From 7140a778bb35eb1c57025b7fdcb7920fb3622519 Mon Sep 17 00:00:00 2001
From: Kenny Kerr <kenny@kennykerr.ca>
Date: Mon, 13 Sep 2021 07:57:16 -0700
Subject: [PATCH 1/2] observable_index_of

---
 strings/base_collections_vector.h | 22 ++++++++++++++----
 test/test/observable_index_of.cpp | 37 +++++++++++++++++++++++++++++++
 test/test/test.vcxproj            |  1 +
 3 files changed, 56 insertions(+), 4 deletions(-)
 create mode 100644 test/test/observable_index_of.cpp

diff --git a/strings/base_collections_vector.h b/strings/base_collections_vector.h
index b82ba3853..27288be22 100644
--- a/strings/base_collections_vector.h
+++ b/strings/base_collections_vector.h
@@ -115,13 +115,27 @@ namespace winrt::impl
 
         bool IndexOf(Windows::Foundation::IInspectable const& value, uint32_t& index) const
         {
-            try
+            if constexpr (is_com_interface_v<T>)
             {
-                return IndexOf(unbox_value<T>(value), index);
+                if (!value)
+                {
+                    return base_type::IndexOf(nullptr, index);
+                }
+                else if (auto as = value.try_as<T>())
+                {
+                    return base_type::IndexOf(as, index);
+                }
+                else
+                {
+                    return false;
+                }
+            }
+            else if (auto as = value.try_as<T>())
+            {
+                return base_type::IndexOf(as.value(), index);
             }
-            catch (hresult_no_interface const&)
+            else
             {
-                index = 0;
                 return false;
             }
         }
diff --git a/test/test/observable_index_of.cpp b/test/test/observable_index_of.cpp
new file mode 100644
index 000000000..14d434d34
--- /dev/null
+++ b/test/test/observable_index_of.cpp
@@ -0,0 +1,37 @@
+#include "pch.h"
+
+using namespace winrt;
+using namespace Windows::Foundation;
+using namespace Windows::Foundation::Collections;
+
+TEST_CASE("observable_index_of")
+{
+    {
+        auto v = single_threaded_observable_vector<int>().as<IVector<IInspectable>>();
+        v.Append(box_value(123));
+        uint32_t index = 0;
+        REQUIRE(v.IndexOf(box_value(123), index));
+        REQUIRE(!v.IndexOf(nullptr, index));
+        REQUIRE(!v.IndexOf(box_value(456), index));
+        REQUIRE(!v.IndexOf(Uri(L"http://kennykerr.ca"), index));
+    }
+    {
+        auto value = Uri(L"http://kennykerr.ca");
+
+        auto v = single_threaded_observable_vector<IStringable>().as<IVector<IInspectable>>();
+        v.Append(value);
+        uint32_t index = 0;
+        REQUIRE(v.IndexOf(value, index));
+        REQUIRE(!v.IndexOf(nullptr, index));
+        REQUIRE(!v.IndexOf(box_value(456), index));
+        REQUIRE(!v.IndexOf(Uri(L"http://kennykerr.ca"), index));
+    }
+    {
+        auto v = single_threaded_observable_vector<IStringable>().as<IVector<IInspectable>>();
+        v.Append(nullptr);
+        uint32_t index = 0;
+        REQUIRE(v.IndexOf(nullptr, index));
+        REQUIRE(!v.IndexOf(box_value(456), index));
+        REQUIRE(!v.IndexOf(Uri(L"http://kennykerr.ca"), index));
+    }
+}
diff --git a/test/test/test.vcxproj b/test/test/test.vcxproj
index ed6e934bd..b6c9c229a 100644
--- a/test/test/test.vcxproj
+++ b/test/test/test.vcxproj
@@ -417,6 +417,7 @@
     <ClCompile Include="notify_awaiter.cpp" />
     <ClCompile Include="no_make_detection.cpp" />
     <ClCompile Include="numerics.cpp" />
+    <ClCompile Include="observable_index_of.cpp" />
     <ClCompile Include="out_params.cpp" />
     <ClCompile Include="out_params_abi.cpp" />
     <ClCompile Include="out_params_bad.cpp" />

From 03444f9635160d549f244af681a85d06d2cbc8bf Mon Sep 17 00:00:00 2001
From: Kenny Kerr <kenny@kennykerr.ca>
Date: Mon, 13 Sep 2021 09:18:38 -0700
Subject: [PATCH 2/2] make it clear

---
 strings/base_collections_vector.h | 15 ++++++---------
 1 file changed, 6 insertions(+), 9 deletions(-)

diff --git a/strings/base_collections_vector.h b/strings/base_collections_vector.h
index 27288be22..ff0ad6bec 100644
--- a/strings/base_collections_vector.h
+++ b/strings/base_collections_vector.h
@@ -125,19 +125,16 @@ namespace winrt::impl
                 {
                     return base_type::IndexOf(as, index);
                 }
-                else
-                {
-                    return false;
-                }
-            }
-            else if (auto as = value.try_as<T>())
-            {
-                return base_type::IndexOf(as.value(), index);
             }
             else
             {
-                return false;
+                if (auto as = value.try_as<T>())
+                {
+                    return base_type::IndexOf(as.value(), index);
+                }
             }
+
+            return false;
         }
 
         using base_type::GetMany;