[Python-checkins] cpython (3.5): Issue #24528: Improve error message for awaits in comprehensions

[yury.selivanov]

https://hg.python.org/cpython/rev/30b676e8b21f
changeset:   96724:30b676e8b21f
branch:      3.5
parent:      96722:6ae8842e9b60
user:        Yury Selivanov <yselivanov at sprymix.com>
date:        Tue Jun 30 12:49:04 2015 -0400
summary:
  Issue #24528: Improve error message for awaits in comprehensions

files:
  Lib/test/test_coroutines.py |  10 ++++++++++
  Python/compile.c            |   5 ++++-
  2 files changed, 14 insertions(+), 1 deletions(-)


diff --git a/Lib/test/test_coroutines.py b/Lib/test/test_coroutines.py
--- a/Lib/test/test_coroutines.py
+++ b/Lib/test/test_coroutines.py
@@ -106,6 +106,16 @@
         with self.assertRaisesRegex(SyntaxError, 'invalid syntax'):
             import test.badsyntax_async9
 
+    def test_badsyntax_10(self):
+        ns = {}
+        for comp in {'(await a for a in b)',
+                     '[await a for a in b]',
+                     '{await a for a in b}',
+                     '{await a: c for a in b}'}:
+
+            with self.assertRaisesRegex( SyntaxError, 'await.*in comprehen'):
+                exec('async def f():\n\t{}'.format(comp), ns, ns)
+
 
 class TokenizerRegrTest(unittest.TestCase):
 
diff --git a/Python/compile.c b/Python/compile.c
--- a/Python/compile.c
+++ b/Python/compile.c
@@ -3856,7 +3856,10 @@
         if (c->u->u_ste->ste_type != FunctionBlock)
             return compiler_error(c, "'await' outside function");
 
-        /* this check won't be triggered while we have AWAIT token */
+        if (c->u->u_scope_type == COMPILER_SCOPE_COMPREHENSION)
+            return compiler_error(
+                c, "'await' expressions in comprehensions are not supported");
+
         if (c->u->u_scope_type != COMPILER_SCOPE_ASYNC_FUNCTION)
             return compiler_error(c, "'await' outside async function");
 

-- 
Repository URL: https://hg.python.org/cpython