use never and unbound

crates/red_knot_python_semantic/src/types/infer.rs

@@ -1577,7 +1577,7 @@ impl<'db> TypeInferenceBuilder<'db> {
         let member_ty = module_ty.member(self.db, &ast::name::Name::new(&name.id));
 
         // TODO: What if it's a union where one of the elements is `Unbound`?
-        if member_ty.is_unbound() {
+        if member_ty.is_unbound() || member_ty.is_never() {
             self.add_diagnostic(
                 AnyNodeRef::Alias(alias),
                 "unresolved-import",
@@ -1594,7 +1594,9 @@ impl<'db> TypeInferenceBuilder<'db> {
         // the runtime error will occur immediately (rather than when the symbol is *used*,
         // as would be the case for a symbol with type `Unbound`), so it's appropriate to
         // think of the type of the imported symbol as `Unknown` rather than `Unbound`
-        let ty = member_ty.replace_unbound_with(self.db, Type::Unknown);
+        let ty = member_ty
+            .replace_never_with(self.db, Type::Unknown)
+            .replace_unbound_with(self.db, Type::Unknown);
 
         self.add_declaration_with_binding(alias.into(), definition, ty, ty);
     }
@@ -2207,6 +2209,7 @@ impl<'db> TypeInferenceBuilder<'db> {
                     return symbol_ty(self.db, enclosing_scope_id, name);
                 }
             }
+
             // No nonlocal binding, check module globals. Avoid infinite recursion if `self.scope`
             // already is module globals.
             let ty = if file_scope_id.is_global() {
@@ -3356,20 +3359,19 @@ mod tests {
         Ok(())
     }
 
-    #[test_case(""; "unannotated")]
-    #[test_case(": int"; "annotated")]
-    fn imported_unbound_symbol_is_unknown(annotation: &'static str) -> anyhow::Result<()> {
+    #[test]
+    fn imported_unbound_symbol_is_unknown() -> anyhow::Result<()> {
         let mut db = setup_db();
 
         db.write_files([
             ("src/package/__init__.py", ""),
-            ("src/package/foo.py", &format!("x{annotation}")),
+            ("src/package/foo.py", "x"),
             ("src/package/bar.py", "from package.foo import x"),
         ])?;
 
         // the type as seen from external modules (`Unknown`)
-        // is different from the type inside the module itself (`Unbound`):
-        assert_public_ty(&db, "src/package/foo.py", "x", "Unknown");
+        // is different from the type inside the module itself (`Never`):
+        assert_public_ty(&db, "src/package/foo.py", "x", "Never");
         assert_public_ty(&db, "src/package/bar.py", "x", "Unknown");
 
         Ok(())