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

README.md

@@ -13,12 +13,11 @@ parsers.  `typed_ast` runs on Python 3.3-3.6 on Linux, OS X and Windows.
 
 ## Development Philosophy
 
-This project is a 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
+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 all 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.
 

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

@@ -1828,12 +1828,6 @@ 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