From 3e05a8d763eb62df7667b97192acdd74d5956229 Mon Sep 17 00:00:00 2001
From: Siegfried Pammer <siegfriedpammer@gmail.com>
Date: Tue, 10 May 2022 22:21:48 +0200
Subject: [PATCH] #2685: Emit 'override' without 'newslot' as 'virtual' if
 there is no (known) method to override.

---
 ICSharpCode.Decompiler/CSharp/CSharpDecompiler.cs | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/ICSharpCode.Decompiler/CSharp/CSharpDecompiler.cs b/ICSharpCode.Decompiler/CSharp/CSharpDecompiler.cs
index ebf80585a..049042ea2 100644
--- a/ICSharpCode.Decompiler/CSharp/CSharpDecompiler.cs
+++ b/ICSharpCode.Decompiler/CSharp/CSharpDecompiler.cs
@@ -1567,6 +1567,14 @@ namespace ICSharpCode.Decompiler.CSharp
 				{
 					SetNewModifier(methodDecl);
 				}
+				else if (!method.IsVirtual && method.IsOverride && InheritanceHelper.GetBaseMember(method) == null)
+				{
+					methodDecl.Modifiers &= ~Modifiers.Override;
+					if (!method.DeclaringTypeDefinition.IsSealed)
+					{
+						methodDecl.Modifiers |= Modifiers.Virtual;
+					}
+				}
 				if (IsCovariantReturnOverride(method))
 				{
 					RemoveAttribute(methodDecl, KnownAttribute.PreserveBaseOverrides);