Issue #28008: Implement PEP 530 -- asynchronous comprehensions.

2 files changed, 19 insertions, 1 deletions

diff --git a/Lib/lib2to3/Grammar.txt b/Lib/lib2to3/Grammar.txt
index abe1268..dcdd02d 100644
--- a/Lib/lib2to3/Grammar.txt
+++ b/Lib/lib2to3/Grammar.txt
@@ -150,7 +150,7 @@ arglist: (argument ',')* (argument [',']
 argument: test [comp_for] | test '=' test  # Really [keyword '='] test
 
 comp_iter: comp_for | comp_if
-comp_for: 'for' exprlist 'in' testlist_safe [comp_iter]
+comp_for: [ASYNC] 'for' exprlist 'in' testlist_safe [comp_iter]
 comp_if: 'if' old_test [comp_iter]
 
 testlist1: test (',' test)*
diff --git a/Lib/lib2to3/tests/test_parser.py b/Lib/lib2to3/tests/test_parser.py
index b378163..7613f53 100644
--- a/Lib/lib2to3/tests/test_parser.py
+++ b/Lib/lib2to3/tests/test_parser.py
@@ -134,6 +134,24 @@ class TestAsyncAwait(GrammarTest):
                       """)
 
         self.validate("""async def foo():
+                             [i async for i in b]
+                      """)
+
+        self.validate("""async def foo():
+                             {i for i in b
+                                async for i in a if await i
+                                  for b in i}
+                      """)
+
+        self.validate("""async def foo():
+                             [await i for i in b if await c]
+                      """)
+
+        self.validate("""async def foo():
+                             [ i for i in b if c]
+                      """)
+
+        self.validate("""async def foo():
 
             def foo(): pass