diff --git a/.appveyor.yml b/.appveyor.yml
index 4749acc..8a78fd8 100644
--- a/.appveyor.yml
+++ b/.appveyor.yml
@@ -9,11 +9,11 @@ install:
 build_script:
   - mkdir build
   - cd build
-  - cmake .. -DCLI_SINGLE_FILE_TESTS=ON -DCMAKE_BUILD_TYPE=RelWithDebInfo -DCMAKE_GENERATOR="Visual Studio 14 2015"
+  - cmake .. -DCLI_SINGLE_FILE_TESTS=ON -DCMAKE_BUILD_TYPE=Debug -DCMAKE_GENERATOR="Visual Studio 14 2015"
   - cmake --build .
 
 test_script:
-  - ctest --output-on-failure -C RelWithDebInfo
+  - ctest --output-on-failure -C Debug
 
 notifications:
   - provider: Webhook
diff --git a/include/CLI/App.hpp b/include/CLI/App.hpp
index 5e68f33..209b5a4 100644
--- a/include/CLI/App.hpp
+++ b/include/CLI/App.hpp
@@ -910,9 +910,9 @@ class App {
 
                 subcmd_groups_seen.insert(group_key);
                 out << std::endl << com->get_group() << ":" << std::endl;
-                for(const App_p &com : subcommands_)
-                    if(detail::to_lower(com->get_group()) == group_key)
-                        detail::format_help(out, com->get_name(), com->description_, wid);
+                for(const App_p &new_com : subcommands_)
+                    if(detail::to_lower(new_com->get_group()) == group_key)
+                        detail::format_help(out, new_com->get_name(), new_com->description_, wid);
             }
         }
 
diff --git a/include/CLI/Option.hpp b/include/CLI/Option.hpp
index 9799200..bf0161d 100644
--- a/include/CLI/Option.hpp
+++ b/include/CLI/Option.hpp
@@ -408,17 +408,18 @@ class Option : public OptionBase<Option> {
 
     /// Process the callback
     void run_callback() const {
-        bool result;
+        bool local_result;
         // If take_last, only operate on the final item
         if(last_) {
             results_t partial_result = {results_.back()};
-            result = !callback_(partial_result);
+            local_result = !callback_(partial_result);
         } else {
-            result = !callback_(results_);
+            local_result = !callback_(results_);
         }
 
-        if(result)
+        if(local_result)
             throw ConversionError(get_name() + "=" + detail::join(results_));
+
         if(!validators_.empty()) {
             for(const std::string &result : results_)
                 for(const std::function<bool(std::string)> &vali : validators_)