Raymond's suggestion to mark try_as_with_reason as private so composed classes dont see it

Author: dmachaj

cppwinrt/code_writers.h

@@ -1137,7 +1137,7 @@ namespace cppwinrt
     {%
         if constexpr (!std::is_same_v<D, %>)
         {
-            auto const& [castedResult, code] = static_cast<D const*>(this)->template try_as_with_reason<%>();
+            auto const [castedResult, code] = impl::try_as_with_reason<%, D const*>(static_cast<D const*>(this));
             check_hresult(code);
             auto const abiType = *(abi_t<%>**)&castedResult;
             abiType->%(%);
@@ -1156,7 +1156,7 @@ namespace cppwinrt
     {%
         if constexpr (!std::is_same_v<D, %>)
         {
-            auto const& [castedResult, code] = static_cast<D const*>(this)->template try_as_with_reason<%>();
+            auto const [castedResult, code] = impl::try_as_with_reason<%, D const*>(static_cast<D const*>(this));
             check_hresult(code);
             auto const abiType = *(abi_t<%>**)&castedResult;
             WINRT_VERIFY_(0, abiType->%(%));
@@ -1176,7 +1176,7 @@ namespace cppwinrt
     {%
         if constexpr (!std::is_same_v<D, %>)
         {
-            auto const& [castedResult, code] = static_cast<D const*>(this)->template try_as_with_reason<%>();
+            auto const [castedResult, code] = impl::try_as_with_reason<%, D const*>(static_cast<D const*>(this));
             check_hresult(code);
             auto const abiType = *(abi_t<%>**)&castedResult;
             check_hresult(abiType->%(%));

strings/base_implements.h

@@ -788,19 +788,24 @@ namespace winrt::impl
             return m_inner.try_as<Qi>();
         }
 
-        template <typename Qi>
-        auto try_as_with_reason() const noexcept
-        {
-            return m_inner.try_as_with_reason<Qi>();
-        }
-
         explicit operator bool() const noexcept
         {
             return m_inner.operator bool();
         }
+
+        template <typename To, typename From>
+        friend auto winrt::impl::try_as_with_reason(From ptr) noexcept;
+
     protected:
         static constexpr bool is_composing = true;
         Windows::Foundation::IInspectable m_inner;
+
+    private:
+        template <typename Qi>
+        auto try_as_with_reason() const noexcept
+        {
+            return m_inner.try_as_with_reason<Qi>();
+        }
     };
 
     template <typename D, bool>

strings/base_windows.h

@@ -148,6 +148,12 @@ namespace winrt::impl
         hresult code = ptr->QueryInterface(guid_of<To>(), &result);
         return { wrap_as_result<To>(result), code };
     }
+
+    template <typename To, typename From>
+    auto try_as_with_reason(From ptr) noexcept
+    {
+        return ptr->template try_as_with_reason<To>();
+    }
 }
 
 WINRT_EXPORT namespace winrt::Windows::Foundation