From aa97ea1ad43596ed368a597bde0885686dc59c9c Mon Sep 17 00:00:00 2001
From: martincostello <martin@martincostello.com>
Date: Fri, 1 Aug 2025 11:39:15 +0100
Subject: [PATCH] [Mvc] Avoid exception in route analyzer

Resolves #59735.
---
 src/Shared/Roslyn/MvcFacts.cs | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/src/Shared/Roslyn/MvcFacts.cs b/src/Shared/Roslyn/MvcFacts.cs
index f8408803a598..d4c74f64fb78 100644
--- a/src/Shared/Roslyn/MvcFacts.cs
+++ b/src/Shared/Roslyn/MvcFacts.cs
@@ -70,7 +70,8 @@ public static bool IsControllerAction(IMethodSymbol method, INamedTypeSymbol non
         }
 
         // Overridden methods from Object class, e.g. Equals(Object), GetHashCode(), etc., are not valid.
-        if (GetDeclaringType(method).SpecialType == SpecialType.System_Object)
+        var declaringType = GetDeclaringType(method);
+        if (declaringType == null || declaringType.SpecialType == SpecialType.System_Object)
         {
             return false;
         }
@@ -98,13 +99,13 @@ public static bool IsControllerAction(IMethodSymbol method, INamedTypeSymbol non
         return method.DeclaredAccessibility == Accessibility.Public;
     }
 
-    private static INamedTypeSymbol GetDeclaringType(IMethodSymbol method)
+    private static INamedTypeSymbol? GetDeclaringType(IMethodSymbol method)
     {
         while (method.IsOverride)
         {
             if (method.OverriddenMethod == null)
             {
-                throw new InvalidOperationException($"{nameof(method.OverriddenMethod)} cannot be null.");
+                return null;
             }
 
             method = method.OverriddenMethod;