some more fixes for 3.8

IPython/core/async_helpers.py

@@ -150,9 +150,11 b' def _should_be_async(cell: str) -> bool:'
     level, it will be seen as async. This is a know limitation.
     """
     if sys.version_info > (3, 8):
-        code = compile(cell, "<>", "exec", flags=getattr(ast,'PyCF_ALLOW_TOP_LEVEL_AWAIT', 0x0))
-        return inspect.CO_COROUTINE & code.co_flags == inspect.CO_COROUTINE
-
+        try:
+            code = compile(cell, "<>", "exec", flags=getattr(ast,'PyCF_ALLOW_TOP_LEVEL_AWAIT', 0x0))
+            return inspect.CO_COROUTINE & code.co_flags == inspect.CO_COROUTINE
+        except SyntaxError:
+            return False
     try:
         # we can't limit ourself to ast.parse, as it __accepts__ to parse on
         # 3.7+, but just does not _compile_

IPython/core/compilerop.py

@@ -137,12 +137,17 b' class CachingCompiler(codeop.Compile):'
 
     @contextmanager
     def extra_flags(self, flags):
-        old_flags = self.flags
+        ## bits that we'll set to 1
+        turn_on_bits = ~self.flags & flags
+
+
         self.flags = self.flags | flags
         try:
             yield
         finally:
-            self.flags = old_flags
+            # turn off only the bits we turned on so that something like
+            # __future__ that set flags stays. 
+            self.flags &= ~turn_on_bits
 
 
 def check_linecache_ipython(*args):