Modify S3993: Promote C# rule to Sonar-way

rules/S2674/csharp/rule.adoc

@@ -5,6 +5,7 @@ Invoking a stream reading method without verifying the number of bytes read can
 Neglecting the returned length read can result in a bug that is difficult to reproduce.
 
 This rule raises an issue when the returned value is ignored for the following methods:
+
 * https://learn.microsoft.com/en-us/dotnet/api/system.io.stream.read[Stream.Read]
 * https://learn.microsoft.com/en-us/dotnet/api/system.io.stream.readasync[Stream.ReadAsync]
 * https://learn.microsoft.com/en-us/dotnet/api/system.io.stream.readatleast[Stream.ReadAtLeast]

rules/S3993/csharp/rule.adoc

@@ -1,4 +1,56 @@
-include::../rule.adoc[]
+== Why is this an issue?
+
+When defining custom attributes, https://learn.microsoft.com/en-us/dotnet/api/system.attributeusageattribute[AttributeUsageAttribute] must be used to indicate where the attribute can be applied. This will:
+
+* indicate how the attribute can be used
+* prevent it from being used at invalid locations
+
+== How to fix it
+
+=== Code examples
+
+==== Noncompliant code example
+
+[source,csharp,diff-id=1,diff-type=noncompliant]
+----
+public sealed class MyAttribute : Attribute // Noncompliant - AttributeUsage is missing
+{
+    private string text;
+
+    public MyAttribute(string text)
+    {
+        this.text = text;
+    }
+
+    public string Text => text;
+}
+----
+
+==== Compliant solution
+
+[source,csharp,diff-id=1,diff-type=compliant]
+----
+[AttributeUsage(AttributeTargets.Class | AttributeTargets.Enum | AttributeTargets.Interface | AttributeTargets.Delegate)]
+public sealed class MyAttribute : Attribute
+{
+    private string text;
+
+    public MyAttribute(string text)
+    {
+        this.text = text;
+    }
+
+    public string Text => text;
+}
+----
+
+== Resources
+
+=== Documentation
+
+* Microsoft Learn - https://learn.microsoft.com/en-us/dotnet/csharp/advanced-topics/reflection-and-attributes/creating-custom-attributes[Create custom attributes]
+* Microsoft Learn - https://learn.microsoft.com/en-us/dotnet/api/system.attributeusageattribute[AttributeUsageAttribute class]
+* Microsoft Learn - https://learn.microsoft.com/en-us/dotnet/api/system.attribute[Attribute class]
 
 ifdef::env-github,rspecator-view[]
 

rules/S3993/metadata.json

@@ -28,7 +28,7 @@
   "sqKey": "S3993",
   "scope": "All",
   "defaultQualityProfiles": [
-
+    "Sonar way"
   ],
   "quickfix": "unknown"
 }