Don't forget to pass instantiation context after devirtualizing

src/coreclr/tools/Common/JitInterface/CorInfoImpl.cs

@@ -1179,14 +1179,19 @@ private bool resolveVirtualMethod(CORINFO_DEVIRTUALIZATION_INFO* info)
                 return false;
             }
 
+            TypeDesc owningType = impl.OwningType;
+
+            // RyuJIT expects to get the canonical form back
+            impl = impl.GetCanonMethodTarget(CanonicalFormKind.Specific);
+
             if (impl.OwningType.IsValueType)
             {
                 impl = getUnboxingThunk(impl);
             }
 
             info->devirtualizedMethod = ObjectToHandle(impl);
             info->requiresInstMethodTableArg = false;
-            info->exactContext = contextFromType(impl.OwningType);
+            info->exactContext = contextFromType(owningType);
 
             return true;
         }

src/tests/JIT/opt/Devirtualization/generic_noinline.cs

@@ -0,0 +1,30 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System;
+using System.Runtime.CompilerServices;
+
+class Program
+{
+    static int Main()
+    {
+        MyStruct<Atom> s = default;
+
+        // RyuJIT can devirtualize this, but NoInlining prevents the inline
+        // This checks that we properly pass the instantiation context to the shared generic method.
+        return ((IFoo)s).GetTheType() == typeof(Atom) ? 100 : -1;
+    }
+}
+
+interface IFoo
+{
+    Type GetTheType();
+}
+
+struct MyStruct<T> : IFoo
+{
+    [MethodImpl(MethodImplOptions.NoInlining)]
+    Type IFoo.GetTheType() => typeof(T);
+}
+
+class Atom { }

src/tests/JIT/opt/Devirtualization/generic_noinline.csproj

@@ -0,0 +1,13 @@
+<Project Sdk="Microsoft.NET.Sdk">
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <CLRTestPriority>0</CLRTestPriority>
+  </PropertyGroup>
+  <PropertyGroup>
+    <DebugType>PdbOnly</DebugType>
+    <Optimize>True</Optimize>
+  </PropertyGroup>
+  <ItemGroup>
+    <Compile Include="generic_noinline.cs" />
+  </ItemGroup>
+</Project>