PEP 702 (@deprecated): handle "combined" overloads (#19626)

This change is taken from #18682. The new code and the tests are
unmodified. I only had to remove two now unnecessary calls of
`warn_deprecated` which were introduced after opening #18682.

Author: tyralla

mypy/checkexpr.py

@@ -2722,6 +2722,7 @@ def check_overload_call(
         #         for example, when we have a fallback alternative that accepts an unrestricted
         #         typevar. See https://github.com/python/mypy/issues/4063 for related discussion.
         erased_targets: list[CallableType] | None = None
+        inferred_types: list[Type] | None = None
         unioned_result: tuple[Type, Type] | None = None
 
         # Determine whether we need to encourage union math. This should be generally safe,
@@ -2749,13 +2750,14 @@ def check_overload_call(
                 # Record if we succeeded. Next we need to see if maybe normal procedure
                 # gives a narrower type.
                 if unioned_return:
-                    returns, inferred_types = zip(*unioned_return)
+                    returns = [u[0] for u in unioned_return]
+                    inferred_types = [u[1] for u in unioned_return]
                     # Note that we use `combine_function_signatures` instead of just returning
                     # a union of inferred callables because for example a call
                     # Union[int -> int, str -> str](Union[int, str]) is invalid and
                     # we don't want to introduce internal inconsistencies.
                     unioned_result = (
-                        make_simplified_union(list(returns), context.line, context.column),
+                        make_simplified_union(returns, context.line, context.column),
                         self.combine_function_signatures(get_proper_types(inferred_types)),
                     )
 
@@ -2770,19 +2772,26 @@ def check_overload_call(
             object_type,
             context,
         )
-        # If any of checks succeed, stop early.
+        # If any of checks succeed, perform deprecation tests and stop early.
         if inferred_result is not None and unioned_result is not None:
             # Both unioned and direct checks succeeded, choose the more precise type.
             if (
                 is_subtype(inferred_result[0], unioned_result[0])
                 and not isinstance(get_proper_type(inferred_result[0]), AnyType)
                 and not none_type_var_overlap
             ):
-                return inferred_result
-            return unioned_result
-        elif unioned_result is not None:
+                unioned_result = None
+            else:
+                inferred_result = None
+        if unioned_result is not None:
+            if inferred_types is not None:
+                for inferred_type in inferred_types:
+                    if isinstance(c := get_proper_type(inferred_type), CallableType):
+                        self.chk.warn_deprecated(c.definition, context)
             return unioned_result
-        elif inferred_result is not None:
+        if inferred_result is not None:
+            if isinstance(c := get_proper_type(inferred_result[1]), CallableType):
+                self.chk.warn_deprecated(c.definition, context)
             return inferred_result
 
         # Step 4: Failure. At this point, we know there is no match. We fall back to trying
@@ -2936,8 +2945,6 @@ def infer_overload_return_type(
                 # check for ambiguity due to 'Any' below.
                 if not args_contain_any:
                     self.chk.store_types(m)
-                    if isinstance(infer_type, ProperType) and isinstance(infer_type, CallableType):
-                        self.chk.warn_deprecated(infer_type.definition, context)
                     return ret_type, infer_type
                 p_infer_type = get_proper_type(infer_type)
                 if isinstance(p_infer_type, CallableType):
@@ -2974,11 +2981,6 @@ def infer_overload_return_type(
         else:
             # Success! No ambiguity; return the first match.
             self.chk.store_types(type_maps[0])
-            inferred_callable = inferred_types[0]
-            if isinstance(inferred_callable, ProperType) and isinstance(
-                inferred_callable, CallableType
-            ):
-                self.chk.warn_deprecated(inferred_callable.definition, context)
             return return_types[0], inferred_types[0]
 
     def overload_erased_call_targets(

test-data/unit/check-deprecated.test

@@ -671,9 +671,11 @@ C().g = "x"  # E: function __main__.C.g is deprecated: use g2 instead \
 [case testDeprecatedDescriptor]
 # flags: --enable-error-code=deprecated
 
-from typing import Any, Optional, Union, overload
+from typing import Any, Generic, Optional, overload, TypeVar, Union
 from typing_extensions import deprecated
 
+T = TypeVar("T")
+
 @deprecated("use E1 instead")
 class D1:
     def __get__(self, obj: Optional[C], objtype: Any) -> Union[D1, int]: ...
@@ -701,10 +703,19 @@ class D3:
     def __set__(self, obj: C, value: str) -> None: ...
     def __set__(self, obj: C, value: Union[int, str]) -> None: ...
 
