internal: vendor query-group-macro

crates/query-group-macro/tests/supertrait.rs

@@ -0,0 +1,19 @@
+use query_group_macro::query_group;
+
+#[salsa::db]
+pub trait SourceDb: salsa::Database {
+    /// Text of the file.
+    fn file_text(&self, id: usize) -> String;
+}
+
+#[query_group]
+pub trait RootDb: SourceDb {
+    fn parse(&self, id: usize) -> String;
+}
+
+fn parse(db: &dyn RootDb, id: usize) -> String {
+    // this is the test: does the following compile?
+    db.file_text(id);
+
+    String::new()
+}