From 1dfda502ea39172c865b360b215ea683240cbf3f Mon Sep 17 00:00:00 2001
From: Daniel Grunwald <daniel@danielgrunwald.de>
Date: Sat, 24 Feb 2018 18:06:01 +0100
Subject: [PATCH] Remove redundant 'box' opcodes. This eliminates some
 unnecessary (object)-casts in generic code.

---
 .../IL/Transforms/ExpressionTransforms.cs             | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/ICSharpCode.Decompiler/IL/Transforms/ExpressionTransforms.cs b/ICSharpCode.Decompiler/IL/Transforms/ExpressionTransforms.cs
index 59c8446ba..f844c6a8b 100644
--- a/ICSharpCode.Decompiler/IL/Transforms/ExpressionTransforms.cs
+++ b/ICSharpCode.Decompiler/IL/Transforms/ExpressionTransforms.cs
@@ -155,6 +155,17 @@ namespace ICSharpCode.Decompiler.IL.Transforms
 			}
 		}
 
+		protected internal override void VisitBox(Box inst)
+		{
+			inst.Argument.AcceptVisitor(this);
+			if (inst.Type.IsReferenceType == true && inst.Argument.ResultType == inst.ResultType) {
+				// For reference types, box is a no-op.
+				context.Step("box ref-type(arg) => arg", inst);
+				inst.Argument.AddILRange(inst.ILRange);
+				inst.ReplaceWith(inst.Argument);
+			}
+		}
+
 		protected internal override void VisitLdElema(LdElema inst)
 		{
 			base.VisitLdElema(inst);