From 443320d148d478751fbe78519cf213e8d12d111e Mon Sep 17 00:00:00 2001
From: Josef Pihrt <josef@pihrt.net>
Date: Tue, 21 Nov 2023 21:58:40 +0100
Subject: [PATCH] Fix RCS1257 (#1264)

---
 ChangeLog.md                                  |  3 +-
 .../CastExpressionCodeFixProvider.cs          |  5 +--
 .../UseEnumFieldExplicitlyAnalyzer.cs         |  6 ++--
 src/Core/ConvertHelpers.cs                    | 14 ++++++++
 .../RCS1257UseEnumFieldExplicitlyTests.cs     | 32 +++++++++++++++++++
 5 files changed, 55 insertions(+), 5 deletions(-)

diff --git a/ChangeLog.md b/ChangeLog.md
index 889b6df971..18658e9547 100644
--- a/ChangeLog.md
+++ b/ChangeLog.md
@@ -17,7 +17,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Fix [RCS1228](https://josefpihrt.github.io/docs/roslynator/analyzers/RCS1228) ([PR](https://github.com/dotnet/roslynator/pull/1249))
 - Fix [RCS1213](https://josefpihrt.github.io/docs/roslynator/analyzers/RCS1213) ([PR](https://github.com/dotnet/roslynator/pull/1254))
 - Fix [RCS1055](https://josefpihrt.github.io/docs/roslynator/analyzers/RCS1055) ([PR](https://github.com/dotnet/roslynator/pull/1253))
-- Fix [RCS1196](https://josefpihrt.github.io/docs/roslynator/analyzers/RCS1196/) ([PR](https://github.com/dotnet/roslynator/pull/1235))
+- Fix [RCS1196](https://josefpihrt.github.io/docs/roslynator/analyzers/RCS1196) ([PR](https://github.com/dotnet/roslynator/pull/1235))
+- Fix [RCS1257](https://josefpihrt.github.io/docs/roslynator/analyzers/RCS1257) ([PR](https://github.com/dotnet/roslynator/pull/1264))
 
 ## [4.6.2] - 2023-11-10
 
diff --git a/src/Analyzers.CodeFixes/CSharp/CodeFixes/CastExpressionCodeFixProvider.cs b/src/Analyzers.CodeFixes/CSharp/CodeFixes/CastExpressionCodeFixProvider.cs
index 1c1bd8025d..d1fb6b4cc0 100644
--- a/src/Analyzers.CodeFixes/CSharp/CodeFixes/CastExpressionCodeFixProvider.cs
+++ b/src/Analyzers.CodeFixes/CSharp/CodeFixes/CastExpressionCodeFixProvider.cs
@@ -1,5 +1,6 @@
 // Copyright (c) .NET Foundation and Contributors. Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
+using System;
 using System.Collections.Generic;
 using System.Collections.Immutable;
 using System.Composition;
@@ -56,7 +57,7 @@ private static async Task<Document> UseEnumFieldExplicitlyAsync(
 
         if (enumSymbol.HasAttribute(MetadataNames.System_FlagsAttribute))
         {
-            ulong value = SymbolUtility.GetEnumValueAsUInt64(constantValueOpt.Value, enumSymbol);
+            ulong value = Convert.ToUInt64(constantValueOpt.Value);
 
             List<ulong> flags = FlagsUtility<ulong>.Instance.GetFlags(value).ToList();
 
@@ -86,7 +87,7 @@ private static async Task<Document> UseEnumFieldExplicitlyAsync(
                 .First(fieldSymbol =>
                 {
                     return fieldSymbol.HasConstantValue
-                        && constantValueOpt.Value.Equals(fieldSymbol.ConstantValue);
+                        && Convert.ToUInt64(constantValueOpt.Value) == Convert.ToUInt64(fieldSymbol.ConstantValue);
                 });
 
             ExpressionSyntax newExpression = CreateEnumFieldExpression(symbol).WithTriviaFrom(castExpression);
diff --git a/src/Analyzers/CSharp/Analysis/UseEnumFieldExplicitlyAnalyzer.cs b/src/Analyzers/CSharp/Analysis/UseEnumFieldExplicitlyAnalyzer.cs
index 7e79e2f0cf..59abf6c73a 100644
--- a/src/Analyzers/CSharp/Analysis/UseEnumFieldExplicitlyAnalyzer.cs
+++ b/src/Analyzers/CSharp/Analysis/UseEnumFieldExplicitlyAnalyzer.cs
@@ -64,13 +64,15 @@ private static void AnalyzeCastExpression(SyntaxNodeAnalysisContext context)
         if (enumSymbol?.EnumUnderlyingType is null)
             return;
 
-        ulong value = SymbolUtility.GetEnumValueAsUInt64(constantValueOpt.Value, enumSymbol);
+        if (!ConvertHelpers.TryConvertToUInt64(constantValueOpt.Value, out ulong value))
+            return;
 
         foreach (ISymbol member in enumSymbol.GetMembers())
         {
             if (member is IFieldSymbol fieldSymbol
                 && fieldSymbol.HasConstantValue
-                && value == SymbolUtility.GetEnumValueAsUInt64(fieldSymbol.ConstantValue, enumSymbol))
+                && ConvertHelpers.TryConvertToUInt64(fieldSymbol.ConstantValue, out ulong fieldValue)
+                && value == fieldValue)
             {
                 context.ReportDiagnostic(DiagnosticRules.UseEnumFieldExplicitly, castExpression);
                 return;
diff --git a/src/Core/ConvertHelpers.cs b/src/Core/ConvertHelpers.cs
index b8d6c014e8..2b9ae354f8 100644
--- a/src/Core/ConvertHelpers.cs
+++ b/src/Core/ConvertHelpers.cs
@@ -99,4 +99,18 @@ public static ulong ConvertToUInt64(object value, SpecialType numericType)
                 throw new ArgumentException("", nameof(numericType));
         }
     }
+
+    public static bool TryConvertToUInt64(object value, out ulong result)
+    {
+        try
+        {
+            result = Convert.ToUInt64(value);
+            return true;
+        }
+        catch (Exception ex) when (ex is InvalidCastException || ex is OverflowException)
+        {
+            result = 0;
+            return false;
+        }
+    }
 }
diff --git a/src/Tests/Analyzers.Tests/RCS1257UseEnumFieldExplicitlyTests.cs b/src/Tests/Analyzers.Tests/RCS1257UseEnumFieldExplicitlyTests.cs
index 2cc4c11345..511104b21c 100644
--- a/src/Tests/Analyzers.Tests/RCS1257UseEnumFieldExplicitlyTests.cs
+++ b/src/Tests/Analyzers.Tests/RCS1257UseEnumFieldExplicitlyTests.cs
@@ -64,6 +64,38 @@ void M()
 ");
     }
 
+    [Fact, Trait(Traits.Analyzer, DiagnosticIdentifiers.UseEnumFieldExplicitly)]
+    public async Task Test_Flags_SByte()
+    {
+        await VerifyDiagnosticAndFixAsync(@"
+class C
+{
+    void M()
+    {
+        var enumValue = [|(TestEnum)2|];
+    }
+}
+
+enum TestEnum : sbyte
+{
+    Foo, Bar, Baz
+}
+", @"
+class C
+{
+    void M()
+    {
+        var enumValue = TestEnum.Baz;
+    }
+}
+
+enum TestEnum : sbyte
+{
+    Foo, Bar, Baz
+}
+");
+    }
+
     [Fact, Trait(Traits.Analyzer, DiagnosticIdentifiers.UseEnumFieldExplicitly)]
     public async Task TestNoDiagnostic_UndefinedValue()
     {