Records: Omit "IEquatable" in base class list

ICSharpCode.Decompiler/CSharp/Syntax/TypeSystemAstBuilder.cs

@@ -1783,22 +1783,30 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			{
 				foreach (IType baseType in typeDefinition.DirectBaseTypes)
 				{
-					// if the declared type is an enum, replace all references to System.Enum with the enum-underlying type
 					if (typeDefinition.Kind == TypeKind.Enum && baseType.IsKnownType(KnownTypeCode.Enum))
 					{
+						// if the declared type is an enum, replace all references to System.Enum with the enum-underlying type
 						if (!typeDefinition.EnumUnderlyingType.IsKnownType(KnownTypeCode.Int32))
 						{
 							decl.BaseTypes.Add(ConvertType(typeDefinition.EnumUnderlyingType));
 						}
-						// if the declared type is a struct, ignore System.ValueType
 					}
 					else if ((typeDefinition.Kind == TypeKind.Struct || typeDefinition.Kind == TypeKind.Void) && baseType.IsKnownType(KnownTypeCode.ValueType))
 					{
+						// if the declared type is a struct, ignore System.ValueType
 						continue;
-						// always ignore System.Object
 					}
 					else if (baseType.IsKnownType(KnownTypeCode.Object))
 					{
+						// always ignore System.Object
+						continue;
+					}
+					else if (SupportRecordClasses && typeDefinition.IsRecord
+						&& baseType.Name == "IEquatable" && baseType.Namespace == "System"
+						&& baseType.TypeArguments.Count == 1
+						&& baseType.TypeArguments[0].Equals(typeDefinition))
+					{
+						// omit "IEquatable<R>" in records
 						continue;
 					}
 					else