Modify rule S4039: Improve description to match the implementation (#…

…4586)

rules/S4039/csharp/rule.adoc

@@ -1,14 +1,22 @@
 == Why is this an issue?
 
-When a base type explicitly implements a public interface method, that method is only accessible in derived types through a reference to the current instance (namely ``++this++``). If the derived type explicitly overrides that interface method, the base implementation becomes inaccessible.
+When a base type explicitly implements a public interface method, property or event, that member is only accessible in derived types through a reference to the current instance (namely `this`). If the derived type explicitly overrides that interface member, the base implementation becomes inaccessible.
 
+This rule raises an issue when an unsealed, externally visible type provides an explicit member implementation of an `interface` and does not provide an alternate, externally visible member with the same name.
 
-This rule raises an issue when an unsealed, externally visible type provides an explicit method implementation of a ``++public interface++`` and does not provide an alternate, externally visible method with the same name.
+=== Exceptions
+
+This rule does not report a violation for an explicit implementation of `IDisposable.Dispose` when an externally visible `Close()` or `System.IDisposable.Dispose(Boolean)` method is provided.
+
+== How to fix it
 
+Make the class sealed, change the class member to a non-explicit declaration, or provide a new class member exposing the functionality of the explicit interface member.
 
-=== Noncompliant code example
+=== Code examples
 
-[source,csharp]
+==== Noncompliant code example
+
+[source,csharp,diff-id=1,diff-type=noncompliant]
 ----
 public interface IMyInterface
 {
@@ -21,27 +29,13 @@ public class Foo : IMyInterface
     {
         MyMethod();
     }
-
-    void MyMethod()
-    {
-        // Do something ...
-    }
-}
-
-public class Bar : Foo, IMyInterface
-{
-    public void MyMethod()
-    {
-        // Can't access base.MyMethod()
-        // ((IMyInterface)this).MyMethod() would be a recursive call
-    }
 }
 ----
 
 
-=== Compliant solution
+==== Compliant solution
 
-[source,csharp]
+[source,csharp,diff-id=1,diff-type=compliant]
 ----
 public interface IMyInterface
 {
@@ -55,26 +49,19 @@ public class Foo : IMyInterface
         MyMethod();
     }
 
-    protected void MyMethod() // or public
+    // This method can be public or protected
+    protected void MyMethod()
     {
         // Do something ...
     }
 }
-
-public class Bar : Foo, IMyInterface
-{
-    public void MyMethod()
-    {
-        // Do something
-        base.MyMethod();
-    }
-}
 ----
 
+== Resources
 
-=== Exceptions
+=== Documentation
 
-This rule does not report a violation for an explicit implementation of ``++IDisposable.Dispose++`` when an externally visible ``++Close()++`` or ``++System.IDisposable.Dispose(Boolean)++`` method is provided.
+* Microsoft Learn - https://learn.microsoft.com/en-us/dotnet/csharp/programming-guide/interfaces/explicit-interface-implementation[Explicit Interface Implementation]
 
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