add EnumPolyfill.IsDefined (#224)

apiCount.include.md

@@ -1 +1 @@
-**API count: 340**
+**API count: 341**

api_list.include.md

@@ -407,6 +407,7 @@
 
  * `String[] GetNames<TEnum>() where TEnum : Enum, ValueType` [reference](https://learn.microsoft.com/en-us/dotnet/api/system.enum.getnames)
  * `TEnum[] GetValues<TEnum>() where TEnum : Enum, ValueType` [reference](https://learn.microsoft.com/en-us/dotnet/api/system.enum.getvalues)
+ * `Boolean IsDefined<TEnum>(TEnum) where TEnum : Enum, ValueType` [reference](https://learn.microsoft.com/en-us/dotnet/api/system.enum.isdefined#system-enum-isdefined-1(-0))
  * `TEnum Parse<TEnum>(String) where TEnum : Enum, ValueType` [reference](https://learn.microsoft.com/en-us/dotnet/api/system.enum.parse#system-enum-parse-1(system-string-system-boolean))
  * `TEnum Parse<TEnum>(String, Boolean) where TEnum : Enum, ValueType` [reference](https://learn.microsoft.com/en-us/dotnet/api/system.enum.parse#system-enum-parse-1(system-string-system-boolean))
  * `TEnum Parse<TEnum>(ReadOnlySpan<Char>) where TEnum : Enum, ValueType` [reference](https://learn.microsoft.com/en-us/dotnet/api/system.enum.parse#system-enum-parse-1(system-readonlyspan((system-char))))

readme.md

@@ -12,7 +12,7 @@ The package targets `netstandard2.0` and is designed to support the following ru
  * `net5.0`, `net6.0`, `net7.0`, `net8.0`, `net9.0`
 
 
-**API count: 340**<!-- singleLineInclude: apiCount. path: /apiCount.include.md -->
+**API count: 341**<!-- singleLineInclude: apiCount. path: /apiCount.include.md -->
 
 
 **See [Milestones](../../milestones?state=closed) for release notes.**
@@ -864,6 +864,7 @@ The class `Polyfill` includes the following extension methods:
 
  * `String[] GetNames<TEnum>() where TEnum : Enum, ValueType` [reference](https://learn.microsoft.com/en-us/dotnet/api/system.enum.getnames)
  * `TEnum[] GetValues<TEnum>() where TEnum : Enum, ValueType` [reference](https://learn.microsoft.com/en-us/dotnet/api/system.enum.getvalues)
+ * `Boolean IsDefined<TEnum>(TEnum) where TEnum : Enum, ValueType` [reference](https://learn.microsoft.com/en-us/dotnet/api/system.enum.isdefined#system-enum-isdefined-1(-0))
  * `TEnum Parse<TEnum>(String) where TEnum : Enum, ValueType` [reference](https://learn.microsoft.com/en-us/dotnet/api/system.enum.parse#system-enum-parse-1(system-string-system-boolean))
  * `TEnum Parse<TEnum>(String, Boolean) where TEnum : Enum, ValueType` [reference](https://learn.microsoft.com/en-us/dotnet/api/system.enum.parse#system-enum-parse-1(system-string-system-boolean))
  * `TEnum Parse<TEnum>(ReadOnlySpan<Char>) where TEnum : Enum, ValueType` [reference](https://learn.microsoft.com/en-us/dotnet/api/system.enum.parse#system-enum-parse-1(system-readonlyspan((system-char))))

src/Directory.Build.props

@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="utf-8"?>
 <Project>
   <PropertyGroup>
-    <Version>6.7.0</Version>
+    <Version>6.8.0</Version>
     <AssemblyVersion>1.0.0</AssemblyVersion>
     <PackageTags>Polyfill</PackageTags>
     <DisableImplicitNamespaceImports>true</DisableImplicitNamespaceImports>

src/Polyfill/EnumPolyfill.cs

@@ -1,4 +1,7 @@
 // <auto-generated />
+
+using System.Runtime.CompilerServices;
+
 #pragma warning disable
 
 namespace Polyfills;
@@ -33,6 +36,20 @@ public static TEnum[] GetValues<TEnum>()
 #endif
     }
 
+    /// <summary>Returns a <see cref="bool"/> telling whether a given integral value exists in a specified enumeration.</summary>
+    /// <typeparam name="TEnum">The type of the enumeration.</typeparam>
+    /// <param name="value">The value in <typeparamref name="TEnum"/>.</param>
+    /// <returns><see langword="true"/> if a given integral value exists in a specified enumeration; <see langword="false"/>, otherwise.</returns>
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    [Link("https://learn.microsoft.com/en-us/dotnet/api/system.enum.isdefined#system-enum-isdefined-1(-0)")]
+    public static bool IsDefined<TEnum> (TEnum value)
+        where TEnum : struct, Enum =>
+#if NET5_0_OR_GREATER
+        Enum.IsDefined<TEnum>(value);
+#else
+        Enum.IsDefined(typeof(TEnum), value);
+#endif
+
     /// <summary>
     /// Retrieves an array of the names of the constants in a specified enumeration type.
     /// </summary>