diff --git a/ast/node.go b/ast/node.go
index 5cc91b1db..ae386c929 100644
--- a/ast/node.go
+++ b/ast/node.go
@@ -695,14 +695,14 @@ func (self *Node) GetByPath(path ...interface{}) *Node {
     }
     var s = self
     for _, p := range path {
-        switch p.(type) {
+        switch p := p.(type) {
         case int:
-            s = s.Index(p.(int))
+            s = s.Index(p)
             if !s.Valid() {
                 return s
             }
         case string:
-            s = s.Get(p.(string))
+            s = s.Get(p)
             if !s.Valid() {
                 return s
             }
diff --git a/ast/search.go b/ast/search.go
index 9e809bb8d..b6357094a 100644
--- a/ast/search.go
+++ b/ast/search.go
@@ -40,13 +40,13 @@ func (self *Searcher) GetByPath(path ...interface{}) (Node, error) {
 
     var err types.ParsingError
     for _, p := range path {
-        switch p.(type) {
+        switch p := p.(type) {
         case int:
-            if err = self.parser.searchIndex(p.(int)); err != 0 {
+            if err = self.parser.searchIndex(p); err != 0 {
                 return Node{}, self.parser.ExportError(err)
             }
         case string:
-            if err = self.parser.searchKey(p.(string)); err != 0 {
+            if err = self.parser.searchKey(p); err != 0 {
                 return Node{}, self.parser.ExportError(err)
             }
         default:
diff --git a/bench.py b/bench.py
index 56618d8b5..1d4c35739 100755
--- a/bench.py
+++ b/bench.py
@@ -86,8 +86,8 @@ def compare(args):
     run("%s %s ./... 2>&1 | tee %s" %(gbench_prefix, args, main))
 
     # diff the result
-    benchstat = "go get golang.org/x/perf/cmd/benchstat && go install golang.org/x/perf/cmd/benchstat"
-    run( "%s && benchstat -sort=delta %s %s"%(benchstat, main, target))
+    # benchstat = "go get golang.org/x/perf/cmd/benchstat && go install golang.org/x/perf/cmd/benchstat"
+    run( "benchstat -sort=delta %s %s"%(main, target))
     run("git checkout -- .")
 
     # restore branch