From 756460f6bb3dafb196c2290064d38efeb71811ae Mon Sep 17 00:00:00 2001
From: stakx <stakx@eml.cc>
Date: Thu, 25 Jan 2018 08:24:59 +0100
Subject: [PATCH 1/3] Add failing test

`CallBase` currently tries to call the base method implementation even
for methods of additional interfaces (i. e. interfaces that were added
to the proxy using `.As<TInterface>()` that the base class does not
implement).
---
 Moq.Tests/Regressions/IssueReportsFixture.cs | 25 ++++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/Moq.Tests/Regressions/IssueReportsFixture.cs b/Moq.Tests/Regressions/IssueReportsFixture.cs
index b19e67aad..8cb97fe4c 100644
--- a/Moq.Tests/Regressions/IssueReportsFixture.cs
+++ b/Moq.Tests/Regressions/IssueReportsFixture.cs
@@ -1810,6 +1810,31 @@ public object DoSomething()
 
 		#endregion
 
+		#region 582
+
+		public sealed class Issue582
+		{
+			public interface IFoo
+			{
+				void Method();
+			}
+
+			public class Bar
+			{
+			}
+
+			[Fact]
+			public void CallBase_has_no_effect_for_methods_of_additional_interfaces()
+			{
+				var bar = new Mock<Bar>() { CallBase = true };
+				var foo = bar.As<IFoo>().Object;
+
+				foo.Method();
+			}
+		}
+
+		#endregion
+
 		// Old @ Google Code
 
 		#region #47

From 94417fcc5e8a3f9a9b06d28a3015b6a81182a7cb Mon Sep 17 00:00:00 2001
From: stakx <stakx@eml.cc>
Date: Thu, 25 Jan 2018 08:28:25 +0100
Subject: [PATCH 2/3] Make CallBase base method detection more accurate

For explicitly implemented interfaces aka `.As<TInterface>()`, there
are actually two subcases to consider wrt to `CallBase`: Reimplemented
and additional interfaces. For the latter, the base class will never
have an implementation, we need to add a check for that.
---
 Source/Interception/InterceptionAspects.cs | 20 ++++++++++++++++----
 1 file changed, 16 insertions(+), 4 deletions(-)

diff --git a/Source/Interception/InterceptionAspects.cs b/Source/Interception/InterceptionAspects.cs
index 2c4fcd903..ecafa6019 100644
--- a/Source/Interception/InterceptionAspects.cs
+++ b/Source/Interception/InterceptionAspects.cs
@@ -345,11 +345,23 @@ public override InterceptionAction Handle(Invocation invocation, Mock mock)
 						Debug.Assert(mock.ImplementsInterface(declaringType));
 
 						// Case 2: Explicitly implemented interface method of a class proxy.
-						// Only call base method if it isn't an event accessor.
-						if (!method.LooksLikeEventAttach() && !method.LooksLikeEventDetach())
+
+						if (mock.InheritedInterfaces.Contains(declaringType))
 						{
-							invocation.ReturnBase();
-							return InterceptionAction.Stop;
+							// Case 2a: Re-implemented interface.
+							// The base class has its own implementation. Only call base method if it isn't an event accessor.
+							if (!method.LooksLikeEventAttach() && !method.LooksLikeEventDetach())
+							{
+								invocation.ReturnBase();
+								return InterceptionAction.Stop;
+							}
+						}
+						else
+						{
+							Debug.Assert(mock.AdditionalInterfaces.Contains(declaringType));
+
+							// Case 2b: Additional interface.
+							// There is no base method to call, so fall through.
 						}
 					}
 				}

From 47f603657703bbd873c7ad98ea072c0ac740220b Mon Sep 17 00:00:00 2001
From: stakx <stakx@eml.cc>
Date: Thu, 25 Jan 2018 08:32:36 +0100
Subject: [PATCH 3/3] Update the changelog

---
 CHANGELOG.md | 1 +
 1 file changed, 1 insertion(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 97da8ffa7..386a13044 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -10,6 +10,7 @@ The format is loosely based on [Keep a Changelog](http://keepachangelog.com/en/1
 #### Fixed
 
 * Wrong parameters count for extension methods in `Callback` and `Returns` (@Caraul, #575)
+* `CallBase` regression with members of additional interfaces (@stakx, #583)
 
 
 ## 4.8.1 (2018-01-08)