use completions in API

crates/ra_analysis/src/completion.rs

@@ -24,7 +24,7 @@
 pub(crate) fn completions(
     db: &db::RootDatabase,
     position: FilePosition,
-) -> Cancelable<Option<Vec<CompletionItem>>> {
+) -> Cancelable<Option<Completions>> {
     let original_file = db.source_file(position.file_id);
     // Insert a fake ident to get a valid parse tree
     let file = {
@@ -53,12 +53,10 @@ pub(crate) fn completions(
             param_completions(&mut acc, name.syntax());
         }
     }
-    let res = if has_completions {
-        Some(acc.into())
-    } else {
-        None
-    };
-    Ok(res)
+    if !has_completions {
+        return Ok(None);
+    }
+    Ok(Some(acc))
 }
 
 /// Complete repeated parametes, both name and type. For example, if all

crates/ra_analysis/src/imp.rs

@@ -219,7 +219,8 @@ pub fn crate_root(&self, crate_id: CrateId) -> FileId {
         self.db.crate_graph().crate_root(crate_id)
     }
     pub fn completions(&self, position: FilePosition) -> Cancelable<Option<Vec<CompletionItem>>> {
-        completions(&self.db, position)
+        let completions = completions(&self.db, position)?;
+        Ok(completions.map(|it| it.into()))
     }
     pub fn approximately_resolve_symbol(
         &self,