[ty] Fix more false positives related to Generic or Protocol being subscripted with a ParamSpec or TypeVarTuple (#19764)

crates/ty_python_semantic/resources/mdtest/generics/legacy/classes.md

@@ -7,18 +7,30 @@ At its simplest, to define a generic class using the legacy syntax, you inherit
 
 ```py
 from ty_extensions import generic_context
-from typing import Generic, TypeVar
+from typing_extensions import Generic, TypeVar, TypeVarTuple, ParamSpec, Unpack
 
 T = TypeVar("T")
 S = TypeVar("S")
+P = ParamSpec("P")
+Ts = TypeVarTuple("Ts")
 
 class SingleTypevar(Generic[T]): ...
 class MultipleTypevars(Generic[T, S]): ...
+class SingleParamSpec(Generic[P]): ...
+class TypeVarAndParamSpec(Generic[P, T]): ...
+class SingleTypeVarTuple(Generic[Unpack[Ts]]): ...
+class TypeVarAndTypeVarTuple(Generic[T, Unpack[Ts]]): ...
 
 # revealed: tuple[T@SingleTypevar]
 reveal_type(generic_context(SingleTypevar))
 # revealed: tuple[T@MultipleTypevars, S@MultipleTypevars]
 reveal_type(generic_context(MultipleTypevars))
+
+# TODO: support `ParamSpec`/`TypeVarTuple` properly (these should not reveal `None`)
+reveal_type(generic_context(SingleParamSpec))  # revealed: None
+reveal_type(generic_context(TypeVarAndParamSpec))  # revealed: None
+reveal_type(generic_context(SingleTypeVarTuple))  # revealed: None
+reveal_type(generic_context(TypeVarAndTypeVarTuple))  # revealed: None
 ```
 
 Inheriting from `Generic` multiple times yields a `duplicate-base` diagnostic, just like any other

crates/ty_python_semantic/resources/mdtest/generics/pep695/classes.md

@@ -7,19 +7,30 @@ python-version = "3.13"
 
 ## Defining a generic class
 
-At its simplest, to define a generic class using PEP 695 syntax, you add a list of typevars after
-the class name.
+At its simplest, to define a generic class using PEP 695 syntax, you add a list of `TypeVar`s,
+`ParamSpec`s or `TypeVarTuple`s after the class name.
 
 ```py
 from ty_extensions import generic_context
 
 class SingleTypevar[T]: ...
 class MultipleTypevars[T, S]: ...
+class SingleParamSpec[**P]: ...
+class TypeVarAndParamSpec[T, **P]: ...
+class SingleTypeVarTuple[*Ts]: ...
+class TypeVarAndTypeVarTuple[T, *Ts]: ...
 
 # revealed: tuple[T@SingleTypevar]
 reveal_type(generic_context(SingleTypevar))
 # revealed: tuple[T@MultipleTypevars, S@MultipleTypevars]
 reveal_type(generic_context(MultipleTypevars))
+
+# TODO: support `ParamSpec`/`TypeVarTuple` properly
+# (these should include the `ParamSpec`s and `TypeVarTuple`s in their generic contexts)
+reveal_type(generic_context(SingleParamSpec))  # revealed: tuple[()]
+reveal_type(generic_context(TypeVarAndParamSpec))  # revealed: tuple[T@TypeVarAndParamSpec]
+reveal_type(generic_context(SingleTypeVarTuple))  # revealed: tuple[()]
+reveal_type(generic_context(TypeVarAndTypeVarTuple))  # revealed: tuple[T@TypeVarAndTypeVarTuple]
 ```
 
 You cannot use the same typevar more than once.

