3 files changed, 40 insertions, 11 deletions

diff --git a/crates/ra_db/src/fixture.rs b/crates/ra_db/src/fixture.rs
index 4f4fb4494..209713987 100644
--- a/crates/ra_db/src/fixture.rs
+++ b/crates/ra_db/src/fixture.rs
@@ -149,15 +149,17 @@ fn with_files(
             let crate_id = crate_graph.add_crate_root(
                 file_id,
                 meta.edition,
-                Some(CrateName::new(&krate).unwrap()),
+                Some(krate.clone()),
                 meta.cfg,
                 meta.env,
                 Default::default(),
             );
-            let prev = crates.insert(krate.clone(), crate_id);
+            let crate_name = CrateName::new(&krate).unwrap();
+            let prev = crates.insert(crate_name.clone(), crate_id);
             assert!(prev.is_none());
             for dep in meta.deps {
-                crate_deps.push((krate.clone(), dep))
+                let dep = CrateName::new(&dep).unwrap();
+                crate_deps.push((crate_name.clone(), dep))
             }
         } else if meta.path == "/main.rs" || meta.path == "/lib.rs" {
             assert!(default_crate_root.is_none());
diff --git a/crates/ra_db/src/input.rs b/crates/ra_db/src/input.rs
index 7f3660118..aaa492759 100644
--- a/crates/ra_db/src/input.rs
+++ b/crates/ra_db/src/input.rs
@@ -67,7 +67,7 @@ pub struct CrateGraph {
 #[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
 pub struct CrateId(pub u32);
 
-#[derive(Debug, Clone, PartialEq, Eq)]
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
 pub struct CrateName(SmolStr);
 
 impl CrateName {
@@ -94,6 +94,13 @@ impl fmt::Display for CrateName {
     }
 }
 
+impl ops::Deref for CrateName {
+    type Target = str;
+    fn deref(&self) -> &Self::Target {
+        &*self.0
+    }
+}
+
 #[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
 pub struct ProcMacroId(pub u32);
 
@@ -117,7 +124,7 @@ pub struct CrateData {
     /// The name to display to the end user.
     /// This actual crate name can be different in a particular dependent crate
     /// or may even be missing for some cases, such as a dummy crate for the code snippet.
-    pub display_name: Option<CrateName>,
+    pub display_name: Option<String>,
     pub cfg_options: CfgOptions,
     pub env: Env,
     pub dependencies: Vec<Dependency>,
@@ -138,7 +145,7 @@ pub struct Env {
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct Dependency {
     pub crate_id: CrateId,
-    pub name: SmolStr,
+    pub name: CrateName,
 }
 
 impl CrateGraph {
@@ -146,7 +153,7 @@ impl CrateGraph {
         &mut self,
         file_id: FileId,
         edition: Edition,
-        display_name: Option<CrateName>,
+        display_name: Option<String>,
         cfg_options: CfgOptions,
         env: Env,
         proc_macro: Vec<(SmolStr, Arc<dyn ra_tt::TokenExpander>)>,
@@ -178,7 +185,7 @@ impl CrateGraph {
         if self.dfs_find(from, to, &mut FxHashSet::default()) {
             return Err(CyclicDependenciesError);
         }
-        self.arena.get_mut(&from).unwrap().add_dep(name.0, to);
+        self.arena.get_mut(&from).unwrap().add_dep(name, to);
         Ok(())
     }
 
@@ -190,6 +197,23 @@ impl CrateGraph {
         self.arena.keys().copied()
     }
 
+    /// Returns an iterator over all transitive dependencies of the given crate.
+    pub fn transitive_deps(&self, of: CrateId) -> impl Iterator<Item = CrateId> + '_ {
+        let mut worklist = vec![of];
+        let mut deps = FxHashSet::default();
+
+        while let Some(krate) = worklist.pop() {
+            if !deps.insert(krate) {
+                continue;
+            }
+
+            worklist.extend(self[krate].dependencies.iter().map(|dep| dep.crate_id));
+        }
+
+        deps.remove(&of);
+        deps.into_iter()
+    }
+
     // FIXME: this only finds one crate with the given root; we could have multiple
     pub fn crate_id_for_crate_root(&self, file_id: FileId) -> Option<CrateId> {
         let (&crate_id, _) =
@@ -247,7 +271,7 @@ impl CrateId {
 }
 
 impl CrateData {
-    fn add_dep(&mut self, name: SmolStr, crate_id: CrateId) {
+    fn add_dep(&mut self, name: CrateName, crate_id: CrateId) {
         self.dependencies.push(Dependency { name, crate_id })
     }
 }
@@ -429,7 +453,10 @@ mod tests {
             .is_ok());
         assert_eq!(
             graph[crate1].dependencies,
-            vec![Dependency { crate_id: crate2, name: "crate_name_with_dashes".into() }]
+            vec![Dependency {
+                crate_id: crate2,
+                name: CrateName::new("crate_name_with_dashes").unwrap()
+            }]
         );
     }
 }
diff --git a/crates/ra_db/src/lib.rs b/crates/ra_db/src/lib.rs
index 4a3ba57da..1ddacc1f6 100644
--- a/crates/ra_db/src/lib.rs
+++ b/crates/ra_db/src/lib.rs
@@ -80,7 +80,7 @@ pub struct FilePosition {
     pub offset: TextSize,
 }
 
-#[derive(Clone, Copy, Debug)]
+#[derive(Clone, Copy, Debug, Eq, PartialEq)]
 pub struct FileRange {
     pub file_id: FileId,
     pub range: TextRange,