Use canonical method IL in scanner's ImportCall (#5686)

Simulates what JitInterface operates on.

src/ILCompiler.Compiler/src/IL/ILImporter.Scanner.cs

@@ -19,6 +19,7 @@ namespace Internal.IL
     partial class ILImporter
     {
         private readonly MethodIL _methodIL;
+        private readonly MethodIL _canonMethodIL;
         private readonly ILScanner _compilation;
         private readonly ILScanNodeFactory _factory;
 
@@ -84,6 +85,8 @@ public ILImporter(ILScanner compilation, MethodDesc method, MethodIL methodIL =
 
             _ilBytes = methodIL.GetILBytes();
 
+            _canonMethodIL = methodIL;
+
             // Get the runtime determined method IL so that this works right in shared code
             // and tokens in shared code resolve to runtime determined types.
             MethodIL uninstantiatiedMethodIL = methodIL.GetMethodILDefinition();
@@ -266,11 +269,10 @@ private void ImportCasting(ILOpcode opcode, int token)
 
         private void ImportCall(ILOpcode opcode, int token)
         {
-            // Strip runtime determined characteristics off of the method (because that's how RyuJIT operates)
+            // We get both the canonical and runtime determined form - JitInterface mostly operates
+            // on the canonical form.
             var runtimeDeterminedMethod = (MethodDesc)_methodIL.GetObject(token);
-            MethodDesc method = runtimeDeterminedMethod;
-            if (runtimeDeterminedMethod.IsRuntimeDeterminedExactMethod)
-                method = runtimeDeterminedMethod.GetCanonMethodTarget(CanonicalFormKind.Specific);
+            var method = (MethodDesc)_canonMethodIL.GetObject(token);
 
             if (method.IsRawPInvoke())
             {

tests/src/Simple/Generics/Generics.cs

@@ -32,6 +32,7 @@ static int Main()
         TestFieldAccess.Run();
         TestNativeLayoutGeneration.Run();
         TestInterfaceVTableTracking.Run();
+        TestClassVTableTracking.Run();
 
         return 100;
     }
@@ -2121,4 +2122,28 @@ public static void Run()
             arr.SetValue(new Gen<Gen<string>>(), new int[] { 0, 0 });
         }
     }
+
+    class TestClassVTableTracking
+    {
+        class Unit { }
+
+        class Gen<T, U>
+        {
+            public virtual int Test()
+            {
+                return 42;
+            }
+        }
+
+        static int Call<T>()
+        {
+            return new Gen<T, Unit>().Test();
+        }
+
+        public static void Run()
+        {
+            // This only really tests whether we can compile this.
+            Call<object>();
+        }
+    }
 }