Deduplicate the heap walk and the TypeAttributes tooltip

The #Strings/#US/#Blob nodes each open-coded the same offset-chained
walk, whose subtlety (handle 0 is a real entry despite being the nil
handle) is now documented once in WalkHeap. The TypeDef and
ExportedType entries built byte-identical TypeAttributes flag-group
tooltips; FlagsTooltip.ForTypeAttributes is the shared factory.

Assisted-by: Claude:claude-fable-5[1m]:Claude Code

ILSpy/Metadata/BlobHeapTreeNode.cs

@@ -43,12 +43,8 @@ namespace ILSpy.Metadata
 
 		protected override void LoadEntries(MetadataReader metadata, List<BlobHeapEntry> list)
 		{
-			var handle = MetadataTokens.BlobHandle(0);
-			do
-			{
-				list.Add(new BlobHeapEntry(metadata, handle));
-				handle = metadata.GetNextHandle(handle);
-			} while (!handle.IsNil);
+			WalkHeap(list, MetadataTokens.BlobHandle(0),
+				h => new BlobHeapEntry(metadata, h), metadata.GetNextHandle, h => h.IsNil);
 		}
 
 		public sealed class BlobHeapEntry

ILSpy/Metadata/CorTables/ExportedTypeTableTreeNode.cs

@@ -63,16 +63,7 @@ namespace ILSpy.Metadata.CorTables
 			[ColumnInfo("X8")]
 			public TypeAttributes Attributes => type.Attributes;
 
-			const TypeAttributes otherFlagsMask = ~(TypeAttributes.VisibilityMask | TypeAttributes.LayoutMask | TypeAttributes.ClassSemanticsMask | TypeAttributes.StringFormatMask | TypeAttributes.CustomFormatMask);
-
-			public object AttributesTooltip => new FlagsTooltip {
-				FlagGroup.CreateSingleChoiceGroup(typeof(TypeAttributes), "Visibility: ", (int)TypeAttributes.VisibilityMask, (int)(type.Attributes & TypeAttributes.VisibilityMask), new Flag("NotPublic (0000)", 0, false), includeAny: false),
-				FlagGroup.CreateSingleChoiceGroup(typeof(TypeAttributes), "Class layout: ", (int)TypeAttributes.LayoutMask, (int)(type.Attributes & TypeAttributes.LayoutMask), new Flag("AutoLayout (0000)", 0, false), includeAny: false),
-				FlagGroup.CreateSingleChoiceGroup(typeof(TypeAttributes), "Class semantics: ", (int)TypeAttributes.ClassSemanticsMask, (int)(type.Attributes & TypeAttributes.ClassSemanticsMask), new Flag("Class (0000)", 0, false), includeAny: false),
-				FlagGroup.CreateSingleChoiceGroup(typeof(TypeAttributes), "String format: ", (int)TypeAttributes.StringFormatMask, (int)(type.Attributes & TypeAttributes.StringFormatMask), new Flag("AnsiClass (0000)", 0, false), includeAny: false),
-				FlagGroup.CreateSingleChoiceGroup(typeof(TypeAttributes), "Custom format: ", (int)TypeAttributes.CustomFormatMask, (int)(type.Attributes & TypeAttributes.CustomFormatMask), new Flag("Value0 (0000)", 0, false), includeAny: false),
-				FlagGroup.CreateMultipleChoiceGroup(typeof(TypeAttributes), "Flags:", (int)otherFlagsMask, (int)(type.Attributes & otherFlagsMask), includeAll: false),
-			};
+			public object AttributesTooltip => FlagsTooltip.ForTypeAttributes(type.Attributes);
 
 			[ColumnInfo("X8")]
 			public int TypeDefId => type.GetTypeDefinitionId();

ILSpy/Metadata/CorTables/TypeDefTableTreeNode.cs

@@ -66,16 +66,7 @@ namespace ILSpy.Metadata.CorTables
 			[ColumnInfo("X8")]
 			public TypeAttributes Attributes => typeDef.Attributes;
 
-			const TypeAttributes otherFlagsMask = ~(TypeAttributes.VisibilityMask | TypeAttributes.LayoutMask | TypeAttributes.ClassSemanticsMask | TypeAttributes.StringFormatMask | TypeAttributes.CustomFormatMask);
-
-			public object AttributesTooltip => new FlagsTooltip {
-				FlagGroup.CreateSingleChoiceGroup(typeof(TypeAttributes), "Visibility: ", (int)TypeAttributes.VisibilityMask, (int)(typeDef.Attributes & TypeAttributes.VisibilityMask), new Flag("NotPublic (0000)", 0, false), includeAny: false),
-				FlagGroup.CreateSingleChoiceGroup(typeof(TypeAttributes), "Class layout: ", (int)TypeAttributes.LayoutMask, (int)(typeDef.Attributes & TypeAttributes.LayoutMask), new Flag("AutoLayout (0000)", 0, false), includeAny: false),
-				FlagGroup.CreateSingleChoiceGroup(typeof(TypeAttributes), "Class semantics: ", (int)TypeAttributes.ClassSemanticsMask, (int)(typeDef.Attributes & TypeAttributes.ClassSemanticsMask), new Flag("Class (0000)", 0, false), includeAny: false),
-				FlagGroup.CreateSingleChoiceGroup(typeof(TypeAttributes), "String format: ", (int)TypeAttributes.StringFormatMask, (int)(typeDef.Attributes & TypeAttributes.StringFormatMask), new Flag("AnsiClass (0000)", 0, false), includeAny: false),
-				FlagGroup.CreateSingleChoiceGroup(typeof(TypeAttributes), "Custom format: ", (int)TypeAttributes.CustomFormatMask, (int)(typeDef.Attributes & TypeAttributes.CustomFormatMask), new Flag("Value0 (0000)", 0, false), includeAny: false),
-				FlagGroup.CreateMultipleChoiceGroup(typeof(TypeAttributes), "Flags:", (int)otherFlagsMask, (int)(typeDef.Attributes & otherFlagsMask), includeAll: false),
-			};
+			public object AttributesTooltip => FlagsTooltip.ForTypeAttributes(typeDef.Attributes);
 
 			public string Name => metadataFile.Metadata.GetString(typeDef.Name);
 

