From 9fa66ad826924bce45fa56d853097541fea95e72 Mon Sep 17 00:00:00 2001
From: Tarun Karuturi <tkaruturi@meta.com>
Date: Mon, 4 Nov 2024 22:03:18 -0800
Subject: [PATCH] Make EValue template constructor MSVC friendly (#6631)

Summary:
The current EValue template constructor is not MSVC friendly, in order to make it MSVC friendly had to make some small changes such as:
- Using a default template argument (typename = typename std::enable_if<...>::type). This means that the std::enable_if condition is evaluated when the template is instantiated.
- Separating the SFINAE condition from the function signature.


Reviewed By: dbort

Differential Revision: D65402442
---
 runtime/core/evalue.h              | 13 +++++++------
 runtime/core/exec_aten/exec_aten.h |  1 +
 2 files changed, 8 insertions(+), 6 deletions(-)

diff --git a/runtime/core/evalue.h b/runtime/core/evalue.h
index 8003a89cbf0..500c2bc4f0e 100644
--- a/runtime/core/evalue.h
+++ b/runtime/core/evalue.h
@@ -242,12 +242,13 @@ struct EValue {
   // Template constructor that allows construction from types that can be
   // dereferenced to produce a type that EValue can be implicitly constructed
   // from.
-  template <typename T>
-  /*implicit*/ EValue(
-      T&& value,
-      typename std::enable_if<std::is_convertible<
-          decltype(*std::forward<T>(value)),
-          EValue>::value>::type* = 0) {
+  template <
+      typename T,
+      typename = typename std::enable_if<std::is_convertible<
+          decltype(*std::forward<T>(std::declval<T>())), // declval to simulate
+                                                         // forwarding
+          EValue>::value>::type>
+  /*implicit*/ EValue(T&& value) {
     ET_CHECK_MSG(value != nullptr, "Pointer is null.");
     // Note that this ctor does not initialize this->tag directly; it is set by
     // moving in the new value.
diff --git a/runtime/core/exec_aten/exec_aten.h b/runtime/core/exec_aten/exec_aten.h
index bfb47daa05d..708fb69d577 100644
--- a/runtime/core/exec_aten/exec_aten.h
+++ b/runtime/core/exec_aten/exec_aten.h
@@ -9,6 +9,7 @@
 #pragma once
 
 #include <executorch/runtime/core/tensor_shape_dynamism.h> // @manual
+#include <executorch/runtime/platform/compiler.h>
 #ifdef USE_ATEN_LIB
 #include <ATen/Tensor.h> // @manual
 #include <c10/core/Device.h>