Introduce `PdbExtraTypeInfo` struct and adjusted `IDebugInfoProvider`

ICSharpCode.Decompiler/DebugInfo/IDebugInfoProvider.cs

@@ -17,13 +17,19 @@ namespace ICSharpCode.Decompiler.DebugInfo
 		public string Name { get; }
 	}
 
+	public struct PdbExtraTypeInfo
+	{
+		public string[] TupleElementNames;
+		public bool[] DynamicFlags;
+	}
+
 	public interface IDebugInfoProvider
 	{
 		string Description { get; }
 		IList<SequencePoint> GetSequencePoints(MethodDefinitionHandle method);
 		IList<Variable> GetVariables(MethodDefinitionHandle method);
 		bool TryGetName(MethodDefinitionHandle method, int index, out string name);
-		bool TryGetExtraTypeInfo(MethodDefinitionHandle method, int index, out string[] tupleElementNames, out bool[] dynamicFlags);
+		bool TryGetExtraTypeInfo(MethodDefinitionHandle method, int index, out PdbExtraTypeInfo extraTypeInfo);
 		string SourceFileName { get; }
 	}
 }

ICSharpCode.Decompiler/IL/ApplyPdbLocalTypeInfoTypeVisitor.cs

@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Immutable;
 
+using ICSharpCode.Decompiler.DebugInfo;
 using ICSharpCode.Decompiler.TypeSystem;
 using ICSharpCode.Decompiler.TypeSystem.Implementation;
 
@@ -16,12 +17,19 @@ namespace ICSharpCode.Decompiler.IL
 		private int dynamicTypeIndex = 0;
 		private int tupleTypeIndex = 0;
 
-		public ApplyPdbLocalTypeInfoTypeVisitor(bool[] dynamicData, string[] tupleElementNames)
+		private ApplyPdbLocalTypeInfoTypeVisitor(bool[] dynamicData, string[] tupleElementNames)
 		{
 			this.dynamicData = dynamicData;
 			this.tupleElementNames = tupleElementNames;
 		}
 
+		public static IType Apply(IType type, PdbExtraTypeInfo pdbExtraTypeInfo)
+		{
+			if (pdbExtraTypeInfo.DynamicFlags is null && pdbExtraTypeInfo.TupleElementNames is null)
+				return type;
+			return type.AcceptVisitor(new ApplyPdbLocalTypeInfoTypeVisitor(pdbExtraTypeInfo.DynamicFlags, pdbExtraTypeInfo.TupleElementNames));
+		}
+
 		public override IType VisitModOpt(ModifiedType type)
 		{
 			dynamicTypeIndex++;

ICSharpCode.Decompiler/IL/ILReader.cs

@@ -306,10 +306,9 @@ namespace ICSharpCode.Decompiler.IL
 			}
 
 			if (UseDebugSymbols && DebugInfo is not null &&
-				DebugInfo.TryGetExtraTypeInfo((MethodDefinitionHandle)method.MetadataToken, index,
-					out string[] tupleElementNames, out bool[] dynamicFlags))
+				DebugInfo.TryGetExtraTypeInfo((MethodDefinitionHandle)method.MetadataToken, index, out var pdbExtraTypeInfo))
 			{
-				type = type.AcceptVisitor(new ApplyPdbLocalTypeInfoTypeVisitor(dynamicFlags, tupleElementNames));
+				type = ApplyPdbLocalTypeInfoTypeVisitor.Apply(type, pdbExtraTypeInfo);
 			}
 
 			ILVariable ilVar = new ILVariable(kind, type, index);

ICSharpCode.ILSpyX/PdbProvider/MonoCecilDebugInfoProvider.cs

@@ -136,13 +136,11 @@ namespace ICSharpCode.ILSpyX.PdbProvider
 			return name != null;
 		}
 
-		public bool TryGetExtraTypeInfo(SRM.MethodDefinitionHandle method, int index,
-			[NotNullWhen(true)] out string[]? tupleElementNames, [NotNullWhen(true)] out bool[]? dynamicFlags)
+		public bool TryGetExtraTypeInfo(SRM.MethodDefinitionHandle method, int index, out PdbExtraTypeInfo extraTypeInfo)
 		{
 			// Mono.Cecil's WindowsPDB reader is unable to read tuple element names
 			// and dynamic flags custom debug information.
-			tupleElementNames = null;
-			dynamicFlags = null;
+			extraTypeInfo = default;
 			return false;
 		}
 	}

ICSharpCode.ILSpyX/PdbProvider/PortableDebugInfoProvider.cs

@@ -162,12 +162,10 @@ namespace ICSharpCode.ILSpyX.PdbProvider
 			return false;
 		}
 
-		public bool TryGetExtraTypeInfo(MethodDefinitionHandle method, int index,
-			[NotNullWhen(true)] out string?[]? tupleElementNames, [NotNullWhen(true)] out bool[]? dynamicFlags)
+		public bool TryGetExtraTypeInfo(MethodDefinitionHandle method, int index, out PdbExtraTypeInfo extraTypeInfo)
 		{
 			var metadata = GetMetadataReader();
-			tupleElementNames = null;
-			dynamicFlags = null;
+			extraTypeInfo = default;
 
 			if (metadata == null)
 				return false;
@@ -200,7 +198,7 @@ namespace ICSharpCode.ILSpyX.PdbProvider
 				if (cdi.Value.IsNil || cdi.Kind.IsNil)
 					continue;
 				var kind = metadata.GetGuid(cdi.Kind);
-				if (kind == KnownGuids.TupleElementNames && tupleElementNames is null)
+				if (kind == KnownGuids.TupleElementNames && extraTypeInfo.TupleElementNames is null)
 				{
 					var reader = metadata.GetBlobReader(cdi.Value);
 					var list = new List<string?>();
@@ -212,25 +210,26 @@ namespace ICSharpCode.ILSpyX.PdbProvider
 						list.Add(string.IsNullOrWhiteSpace(s) ? null : s);
 					}
 
-					tupleElementNames = list.ToArray();
+					extraTypeInfo.TupleElementNames = list.ToArray();
 				}
-				else if (kind == KnownGuids.DynamicLocalVariables && dynamicFlags is null)
+				else if (kind == KnownGuids.DynamicLocalVariables && extraTypeInfo.DynamicFlags is null)
 				{
 					var reader = metadata.GetBlobReader(cdi.Value);
+					extraTypeInfo.DynamicFlags = new bool[reader.Length * 8];
 					int j = 0;
 					while (reader.RemainingBytes > 0)
 					{
 						int b = reader.ReadByte();
 						for (int i = 1; i < 0x100; i <<= 1)
-							dynamicFlags[j++] = (b & i) != 0;
+							extraTypeInfo.DynamicFlags[j++] = (b & i) != 0;
 					}
 				}
 
-				if (tupleElementNames != null && dynamicFlags != null)
+				if (extraTypeInfo.TupleElementNames != null && extraTypeInfo.DynamicFlags != null)
 					break;
 			}
 
-			return tupleElementNames != null || dynamicFlags != null;
+			return extraTypeInfo.TupleElementNames != null || extraTypeInfo.DynamicFlags != null;
 		}
 	}
 }