From f44a0652dae715f568bb6cdb6d8c9f563f635756 Mon Sep 17 00:00:00 2001
From: Philip Top <phlptp@gmail.com>
Date: Sun, 18 Aug 2019 16:46:58 -0700
Subject: [PATCH] add separate condition for index into vectors

---
 include/CLI/Option.hpp |  8 ++++++--
 tests/AppTest.cpp      | 13 +++++++++++++
 2 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/include/CLI/Option.hpp b/include/CLI/Option.hpp
index a5725ac53..3e5ccd57d 100644
--- a/include/CLI/Option.hpp
+++ b/include/CLI/Option.hpp
@@ -693,8 +693,12 @@ class Option : public OptionBase<Option> {
         // Run the validators (can change the string)
         if(!validators_.empty()) {
             int index = 0;
-            if(type_size_ > 0 && multi_option_policy_ == CLI::MultiOptionPolicy::TakeLast) {
-                index = type_size_ - static_cast<int>(results_.size());
+            // this is not available until multi_option_policy with type_size_>0 is enabled and functional
+            // if(type_size_ > 0 && multi_option_policy_ == CLI::MultiOptionPolicy::TakeLast) {
+            //    index = type_size_ - static_cast<int>(results_.size());
+            //}
+            if(type_size_ < 0 && multi_option_policy_ == CLI::MultiOptionPolicy::TakeLast) { // for vector operations
+                index = expected_ - static_cast<int>(results_.size());
             }
             for(std::string &result : results_) {
                 auto err_msg = _validate(result, index);
diff --git a/tests/AppTest.cpp b/tests/AppTest.cpp
index 17dd87ccf..186a82945 100644
--- a/tests/AppTest.cpp
+++ b/tests/AppTest.cpp
@@ -800,6 +800,19 @@ TEST_F(TApp, TakeLastOptMulti) {
     EXPECT_EQ(vals, std::vector<int>({2, 3}));
 }
 
+TEST_F(TApp, TakeLastOptMultiCheck) {
+    std::vector<int> vals;
+    auto opt = app.add_option("--long", vals)->expected(2)->take_last();
+
+    opt->check(CLI::Validator(CLI::PositiveNumber).application_index(0));
+    opt->check((!CLI::PositiveNumber).application_index(1));
+    args = {"--long", "-1", "2", "-3"};
+
+    EXPECT_NO_THROW(run());
+
+    EXPECT_EQ(vals, std::vector<int>({2, -3}));
+}
+
 TEST_F(TApp, TakeFirstOptMulti) {
     std::vector<int> vals;
     app.add_option("--long", vals)->expected(2)->take_first();