Implement sequence points for using statement.

ICSharpCode.Decompiler/CSharp/SequencePointBuilder.cs

@@ -126,6 +126,15 @@ namespace ICSharpCode.Decompiler.CSharp
 			VisitAsSequencePoint(lambdaExpression.Body);
 		}
 
+		public override void VisitUsingStatement(UsingStatement usingStatement)
+		{
+			StartSequencePoint(usingStatement);
+			usingStatement.ResourceAcquisition.AcceptVisitor(this);
+			VisitAsSequencePoint(usingStatement.EmbeddedStatement);
+			AddToSequencePoint(usingStatement);
+			EndSequencePoint(usingStatement.StartLocation, usingStatement.RParToken.EndLocation);
+		}
+
 		/// <summary>
 		/// Start a new C# statement = new sequence point.
 		/// </summary>

ICSharpCode.Decompiler/IL/Transforms/UsingTransform.cs

@@ -87,7 +87,7 @@ namespace ICSharpCode.Decompiler.IL.Transforms
 			context.Step("UsingTransform", tryFinally);
 			storeInst.Variable.Kind = VariableKind.UsingLocal;
 			block.Instructions.RemoveAt(i);
-			block.Instructions[i - 1] = new UsingInstruction(storeInst.Variable, storeInst.Value, tryFinally.TryBlock);
+			block.Instructions[i - 1] = new UsingInstruction(storeInst.Variable, storeInst.Value, tryFinally.TryBlock) { ILRange = storeInst.ILRange };
 			return true;
 		}