diff --git a/ICSharpCode.Decompiler/Ast/AstMethodBodyBuilder.cs b/ICSharpCode.Decompiler/Ast/AstMethodBodyBuilder.cs
index e247014f7..fd10936bc 100644
--- a/ICSharpCode.Decompiler/Ast/AstMethodBodyBuilder.cs
+++ b/ICSharpCode.Decompiler/Ast/AstMethodBodyBuilder.cs
@@ -482,11 +482,11 @@ namespace ICSharpCode.Decompiler.Ast
 				case ILCode.Call:
 				case ILCode.CallGetter:
 				case ILCode.CallSetter:
-					return TransformCall(false, operand, args);
+					return TransformCall(false, byteCode, args);
 				case ILCode.Callvirt:
 				case ILCode.CallvirtGetter:
 				case ILCode.CallvirtSetter:
-					return TransformCall(true, operand,  args);
+					return TransformCall(true, byteCode,  args);
 					case ILCode.Ldftn: {
 						Cecil.MethodReference cecilMethod = ((MethodReference)operand);
 						var expr = new Ast.IdentifierExpression(cecilMethod.Name);
@@ -745,9 +745,10 @@ namespace ICSharpCode.Decompiler.Ast
 			return new DefaultValueExpression { Type = AstBuilder.ConvertType(type) };
 		}
 		
-		AstNode TransformCall(bool isVirtual, object operand, List<Ast.Expression> args)
+		AstNode TransformCall(bool isVirtual, ILExpression byteCode, List<Ast.Expression> args)
 		{
-			Cecil.MethodReference cecilMethod = ((MethodReference)operand);
+			Cecil.MethodReference cecilMethod = (MethodReference)byteCode.Operand;
+			Cecil.MethodDefinition cecilMethodDef = cecilMethod.Resolve();
 			Ast.Expression target;
 			List<Ast.Expression> methodArgs = new List<Ast.Expression>(args);
 			if (cecilMethod.HasThis) {
@@ -760,6 +761,17 @@ namespace ICSharpCode.Decompiler.Ast
 					target = ((DirectionExpression)target).Expression;
 					target.Remove(); // detach from DirectionExpression
 				}
+				if (cecilMethodDef != null && cecilMethodDef.DeclaringType.IsInterface) {
+					TypeReference tr = byteCode.Arguments[0].InferredType;
+					if (tr != null) {
+						TypeDefinition td = tr.Resolve();
+						if (td != null && !td.IsInterface) {
+							// Calling an interface method on a non-interface object:
+							// we need to introduce an explicit cast
+							target = target.CastTo(AstBuilder.ConvertType(cecilMethod.DeclaringType));
+						}
+					}
+				}
 			} else {
 				target = new TypeReferenceExpression { Type = AstBuilder.ConvertType(cecilMethod.DeclaringType) };
 			}
@@ -789,8 +801,7 @@ namespace ICSharpCode.Decompiler.Ast
 				return new AssignmentExpression(target.Indexer(methodArgs.GetRange(0, methodArgs.Count - 1)), methodArgs.Last());
 			}
 			
-			// Resolve the method to figure out whether it is an accessor:
-			Cecil.MethodDefinition cecilMethodDef = cecilMethod.Resolve();
+			// Test whether the method is an accessor:
 			if (cecilMethodDef != null) {
 				if (cecilMethodDef.IsGetter && methodArgs.Count == 0) {
 					foreach (var prop in cecilMethodDef.DeclaringType.Properties) {
diff --git a/ICSharpCode.Decompiler/Ast/Transforms/PatternStatementTransform.cs b/ICSharpCode.Decompiler/Ast/Transforms/PatternStatementTransform.cs
index f8de12492..1f9951789 100644
--- a/ICSharpCode.Decompiler/Ast/Transforms/PatternStatementTransform.cs
+++ b/ICSharpCode.Decompiler/Ast/Transforms/PatternStatementTransform.cs
@@ -126,12 +126,20 @@ namespace ICSharpCode.Decompiler.Ast.Transforms
 			));
 		
 		#region using
+		static Expression InvokeDispose(Expression identifier)
+		{
+			return new Choice {
+				identifier.Invoke("Dispose"),
+				identifier.Clone().CastTo(new TypePattern(typeof(IDisposable))).Invoke("Dispose")
+			};
+		}
+		
 		static readonly AstNode usingTryCatchPattern = new TryCatchStatement {
 			TryBlock = new AnyNode("body"),
 			FinallyBlock = new BlockStatement {
 				new Choice {
 					{ "valueType",
-						new ExpressionStatement(new NamedNode("ident", new IdentifierExpression()).ToExpression().Invoke("Dispose"))
+						new ExpressionStatement(InvokeDispose(new NamedNode("ident", new IdentifierExpression())))
 					},
 					{ "referenceType",
 						new IfElseStatement {
@@ -141,7 +149,7 @@ namespace ICSharpCode.Decompiler.Ast.Transforms
 								new NullReferenceExpression()
 							),
 							TrueStatement = new BlockStatement {
-								new ExpressionStatement(new Backreference("ident").ToExpression().Invoke("Dispose"))
+								new ExpressionStatement(InvokeDispose(new Backreference("ident")))
 							}
 						}
 					}
diff --git a/ICSharpCode.Decompiler/Tests/CallOverloadedMethod.cs b/ICSharpCode.Decompiler/Tests/CallOverloadedMethod.cs
new file mode 100644
index 000000000..852551773
--- /dev/null
+++ b/ICSharpCode.Decompiler/Tests/CallOverloadedMethod.cs
@@ -0,0 +1,37 @@
+// Copyright (c) AlphaSierraPapa for the SharpDevelop Team (for details please see \doc\copyright.txt)
+// This code is distributed under MIT X11 license (for details please see \doc\license.txt)
+
+using System;
+using System.Collections.Generic;
+
+public class CallOverloadedMethod
+{
+	public void OverloadedMethod(object a)
+	{
+	}
+	
+	public void OverloadedMethod(int? a)
+	{
+	}
+	
+	public void OverloadedMethod(string a)
+	{
+	}
+	
+	public void Call()
+	{
+		this.OverloadedMethod("(string)");
+		this.OverloadedMethod((object)"(object)");
+		this.OverloadedMethod(5);
+		this.OverloadedMethod((object)5);
+		this.OverloadedMethod(5L);
+		this.OverloadedMethod((object)null);
+		this.OverloadedMethod((string)null);
+		this.OverloadedMethod((int?)null);
+	}
+	
+	public void CallMethodUsingInterface(List<int> list)
+	{
+		((ICollection<int>)list).Clear();
+	}
+}
diff --git a/ICSharpCode.Decompiler/Tests/ICSharpCode.Decompiler.Tests.csproj b/ICSharpCode.Decompiler/Tests/ICSharpCode.Decompiler.Tests.csproj
index d2ccdaff4..70f17e390 100644
--- a/ICSharpCode.Decompiler/Tests/ICSharpCode.Decompiler.Tests.csproj
+++ b/ICSharpCode.Decompiler/Tests/ICSharpCode.Decompiler.Tests.csproj
@@ -52,6 +52,7 @@
     </Reference>
   </ItemGroup>
   <ItemGroup>
+    <Compile Include="CallOverloadedMethod.cs" />
     <Compile Include="CheckedUnchecked.cs" />
     <Compile Include="IncrementDecrement.cs" />
     <Compile Include="Switch.cs" />