From: Yury Selivanov <yselivanov@sprymix.com>
Date: Tue, 30 Jun 2015 16:49:04 +0000 (-0400)
Subject: Issue #24528: Improve error message for awaits in comprehensions
X-Git-Tag: v3.5.0b3~32
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=9dec03571f2ec588dfc15ff438c85fe25989dcc1;p=python

Issue #24528: Improve error message for awaits in comprehensions
---

diff --git a/Lib/test/test_coroutines.py b/Lib/test/test_coroutines.py
index 8d2b1a3490..e869fd216a 100644
--- a/Lib/test/test_coroutines.py
+++ b/Lib/test/test_coroutines.py
@@ -106,6 +106,16 @@ class AsyncBadSyntaxTest(unittest.TestCase):
         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
index 1977c3a1bf..2202e8f3a1 100644
--- a/Python/compile.c
+++ b/Python/compile.c
@@ -3856,7 +3856,10 @@ compiler_visit_expr(struct compiler *c, expr_ty e)
         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");