[red-knot] improve function/bound method type display

crates/red_knot_ide/src/hover.rs

@@ -214,11 +214,11 @@ mod tests {
         "#,
         );
 
-        assert_snapshot!(test.hover(), @r"
-        Literal[foo]
+        assert_snapshot!(test.hover(), @r###"
+        def foo(a, b) -> Unknown
         ---------------------------------------------
         ```text
-        Literal[foo]
+        def foo(a, b) -> Unknown
         ```
         ---------------------------------------------
         info: lint:hover: Hovered content is
@@ -231,7 +231,7 @@ mod tests {
           |             |
           |             source
           |
-        ");
+        "###);
     }
 
     #[test]
@@ -312,11 +312,11 @@ mod tests {
             "#,
         );
 
-        assert_snapshot!(test.hover(), @r"
-        Literal[foo, bar]
+        assert_snapshot!(test.hover(), @r###"
+        (def foo(a, b) -> Unknown) | (def bar(a, b) -> Unknown)
         ---------------------------------------------
         ```text
-        Literal[foo, bar]
+        (def foo(a, b) -> Unknown) | (def bar(a, b) -> Unknown)
         ```
         ---------------------------------------------
         info: lint:hover: Hovered content is
@@ -329,7 +329,7 @@ mod tests {
            |             |
            |             source
            |
-        ");
+        "###);
     }
 
     #[test]

crates/red_knot_python_semantic/resources/mdtest/annotations/callable.md

@@ -289,7 +289,7 @@ def _(c: Callable[[int, Unpack[Ts]], int]):
 from typing import Callable
 
 def _(c: Callable[[int], int]):
-    reveal_type(c.__init__)  # revealed: Literal[__init__]
+    reveal_type(c.__init__)  # revealed: def __init__(self) -> None
     reveal_type(c.__class__)  # revealed: type
 
     # TODO: The member lookup for `Callable` uses `object` which does not have a `__call__`

crates/red_knot_python_semantic/resources/mdtest/attributes.md

@@ -1285,7 +1285,7 @@ from typing import Any
 class Foo(Any): ...
 
 reveal_type(Foo.bar)  # revealed: Any
-reveal_type(Foo.__repr__)  # revealed: Literal[__repr__] & Any
+reveal_type(Foo.__repr__)  # revealed: (def __repr__(self) -> str) & Any
 ```
 
 Similar principles apply if `Any` appears in the middle of an inheritance hierarchy:
@@ -1584,7 +1584,7 @@ Some attributes are special-cased, however:
 
 ```py
 reveal_type(f.__get__)  # revealed: <method-wrapper `__get__` of `f`>
-reveal_type(f.__call__)  # revealed: <bound method `__call__` of `Literal[f]`>
+reveal_type(f.__call__)  # revealed: <method-wrapper `__call__` of `f`>
 ```
 
 ### Int-literal attributes
@@ -1593,7 +1593,7 @@ Most attribute accesses on int-literal types are delegated to `builtins.int`, si
 integers are instances of that class:
 
 ```py
-reveal_type((2).bit_length)  # revealed: <bound method `bit_length` of `Literal[2]`>
+reveal_type((2).bit_length)  # revealed: bound method Literal[2].bit_length() -> int
 reveal_type((2).denominator)  # revealed: Literal[1]
 ```
 
@@ -1610,8 +1610,10 @@ Most attribute accesses on bool-literal types are delegated to `builtins.bool`,
 bools are instances of that class:
 
 ```py
-reveal_type(True.__and__)  # revealed: <bound method `__and__` of `Literal[True]`>
-reveal_type(False.__or__)  # revealed: <bound method `__or__` of `Literal[False]`>
+# revealed: bound method Literal[True].__and__(**kwargs: @Todo(todo signature **kwargs)) -> @Todo(return type of overloaded function)
+reveal_type(True.__and__)
+# revealed: bound method Literal[False].__or__(**kwargs: @Todo(todo signature **kwargs)) -> @Todo(return type of overloaded function)
+reveal_type(False.__or__)
 ```
 
 Some attributes are special-cased, however:
@@ -1626,8 +1628,9 @@ reveal_type(False.real)  # revealed: Literal[0]
 All attribute access on literal `bytes` types is currently delegated to `builtins.bytes`:
 
