Revert 3.7 AST fix

Also start testing on 3.7-dev and build docs on 3.7

.travis.yml

@@ -22,7 +22,7 b' script:'
     - cd /tmp && iptest --coverage xml && cd -
     # On the latest Python only, make sure that the docs build.
     - |
-      if [[ "$TRAVIS_PYTHON_VERSION" == "3.6" ]]; then
+      if [[ "$TRAVIS_PYTHON_VERSION" == "3.7" ]]; then
         pip install -r docs/requirements.txt
         python tools/fixup_whats_new_pr.py
         make -C docs/ html SPHINXOPTS="-W"
@@ -35,6 +35,7 b' after_success:'
 matrix:
     include:
         - { python: "3.7", dist: xenial, sudo: true }
+        - { python: "3.7-dev", dist: xenial, sudo: true }
         - { python: "nightly", dist: xenial, sudo: true }
     allow_failures:
         - python: nightly

IPython/core/compilerop.py

@@ -92,29 +92,12 b' class CachingCompiler(codeop.Compile):'
         linecache.checkcache = check_linecache_ipython
 
 
-    def _fix_module_ds(self, module):
-        """
-        Starting in python 3.7 the AST for mule have changed, and if
-        the first expressions encountered is a string it is attached to the
-        `docstring` attribute of the `Module` ast node.
-
-        This breaks IPython, as if this string is the only expression, IPython
-        will not return it as the result of the current cell.
-        """
-        from ast import Str, Expr, Module, fix_missing_locations
-        docstring = getattr(module, 'docstring', None)
-        if not docstring:
-            return module
-        new_body=[Expr(Str(docstring, lineno=1, col_offset=0), lineno=1, col_offset=0)]
-        new_body.extend(module.body)
-        return fix_missing_locations(Module(new_body))
-
     def ast_parse(self, source, filename='<unknown>', symbol='exec'):
         """Parse code to an AST with the current compiler flags active.
 
         Arguments are exactly the same as ast.parse (in the standard library),
         and are passed to the built-in compile function."""
-        return self._fix_module_ds(compile(source, filename, symbol, self.flags | PyCF_ONLY_AST, 1))
+        return compile(source, filename, symbol, self.flags | PyCF_ONLY_AST, 1)
 
     def reset_compiler_flags(self):
         """Reset compiler flags to default state."""