Reuse params preprocessing logic for generic functions

Author: sterliakov

mypy/checkexpr.py

@@ -1716,33 +1716,9 @@ def check_callable_call(
             callee = callee.copy_modified(ret_type=fresh_ret_type)
 
         if callee.is_generic():
-            need_refresh = any(
-                isinstance(v, (ParamSpecType, TypeVarTupleType)) for v in callee.variables
+            callee, formal_to_actual = self.adjust_generic_callable_params_mapping(
+                callee, args, arg_kinds, arg_names, formal_to_actual, context
             )
-            callee = freshen_function_type_vars(callee)
-            callee = self.infer_function_type_arguments_using_context(callee, context)
-            if need_refresh:
-                # Argument kinds etc. may have changed due to
-                # ParamSpec or TypeVarTuple variables being replaced with an arbitrary
-                # number of arguments; recalculate actual-to-formal map
-                formal_to_actual = map_actuals_to_formals(
-                    arg_kinds,
-                    arg_names,
-                    callee.arg_kinds,
-                    callee.arg_names,
-                    lambda i: self.accept(args[i]),
-                )
-            callee = self.infer_function_type_arguments(
-                callee, args, arg_kinds, arg_names, formal_to_actual, need_refresh, context
-            )
-            if need_refresh:
-                formal_to_actual = map_actuals_to_formals(
-                    arg_kinds,
-                    arg_names,
-                    callee.arg_kinds,
-                    callee.arg_names,
-                    lambda i: self.accept(args[i]),
-                )
 
         param_spec = callee.param_spec()
         if (
@@ -2633,7 +2609,7 @@ def check_overload_call(
         arg_types = self.infer_arg_types_in_empty_context(args)
         # Step 1: Filter call targets to remove ones where the argument counts don't match
         plausible_targets = self.plausible_overload_call_targets(
-            arg_types, arg_kinds, arg_names, callee
+            args, arg_types, arg_kinds, arg_names, callee, context
         )
 
         # Step 2: If the arguments contain a union, we try performing union math first,
@@ -2751,12 +2727,52 @@ def check_overload_call(
             self.chk.fail(message_registry.TOO_MANY_UNION_COMBINATIONS, context)
         return result
 
+    def adjust_generic_callable_params_mapping(
+        self,
+        callee: CallableType,
+        args: list[Expression],
+        arg_kinds: list[ArgKind],
+        arg_names: Sequence[str | None] | None,
+        formal_to_actual: list[list[int]],
+        context: Context,
+    ) -> tuple[CallableType, list[list[int]]]:
+        need_refresh = any(
+            isinstance(v, (ParamSpecType, TypeVarTupleType)) for v in callee.variables
+        )
+        callee = freshen_function_type_vars(callee)
+        callee = self.infer_function_type_arguments_using_context(callee, context)
+        if need_refresh:
+            # Argument kinds etc. may have changed due to
+            # ParamSpec or TypeVarTuple variables being replaced with an arbitrary
+            # number of arguments; recalculate actual-to-formal map
+            formal_to_actual = map_actuals_to_formals(
+                arg_kinds,
+                arg_names,
+                callee.arg_kinds,
+                callee.arg_names,
+                lambda i: self.accept(args[i]),
+            )
+        callee = self.infer_function_type_arguments(
+            callee, args, arg_kinds, arg_names, formal_to_actual, need_refresh, context
+        )
+        if need_refresh:
+            formal_to_actual = map_actuals_to_formals(
+                arg_kinds,
+                arg_names,
+                callee.arg_kinds,
+                callee.arg_names,
+                lambda i: self.accept(args[i]),
+            )
+        return callee, formal_to_actual
+
     def plausible_overload_call_targets(
         self,
+        args: list[Expression],
         arg_types: list[Type],
         arg_kinds: list[ArgKind],
         arg_names: Sequence[str | None] | None,
         overload: Overloaded,
+        context: Context,
     ) -> list[CallableType]:
         """Returns all overload call targets that having matching argument counts.
 
