tiny cleanup

Author: estebank

compiler/rustc_expand/src/expand.rs

@@ -1411,13 +1411,11 @@ impl InvocationCollectorNode for P<ast::Item> {
                     }
                 }
             }
-            let mut idents = vec![];
+            let mut idents = Vec::new();
             collect_use_tree_leaves(&ut, &mut idents);
             idents
-        } else if let Some(ident) = self.kind.ident() {
-            vec![ident]
         } else {
-            vec![]
+            self.kind.ident().into_iter().collect()
         }
     }
 }

compiler/rustc_resolve/src/diagnostics.rs

@@ -803,14 +803,11 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
                 }
 
                 if let Some(segment) = segment {
-                    if let Some(ModuleOrUniformRoot::Module(module)) = module {
-                        let module =
-                            module.opt_def_id().unwrap_or_else(|| CRATE_DEF_ID.to_def_id());
-                        self.find_cfg_stripped(&mut err, &segment, module);
-                    } else {
-                        let module = CRATE_DEF_ID.to_def_id();
-                        self.find_cfg_stripped(&mut err, &segment, module);
-                    }
+                    let module = match module {
+                        Some(ModuleOrUniformRoot::Module(m)) if let Some(id) = m.opt_def_id() => id,
+                        _ => CRATE_DEF_ID.to_def_id(),
+                    };
+                    self.find_cfg_stripped(&mut err, &segment, module);
                 }
 
                 err