Filter outline variable type (#65)

* Test code provided by alexheretic to filter variable type
* Explanation to the filtering of local variables

Author: aldonogueira

lib/index.js

@@ -591,6 +591,23 @@ class RustLanguageClient extends AutoLanguageClient {
       throw new Error("failed to start server: " + e)
     }
   }
+
+  // Extends the outline provider by filtering the type variable, which is s
+  // only used for local variables by RLS. This makes the outline view
+  // cleaner and more useful.
+  provideOutlines() {
+    let provide = super.provideOutlines()
+    let superOutline = provide.getOutline
+
+    provide.getOutline = async (...args) => {
+      let outline = await superOutline.apply(this, args)
+      outline.outlineTrees = outline.outlineTrees
+        .filter(o => o.icon !== "type-variable")
+      return outline
+    }
+
+    return provide
+  }
 }
 
 module.exports = new RustLanguageClient()