diff --git a/.travis.yml b/.travis.yml
index 11e436b..9883f5e 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -7,6 +7,7 @@ script:
   - crystal spec
   - crystal spec --release --no-debug
   - crystal tool format --check
+  - bin/ameba src
 
 matrix:
   allow_failures:
diff --git a/shard.yml b/shard.yml
index 69ec827..6700d8a 100644
--- a/shard.yml
+++ b/shard.yml
@@ -15,6 +15,11 @@ dependencies:
     github: crystal-loot/exception_page
     version: ~> 0.1.1
 
+development_dependencies:
+  ameba:
+    github: veelenga/ameba
+    version: ~> 0.9.0
+
 crystal: 0.27.2
 
 license: MIT
diff --git a/src/kemal/exception_handler.cr b/src/kemal/exception_handler.cr
index 1462832..eee6eec 100644
--- a/src/kemal/exception_handler.cr
+++ b/src/kemal/exception_handler.cr
@@ -14,7 +14,7 @@ module Kemal
       log("Exception: #{ex.inspect_with_backtrace}")
       return call_exception_with_status_code(context, ex, 500) if Kemal.config.error_handlers.has_key?(500)
       verbosity = Kemal.config.env == "production" ? false : true
-      return render_500(context, ex, verbosity)
+      render_500(context, ex, verbosity)
     end
 
     private def call_exception_with_status_code(context : HTTP::Server::Context, exception : Exception, status_code : Int32)
diff --git a/src/kemal/ext/response.cr b/src/kemal/ext/response.cr
index 1f0a8fd..233bdee 100644
--- a/src/kemal/ext/response.cr
+++ b/src/kemal/ext/response.cr
@@ -1,7 +1,7 @@
 class HTTP::Server::Response
   class Output
     def close
-      unless response.wrote_headers? && !response.headers.has_key?("Content-Range")
+      if !response.wrote_headers? && response.headers.has_key?("Content-Range")
         response.content_length = @out_count
       end
 
diff --git a/src/kemal/static_file_handler.cr b/src/kemal/static_file_handler.cr
index 50d1574..11ae98e 100644
--- a/src/kemal/static_file_handler.cr
+++ b/src/kemal/static_file_handler.cr
@@ -52,7 +52,7 @@ module Kemal
           context.response.content_type = "text/html"
           directory_listing(context.response, request_path, file_path)
         else
-          return call_next(context)
+          call_next(context)
         end
       elsif File.exists?(file_path)
         last_modified = modification_time(file_path)