
 """
 
+underscorednumber = """\
+a = 42_42_42
+"""
+
 redundantdef = """\
 def foo():  # type: () -> int
     # type: () -> str
@@ -229,6 +233,10 @@ def test_fstring(self):
         for tree in self.parse_all(fstring, minver=6):
             pass
 
+    def test_underscorednumber(self):
+        for tree in self.parse_all(underscorednumber, minver=6):
+            pass
+
     def test_redundantdef(self):
         for tree in self.parse_all(redundantdef, maxver=0,
                                 expected_regex="^Cannot have two type comments on def"):