Prevent SequencePointBuilder from combining sequence points of lambda expressions.

ICSharpCode.Decompiler/CSharp/SequencePointBuilder.cs

@@ -120,6 +120,12 @@ namespace ICSharpCode.Decompiler.CSharp
 			}
 		}
 
+		public override void VisitLambdaExpression(LambdaExpression lambdaExpression)
+		{
+			AddToSequencePoint(lambdaExpression);
+			VisitAsSequencePoint(lambdaExpression.Body);
+		}
+
 		/// <summary>
 		/// Start a new C# statement = new sequence point.
 		/// </summary>
@@ -160,7 +166,7 @@ namespace ICSharpCode.Decompiler.CSharp
 
 		void AddToSequencePoint(ILInstruction inst)
 		{
-			if (!mappedInstructions.Add(inst)) {
+			if (!mappedInstructions.Add(inst) || inst is ILFunction) {
 				// inst was already used by a nested sequence point within this sequence point
 				return;
 			}

ILSpy/Languages/CSharpILMixedLanguage.cs

@@ -69,7 +69,8 @@ namespace ICSharpCode.ILSpy
 					CSharpDecompiler decompiler = CreateDecompiler(method.Module, options);
 					var st = decompiler.Decompile(method);
 					WriteCode(csharpOutput, options.DecompilerSettings, st, decompiler.TypeSystem);
-					this.sequencePoints = decompiler.CreateSequencePoints(st).FirstOrDefault(kvp => kvp.Key.CecilMethod == method).Value ?? (IList<Decompiler.IL.SequencePoint>)EmptyList<Decompiler.IL.SequencePoint>.Instance;
+					var mapping = decompiler.CreateSequencePoints(st).FirstOrDefault(kvp => kvp.Key.CecilMethod == method);
+					this.sequencePoints = mapping.Value ?? (IList<Decompiler.IL.SequencePoint>)EmptyList<Decompiler.IL.SequencePoint>.Instance;
 					this.codeLines = csharpOutput.ToString().Split(new[] { Environment.NewLine }, StringSplitOptions.None);
 					base.Disassemble(body);
 				} finally {