ILSpy/Metadata/FlagsTooltip.cs

@@ -64,6 +64,25 @@ namespace ILSpy.Metadata
 				panel.Children.Add(group.Build());
 			return panel;
 		}
+
+		/// <summary>
+		/// Tooltip for a <see cref="TypeAttributes"/> column: one single-choice group per
+		/// mutually exclusive sub-range (visibility, layout, class semantics, string format,
+		/// custom format) plus a multiple-choice group for the remaining independent bits.
+		/// Shared by every table whose rows carry type attributes (TypeDef, ExportedType).
+		/// </summary>
+		public static FlagsTooltip ForTypeAttributes(TypeAttributes attributes)
+		{
+			const TypeAttributes otherFlagsMask = ~(TypeAttributes.VisibilityMask | TypeAttributes.LayoutMask | TypeAttributes.ClassSemanticsMask | TypeAttributes.StringFormatMask | TypeAttributes.CustomFormatMask);
+			return new FlagsTooltip {
+				FlagGroup.CreateSingleChoiceGroup(typeof(TypeAttributes), "Visibility: ", (int)TypeAttributes.VisibilityMask, (int)(attributes & TypeAttributes.VisibilityMask), new Flag("NotPublic (0000)", 0, false), includeAny: false),
+				FlagGroup.CreateSingleChoiceGroup(typeof(TypeAttributes), "Class layout: ", (int)TypeAttributes.LayoutMask, (int)(attributes & TypeAttributes.LayoutMask), new Flag("AutoLayout (0000)", 0, false), includeAny: false),
+				FlagGroup.CreateSingleChoiceGroup(typeof(TypeAttributes), "Class semantics: ", (int)TypeAttributes.ClassSemanticsMask, (int)(attributes & TypeAttributes.ClassSemanticsMask), new Flag("Class (0000)", 0, false), includeAny: false),
+				FlagGroup.CreateSingleChoiceGroup(typeof(TypeAttributes), "String format: ", (int)TypeAttributes.StringFormatMask, (int)(attributes & TypeAttributes.StringFormatMask), new Flag("AnsiClass (0000)", 0, false), includeAny: false),
+				FlagGroup.CreateSingleChoiceGroup(typeof(TypeAttributes), "Custom format: ", (int)TypeAttributes.CustomFormatMask, (int)(attributes & TypeAttributes.CustomFormatMask), new Flag("Value0 (0000)", 0, false), includeAny: false),
+				FlagGroup.CreateMultipleChoiceGroup(typeof(TypeAttributes), "Flags:", (int)otherFlagsMask, (int)(attributes & otherFlagsMask), includeAll: false),
+			};
+		}
 	}
 
 	public readonly struct Flag

ILSpy/Metadata/MetadataHeapTreeNode.cs

@@ -92,5 +92,24 @@ namespace ILSpy.Metadata
 
 		/// <summary>Materialises every heap row into <paramref name="list"/>.</summary>
 		protected abstract void LoadEntries(MetadataReader metadata, List<TEntry> list);
+
+		/// <summary>
+		/// Shared walk for the offset-chained heaps (#Strings, #US, #Blob). Handle 0 is a
+		/// real first entry (the heap's empty/zero slot) even though it is the nil handle,
+		/// so each entry is added before <paramref name="getNextHandle"/> is consulted; the
+		/// walk ends when the returned handle is nil.
+		/// </summary>
+		protected static void WalkHeap<THandle>(List<TEntry> list, THandle firstHandle,
+			Func<THandle, TEntry> createEntry, Func<THandle, THandle> getNextHandle,
+			Predicate<THandle> isNil)
+			where THandle : struct
+		{
+			var handle = firstHandle;
+			do
+			{
+				list.Add(createEntry(handle));
+				handle = getNextHandle(handle);
+			} while (!isNil(handle));
+		}
 	}
 }

ILSpy/Metadata/StringHeapTreeNode.cs

@@ -43,12 +43,8 @@ namespace ILSpy.Metadata
 
 		protected override void LoadEntries(MetadataReader metadata, List<StringHeapEntry> list)
 		{
-			var handle = MetadataTokens.StringHandle(0);
-			do
-			{
-				list.Add(new StringHeapEntry(metadata, handle));
-				handle = metadata.GetNextHandle(handle);
-			} while (!handle.IsNil);
+			WalkHeap(list, MetadataTokens.StringHandle(0),
+				h => new StringHeapEntry(metadata, h), metadata.GetNextHandle, h => h.IsNil);
 		}
 
 		public sealed class StringHeapEntry

ILSpy/Metadata/UserStringHeapTreeNode.cs

@@ -42,12 +42,8 @@ namespace ILSpy.Metadata
 
 		protected override void LoadEntries(MetadataReader metadata, List<UserStringHeapEntry> list)
 		{
-			var handle = MetadataTokens.UserStringHandle(0);
-			do
-			{
-				list.Add(new UserStringHeapEntry(metadata, handle));
-				handle = metadata.GetNextHandle(handle);
-			} while (!handle.IsNil);
+			WalkHeap(list, MetadataTokens.UserStringHandle(0),
+				h => new UserStringHeapEntry(metadata, h), metadata.GetNextHandle, h => h.IsNil);
 		}
 
 		public sealed class UserStringHeapEntry