Traverse type alias args in collect visitor (#19943)

Fixes #19941

Fix is trivial (and a bit embarrassing, LOL).

Author: ilevkivskyi

mypy/type_visitor.py

@@ -51,7 +51,7 @@
     get_proper_type,
 )
 
-T = TypeVar("T")
+T = TypeVar("T", covariant=True)
 
 
 @trait

mypy/types.py

@@ -3938,8 +3938,12 @@ def visit_type_alias_type(self, t: TypeAliasType, /) -> list[mypy.nodes.TypeAlia
         assert t.alias is not None
         if t.alias not in self.seen_alias_nodes:
             self.seen_alias_nodes.add(t.alias)
-            return [t.alias] + t.alias.target.accept(self)
-        return []
+            res = [t.alias] + t.alias.target.accept(self)
+        else:
+            res = []
+        for arg in t.args:
+            res.extend(arg.accept(self))
+        return res
 
 
 def is_named_instance(t: Type, fullnames: str | tuple[str, ...]) -> TypeGuard[Instance]:

test-data/unit/check-recursive-types.test

@@ -1014,3 +1014,12 @@ from bogus import Foo  # type: ignore
 
 A = Callable[[Foo, "B"], Foo]  # E: Type alias target becomes "Callable[[Any, B], Any]" due to an unfollowed import
 B = Callable[[Foo, A], Foo]  # E: Type alias target becomes "Callable[[Any, A], Any]" due to an unfollowed import
+
+[case testRecursiveAliasOnArgumentDetected]
+from typing import TypeVar
+
+T = TypeVar("T")
+L = list[T]
+
+A = L[A]
+a: A = 1  # E: Incompatible types in assignment (expression has type "int", variable has type "A")