Add polyfills for Enum.IsDefined<T>(...) and Enum.HasFlag(...) (#57)

Author: Tyrrrz

PolyShim.Tests/Net50/EnumTests.cs

@@ -6,6 +6,15 @@ namespace PolyShim.Tests.Net50;
 
 public class EnumTests
 {
+    [Fact]
+    public void IsDefined_Test()
+    {
+        // Act & assert
+        Enum.IsDefined((DayOfWeek)0).Should().BeTrue();
+        Enum.IsDefined((DayOfWeek)3).Should().BeTrue();
+        Enum.IsDefined((DayOfWeek)7).Should().BeFalse();
+    }
+
     [Fact]
     public void GetNames_Test()
     {

PolyShim/Net50/Enum.cs

@@ -11,6 +11,10 @@ internal static partial class PolyfillExtensions
 {
     extension(Enum)
     {
+        // https://learn.microsoft.com/dotnet/api/system.enum.isdefined#system-enum-isdefined-1(-0)
+        public static bool IsDefined<T>(T value)
+            where T : struct, Enum => Enum.IsDefined(typeof(T), value);
+
         // https://learn.microsoft.com/dotnet/api/system.enum.getnames#system-enum-getnames-1
         public static string[] GetNames<T>()
             where T : struct, Enum => Enum.GetNames(typeof(T));

PolyShim/NetCore10/Enum.cs

@@ -9,6 +9,18 @@
 
 internal static partial class PolyfillExtensions
 {
+    extension(Enum enumValue)
+    {
+        // https://learn.microsoft.com/dotnet/api/system.enum.hasflag
+        public bool HasFlag(Enum flag)
+        {
+            var thisValue = Convert.ToInt64(enumValue);
+            var flagValue = Convert.ToInt64(flag);
+
+            return (thisValue & flagValue) == flagValue;
+        }
+    }
+
     extension(Enum)
     {
         // https://learn.microsoft.com/dotnet/api/system.enum.tryparse#system-enum-tryparse-1(system-string-system-boolean-0@)

PolyShim/Signatures.md

@@ -1,8 +1,8 @@
 # Signatures
 
-- **Total:** 244
+- **Total:** 246
 - **Types:** 62
-- **Members:** 182
+- **Members:** 184
 
 ___
 
@@ -43,6 +43,8 @@ ___
 - `DynamicallyAccessedMemberTypes`
   - [**[enum]**](https://learn.microsoft.com/dotnet/api/system.diagnostics.codeanalysis.dynamicallyaccessedmembertypes) <sup><sub>.NET 5.0</sub></sup>
 - `Enum`
+  - [`bool HasFlag(Enum)`](https://learn.microsoft.com/dotnet/api/system.enum.hasflag) <sup><sub>.NET Core 1.0</sub></sup>
+  - [`bool IsDefined<T>(T) where T : struct, Enum`](https://learn.microsoft.com/dotnet/api/system.enum.isdefined#system-enum-isdefined-1(-0)) <sup><sub>.NET 5.0</sub></sup>
   - [`bool TryParse<T>(string, bool, out T) where T : struct, Enum`](https://learn.microsoft.com/dotnet/api/system.enum.tryparse#system-enum-tryparse-1(system-string-system-boolean-0@)) <sup><sub>.NET Core 1.0</sub></sup>
   - [`bool TryParse<T>(string, out T) where T : struct, Enum`](https://learn.microsoft.com/dotnet/api/system.enum.tryparse#system-enum-tryparse-1(system-string-0@)) <sup><sub>.NET Core 1.0</sub></sup>
   - [`string[] GetNames<T>() where T : struct, Enum`](https://learn.microsoft.com/dotnet/api/system.enum.getnames#system-enum-getnames-1) <sup><sub>.NET 5.0</sub></sup>