 ```py
-reveal_type(b"foo".join)  # revealed: <bound method `join` of `Literal[b"foo"]`>
-reveal_type(b"foo".endswith)  # revealed: <bound method `endswith` of `Literal[b"foo"]`>
+reveal_type(b"foo".join)  # revealed: bound method Literal[b"foo"].join(iterable_of_bytes: @Todo(generics), /) -> bytes
+# revealed: bound method Literal[b"foo"].endswith(suffix: @Todo(Support for `typing.TypeAlias`), start: SupportsIndex | None = ellipsis, end: SupportsIndex | None = ellipsis, /) -> bool
+reveal_type(b"foo".endswith)
 ```
 
 ## Instance attribute edge cases

crates/red_knot_python_semantic/resources/mdtest/binary/custom.md

@@ -350,30 +350,30 @@ reveal_type(no() + no())  # revealed: Unknown
 def f():
     pass
 
-# error: [unsupported-operator] "Operator `+` is unsupported between objects of type `Literal[f]` and `Literal[f]`"
+# error: [unsupported-operator] "Operator `+` is unsupported between objects of type `def f() -> Unknown` and `def f() -> Unknown`"
 reveal_type(f + f)  # revealed: Unknown
-# error: [unsupported-operator] "Operator `-` is unsupported between objects of type `Literal[f]` and `Literal[f]`"
+# error: [unsupported-operator] "Operator `-` is unsupported between objects of type `def f() -> Unknown` and `def f() -> Unknown`"
 reveal_type(f - f)  # revealed: Unknown
-# error: [unsupported-operator] "Operator `*` is unsupported between objects of type `Literal[f]` and `Literal[f]`"
+# error: [unsupported-operator] "Operator `*` is unsupported between objects of type `def f() -> Unknown` and `def f() -> Unknown`"
 reveal_type(f * f)  # revealed: Unknown
-# error: [unsupported-operator] "Operator `@` is unsupported between objects of type `Literal[f]` and `Literal[f]`"
+# error: [unsupported-operator] "Operator `@` is unsupported between objects of type `def f() -> Unknown` and `def f() -> Unknown`"
 reveal_type(f @ f)  # revealed: Unknown
-# error: [unsupported-operator] "Operator `/` is unsupported between objects of type `Literal[f]` and `Literal[f]`"
+# error: [unsupported-operator] "Operator `/` is unsupported between objects of type `def f() -> Unknown` and `def f() -> Unknown`"
 reveal_type(f / f)  # revealed: Unknown
-# error: [unsupported-operator] "Operator `%` is unsupported between objects of type `Literal[f]` and `Literal[f]`"
+# error: [unsupported-operator] "Operator `%` is unsupported between objects of type `def f() -> Unknown` and `def f() -> Unknown`"
 reveal_type(f % f)  # revealed: Unknown
-# error: [unsupported-operator] "Operator `**` is unsupported between objects of type `Literal[f]` and `Literal[f]`"
+# error: [unsupported-operator] "Operator `**` is unsupported between objects of type `def f() -> Unknown` and `def f() -> Unknown`"
 reveal_type(f**f)  # revealed: Unknown
-# error: [unsupported-operator] "Operator `<<` is unsupported between objects of type `Literal[f]` and `Literal[f]`"
+# error: [unsupported-operator] "Operator `<<` is unsupported between objects of type `def f() -> Unknown` and `def f() -> Unknown`"
 reveal_type(f << f)  # revealed: Unknown
-# error: [unsupported-operator] "Operator `>>` is unsupported between objects of type `Literal[f]` and `Literal[f]`"
+# error: [unsupported-operator] "Operator `>>` is unsupported between objects of type `def f() -> Unknown` and `def f() -> Unknown`"
 reveal_type(f >> f)  # revealed: Unknown
-# error: [unsupported-operator] "Operator `|` is unsupported between objects of type `Literal[f]` and `Literal[f]`"
+# error: [unsupported-operator] "Operator `|` is unsupported between objects of type `def f() -> Unknown` and `def f() -> Unknown`"
 reveal_type(f | f)  # revealed: Unknown
-# error: [unsupported-operator] "Operator `^` is unsupported between objects of type `Literal[f]` and `Literal[f]`"
+# error: [unsupported-operator] "Operator `^` is unsupported between objects of type `def f() -> Unknown` and `def f() -> Unknown`"
 reveal_type(f ^ f)  # revealed: Unknown
-# error: [unsupported-operator] "Operator `&` is unsupported between objects of type `Literal[f]` and `Literal[f]`"
+# error: [unsupported-operator] "Operator `&` is unsupported between objects of type `def f() -> Unknown` and `def f() -> Unknown`"
 reveal_type(f & f)  # revealed: Unknown
-# error: [unsupported-operator] "Operator `//` is unsupported between objects of type `Literal[f]` and `Literal[f]`"
+# error: [unsupported-operator] "Operator `//` is unsupported between objects of type `def f() -> Unknown` and `def f() -> Unknown`"
 reveal_type(f // f)  # revealed: Unknown
 ```

