fix **kwargs: Never calls (#446)

docs/changelog.md

@@ -2,6 +2,7 @@
 
 ## Unreleased
 
+- Treat `NoReturn` like `Any` in `**kwargs` calls (#446)
 - Improve error messages for overloaded calls (#445)
 - Infer `NoReturn` instead of `Any` for unreachable code (#443)
 - Make `NoReturn` compatible with all other types (#442)

pyanalyze/signature.py

@@ -1730,6 +1730,11 @@ def preprocess_args(
         elif label is KWARGS:
             items = {}
             extra_values = []
+            if arg.value is NO_RETURN_VALUE:
+                new_value = GenericValue(dict, [TypedValue(str), NO_RETURN_VALUE])
+                processed_args.append((Composite(new_value), KWARGS))
+                continue
+
             # We union all the kwargs that may be provided by any union member, so that
             # we give an error if
             for subval in flatten_values(arg.value, unwrap_annotated=True):

pyanalyze/test_never.py

@@ -50,3 +50,17 @@ def capybara(x: Union[int, str]) -> None:
                 print("str")
             else:
                 assert_never(x)
+
+
+class TestNeverCall(TestNameCheckVisitorBase):
+    @assert_passes()
+    def test_empty_list(self):
+        def callee(a: int):
+            pass
+
+        def capybara():
+            for args in []:
+                callee(*args)
+
+            for kwargs in []:
+                callee(**kwargs)