[DO NOT MERGE] Fix def line numbers for decorated nodes

README.md

@@ -13,14 +13,17 @@ parsers.  `typed_ast` runs on Python 3.3-3.7 on Linux, OS X and Windows.
 
 ## Development Philosophy
 
-This project is a (mostly) drop-in replacement for the builtin `ast` module.  It is
+This project is a near drop-in replacement for the builtin `ast` module.  It is
 intended to be bug-for-bug compatible and behave identically, except for the
 presence of a few additional fields on the returned classes and a few
-additional optional arguments to the `parse` call.  Therefore, `typed_ast` will
-not accept any bugfixes for bugs in `ast` -- they should be fixed upstream
-instead.  To avoid feature bloat, any new features for `typed_ast` should have
-the potential to be broadly useful and not be built just for one niche usecase
-or in a manner such that only one project can use them.
+additional optional arguments to the `parse` call. From time to time we may
+backport important bug fixes from upstream. Therefore, `typed_ast` will not
+accept most bugfixes for bugs in `ast`. Before a bug fix is considered, it
+must be merged upstream first. In other words, we only will take select
+backports from the upstream ast module.  To avoid feature bloat, any new
+features for `typed_ast` should have the potential to be broadly useful and not
+be built just for one niche usecase or in a manner such that only one project
+can use them.
 
 ### Incompatabilities
 
@@ -40,11 +43,11 @@ not treated as keywords.
 The `ast3` parser produces the AST from a recent version of Python 3
 (currently Python 3.6).  When new versions of Python 3 are released, it will be
 updated to match any changes in their AST.  (For rationale and technical
-details, see [here](update_process.md).)  The AST it currently produces is described in
-[ast3/Parser/Python.asdl](ast3/Parser/Python.asdl).  If you wish to limit
-parsing to older versions of Python 3, `ast3` can be configured to to give a
-SyntaxError for new syntax features introduced beyond a given Python version.
-For more information, see the module docstring in
+details, see [here](update_process.md).)  The AST it currently produces is
+described in [ast3/Parser/Python.asdl](ast3/Parser/Python.asdl).  If you wish
+to limit parsing to older versions of Python 3, `ast3` can be configured to to
+give a SyntaxError for new syntax features introduced beyond a given Python
+version. For more information, see the module docstring in
 [typed\_ast/ast3.py](typed_ast/ast3.py).
 
 ### ast27
@@ -64,6 +67,8 @@ Note: as these parsers consider type comments part of the grammar, incorrectly
 placed type comments are considered syntax errors.
 
 ## Updates and Releases
-To update `typed_ast` for new major Python releases, see [`update_process.md`](update_process.md).
+To update `typed_ast` for new major Python releases, see
+[`update_process.md`](update_process.md).
 
-To make a new `typed_ast` release, see [`release_process.md`](release_process.md).
+To make a new `typed_ast` release, see
+[`release_process.md`](release_process.md).

ast27/Python/ast.c

@@ -1061,12 +1061,6 @@ ast_for_decorated(struct compiling *c, const node *n)
     } else if (TYPE(CHILD(n, 1)) == classdef) {
       thing = ast_for_classdef(c, CHILD(n, 1), decorator_seq);
     }
-    /* we count the decorators in when talking about the class' or
-       function's line number */
-    if (thing) {
-        thing->lineno = LINENO(n);
-        thing->col_offset = n->n_col_offset;
-    }
     return thing;
 }
 

ast3/Python/ast.c

@@ -1879,12 +1879,6 @@ ast_for_decorated(struct compiling *c, const node *n)
     } else if (TYPE(CHILD(n, 1)) == async_funcdef) {
       thing = ast_for_async_funcdef(c, CHILD(n, 1), decorator_seq);
     }
-    /* we count the decorators in when talking about the class' or
-     * function's line number */
-    if (thing) {
-        thing->lineno = LINENO(n);
-        thing->col_offset = n->n_col_offset;
-    }
     return thing;
 }
 

typed_ast/ast27.py

@@ -21,6 +21,8 @@
       lines which have been `# type: ignore`d.
     - `Str` has a `kind` string field which preserves the original string
       prefix, so that `ast27.parse('br"test"').body[0].value.kind == 'br'`.
+    - Fixed line number information for decorated AST nodes.
+      (Based on https://github.com/python/cpython/pull/9731)
 
     An abstract syntax tree can be generated by using the `parse()`
     function from this module.  The result will be a tree of objects whose

typed_ast/ast3.py

@@ -23,6 +23,8 @@
       lines which have been `# type: ignore`d.
     - `Str` has a `kind` string field which preserves the original string
       prefix, so that `ast3.parse('u"test"').body[0].value.kind == 'u'`.
+    - Fixed line number information for decorated AST nodes.
+      (Based on https://github.com/python/cpython/pull/9731)
 
     An abstract syntax tree can be generated by using the `parse()`
     function from this module.  The result will be a tree of objects whose