crates/red_knot_python_semantic/resources/mdtest/call/getattr_static.md

@@ -57,7 +57,8 @@ We can access attributes on objects of all kinds:
 import sys
 
 reveal_type(inspect.getattr_static(sys, "dont_write_bytecode"))  # revealed: bool
-reveal_type(inspect.getattr_static(inspect, "getattr_static"))  # revealed: Literal[getattr_static]
+# revealed: def getattr_static(obj: object, attr: str, default: Any | None = ellipsis) -> Any
+reveal_type(inspect.getattr_static(inspect, "getattr_static"))
 
 reveal_type(inspect.getattr_static(1, "real"))  # revealed: property
 ```
@@ -143,8 +144,9 @@ from typing import Any
 def _(a: Any, tuple_of_any: tuple[Any]):
     reveal_type(inspect.getattr_static(a, "x", "default"))  # revealed: Any | Literal["default"]
 
-    # TODO: Ideally, this would just be `Literal[index]`
-    reveal_type(inspect.getattr_static(tuple_of_any, "index", "default"))  # revealed: Literal[index] | Literal["default"]
+    # TODO: Ideally, this would just be `def index(self, value: Any, start: SupportsIndex = Literal[0], stop: SupportsIndex = int, /) -> int`
+    # revealed: (def index(self, value: Any, start: SupportsIndex = Literal[0], stop: SupportsIndex = int, /) -> int) | Literal["default"]
+    reveal_type(inspect.getattr_static(tuple_of_any, "index", "default"))
 ```
 
 [official documentation]: https://docs.python.org/3/library/inspect.html#inspect.getattr_static

crates/red_knot_python_semantic/resources/mdtest/call/methods.md

@@ -32,20 +32,20 @@ the latter case, it returns a *bound method* object:
 ```py
 from inspect import getattr_static
 
-reveal_type(getattr_static(C, "f"))  # revealed: Literal[f]
+reveal_type(getattr_static(C, "f"))  # revealed: def f(self, x: int) -> str
 
 reveal_type(getattr_static(C, "f").__get__)  # revealed: <method-wrapper `__get__` of `f`>
 
-reveal_type(getattr_static(C, "f").__get__(None, C))  # revealed: Literal[f]
-reveal_type(getattr_static(C, "f").__get__(C(), C))  # revealed: <bound method `f` of `C`>
+reveal_type(getattr_static(C, "f").__get__(None, C))  # revealed: def f(self, x: int) -> str
+reveal_type(getattr_static(C, "f").__get__(C(), C))  # revealed: bound method C.f(x: int) -> str
 ```
 
 In conclusion, this is why we see the following two types when accessing the `f` attribute on the
 class object `C` and on an instance `C()`:
 
 ```py
-reveal_type(C.f)  # revealed: Literal[f]
-reveal_type(C().f)  # revealed: <bound method `f` of `C`>
+reveal_type(C.f)  # revealed: def f(self, x: int) -> str
+reveal_type(C().f)  # revealed: bound method C.f(x: int) -> str
 ```
 
 A bound method is a callable object that contains a reference to the `instance` that it was called
@@ -56,7 +56,7 @@ via `__func__`):
 bound_method = C().f
 
 reveal_type(bound_method.__self__)  # revealed: C
-reveal_type(bound_method.__func__)  # revealed: Literal[f]
+reveal_type(bound_method.__func__)  # revealed: def f(self, x: int) -> str
 ```
 
 When we call the bound method, the `instance` is implicitly passed as the first argument (`self`):
@@ -80,13 +80,13 @@ When we access methods from derived classes, they will be bound to instances of
 class D(C):
     pass
 
-reveal_type(D().f)  # revealed: <bound method `f` of `D`>
+reveal_type(D().f)  # revealed: bound method D.f(x: int) -> str
 ```
 