+class D4(Generic[T]):
+    @overload
+    def __get__(self, obj: None, objtype: Any) -> T: ...
+    @overload
+    @deprecated("deprecated instance access")
+    def __get__(self, obj: C, objtype: Any) -> T: ...
+    def __get__(self, obj: Optional[C], objtype: Any) -> T: ...
+
 class C:
     d1 = D1()  # E: class __main__.D1 is deprecated: use E1 instead
     d2 = D2()
     d3 = D3()
+    d4 = D4[int]()
 
 c: C
 C.d1
@@ -719,15 +730,21 @@ C.d3  # E: overload def (self: __main__.D3, obj: None, objtype: Any) -> __main__
 c.d3  # E: overload def (self: __main__.D3, obj: __main__.C, objtype: Any) -> builtins.int of function __main__.D3.__get__ is deprecated: use E3.__get__ instead
 c.d3 = 1
 c.d3 = "x"  # E: overload def (self: __main__.D3, obj: __main__.C, value: builtins.str) of function __main__.D3.__set__ is deprecated: use E3.__set__ instead
+
+C.d4
+c.d4  # E: overload def (self: __main__.D4[T`1], obj: __main__.C, objtype: Any) -> T`1 of function __main__.D4.__get__ is deprecated: deprecated instance access
 [builtins fixtures/property.pyi]
 
 
 [case testDeprecatedOverloadedFunction]
 # flags: --enable-error-code=deprecated
 
-from typing import Union, overload
+from typing import Any, overload, Union
 from typing_extensions import deprecated
 
+int_or_str: Union[int, str]
+any: Any
+
 @overload
 def f(x: int) -> int: ...
 @overload
@@ -738,6 +755,8 @@ def f(x: Union[int, str]) -> Union[int, str]: ...
 f  # E: function __main__.f is deprecated: use f2 instead
 f(1)  # E: function __main__.f is deprecated: use f2 instead
 f("x")  # E: function __main__.f is deprecated: use f2 instead
+f(int_or_str)  # E: function __main__.f is deprecated: use f2 instead
+f(any)  # E: function __main__.f is deprecated: use f2 instead
 f(1.0)  # E: function __main__.f is deprecated: use f2 instead \
         # E: No overload variant of "f" matches argument type "float" \
         # N: Possible overload variants: \
@@ -754,6 +773,8 @@ def g(x: Union[int, str]) -> Union[int, str]: ...
 g
 g(1)  # E: overload def (x: builtins.int) -> builtins.int of function __main__.g is deprecated: work with str instead
 g("x")
+g(int_or_str)  # E: overload def (x: builtins.int) -> builtins.int of function __main__.g is deprecated: work with str instead
+g(any)
 g(1.0)  # E: No overload variant of "g" matches argument type "float" \
         # N: Possible overload variants: \
         # N:     def g(x: int) -> int \
@@ -769,13 +790,62 @@ def h(x: Union[int, str]) -> Union[int, str]: ...
 h
 h(1)
 h("x")  # E: overload def (x: builtins.str) -> builtins.str of function __main__.h is deprecated: work with int instead
+h(int_or_str)  # E: overload def (x: builtins.str) -> builtins.str of function __main__.h is deprecated: work with int instead
+h(any)
 h(1.0)  # E: No overload variant of "h" matches argument type "float" \
         # N: Possible overload variants: \
         # N:     def h(x: int) -> int \
         # N:     def h(x: str) -> str
 
-[builtins fixtures/tuple.pyi]
+@overload
+def i(x: int) -> int: ...
+@overload
+@deprecated("work with int instead")
+def i(x: str) -> str: ...
+@overload
+def i(x: Any) -> Any: ...
+def i(x: Union[int, str]) -> Union[int, str]: ...
 
+i
+i(1)
+i("x")  # E: overload def (x: builtins.str) -> builtins.str of function __main__.i is deprecated: work with int instead
+i(int_or_str)  # E: overload def (x: builtins.str) -> builtins.str of function __main__.i is deprecated: work with int instead
+i(any)
+i(1.0)
+
+@overload
+def j(x: int) -> int: ...
+@overload
+def j(x: str) -> str: ...
+@overload
+@deprecated("work with int or str instead")
+def j(x: Any) -> Any: ...
+def j(x: Union[int, str]) -> Union[int, str]: ...
+
+j
+j(1)
+j("x")
+j(int_or_str)
+j(any)
+j(1.0)  # E: overload def (x: Any) -> Any of function __main__.j is deprecated: work with int or str instead
+
+@overload
+@deprecated("work with str instead")
+def k(x: int) -> int: ...
+@overload
+def k(x: str) -> str: ...
+@overload
+@deprecated("work with str instead")
+def k(x: object) -> Any: ...
+def k(x: object) -> Union[int, str]: ...
+
+k
+k(1)  # E: overload def (x: builtins.int) -> builtins.int of function __main__.k is deprecated: work with str instead
+k("x")
+k(int_or_str)  # E: overload def (x: builtins.int) -> builtins.int of function __main__.k is deprecated: work with str instead
+k(any)
+k(1.0)  # E: overload def (x: builtins.object) -> Any of function __main__.k is deprecated: work with str instead
+[builtins fixtures/tuple.pyi]
 
 [case testDeprecatedImportedOverloadedFunction]
 # flags: --enable-error-code=deprecated