1 files changed, 123 insertions, 0 deletions

diff --git a/crates/ra_hir/src/nameres/tests/incremental.rs b/crates/ra_hir/src/nameres/tests/incremental.rs
new file mode 100644
index 000000000..698781923
--- /dev/null
+++ b/crates/ra_hir/src/nameres/tests/incremental.rs
@@ -0,0 +1,123 @@
+use super::*;
+
+use std::sync::Arc;
+
+use ra_db::SourceDatabase;
+
+fn check_def_map_is_not_recomputed(initial: &str, file_change: &str) {
+    let (mut db, pos) = MockDatabase::with_position(initial);
+    let crate_id = db.crate_graph().iter().next().unwrap();
+    let krate = Crate { crate_id };
+    {
+        let events = db.log_executed(|| {
+            db.crate_def_map(krate);
+        });
+        assert!(format!("{:?}", events).contains("crate_def_map"), "{:#?}", events)
+    }
+    db.set_file_text(pos.file_id, Arc::new(file_change.to_string()));
+
+    {
+        let events = db.log_executed(|| {
+            db.crate_def_map(krate);
+        });
+        assert!(!format!("{:?}", events).contains("crate_def_map"), "{:#?}", events)
+    }
+}
+
+#[test]
+fn typing_inside_a_function_should_not_invalidate_def_map() {
+    check_def_map_is_not_recomputed(
+        "
+        //- /lib.rs
+        mod foo;<|>
+
+        use crate::foo::bar::Baz;
+
+        fn foo() -> i32 {
+            1 + 1
+        }
+        //- /foo/mod.rs
+        pub mod bar;
+
+        //- /foo/bar.rs
+        pub struct Baz;
+        ",
+        "
+        mod foo;
+
+        use crate::foo::bar::Baz;
+
+        fn foo() -> i32 { 92 }
+        ",
+    );
+}
+
+#[test]
+fn adding_inner_items_should_not_invalidate_def_map() {
+    check_def_map_is_not_recomputed(
+        "
+        //- /lib.rs
+        struct S { a: i32}
+        enum E { A }
+        trait T {
+            fn a() {}
+        }
+        mod foo;<|>
+        impl S {
+            fn a() {}
+        }
+        use crate::foo::bar::Baz;
+        //- /foo/mod.rs
+        pub mod bar;
+
+        //- /foo/bar.rs
+        pub struct Baz;
+        ",
+        "
+        struct S { a: i32, b: () }
+        enum E { A, B }
+        trait T {
+            fn a() {}
+            fn b() {}
+        }
+        mod foo;<|>
+        impl S {
+            fn a() {}
+            fn b() {}
+        }
+        use crate::foo::bar::Baz;
+        ",
+    );
+}
+
+// It would be awesome to make this work, but it's unclear how
+#[test]
+#[ignore]
+fn typing_inside_a_function_inside_a_macro_should_not_invalidate_def_map() {
+    check_def_map_is_not_recomputed(
+        "
+        //- /lib.rs
+        mod foo;
+
+        use crate::foo::bar::Baz;
+
+        //- /foo/mod.rs
+        pub mod bar;
+
+        //- /foo/bar.rs
+        <|>
+        salsa::query_group! {
+            trait Baz {
+                fn foo() -> i32 { 1 + 1 }
+            }
+        }
+        ",
+        "
+        salsa::query_group! {
+            trait Baz {
+                fn foo() -> i32 { 92 }
+            }
+        }
+        ",
+    );
+}