Fix invalid code in an omitted trailer on large expressions

Fixes #237

README.md

@@ -654,7 +654,11 @@ More details can be found in [CONTRIBUTING](CONTRIBUTING.md).
 ### 18.5b1 (unreleased)
 
 * Python grammar pickle caches are stored with the formatting caches, making
-  *Black* work in environments where site-packages is not user-writable (#192).
+  *Black* work in environments where site-packages is not user-writable (#192)
+
+* fixed invalid code produced when standalone comments were present in a trailer
+  that was omitted from line splitting on a large expression (#237)
+
 
 ### 18.5b0
 

black.py

@@ -2606,6 +2606,9 @@ def generate_trailers_to_omit(line: Line, line_length: int) -> Iterator[Set[Leaf
         if length > line_length:
             break
 
+        if leaf.type == STANDALONE_COMMENT:
+            break
+
         optional_brackets.discard(id(leaf))
         if opening_bracket:
             if leaf is opening_bracket:

tests/composition.py

@@ -32,6 +32,14 @@ def test(self) -> None:
                         # Another
                     ):
                         print(i)
+        xxxxxxxxxxxxxxxx = Yyyy2YyyyyYyyyyy(
+            push_manager=context.request.resource_manager,
+            max_items_to_push=num_items,
+            batch_size=Yyyy2YyyyYyyyyYyyy.FULL_SIZE,
+        ).push(
+            # Only send the first n items.
+            items=items[:num_items]
+        )
         return (
             "Utterly failed doctest test for %s\n"
             '  File "%s", line %s, in %s\n\n%s'