@@ -2790,6 +2806,10 @@ def has_shape(typ: Type) -> bool:
             formal_to_actual = map_actuals_to_formals(
                 arg_kinds, arg_names, typ.arg_kinds, typ.arg_names, lambda i: arg_types[i]
             )
+            if typ.is_generic():
+                typ, formal_to_actual = self.adjust_generic_callable_params_mapping(
+                    typ, args, arg_kinds, arg_names, formal_to_actual, context
+                )
 
             with self.msg.filter_errors():
                 if self.check_argument_count(

test-data/unit/check-parameter-specification.test

@@ -2211,12 +2211,22 @@ from typing import Callable
 
 _P = ParamSpec("_P")
 
-def run(predicate: Callable[_P, str], *args: _P.args, **kwargs: _P.kwargs) -> None:
+def run(predicate: Callable[_P, None], *args: _P.args, **kwargs: _P.kwargs) -> None:  # N: "run" defined here
     predicate()  # E: Too few arguments
     predicate(*args)  # E: Too few arguments
     predicate(**kwargs)  # E: Too few arguments
     predicate(*args, **kwargs)
 
+def fn() -> None: ...
+def fn_args(x: int) -> None: ...
+def fn_posonly(x: int, /) -> None: ...
+
+run(fn)
+run(fn_args, 1)
+run(fn_args, x=1)
+run(fn_posonly, 1)
+run(fn_posonly, x=1)  # E: Unexpected keyword argument "x" for "run"
+
 [builtins fixtures/paramspec.pyi]
 
 [case testRunParamSpecConcatenateInsufficientArgs]
@@ -2225,7 +2235,7 @@ from typing import Callable
 
 _P = ParamSpec("_P")
 
-def run(predicate: Callable[Concatenate[int, _P], str], *args: _P.args, **kwargs: _P.kwargs) -> None:
+def run(predicate: Callable[Concatenate[int, _P], None], *args: _P.args, **kwargs: _P.kwargs) -> None:  # N: "run" defined here
     predicate()  # E: Too few arguments
     predicate(1)  # E: Too few arguments
     predicate(1, *args)  # E: Too few arguments
@@ -2234,6 +2244,22 @@ def run(predicate: Callable[Concatenate[int, _P], str], *args: _P.args, **kwargs
     predicate(*args, **kwargs)  # E: Argument 1 has incompatible type "*_P.args"; expected "int"
     predicate(1, *args, **kwargs)
 
+def fn() -> None: ...
+def fn_args(x: int, y: str) -> None: ...
+def fn_posonly(x: int, /) -> None: ...
+def fn_posonly_args(x: int, /, y: str) -> None: ...
+
+run(fn)  # E: Argument 1 to "run" has incompatible type "Callable[[], None]"; expected "Callable[[int], None]"
+run(fn_args, 1, 'a')  # E: Too many arguments for "run" \
+                      # E: Argument 2 to "run" has incompatible type "int"; expected "str"
+run(fn_args, y='a')
+run(fn_args, 'a')
+run(fn_posonly)
+run(fn_posonly, x=1)  # E: Unexpected keyword argument "x" for "run"
+run(fn_posonly_args)  # E: Missing positional argument "y" in call to "run"
+run(fn_posonly_args, 'a')
+run(fn_posonly_args, y='a')
+
 [builtins fixtures/paramspec.pyi]
 
 [case testRunParamSpecConcatenateInsufficientArgsInDecorator]
@@ -2255,3 +2281,37 @@ def decorator(fn: Callable[Concatenate[str, P], None]) -> Callable[P, None]:
 def foo(s: str, s2: str) -> None: ...
 
 [builtins fixtures/paramspec.pyi]
+
+[case testRunParamSpecOverload]
+from typing_extensions import ParamSpec, Concatenate
+from typing import Callable, overload, NoReturn, TypeVar, Union
+
+P = ParamSpec("P")
+T = TypeVar("T")
+
+@overload
+def capture(
+    sync_fn: Callable[P, NoReturn],
+    *args: P.args,
+    **kwargs: P.kwargs,
+) -> int: ...
+@overload
+def capture(
+    sync_fn: Callable[P, T],
+    *args: P.args,
+    **kwargs: P.kwargs,
+) -> Union[T, int]: ...
+def capture(
+    sync_fn: Callable[P, T],
+    *args: P.args,
+    **kwargs: P.kwargs,
+) -> Union[T, int]:
+    return sync_fn(*args, **kwargs)
+
+def fn() -> str: return ''
+def err() -> NoReturn: ...
+
+reveal_type(capture(fn))  # N: Revealed type is "Union[builtins.str, builtins.int]"
+reveal_type(capture(err))  # N: Revealed type is "builtins.int"
+
+[builtins fixtures/paramspec.pyi]