Fix StringIO initialization, fixes #408

Author: davidhalter

crates/zuban_python/src/file/type_computation/class.rs

@@ -1651,8 +1651,7 @@ impl<'db: 'a, 'a> ClassInitializer<'a> {
                     .any(|&l| NodeRef::from_link(db, l).as_code() == name)
             {
                 for (i, base) in mro.iter().enumerate() {
-                    if base.is_direct_base
-                        && mro_index != i
+                    if mro_index != i
                         && let Type::Class(c) = &base.type_
                     {
                         let class = c.class(db);

crates/zuban_python/tests/mypylike/tests/classes.test

@@ -2795,3 +2795,9 @@ class Movie(TypedDict):
 @disjoint_base  # E: @disjoint_base cannot be used with protocol class
 class SupportsClose(Protocol):
     def close(self) -> None: ...
+
+[case string_io_initialization]
+# From GH #408
+from io import StringIO
+
+StringIO()