[ty] Infer type of self for decorated methods and properties (#21123)

## Summary

Infer a type of unannotated `self` parameters in decorated methods /
properties.

closes https://github.com/astral-sh/ty/issues/1448

## Test Plan

Existing tests, some new tests.

crates/ty_python_semantic/resources/mdtest/annotations/self.md

@@ -116,7 +116,7 @@ A.implicit_self(1)
 Passing `self` implicitly also verifies the type:
 
 ```py
-from typing import Never
+from typing import Never, Callable
 
 class Strange:
     def can_not_be_called(self: Never) -> None: ...
@@ -139,6 +139,9 @@ The first parameter of instance methods always has type `Self`, if it is not exp
 The name `self` is not special in any way.
 
 ```py
+def some_decorator(f: Callable) -> Callable:
+    return f
+
 class B:
     def name_does_not_matter(this) -> Self:
         reveal_type(this)  # revealed: Self@name_does_not_matter
@@ -153,18 +156,45 @@ class B:
         reveal_type(self)  # revealed: Self@keyword_only
         return self
 
+    @some_decorator
+    def decorated_method(self) -> Self:
+        reveal_type(self)  # revealed: Self@decorated_method
+        return self
+
     @property
     def a_property(self) -> Self:
-        # TODO: Should reveal Self@a_property
-        reveal_type(self)  # revealed: Unknown
+        reveal_type(self)  # revealed: Self@a_property
         return self
 
+    async def async_method(self) -> Self:
+        reveal_type(self)  # revealed: Self@async_method
+        return self
+
+    @staticmethod
+    def static_method(self):
+        # The parameter can be called `self`, but it is not treated as `Self`
+        reveal_type(self)  # revealed: Unknown
+
+    @staticmethod
+    @some_decorator
+    def decorated_static_method(self):
+        reveal_type(self)  # revealed: Unknown
+    # TODO: On Python <3.10, this should ideally be rejected, because `staticmethod` objects were not callable.
+    @some_decorator
+    @staticmethod
+    def decorated_static_method_2(self):
+        reveal_type(self)  # revealed: Unknown
+
 reveal_type(B().name_does_not_matter())  # revealed: B
 reveal_type(B().positional_only(1))  # revealed: B
 reveal_type(B().keyword_only(x=1))  # revealed: B
+reveal_type(B().decorated_method())  # revealed: Unknown
 
 # TODO: this should be B
 reveal_type(B().a_property)  # revealed: Unknown
+
+async def _():
+    reveal_type(await B().async_method())  # revealed: B
 ```
 
 This also works for generic classes:

crates/ty_python_semantic/resources/mdtest/overloads.md

@@ -598,6 +598,7 @@ class CheckClassMethod:
     # error: [invalid-overload]
     def try_from3(cls, x: int | str) -> CheckClassMethod | None:
         if isinstance(x, int):
+            # error: [call-non-callable]
             return cls(x)
         return None
 

crates/ty_python_semantic/resources/mdtest/snapshots/overloads.md_-_Overloads_-_Invalid_-_Inconsistent_decorat…_-_`@classmethod`_(aaa04d4cfa3adaba).snap

@@ -53,20 +53,21 @@ mdtest path: crates/ty_python_semantic/resources/mdtest/overloads.md
 39 |     # error: [invalid-overload]
 40 |     def try_from3(cls, x: int | str) -> CheckClassMethod | None:
 41 |         if isinstance(x, int):
-42 |             return cls(x)
-43 |         return None
-44 | 
-45 |     @overload
-46 |     @classmethod
-47 |     def try_from4(cls, x: int) -> CheckClassMethod: ...
-48 |     @overload
-49 |     @classmethod
-50 |     def try_from4(cls, x: str) -> None: ...
-51 |     @classmethod
-52 |     def try_from4(cls, x: int | str) -> CheckClassMethod | None:
-53 |         if isinstance(x, int):
-54 |             return cls(x)
-55 |         return None
+42 |             # error: [call-non-callable]
+43 |             return cls(x)
+44 |         return None
+45 | 
+46 |     @overload
+47 |     @classmethod
+48 |     def try_from4(cls, x: int) -> CheckClassMethod: ...
+49 |     @overload
+50 |     @classmethod
+51 |     def try_from4(cls, x: str) -> None: ...
+52 |     @classmethod
+53 |     def try_from4(cls, x: int | str) -> CheckClassMethod | None:
+54 |         if isinstance(x, int):
+55 |             return cls(x)
+56 |         return None
 ```
 
 # Diagnostics
@@ -124,8 +125,22 @@ error[invalid-overload]: Overloaded function `try_from3` does not use the `@clas
    |         |
    |         Missing here
 41 |         if isinstance(x, int):
-42 |             return cls(x)
+42 |             # error: [call-non-callable]
    |
 info: rule `invalid-overload` is enabled by default
 
 ```
+
+```
+error[call-non-callable]: Object of type `CheckClassMethod` is not callable
+  --> src/mdtest_snippet.py:43:20
+   |
+41 |         if isinstance(x, int):
+42 |             # error: [call-non-callable]
+43 |             return cls(x)
+   |                    ^^^^^^
+44 |         return None
+   |
+info: rule `call-non-callable` is enabled by default
+
+```