Cleanup ameba warnings (#551)

.ameba.yml

@@ -1,5 +1,5 @@
 # This configuration file was generated by `ameba --gen-config`
-# on 2019-06-14 15:05:57 UTC using Ameba version 0.10.0.
+# on 2019-08-25 09:29:24 UTC using Ameba version 0.10.0.
 # The point is for the user to remove these configuration records
 # one by one as the reported problems are removed from the code base.
 
@@ -11,32 +11,3 @@ Lint/UselessAssign:
   Severity: Warning
   Excluded:
   - spec/view_spec.cr
-
-# Problems found: 1
-# Run `ameba --only Lint/ShadowingOuterLocalVar` for details
-Lint/ShadowingOuterLocalVar:
-  Description: Disallows the usage of the same name as outer local variables for block
-    or proc arguments.
-  Enabled: true
-  Severity: Warning
-  Excluded:
-  - spec/run_spec.cr
-
-# Problems found: 1
-# Run `ameba --only Style/NegatedConditionsInUnless` for details
-Style/NegatedConditionsInUnless:
-  Description: Disallows negated conditions in unless
-  Enabled: true
-  Severity: Convention
-  Excluded:
-  - src/kemal/ext/response.cr
-
-# Problems found: 1
-# Run `ameba --only Metrics/CyclomaticComplexity` for details
-Metrics/CyclomaticComplexity:
-  Description: Disallows methods with a cyclomatic complexity higher than `MaxComplexity`
-  MaxComplexity: 10
-  Enabled: true
-  Severity: Convention
-  Excluded:
-  - src/kemal/static_file_handler.cr

spec/helpers_spec.cr

@@ -70,7 +70,7 @@ describe "Macros" do
         halt env, status_code: 400, response: "Missing origin."
       end
 
-      get "/" do |env|
+      get "/" do |_env|
         "Hello world"
       end
 

spec/run_spec.cr

@@ -6,12 +6,10 @@ private def run(code)
     #{code}
     CR
   String.build do |stdout|
-    stderr = String.build do |stderr|
-      Process.new("crystal", ["eval"], input: IO::Memory.new(code), output: stdout, error: stderr).wait
-    end
-    unless stderr.empty?
-      fail(stderr)
+    stderr = String.build do |io|
+      Process.new("crystal", ["eval"], input: IO::Memory.new(code), output: stdout, error: io).wait
     end
+    fail(stderr) unless stderr.empty?
   end
 end
 

src/kemal/ext/response.cr

@@ -1,6 +1,7 @@
 class HTTP::Server::Response
   class Output
     def close
+      # ameba:disable Style/NegatedConditionsInUnless
       unless response.wrote_headers? && !response.headers.has_key?("Content-Range")
         response.content_length = @out_count
       end

src/kemal/static_file_handler.cr

@@ -4,6 +4,7 @@
 
 module Kemal
   class StaticFileHandler < HTTP::StaticFileHandler
+    # ameba:disable Metrics/CyclomaticComplexity
     def call(context : HTTP::Server::Context)
       return call_next(context) if context.request.path.not_nil! == "/"