2 files changed, 48 insertions, 6 deletions

diff --git a/crates/ra_hir/src/mock.rs b/crates/ra_hir/src/mock.rs
index 7da15eca0..2bba11e42 100644
--- a/crates/ra_hir/src/mock.rs
+++ b/crates/ra_hir/src/mock.rs
@@ -2,7 +2,8 @@ use std::{sync::Arc, panic};
 
 use parking_lot::Mutex;
 use ra_db::{
-    CheckCanceled, FilePosition, FileId, CrateGraph, SourceRoot, SourceRootId, SourceDatabase, salsa,
+    mock::FileMap, CheckCanceled, CrateGraph, FileId, FilePosition, SourceDatabase,
+    SourceRoot, SourceRootId, salsa
 };
 use relative_path::RelativePathBuf;
 use test_utils::{parse_fixture, CURSOR_MARKER, extract_offset};
@@ -17,7 +18,7 @@ pub(crate) struct MockDatabase {
     events: Mutex<Option<Vec<salsa::Event<MockDatabase>>>>,
     runtime: salsa::Runtime<MockDatabase>,
     interner: Arc<HirInterner>,
-    file_counter: u32,
+    file_map: Arc<FileMap>,
 }
 
 impl panic::RefUnwindSafe for MockDatabase {}
@@ -43,6 +44,10 @@ impl MockDatabase {
         (db, position)
     }
 
+    pub(crate) fn file_id(&self, file: &str) -> FileId {
+        self.file_map.file_id(file)
+    }
+
     fn from_fixture(fixture: &str) -> (MockDatabase, SourceRoot, Option<FilePosition>) {
         let mut db = MockDatabase::default();
 
@@ -89,8 +94,7 @@ impl MockDatabase {
         let is_crate_root = path == "/lib.rs" || path == "/main.rs";
 
         let path = RelativePathBuf::from_path(&path[1..]).unwrap();
-        let file_id = FileId(self.file_counter);
-        self.file_counter += 1;
+        let file_id = Arc::make_mut(&mut self.file_map).add(path.clone());
         let text = Arc::new(text.to_string());
         self.set_file_text(file_id, text);
         self.set_file_relative_path(file_id, path.clone());
@@ -137,7 +141,7 @@ impl Default for MockDatabase {
             events: Default::default(),
             runtime: salsa::Runtime::default(),
             interner: Default::default(),
-            file_counter: 0,
+            file_map: Default::default(),
         };
         db.set_crate_graph(Default::default());
         db
@@ -150,7 +154,7 @@ impl salsa::ParallelDatabase for MockDatabase {
             events: Default::default(),
             runtime: self.runtime.snapshot(self),
             interner: Arc::clone(&self.interner),
-            file_counter: self.file_counter,
+            file_map: Arc::clone(&self.file_map),
         })
     }
 }
diff --git a/crates/ra_hir/src/nameres/tests.rs b/crates/ra_hir/src/nameres/tests.rs
index e72781f51..5b161cf49 100644
--- a/crates/ra_hir/src/nameres/tests.rs
+++ b/crates/ra_hir/src/nameres/tests.rs
@@ -19,6 +19,19 @@ fn item_map(fixture: &str) -> (Arc<ItemMap>, ModuleId) {
     (db.item_map(krate.crate_id), module_id)
 }
 
+fn item_map_custom_crate_root(fixture: &str, root: &str) -> (Arc<ItemMap>, ModuleId) {
+    let (mut db, pos) = MockDatabase::with_position(fixture);
+
+    let mut crate_graph = CrateGraph::default();
+    crate_graph.add_crate_root(db.file_id(root));
+    db.set_crate_graph(Arc::new(crate_graph));
+
+    let module = crate::source_binder::module_from_position(&db, dbg!(pos)).unwrap();
+    let krate = module.krate(&db).unwrap();
+    let module_id = module.module_id;
+    (db.item_map(krate.crate_id), module_id)
+}
+
 fn check_module_item_map(map: &ItemMap, module_id: ModuleId, expected: &str) {
     let mut lines = map[module_id]
         .items
@@ -134,6 +147,31 @@ fn re_exports() {
 }
 
 #[test]
+fn module_resolution_works_for_non_standard_filenames() {
+    let (item_map, module_id) = item_map_custom_crate_root(
+        "
+        //- /my_library.rs
+        mod foo;
+
+        use self::foo::Bar;
+        <|>
+
+        //- /foo/mod.rs
+        pub struct Bar;
+    ",
+        "/my_library.rs",
+    );
+    check_module_item_map(
+        &item_map,
+        module_id,
+        "
+            Bar: t v
+            foo: t
+        ",
+    );
+}
+
+#[test]
 fn name_res_works_for_broken_modules() {
     covers!(name_res_works_for_broken_modules);
     let (item_map, module_id) = item_map(