From 48183632f69c4ac2a2ea8b741272240d1ba2a3f8 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Michal=20Strehovsk=C3=BD?= <michals@microsoft.com>
Date: Fri, 19 Jan 2018 13:31:59 +0100
Subject: [PATCH] Make reflection tracking work with unnormalized
 VirtualMethodUse

---
 .../ReflectableMethodNode.cs                  |  4 +++-
 .../VirtualMethodUseNode.cs                   |  4 +++-
 tests/src/Simple/Reflection/Reflection.cs     | 20 +++++++++++++++++++
 3 files changed, 26 insertions(+), 2 deletions(-)

diff --git a/src/ILCompiler.Compiler/src/Compiler/DependencyAnalysis/ReflectableMethodNode.cs b/src/ILCompiler.Compiler/src/Compiler/DependencyAnalysis/ReflectableMethodNode.cs
index 2664308a8..78d27ef41 100644
--- a/src/ILCompiler.Compiler/src/Compiler/DependencyAnalysis/ReflectableMethodNode.cs
+++ b/src/ILCompiler.Compiler/src/Compiler/DependencyAnalysis/ReflectableMethodNode.cs
@@ -22,6 +22,8 @@ namespace ILCompiler.DependencyAnalysis
         public ReflectableMethodNode(MethodDesc method)
         {
             Debug.Assert(method.IsAbstract || method.IsPInvoke);
+            Debug.Assert(!method.IsCanonicalMethod(CanonicalFormKind.Any) ||
+                method.GetCanonMethodTarget(CanonicalFormKind.Specific) == method);
             _method = method;
         }
 
@@ -45,4 +47,4 @@ namespace ILCompiler.DependencyAnalysis
         public override IEnumerable<CombinedDependencyListEntry> GetConditionalStaticDependencies(NodeFactory factory) => null;
         public override IEnumerable<CombinedDependencyListEntry> SearchDynamicDependencies(List<DependencyNodeCore<NodeFactory>> markedNodes, int firstNode, NodeFactory factory) => null;
     }
-}
\ No newline at end of file
+}
diff --git a/src/ILCompiler.Compiler/src/Compiler/DependencyAnalysis/VirtualMethodUseNode.cs b/src/ILCompiler.Compiler/src/Compiler/DependencyAnalysis/VirtualMethodUseNode.cs
index 7d4f17df7..aec52ca2d 100644
--- a/src/ILCompiler.Compiler/src/Compiler/DependencyAnalysis/VirtualMethodUseNode.cs
+++ b/src/ILCompiler.Compiler/src/Compiler/DependencyAnalysis/VirtualMethodUseNode.cs
@@ -68,7 +68,9 @@ namespace ILCompiler.DependencyAnalysis
 
             dependencies.Add(new DependencyListEntry(factory.VTable(_decl.OwningType), "VTable of a VirtualMethodUse"));
 
-            factory.MetadataManager.GetDependenciesDueToVirtualMethodReflectability(ref dependencies, factory, _decl);
+            // Do not report things like Foo<object, __Canon>.Frob().
+            if (!_decl.IsCanonicalMethod(CanonicalFormKind.Any) || canonDecl == _decl)
+                factory.MetadataManager.GetDependenciesDueToVirtualMethodReflectability(ref dependencies, factory, _decl);
 
             return dependencies;
         }
diff --git a/tests/src/Simple/Reflection/Reflection.cs b/tests/src/Simple/Reflection/Reflection.cs
index 4454e9415..322650a2c 100644
--- a/tests/src/Simple/Reflection/Reflection.cs
+++ b/tests/src/Simple/Reflection/Reflection.cs
@@ -423,6 +423,21 @@ internal class ReflectionTest
             }
         }
 
+        class Gen<T> { }
+
+        interface IFoo<out T>
+        {
+            string Frob();
+        }
+
+        class Foo<T> : IFoo<Gen<T>>
+        {
+            public string Frob()
+            {
+                return typeof(T).ToString();
+            }
+        }
+
         public static void Run()
         {
             Console.WriteLine(nameof(TestInterfaceMethod));
@@ -431,11 +446,16 @@ internal class ReflectionTest
             if (string.Empty.Length > 0)
             {
                 ((IFoo)new Foo()).Frob(1);
+                ((IFoo<object>)new Foo<string>()).Frob();
             }
 
             object result = InvokeTestMethod(typeof(IFoo), "Frob", new Foo(), 42);
             if ((string)result != "42")
                 throw new Exception();
+
+            result = InvokeTestMethod(typeof(IFoo<object>), "Frob", new Foo<string>());
+            if ((string)result != "System.String")
+                throw new Exception();
         }
     }