From 4d83e375dee051d66dc573c0b24b0568eb653b0a Mon Sep 17 00:00:00 2001
From: Jan Kotas <jkotas@microsoft.com>
Date: Thu, 9 Sep 2021 13:00:03 -0700
Subject: [PATCH] Fix null reference exception in library mode (#1546)

---
 .../StartupCode/StartupCodeHelpers.Reflection.cs              | 4 ++--
 .../src/System/Reflection/Assembly.CoreRT.cs                  | 2 +-
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/coreclr/nativeaot/System.Private.CoreLib/src/Internal/Runtime/CompilerHelpers/StartupCode/StartupCodeHelpers.Reflection.cs b/src/coreclr/nativeaot/System.Private.CoreLib/src/Internal/Runtime/CompilerHelpers/StartupCode/StartupCodeHelpers.Reflection.cs
index 39aca56ad956..7fc2641f43ce 100644
--- a/src/coreclr/nativeaot/System.Private.CoreLib/src/Internal/Runtime/CompilerHelpers/StartupCode/StartupCodeHelpers.Reflection.cs
+++ b/src/coreclr/nativeaot/System.Private.CoreLib/src/Internal/Runtime/CompilerHelpers/StartupCode/StartupCodeHelpers.Reflection.cs
@@ -16,9 +16,9 @@ internal static void InitializeEntryAssembly(RuntimeTypeHandle entryAssemblyType
             s_entryAssemblyType = entryAssemblyType;
         }
 
-        internal static Assembly GetEntryAssembly()
+        internal static Assembly? GetEntryAssembly()
         {
-            return Type.GetTypeFromHandle(s_entryAssemblyType).Assembly;
+            return Type.GetTypeFromHandle(s_entryAssemblyType)?.Assembly;
         }
     }
 }
diff --git a/src/coreclr/nativeaot/System.Private.CoreLib/src/System/Reflection/Assembly.CoreRT.cs b/src/coreclr/nativeaot/System.Private.CoreLib/src/System/Reflection/Assembly.CoreRT.cs
index c258a62962a6..67332c612fdd 100644
--- a/src/coreclr/nativeaot/System.Private.CoreLib/src/System/Reflection/Assembly.CoreRT.cs
+++ b/src/coreclr/nativeaot/System.Private.CoreLib/src/System/Reflection/Assembly.CoreRT.cs
@@ -12,7 +12,7 @@ namespace System.Reflection
 {
     public abstract partial class Assembly : ICustomAttributeProvider, ISerializable
     {
-        private static Assembly GetEntryAssemblyInternal() => Internal.Runtime.CompilerHelpers.StartupCodeHelpers.GetEntryAssembly();
+        private static Assembly? GetEntryAssemblyInternal() => Internal.Runtime.CompilerHelpers.StartupCodeHelpers.GetEntryAssembly();
 
         [System.Runtime.CompilerServices.Intrinsic]
         public static Assembly GetExecutingAssembly() { throw NotImplemented.ByDesign; } //Implemented by toolchain.