Don't make parentheses invisible around yield expressions

black.py

@@ -2258,6 +2258,7 @@ def maybe_make_parens_invisible_in_atom(node: LN) -> bool:
         node.type != syms.atom
         or is_empty_tuple(node)
         or is_one_tuple(node)
+        or is_yield(node)
         or max_delimiter_priority_in_atom(node) >= COMMA_PRIORITY
     ):
         return False
@@ -2308,6 +2309,27 @@ def is_one_tuple(node: LN) -> bool:
     )
 
 
+def is_yield(node: LN) -> bool:
+    """Return True if `node` holds a `yield` or `yield from` expression."""
+    if node.type == syms.yield_expr:
+        return True
+
+    if node.type == token.NAME and node.value == "yield":  # type: ignore
+        return True
+
+    if node.type != syms.atom:
+        return False
+
+    if len(node.children) != 3:
+        return False
+
+    lpar, expr, rpar = node.children
+    if lpar.type == token.LPAR and rpar.type == token.RPAR:
+        return is_yield(expr)
+
+    return False
+
+
 def is_vararg(leaf: Leaf, within: Set[NodeType]) -> bool:
     """Return True if `leaf` is a star or double star in a vararg or kwarg.
 

tests/expression.diff

@@ -192,10 +192,9 @@
 +
  def gen():
      yield from outside_of_generator
--    a = (yield)
+     a = (yield)
-+    a = yield
-+
  
++
  async def f():
      await some.complicated[0].call(with_args=(True or (1 is not 1)))
 -print(* [] or [1])

tests/expression.py

@@ -426,7 +426,7 @@ async def f():
 
 def gen():
     yield from outside_of_generator
-    a = yield
+    a = (yield)
 
 
 async def f():

tests/function.py

@@ -85,11 +85,14 @@ def f(
   a,
   **kwargs,
 ) -> A:
-    return A(
+    return (
-        very_long_argument_name1=very_long_value_for_the_argument,
+        yield from A(
-        very_long_argument_name2=very_long_value_for_the_argument,
+            very_long_argument_name1=very_long_value_for_the_argument,
-        **kwargs,
+            very_long_argument_name2=very_long_value_for_the_argument,
+            **kwargs,
+        )
     )
+def __await__(): return (yield)
 
 # output
 
@@ -224,8 +227,14 @@ def trailing_comma():
 
 
 def f(a, **kwargs) -> A:
-    return A(
+    return (
-        very_long_argument_name1=very_long_value_for_the_argument,
+        yield from A(
-        very_long_argument_name2=very_long_value_for_the_argument,
+            very_long_argument_name1=very_long_value_for_the_argument,
-        **kwargs,
+            very_long_argument_name2=very_long_value_for_the_argument,
+            **kwargs,
+        )
     )
+
+
+def __await__():
+    return (yield)