 If we access an attribute on a bound method object itself, it will defer to `types.MethodType`:
 
 ```py
-reveal_type(bound_method.__hash__)  # revealed: <bound method `__hash__` of `MethodType`>
+reveal_type(bound_method.__hash__)  # revealed: bound method MethodType.__hash__() -> int
 ```
 
 If an attribute is not available on the bound method object, it will be looked up on the underlying
@@ -181,10 +181,10 @@ class B:
         return "a"
 
 def f(a_or_b: A | B, any_or_a: Any | A):
-    reveal_type(a_or_b.f)  # revealed: <bound method `f` of `A`> | <bound method `f` of `B`>
+    reveal_type(a_or_b.f)  # revealed: (bound method A.f() -> int) | (bound method B.f() -> str)
     reveal_type(a_or_b.f())  # revealed: int | str
 
-    reveal_type(any_or_a.f)  # revealed: Any | <bound method `f` of `A`>
+    reveal_type(any_or_a.f)  # revealed: Any | (bound method A.f() -> int)
     reveal_type(any_or_a.f())  # revealed: Any | int
 ```
 
@@ -198,7 +198,7 @@ python-version = "3.12"
 ```py
 type IntOrStr = int | str
 
-reveal_type(IntOrStr.__or__)  # revealed: <bound method `__or__` of `typing.TypeAliasType`>
+reveal_type(IntOrStr.__or__)  # revealed: bound method typing.TypeAliasType.__or__(right: Any) -> _SpecialForm
 ```
 
 ## Error cases: Calling `__get__` for methods
@@ -270,7 +270,7 @@ class Meta(type):
 class C(metaclass=Meta):
     pass
 
-reveal_type(C.f)  # revealed: <bound method `f` of `Literal[C]`>
+reveal_type(C.f)  # revealed: bound method Literal[C].f(arg: int) -> str
 reveal_type(C.f(1))  # revealed: str
 ```
 
@@ -322,8 +322,8 @@ class C:
     def f(cls: type[C], x: int) -> str:
         return "a"
 
-reveal_type(C.f)  # revealed: <bound method `f` of `Literal[C]`>
-reveal_type(C().f)  # revealed: <bound method `f` of `type[C]`>
+reveal_type(C.f)  # revealed: bound method Literal[C].f(x: int) -> str
+reveal_type(C().f)  # revealed: bound method type[C].f(x: int) -> str
 ```
 
 The `cls` method argument is then implicitly passed as the first argument when calling the method:
@@ -360,8 +360,8 @@ When a class method is accessed on a derived class, it is bound to that derived
 class Derived(C):
     pass
 
-reveal_type(Derived.f)  # revealed: <bound method `f` of `Literal[Derived]`>
-reveal_type(Derived().f)  # revealed: <bound method `f` of `type[Derived]`>
+reveal_type(Derived.f)  # revealed: bound method Literal[Derived].f(x: int) -> str
+reveal_type(Derived().f)  # revealed: bound method type[Derived].f(x: int) -> str
 
 reveal_type(Derived.f(1))  # revealed: str
 reveal_type(Derived().f(1))  # revealed: str
@@ -379,22 +379,22 @@ class C:
     @classmethod
     def f(cls): ...
 
-reveal_type(getattr_static(C, "f"))  # revealed: Literal[f]
+reveal_type(getattr_static(C, "f"))  # revealed: def f(cls) -> Unknown
 reveal_type(getattr_static(C, "f").__get__)  # revealed: <method-wrapper `__get__` of `f`>
 ```
 
 But we correctly model how the `classmethod` descriptor works:
 
 ```py
-reveal_type(getattr_static(C, "f").__get__(None, C))  # revealed: <bound method `f` of `Literal[C]`>
-reveal_type(getattr_static(C, "f").__get__(C(), C))  # revealed: <bound method `f` of `Literal[C]`>
-reveal_type(getattr_static(C, "f").__get__(C()))  # revealed: <bound method `f` of `type[C]`>
+reveal_type(getattr_static(C, "f").__get__(None, C))  # revealed: bound method Literal[C].f() -> Unknown
+reveal_type(getattr_static(C, "f").__get__(C(), C))  # revealed: bound method Literal[C].f() -> Unknown
+reveal_type(getattr_static(C, "f").__get__(C()))  # revealed: bound method type[C].f() -> Unknown
 ```
 
