diff --git a/com.code-philosophy.obfuz/Editor/ObfusPasses/SymbolObfus/RenameRecordMap.cs b/com.code-philosophy.obfuz/Editor/ObfusPasses/SymbolObfus/RenameRecordMap.cs
index 6825fb2..97c5b30 100644
--- a/com.code-philosophy.obfuz/Editor/ObfusPasses/SymbolObfus/RenameRecordMap.cs
+++ b/com.code-philosophy.obfuz/Editor/ObfusPasses/SymbolObfus/RenameRecordMap.cs
@@ -591,7 +591,7 @@ namespace Obfuz.ObfusPasses.SymbolObfus
             {
                 status = RenameStatus.Renamed,
                 signature = methodRecord != null ? methodRecord.signature : TypeSigUtil.ComputeMethodDefSignature(firstMethod),
-                oldName = methodRecord != null ? methodRecord.oldName : firstMethod.Name,
+                oldName = methodRecord != null ? methodRecord.oldName : (string)firstMethod.Name,
                 newName = newName,
             });
         }
diff --git a/com.code-philosophy.obfuz/Editor/Settings/ObfuzSettings.cs b/com.code-philosophy.obfuz/Editor/Settings/ObfuzSettings.cs
index 8759996..b137d18 100644
--- a/com.code-philosophy.obfuz/Editor/Settings/ObfuzSettings.cs
+++ b/com.code-philosophy.obfuz/Editor/Settings/ObfuzSettings.cs
@@ -82,7 +82,7 @@ namespace Obfuz.Settings
             }
             else
             {
-                s_Instance ??= CreateInstance<ObfuzSettings>();
+                s_Instance = s_Instance ?? CreateInstance<ObfuzSettings>();
             }
             return s_Instance;
         }
diff --git a/com.code-philosophy.obfuz/Editor/Utils/MetaUtil.cs b/com.code-philosophy.obfuz/Editor/Utils/MetaUtil.cs
index c22846a..cd0697a 100644
--- a/com.code-philosophy.obfuz/Editor/Utils/MetaUtil.cs
+++ b/com.code-philosophy.obfuz/Editor/Utils/MetaUtil.cs
@@ -802,7 +802,7 @@ namespace Obfuz.Utils
 
         public static ObfuzScope? GetObfuzIgnoreScope(IHasCustomAttribute obj)
         {
-            var ca = obj.CustomAttributes.FirstOrDefault(ca => ca.AttributeType.FullName == "Obfuz.ObfuzIgnoreAttribute");
+            var ca = obj.CustomAttributes.FirstOrDefault(c => c.AttributeType.FullName == "Obfuz.ObfuzIgnoreAttribute");
             if (ca == null)
             {
                 return null;
@@ -816,13 +816,13 @@ namespace Obfuz.Utils
             TypeDef cur = typeDef;
             while (cur != null)
             {
-                var ca = cur.CustomAttributes?.FirstOrDefault(ca => ca.AttributeType.FullName == "Obfuz.ObfuzIgnoreAttribute");
+                var ca = cur.CustomAttributes?.FirstOrDefault(c => c.AttributeType.FullName == "Obfuz.ObfuzIgnoreAttribute");
                 if (ca != null)
                 {
                     var scope = (ObfuzScope)ca.ConstructorArguments[0].Value;
                     CANamedArgument inheritByNestedTypesArg = ca.GetNamedArgument("InheritByNestedTypes", false);
                     bool inheritByNestedTypes = inheritByNestedTypesArg == null || (bool)inheritByNestedTypesArg.Value;
-                    return cur == typeDef || inheritByNestedTypes ? scope : null;
+                    return cur == typeDef || inheritByNestedTypes ? (ObfuzScope?) scope : null;
                 }
                 cur = cur.DeclaringType;
             }