Fix multiple interface constraints for methods.

Author: hypercodeplace

LazyProxy.Tests/LazyProxyBuilderTests.cs

@@ -9,11 +9,13 @@ public class LazyProxyBuilderTests
     {
         public interface IBaseArgument { }
 
+        public interface IOtherBaseArgument { }
+
         public abstract class BaseArgument : IBaseArgument { }
 
         public abstract class BaseArgument2 { }
 
-        public struct TestArgument : IBaseArgument { }
+        public struct TestArgument : IBaseArgument, IOtherBaseArgument { }
 
         // ReSharper disable once MemberCanBePrivate.Global
         public class TestArgument2 : BaseArgument { }
@@ -44,6 +46,10 @@ public interface ITestService : IParentTestService
             string MethodWithDefaultValue(string arg = "arg");
             string MethodWithOutValue(out string arg);
             string MethodWithRefValue(ref TestArgument arg);
+
+            void GenericMethod<T>()
+                where T : IBaseArgument, IOtherBaseArgument { }
+
             string GenericMethod<T1, T2, T3>(string arg)
                 where T1 : class, IBaseArgument, new()
                 where T2 : struct
@@ -76,7 +82,7 @@ public void ProxyMustImplementInterface()
         public void ExceptionMustBeThrownForBuildingProxyByClass()
         {
             Assert.Throws<NotSupportedException>(
-                () => LazyProxyBuilder.GetType<AbstractTestService>());
+                LazyProxyBuilder.GetType<AbstractTestService>);
         }
 
         [Fact]
@@ -407,5 +413,12 @@ public void GenericInterfaceWithDifferentTypeParametersMustBeCreatedWithoutExcep
 
             Assert.Null(exception);
         }
+
+        [Fact]
+        public void GenericMethodWithMultipleInterfaceConstraintsMustBeProxied()
+        {
+            var proxy = LazyProxyBuilder.CreateInstance(Mock.Of<ITestService>);
+            proxy.GenericMethod<TestArgument>();
+        }
     }
 }

LazyProxy/LazyProxyBuilder.cs

@@ -312,18 +312,29 @@ private static void AddGenericParameters(
                 definedGenericParameter.SetGenericParameterAttributes(genericParameterAttributes);
 
                 var genericParameterConstraints = genericParameter.GetGenericParameterConstraints();
+                if (!genericParameterConstraints.Any())
+                {
+                    return;
+                }
+
+                var interfaceConstraints = new List<Type>(genericParameterConstraints.Length);
 
                 foreach (var constraint in genericParameterConstraints)
                 {
                     if (constraint.IsInterface)
                     {
-                        definedGenericParameter.SetInterfaceConstraints(constraint);
+                        interfaceConstraints.Add(constraint);
                     }
                     else
                     {
                         definedGenericParameter.SetBaseTypeConstraint(constraint);
                     }
                 }
+
+                if (interfaceConstraints.Any())
+                {
+                    definedGenericParameter.SetInterfaceConstraints(interfaceConstraints.ToArray());
+                }
             }
         }
     }