Sync tests again, account for optional kwonly args

python · sterliakov · Jun 29, 2025 · Jun 29, 2025 · Jun 29, 2025 · Jun 29, 2025
commit f0a5dd3fe8b63b67c84021373bd09342a95214dd
diff --git a/mypy/checkexpr.py b/mypy/checkexpr.py
@@ -2393,7 +2393,11 @@ def check_argument_count(
         seen_kw = False
         for i, kind in enumerate(callee.arg_kinds):
             mapped_args = formal_to_actual[i]
-            seen_kw = seen_kw or any(actual_kinds[k].is_named(star=True) for k in mapped_args)
+            seen_kw = (
+                seen_kw
+                or kind == ArgKind.ARG_NAMED_OPT
+                or any(actual_kinds[k].is_named(star=True) for k in mapped_args)
+            )
             if kind.is_required() and not mapped_args and not is_unexpected_arg_error:
                 # No actual for a mandatory formal
                 if (

diff --git a/test-data/unit/check-classes.test b/test-data/unit/check-classes.test
@@ -2008,7 +2008,7 @@ class D:
     def __set__(self, inst, v, other): pass
 class A:
     f = D()
-A().f = 'x'  # E: Too few arguments for "__set__"
+A().f = 'x'  # E: Missing positional argument "other" in call to "__set__"
 
 [case testDescriptorDunderSetWrongArgTypes]
 class D:
@@ -2036,7 +2036,7 @@ class D:
     def __get__(self, inst, own, other): pass
 class A:
     f = D()
-A().f = 'x'  # E: Too few arguments for "__get__"
+A().f = 'x'  # E: Missing positional argument "other" in call to "__get__"
 
 [case testDescriptorDunderGetWrongArgTypeForInstance]
 from typing import Any

diff --git a/test-data/unit/check-dataclasses.test b/test-data/unit/check-dataclasses.test
@@ -425,10 +425,11 @@ class Application:
     name: str = 'Unnamed'
     rating: int = field(kw_only=False)  # E: Attributes without a default cannot follow attributes with one
 
+reveal_type(Application)  # N: Revealed type is "def (name: builtins.str =, rating: builtins.int) -> __main__.Application"
 Application(name='name', rating=5)
 Application('name', 123)
 Application('name', rating=123)
-Application()  # E: Missing positional argument "name" in call to "Application"
+Application()  # E: Too few arguments for "Application"
 Application('name')  # E: Too few arguments for "Application"
 
 [builtins fixtures/dataclasses.pyi]

diff --git a/test-data/unit/check-functools.test b/test-data/unit/check-functools.test
@@ -495,9 +495,9 @@ def main5(**d2: Unpack[D2]) -> None:
     partial(fn2, **d2)()  # E: Extra argument "a2" from **args for "fn2"
 
 def main6(a2good: A2Good, a2bad: A2Bad, **d1: Unpack[D1]) -> None:
-    partial(fn3, **d1)()  # E: Missing positional argument "a1" in call to "fn3"
+    partial(fn3, **d1)()  # E: Missing named argument "a2" for "fn3"
     partial(fn3, **d1)("asdf")  # E: Too many positional arguments for "fn3" \
-                                # E: Too few arguments for "fn3" \
+                                # E: Missing named argument "a2" for "fn3" \
                                 # E: Argument 1 to "fn3" has incompatible type "str"; expected "int"
     partial(fn3, **d1)(a2="asdf")
     partial(fn3, **d1)(**a2good)
@@ -530,7 +530,7 @@ reveal_type(first_kw(args=[1]))  # N: Revealed type is "builtins.int"
 
 # TODO: this is indeed invalid, but the error is incomprehensible.
 first_kw([1])  # E: Too many positional arguments for "get" \
-               # E: Too few arguments for "get" \
+               # E: Missing named argument "args" for "get" \
                # E: Argument 1 to "get" has incompatible type "list[int]"; expected "int"
 [builtins fixtures/list.pyi]
 

diff --git a/test-data/unit/check-statements.test b/test-data/unit/check-statements.test
@@ -453,9 +453,9 @@ if object():
 if object():
     raise MyErrorWithDefault
 if object():
-    raise MyBaseError  # E: Too few arguments for "MyBaseError"
+    raise MyBaseError  # E: Missing positional argument "required" in call to "MyBaseError"
 if object():
-    raise MyError  # E: Too few arguments for "MyError"
+    raise MyError  # E: Missing positional arguments "required1", "required2" in call to "MyError"
 if object():
     raise MyKwError  # E: Missing named argument "kwonly" for "MyKwError"
 [builtins fixtures/exception.pyi]

diff --git a/test-data/unit/check-varargs.test b/test-data/unit/check-varargs.test
@@ -266,7 +266,7 @@ f(*(a, b, b)) # E: Argument 1 to "f" has incompatible type "*tuple[A, B, B]"; ex
 f(*(b, b, c)) # E: Argument 1 to "f" has incompatible type "*tuple[B, B, C]"; expected "A"
 f(a, *(b, b)) # E: Argument 2 to "f" has incompatible type "*tuple[B, B]"; expected "C"
 f(b, *(b, c)) # E: Argument 1 to "f" has incompatible type "B"; expected "A"
-f(*(a, b))    # E: Missing positional arguments "b", "c" in call to "f"
+f(*(a, b))    # E: Missing positional argument "c" in call to "f"
 f(*(a, b, c, c)) # E: Too many arguments for "f"
 f(a, *(b, c, c)) # E: Too many arguments for "f"
 f(*(a, b, c))
@@ -342,7 +342,7 @@ f(b, *(b, b))   # E: Argument 1 to "f" has incompatible type "B"; expected "A"
 f(b, b, *(b,))  # E: Argument 1 to "f" has incompatible type "B"; expected "A"
 f(a, a, *(b,))  # E: Argument 2 to "f" has incompatible type "A"; expected "B"
 f(a, b, *(a,))  # E: Argument 3 to "f" has incompatible type "*tuple[A]"; expected "B"
-f(*())          # E: Too few arguments for "f"
+f(*())          # E: Missing positional argument "a" in call to "f"
 f(*(a, b, b))
 f(a, *(b, b))
 f(a, b, *(b,))
@@ -400,7 +400,7 @@ class A: pass
 class B: pass
 
 a, b = None, None # type: (A, B)
-f(*())        # E: Too few arguments for "f"
+f(*())        # E: Missing positional argument "a" in call to "f"
 f(a, *[a])    # E: Argument 2 to "f" has incompatible type "*list[A]"; expected "Optional[B]" \
               # E: Argument 2 to "f" has incompatible type "*list[A]"; expected "B"
 f(a, b, *[a]) # E: Argument 3 to "f" has incompatible type "*list[A]"; expected "B"