Fix collections.abc integration test and add special-casing for Sized to reduce false positives

Author: AlexWaygood

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

@@ -81,8 +81,7 @@ reveal_type(DictSubclass.__mro__)
 
 class SetSubclass(typing.Set): ...
 
-# TODO: should have `Generic`, should not have `Unknown`
-# revealed: tuple[Literal[SetSubclass], Literal[set], Unknown, Literal[object]]
+# revealed: tuple[Literal[SetSubclass], Literal[set], Literal[MutableSet], Literal[AbstractSet], Literal[Collection], Literal[Iterable], Literal[Container], @Todo(protocol), Literal[object]]
 reveal_type(SetSubclass.__mro__)
 
 class FrozenSetSubclass(typing.FrozenSet): ...
@@ -114,8 +113,7 @@ reveal_type(DefaultDictSubclass.__mro__)
 
 class DequeSubclass(typing.Deque): ...
 
-# TODO: Should be (DequeSubclass, deque, MutableSequence, Sequence, Reversible, Collection, Sized, Iterable, Container, Generic, object)
-# revealed: tuple[Literal[DequeSubclass], Literal[deque], Unknown, Literal[object]]
+# revealed: tuple[Literal[DequeSubclass], Literal[deque], Literal[MutableSequence], Literal[Sequence], Literal[Reversible], Literal[Collection], Literal[Iterable], Literal[Container], @Todo(protocol), Literal[object]]
 reveal_type(DequeSubclass.__mro__)
 
 class OrderedDictSubclass(typing.OrderedDict): ...

crates/red_knot_python_semantic/resources/mdtest/attributes.md

@@ -551,6 +551,7 @@ reveal_type(C().x)  # revealed: str
 class C:
     def __init__(self) -> None:
         # error: [too-many-positional-arguments]
+        # error: [invalid-argument-type]
         self.x: int = len(1, 2, 3)
 ```
 

crates/red_knot_python_semantic/resources/mdtest/expression/len.md

@@ -229,6 +229,6 @@ reveal_type(len(SecondRequiredArgument()))  # revealed: Literal[1]
 ```py
 class NoDunderLen: ...
 
-# TODO: Emit a diagnostic
+# error: [invalid-argument-type]
 reveal_type(len(NoDunderLen()))  # revealed: int
 ```

crates/red_knot_python_semantic/resources/mdtest/import/star.md

@@ -306,12 +306,13 @@ For `.pyi` files, we should consider all imports private to the stub unless they
 
 ```pyi
 X: bool = True
+Y: bool = True
 ```
 
 `b.pyi`:
 
 ```pyi
-from a import X
+from a import X, Y as Y
 ```
 
 `c.py`:
@@ -323,6 +324,8 @@ from b import *
 #
 # error: [unresolved-reference]
 reveal_type(X)  # revealed: Unknown
+
+reveal_type(Y)  # revealed: bool
 ```
 
 ### Symbols in statically known branches
@@ -717,11 +720,8 @@ are present due to `*` imports.
 import typing
 import collections.abc
 
-# TODO these should not error, should not reveal `Unknown`
-# error: [unresolved-attribute]
-reveal_type(collections.abc.Sequence)  # revealed: Unknown
-# error: [unresolved-attribute]
-reveal_type(collections.abc.Callable)  # revealed: Unknown
+reveal_type(collections.abc.Sequence)  # revealed: Literal[Sequence]
+reveal_type(collections.abc.Callable)  # revealed: typing.Callable
 ```
 
 ## Invalid `*` imports

crates/red_knot_python_semantic/src/semantic_index/re_exports.rs

@@ -73,7 +73,7 @@ impl<'db> Visitor<'db> for ExportFinder<'db> {
         if self.file.is_stub(self.db.upcast()) {
             // If the source is a stub, names defined by imports are only exported
             // if they use the explicit `foo as foo` syntax:
-            if asname.as_ref() == Some(name) {
+            if asname.as_ref().is_some_and(|asname| asname.id == name.id) {
                 self.possibly_add_export(&name.id);
             }
         } else {

crates/red_knot_python_semantic/src/types.rs

@@ -887,6 +887,19 @@ impl<'db> Type<'db> {
                 }
             }
 
+            // TODO: ditto for avoiding false positives when checking function calls with `Sized` parameters.
+            (lhs, Type::Instance(InstanceType { class }))
+                if class.is_known(db, KnownClass::Sized) =>
+            {
+                matches!(
+                    lhs.to_meta_type(db).member(db, "__len__"),
+                    SymbolAndQualifiers {
+                        symbol: Symbol::Type(..),
+                        ..
+                    }
+                )
+            }
+
             // TODO other types containing gradual forms (e.g. generics containing Any/Unknown)
             _ => self.is_subtype_of(db, target),
         }

crates/red_knot_python_semantic/src/types/class.rs

@@ -846,6 +846,7 @@ pub enum KnownClass {
     TypeAliasType,
     NoDefaultType,
     NewType,
+    Sized,
     // TODO: This can probably be removed when we have support for protocols
     SupportsIndex,
     // Collections
@@ -923,6 +924,7 @@ impl<'db> KnownClass {
             | Self::DefaultDict
             | Self::Deque
             | Self::Float
+            | Self::Sized
             | Self::Classmethod => Truthiness::Ambiguous,
         }
     }
@@ -967,6 +969,7 @@ impl<'db> KnownClass {
             Self::Counter => "Counter",
             Self::DefaultDict => "defaultdict",
             Self::Deque => "deque",
+            Self::Sized => "Sized",
             Self::OrderedDict => "OrderedDict",
             // For example, `typing.List` is defined as `List = _Alias()` in typeshed
             Self::StdlibAlias => "_Alias",
@@ -1127,9 +1130,11 @@ impl<'db> KnownClass {
             | Self::MethodWrapperType
             | Self::WrapperDescriptorType => KnownModule::Types,
             Self::NoneType => KnownModule::Typeshed,
-            Self::SpecialForm | Self::TypeVar | Self::StdlibAlias | Self::SupportsIndex => {
-                KnownModule::Typing
-            }
+            Self::SpecialForm
+            | Self::TypeVar
+            | Self::StdlibAlias
+            | Self::SupportsIndex
+            | Self::Sized => KnownModule::Typing,
             Self::TypeAliasType | Self::TypeVarTuple | Self::ParamSpec | Self::NewType => {
                 KnownModule::TypingExtensions
             }
@@ -1207,6 +1212,7 @@ impl<'db> KnownClass {
             | Self::TypeVar
             | Self::ParamSpec
             | Self::TypeVarTuple
+            | Self::Sized
             | Self::NewType => false,
         }
     }
@@ -1259,6 +1265,7 @@ impl<'db> KnownClass {
             | Self::TypeVar
             | Self::ParamSpec
             | Self::TypeVarTuple
+            | Self::Sized
             | Self::NewType => false,
         }
     }
@@ -1311,6 +1318,7 @@ impl<'db> KnownClass {
             "_SpecialForm" => Self::SpecialForm,
             "_NoDefaultType" => Self::NoDefaultType,
             "SupportsIndex" => Self::SupportsIndex,
+            "Sized" => Self::Sized,
             "_version_info" => Self::VersionInfo,
             "ellipsis" if Program::get(db).python_version(db) <= PythonVersion::PY39 => {
                 Self::EllipsisType
@@ -1370,6 +1378,7 @@ impl<'db> KnownClass {
             | Self::SupportsIndex
             | Self::ParamSpec
             | Self::TypeVarTuple
+            | Self::Sized
             | Self::NewType => matches!(module, KnownModule::Typing | KnownModule::TypingExtensions),
         }
     }