[flake8-async] allow async generators (ASYNC100) (#13639)

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## Summary

Treat async generators as "await" in ASYNC100.

Fixes #13637

## Test Plan

Updated snapshot

crates/ruff_linter/resources/test/fixtures/flake8_async/ASYNC100.py

@@ -36,6 +36,11 @@ async def func():
             ...
 
 
+async def main():
+    async with asyncio.timeout(7):
+        print({i async for i in long_running_range()})
+
+
 async def func():
     with anyio.move_on_after(delay=0.2):
         ...

crates/ruff_linter/src/rules/flake8_async/snapshots/ruff_linter__rules__flake8_async__tests__ASYNC100_ASYNC100.py.snap

@@ -19,28 +19,19 @@ ASYNC100.py:18:5: ASYNC100 A `with trio.move_on_after(...):` context does not co
    | |___________^ ASYNC100
    |
 
-ASYNC100.py:40:5: ASYNC100 A `with anyio.move_on_after(...):` context does not contain any `await` statements. This makes it pointless, as the timeout can only be triggered by a checkpoint.
-   |
-39 |   async def func():
-40 |       with anyio.move_on_after(delay=0.2):
-   |  _____^
-41 | |         ...
-   | |___________^ ASYNC100
-   |
-
-ASYNC100.py:45:5: ASYNC100 A `with anyio.fail_after(...):` context does not contain any `await` statements. This makes it pointless, as the timeout can only be triggered by a checkpoint.
+ASYNC100.py:45:5: ASYNC100 A `with anyio.move_on_after(...):` context does not contain any `await` statements. This makes it pointless, as the timeout can only be triggered by a checkpoint.
    |
 44 |   async def func():
-45 |       with anyio.fail_after():
+45 |       with anyio.move_on_after(delay=0.2):
    |  _____^
 46 | |         ...
    | |___________^ ASYNC100
    |
 
-ASYNC100.py:50:5: ASYNC100 A `with anyio.CancelScope(...):` context does not contain any `await` statements. This makes it pointless, as the timeout can only be triggered by a checkpoint.
+ASYNC100.py:50:5: ASYNC100 A `with anyio.fail_after(...):` context does not contain any `await` statements. This makes it pointless, as the timeout can only be triggered by a checkpoint.
    |
 49 |   async def func():
-50 |       with anyio.CancelScope():
+50 |       with anyio.fail_after():
    |  _____^
 51 | |         ...
    | |___________^ ASYNC100
@@ -49,7 +40,7 @@ ASYNC100.py:50:5: ASYNC100 A `with anyio.CancelScope(...):` context does not con
 ASYNC100.py:55:5: ASYNC100 A `with anyio.CancelScope(...):` context does not contain any `await` statements. This makes it pointless, as the timeout can only be triggered by a checkpoint.
    |
 54 |   async def func():
-55 |       with anyio.CancelScope(), nullcontext():
+55 |       with anyio.CancelScope():
    |  _____^
 56 | |         ...
    | |___________^ ASYNC100
@@ -58,44 +49,53 @@ ASYNC100.py:55:5: ASYNC100 A `with anyio.CancelScope(...):` context does not con
 ASYNC100.py:60:5: ASYNC100 A `with anyio.CancelScope(...):` context does not contain any `await` statements. This makes it pointless, as the timeout can only be triggered by a checkpoint.
    |
 59 |   async def func():
-60 |       with nullcontext(), anyio.CancelScope():
+60 |       with anyio.CancelScope(), nullcontext():
    |  _____^
 61 | |         ...
    | |___________^ ASYNC100
    |
 
-ASYNC100.py:65:5: ASYNC100 A `with asyncio.timeout(...):` context does not contain any `await` statements. This makes it pointless, as the timeout can only be triggered by a checkpoint.
+ASYNC100.py:65:5: ASYNC100 A `with anyio.CancelScope(...):` context does not contain any `await` statements. This makes it pointless, as the timeout can only be triggered by a checkpoint.
    |
 64 |   async def func():
-65 |       async with asyncio.timeout(delay=0.2):
+65 |       with nullcontext(), anyio.CancelScope():
    |  _____^
 66 | |         ...
    | |___________^ ASYNC100
    |
 
-ASYNC100.py:70:5: ASYNC100 A `with asyncio.timeout_at(...):` context does not contain any `await` statements. This makes it pointless, as the timeout can only be triggered by a checkpoint.
+ASYNC100.py:70:5: ASYNC100 A `with asyncio.timeout(...):` context does not contain any `await` statements. This makes it pointless, as the timeout can only be triggered by a checkpoint.
    |
 69 |   async def func():
-70 |       async with asyncio.timeout_at(when=0.2):
+70 |       async with asyncio.timeout(delay=0.2):
    |  _____^
 71 | |         ...
    | |___________^ ASYNC100
    |
 
-ASYNC100.py:80:5: ASYNC100 A `with asyncio.timeout(...):` context does not contain any `await` statements. This makes it pointless, as the timeout can only be triggered by a checkpoint.
+ASYNC100.py:75:5: ASYNC100 A `with asyncio.timeout_at(...):` context does not contain any `await` statements. This makes it pointless, as the timeout can only be triggered by a checkpoint.
+   |
+74 |   async def func():
+75 |       async with asyncio.timeout_at(when=0.2):
+   |  _____^
+76 | |         ...
+   | |___________^ ASYNC100
+   |
+
+ASYNC100.py:85:5: ASYNC100 A `with asyncio.timeout(...):` context does not contain any `await` statements. This makes it pointless, as the timeout can only be triggered by a checkpoint.
    |
-79 |   async def func():
-80 |       async with asyncio.timeout(delay=0.2), asyncio.TaskGroup(), asyncio.timeout(delay=0.2):
+84 |   async def func():
+85 |       async with asyncio.timeout(delay=0.2), asyncio.TaskGroup(), asyncio.timeout(delay=0.2):
    |  _____^
-81 | |         ...
+86 | |         ...
    | |___________^ ASYNC100
    |
 
-ASYNC100.py:90:5: ASYNC100 A `with asyncio.timeout(...):` context does not contain any `await` statements. This makes it pointless, as the timeout can only be triggered by a checkpoint.
+ASYNC100.py:95:5: ASYNC100 A `with asyncio.timeout(...):` context does not contain any `await` statements. This makes it pointless, as the timeout can only be triggered by a checkpoint.
    |
-89 |   async def func():
-90 |       async with asyncio.timeout(delay=0.2), asyncio.timeout(delay=0.2):
+94 |   async def func():
+95 |       async with asyncio.timeout(delay=0.2), asyncio.timeout(delay=0.2):
    |  _____^
-91 | |         ...
+96 | |         ...
    | |___________^ ASYNC100
    |

crates/ruff_python_ast/src/helpers.rs

@@ -1004,6 +1004,14 @@ impl Visitor<'_> for AwaitVisitor {
             crate::visitor::walk_expr(self, expr);
         }
     }
+
+    fn visit_comprehension(&mut self, comprehension: &'_ crate::Comprehension) {
+        if comprehension.is_async {
+            self.seen_await = true;
+        } else {
+            crate::visitor::walk_comprehension(self, comprehension);
+        }
+    }
 }
 
 /// Return `true` if a `Stmt` is a docstring.