crates/ty_python_semantic/src/types.rs

@@ -6374,6 +6374,8 @@ pub enum DynamicType {
     /// A special Todo-variant for type aliases declared using `typing.TypeAlias`.
     /// A temporary variant to detect and special-case the handling of these aliases in autocomplete suggestions.
     TodoTypeAlias,
+    /// A special Todo-variant for `Unpack[Ts]`, so that we can treat it specially in `Generic[Unpack[Ts]]`
+    TodoUnpack,
 }
 
 impl DynamicType {
@@ -6398,6 +6400,13 @@ impl std::fmt::Display for DynamicType {
                     f.write_str("@Todo")
                 }
             }
+            DynamicType::TodoUnpack => {
+                if cfg!(debug_assertions) {
+                    f.write_str("@Todo(typing.Unpack)")
+                } else {
+                    f.write_str("@Todo")
+                }
+            }
             DynamicType::TodoTypeAlias => {
                 if cfg!(debug_assertions) {
                     f.write_str("@Todo(Support for `typing.TypeAlias`)")

crates/ty_python_semantic/src/types/class_base.rs

@@ -52,7 +52,8 @@ impl<'db> ClassBase<'db> {
             ClassBase::Dynamic(
                 DynamicType::Todo(_)
                 | DynamicType::TodoPEP695ParamSpec
-                | DynamicType::TodoTypeAlias,
+                | DynamicType::TodoTypeAlias
+                | DynamicType::TodoUnpack,
             ) => "@Todo",
             ClassBase::Protocol => "Protocol",
             ClassBase::Generic => "Generic",

crates/ty_python_semantic/src/types/infer.rs

@@ -7286,6 +7286,7 @@ impl<'db, 'ast> TypeInferenceBuilder<'db, 'ast> {
                 todo @ Type::Dynamic(
                     DynamicType::Todo(_)
                     | DynamicType::TodoPEP695ParamSpec
+                    | DynamicType::TodoUnpack
                     | DynamicType::TodoTypeAlias,
                 ),
                 _,
@@ -7296,6 +7297,7 @@ impl<'db, 'ast> TypeInferenceBuilder<'db, 'ast> {
                 todo @ Type::Dynamic(
                     DynamicType::Todo(_)
                     | DynamicType::TodoPEP695ParamSpec
+                    | DynamicType::TodoUnpack
                     | DynamicType::TodoTypeAlias,
                 ),
                 _,
@@ -8803,6 +8805,10 @@ impl<'db, 'ast> TypeInferenceBuilder<'db, 'ast> {
                 Some(todo_type!("doubly-specialized typing.Generic"))
             }
 
+            (Type::SpecialForm(SpecialFormType::Unpack), _) => {
+                Some(Type::Dynamic(DynamicType::TodoUnpack))
+            }
+
             (Type::SpecialForm(special_form), _) if special_form.class().is_special_form() => {
                 Some(todo_type!("Inference of subscript on special form"))
             }
@@ -8969,6 +8975,7 @@ impl<'db, 'ast> TypeInferenceBuilder<'db, 'ast> {
             .iter()
             .map(|typevar| match typevar {
                 Type::KnownInstance(KnownInstanceType::TypeVar(typevar)) => Ok(*typevar),
+                Type::Dynamic(DynamicType::TodoUnpack) => Err(GenericContextError::NotYetSupported),
                 Type::NominalInstance(NominalInstanceType { class, .. })
                     if matches!(
                         class.known(self.db()),

crates/ty_python_semantic/src/types/type_ordering.rs

@@ -262,6 +262,9 @@ fn dynamic_elements_ordering(left: DynamicType, right: DynamicType) -> Ordering
         (DynamicType::TodoPEP695ParamSpec, _) => Ordering::Less,
         (_, DynamicType::TodoPEP695ParamSpec) => Ordering::Greater,
 
+        (DynamicType::TodoUnpack, _) => Ordering::Less,
+        (_, DynamicType::TodoUnpack) => Ordering::Greater,
+
         (DynamicType::TodoTypeAlias, _) => Ordering::Less,
         (_, DynamicType::TodoTypeAlias) => Ordering::Greater,
     }