Fix #2791: Ensure that the capture scope used is either a loop or the ILFunction root container.

ICSharpCode.Decompiler.Tests/TestCases/Pretty/DelegateConstruction.cs

@@ -601,6 +601,50 @@ namespace ICSharpCode.Decompiler.Tests.TestCases.Pretty.DelegateConstruction
 		}
 	}
 
+	internal class Issue2791
+	{
+		public void M()
+		{
+			Run(delegate (object o) {
+				try
+				{
+					List<int> list = o as List<int>;
+					Action action = delegate {
+						list.Select((int x) => x * 2);
+					};
+#if OPT && ROSLYN
+					Action obj = delegate {
+#else
+					Action action2 = delegate {
+#endif
+						list.Select((int x) => x * 2);
+					};
+					Console.WriteLine();
+					action();
+					Console.WriteLine();
+#if OPT && ROSLYN
+					obj();
+#else
+					action2();
+#endif
+				}
+				catch (Exception)
+				{
+					Console.WriteLine("catch");
+				}
+				finally
+				{
+					Console.WriteLine("finally");
+				}
+			}, null);
+		}
+
+		private void Run(ParameterizedThreadStart del, object x)
+		{
+			del(x);
+		}
+	}
+
 	[AttributeUsage(AttributeTargets.All)]
 	internal class MyAttribute : Attribute
 	{

ICSharpCode.Decompiler/CSharp/Transforms/DeclareVariables.cs

@@ -281,7 +281,7 @@ namespace ICSharpCode.Decompiler.CSharp.Transforms
 		void FindInsertionPoints(AstNode node, int nodeLevel)
 		{
 			BlockContainer scope = node.Annotation<BlockContainer>();
-			if (scope != null && (scope.EntryPoint.IncomingEdgeCount > 1 || scope.Parent is ILFunction))
+			if (scope != null && IsRelevantScope(scope))
 			{
 				// track loops and function bodies as scopes, for comparison with CaptureScope.
 				scopeTracking.Add((new InsertionPoint { level = nodeLevel, nextNode = node }, scope));
@@ -316,9 +316,14 @@ namespace ICSharpCode.Decompiler.CSharp.Transforms
 					{
 						InsertionPoint newPoint;
 						int startIndex = scopeTracking.Count - 1;
-						if (variable.CaptureScope != null && startIndex > 0 && variable.CaptureScope != scopeTracking[startIndex].Scope)
+						BlockContainer captureScope = variable.CaptureScope;
+						while (captureScope != null && !IsRelevantScope(captureScope))
 						{
-							while (startIndex > 0 && scopeTracking[startIndex].Scope != variable.CaptureScope)
+							captureScope = BlockContainer.FindClosestContainer(captureScope.Parent);
+						}
+						if (captureScope != null && startIndex > 0 && captureScope != scopeTracking[startIndex].Scope)
+						{
+							while (startIndex > 0 && scopeTracking[startIndex].Scope != captureScope)
 								startIndex--;
 							newPoint = scopeTracking[startIndex + 1].InsertionPoint;
 						}
@@ -366,6 +371,11 @@ namespace ICSharpCode.Decompiler.CSharp.Transforms
 			}
 		}
 
+		private static bool IsRelevantScope(BlockContainer scope)
+		{
+			return scope.EntryPoint.IncomingEdgeCount > 1 || scope.Parent is ILFunction;
+		}
+
 		internal static bool VariableNeedsDeclaration(VariableKind kind)
 		{
 			switch (kind)

ICSharpCode.Decompiler/IL/ILVariable.cs

@@ -209,7 +209,7 @@ namespace ICSharpCode.Decompiler.IL
 		/// <summary>
 		/// Gets the block container in which this variable is captured.
 		/// For captured variables declared inside the loop, the capture scope is the BlockContainer of the loop.
-		/// For captured variables declared outside of the loop, the capture scope is the BlockContainer of the parent. 
+		/// For captured variables declared outside of the loop, the capture scope is the BlockContainer of the parent function.
 		/// </summary>
 		/// <remarks>
 		/// This property returns null for variables that are not captured.