From 2355b26cadb331128cc3a86abfb51de9c441c973 Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Sat, 30 May 2026 16:53:38 +0000
Subject: [PATCH] Return false when system assembly is null in
 ManagedTypeSource_1.TryResolveType

Co-authored-by: rcj1 <77995559+rcj1@users.noreply.github.com>
---
 .../Contracts/ManagedTypeSource_1.cs                        | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Contracts/ManagedTypeSource_1.cs b/src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Contracts/ManagedTypeSource_1.cs
index 74c1282a5e4a5c..ded96b35d622ba 100644
--- a/src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Contracts/ManagedTypeSource_1.cs
+++ b/src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Contracts/ManagedTypeSource_1.cs
@@ -246,6 +246,12 @@ private bool TryResolveType(string managedFqName, out TypeHandle th, [NotNullWhe
 
         ILoader loader = _target.Contracts.Loader;
         TargetPointer systemAssembly = loader.GetSystemAssembly();
+        if (systemAssembly == TargetPointer.Null)
+        {
+            mdReader = null;
+            return false;
+        }
+
         ModuleHandle moduleHandle = loader.GetModuleHandleFromAssemblyPtr(systemAssembly);
 
         if (!TryFindTypeDefinition(moduleHandle, managedFqName, out mdReader, out TypeDefinitionHandle typeDefHandle))