 The `owner` argument takes precedence over the `instance` argument:
 
 ```py
-reveal_type(getattr_static(C, "f").__get__("dummy", C))  # revealed: <bound method `f` of `Literal[C]`>
+reveal_type(getattr_static(C, "f").__get__("dummy", C))  # revealed: bound method Literal[C].f() -> Unknown
 ```
 
 ### Classmethods mixed with other decorators

crates/red_knot_python_semantic/resources/mdtest/decorators.md

@@ -207,7 +207,7 @@ first argument:
 def wrong_signature(f: int) -> str:
     return "a"
 
-# error: [invalid-argument-type] "Argument to this function is incorrect: Expected `int`, found `Literal[f]`"
+# error: [invalid-argument-type] "Argument to this function is incorrect: Expected `int`, found `def f(x) -> Unknown`"
 @wrong_signature
 def f(x): ...
 

crates/red_knot_python_semantic/resources/mdtest/descriptor_protocol.md

@@ -563,18 +563,18 @@ from inspect import getattr_static
 def f(x: object) -> str:
     return "a"
 
-reveal_type(f)  # revealed: Literal[f]
+reveal_type(f)  # revealed: def f(x: object) -> str
 reveal_type(f.__get__)  # revealed: <method-wrapper `__get__` of `f`>
-reveal_type(f.__get__(None, type(f)))  # revealed: Literal[f]
+reveal_type(f.__get__(None, type(f)))  # revealed: def f(x: object) -> str
 reveal_type(f.__get__(None, type(f))(1))  # revealed: str
 
 wrapper_descriptor = getattr_static(f, "__get__")
 
 reveal_type(wrapper_descriptor)  # revealed: <wrapper-descriptor `__get__` of `function` objects>
-reveal_type(wrapper_descriptor(f, None, type(f)))  # revealed: Literal[f]
+reveal_type(wrapper_descriptor(f, None, type(f)))  # revealed: def f(x: object) -> str
 
 # Attribute access on the method-wrapper `f.__get__` falls back to `MethodWrapperType`:
-reveal_type(f.__get__.__hash__)  # revealed: <bound method `__hash__` of `MethodWrapperType`>
+reveal_type(f.__get__.__hash__)  # revealed: bound method MethodWrapperType.__hash__() -> int
 
 # Attribute access on the wrapper-descriptor falls back to `WrapperDescriptorType`:
 reveal_type(wrapper_descriptor.__qualname__)  # revealed: str
@@ -587,7 +587,7 @@ class C: ...
 
 bound_method = wrapper_descriptor(f, C(), C)
 
-reveal_type(bound_method)  # revealed: <bound method `f` of `C`>
+reveal_type(bound_method)  # revealed: bound method C.f() -> str
 ```
 
 We can then call it, and the instance of `C` is implicitly passed to the first parameter of `f`

crates/red_knot_python_semantic/resources/mdtest/exception/control_flow.md

@@ -591,9 +591,9 @@ try:
             reveal_type(x)  # revealed: B | D
         reveal_type(x)  # revealed: B | D
     x = foo
-    reveal_type(x)  # revealed: Literal[foo]
+    reveal_type(x)  # revealed: def foo(param=A) -> Unknown
 except:
-    reveal_type(x)  # revealed: Literal[1] | Literal[foo]
+    reveal_type(x)  # revealed: Literal[1] | (def foo(param=A) -> Unknown)
 
     class Bar:
         x = could_raise_returns_E()
@@ -603,9 +603,9 @@ except:
     reveal_type(x)  # revealed: Literal[Bar]
 finally:
     # TODO: should be `Literal[1] | Literal[foo] | Literal[Bar]`
-    reveal_type(x)  # revealed: Literal[foo] | Literal[Bar]
+    reveal_type(x)  # revealed: (def foo(param=A) -> Unknown) | Literal[Bar]
 
-reveal_type(x)  # revealed: Literal[foo] | Literal[Bar]
+reveal_type(x)  # revealed: (def foo(param=A) -> Unknown) | Literal[Bar]
 ```
 
 [1]: https://astral-sh.notion.site/Exception-handler-control-flow-11348797e1ca80bb8ce1e9aedbbe439d