Use traits from prelude for method resolution

2 files changed, 30 insertions, 1 deletions

diff --git a/crates/ra_hir/src/ty/method_resolution.rs b/crates/ra_hir/src/ty/method_resolution.rs
index e8cfa0b85..34817a5ec 100644
--- a/crates/ra_hir/src/ty/method_resolution.rs
+++ b/crates/ra_hir/src/ty/method_resolution.rs
@@ -185,7 +185,7 @@ fn iterate_trait_method_candidates<T>(
     mut callback: impl FnMut(&Ty, Function) -> Option<T>,
 ) -> Option<T> {
     let krate = resolver.krate()?;
-    'traits: for t in resolver.traits_in_scope() {
+    'traits: for t in resolver.traits_in_scope(db) {
         let data = t.trait_data(db);
         // we'll be lazy about checking whether the type implements the
         // trait, but if we find out it doesn't, we'll skip the rest of the
diff --git a/crates/ra_hir/src/ty/tests.rs b/crates/ra_hir/src/ty/tests.rs
index 510fa5333..978cc2587 100644
--- a/crates/ra_hir/src/ty/tests.rs
+++ b/crates/ra_hir/src/ty/tests.rs
@@ -2502,6 +2502,35 @@ fn test() { (&S).foo()<|>; }
 }
 
 #[test]
+fn method_resolution_trait_from_prelude() {
+    let (mut db, pos) = MockDatabase::with_position(
+        r#"
+//- /main.rs
+struct S;
+impl Clone for S {}
+
+fn test() {
+    S.clone()<|>;
+}
+
+//- /lib.rs
+#[prelude_import] use foo::*;
+
+mod foo {
+    trait Clone {
+        fn clone(&self) -> Self;
+    }
+}
+"#,
+    );
+    db.set_crate_graph_from_fixture(crate_graph! {
+        "main": ("/main.rs", ["other_crate"]),
+        "other_crate": ("/lib.rs", []),
+    });
+    assert_eq!("S", type_at_pos(&db, pos));
+}
+
+#[test]
 fn method_resolution_where_clause_for_unknown_trait() {
     // The blanket impl shouldn't apply because we can't even resolve UnknownTrait
     let t = type_at(