add support for PinnedType in DecompilerTypeSystem

ICSharpCode.Decompiler/TypeSystem/DecompilerTypeSystem.cs

@@ -117,8 +117,12 @@ namespace ICSharpCode.Decompiler
 			if (typeReference == null)
 				return SpecialType.UnknownType;
 			ITypeReference typeRef;
+			if (typeReference is PinnedType) {
+				typeRef = new NRefactory.TypeSystem.ByReferenceType(Resolve(((PinnedType)typeReference).ElementType)).ToTypeReference();
+			} else {
 				lock (typeReferenceCecilLoader)
 					typeRef = typeReferenceCecilLoader.ReadTypeReference(typeReference);
+			}
 			return typeRef.Resolve(context);
 		}
 		#endregion