Use nested class for Failure.Exeption

src/core-taggeds-failure/Failure/Failure.T/Failure.T.cs

@@ -34,5 +34,5 @@ public string FailureMessage
         =>
         failureMessage ?? string.Empty;
 
-    public Exception? SourceException { get; init; } = null;
+    public System.Exception? SourceException { get; init; } = null;
 }

src/core-taggeds-failure/Failure/Failure.T/T.Deconstruct.cs

@@ -8,7 +8,7 @@ public void Deconstruct(out TFailureCode failureCode, out string failureMessage)
         failureMessage = FailureMessage;
     }
 
-    public void Deconstruct(out TFailureCode failureCode, out string failureMessage, out Exception? sourceException)
+    public void Deconstruct(out TFailureCode failureCode, out string failureMessage, out System.Exception? sourceException)
     {
         failureCode = FailureCode;
         failureMessage = FailureMessage;

src/core-taggeds-failure/Failure/Failure.T/T.Exception.To.cs

@@ -0,0 +1,11 @@
+namespace System;
+
+partial struct Failure<TFailureCode>
+{
+    public Failure<TFailureCode>.Exception ToException()
+        =>
+        new(
+            failureCode: FailureCode,
+            message: failureMessage,
+            innerException: SourceException);
+}

src/core-taggeds-failure/Failure/Failure.T/T.Exception.cs

@@ -0,0 +1,14 @@
+namespace System;
+
+partial struct Failure<TFailureCode>
+{
+    public sealed class Exception : System.Exception
+    {
+        public Exception(TFailureCode failureCode, string? message, System.Exception? innerException)
+            : base(message, innerException)
+            =>
+            FailureCode = failureCode;
+
+        public TFailureCode FailureCode { get; }
+    }
+}