SA1133 now longer considers attributes on parameters and type parameters

Author: vweijsters

StyleCop.Analyzers/StyleCop.Analyzers.Test/ReadabilityRules/SA1133UnitTests.cs

@@ -276,6 +276,36 @@ internal class BarAttribute : Attribute
             await this.VerifyCSharpFixAsync(testCode, fixedTestCode).ConfigureAwait(false);
         }
 
+        /// <summary>
+        /// Verifies that attribute list with multiple attributes for (generic) parameters will not produce diagnostics.
+        /// Regression test for #1882
+        /// </summary>
+        /// <returns>A <see cref="Task"/> representing the asynchronous unit test.</returns>
+        [Fact]
+        public async Task VerifyAttributeListForParametersAsync()
+        {
+            var testCode = @"using System;
+
+internal class TestClass
+{
+    internal T TestMethod<[Foo, Bar]T>([Bar, Foo] int value)
+    {
+        return default(T);
+    }
+}
+
+internal class FooAttribute : Attribute
+{
+}
+
+internal class BarAttribute : Attribute
+{
+}
+";
+
+            await this.VerifyCSharpDiagnosticAsync(testCode, EmptyDiagnosticResults, CancellationToken.None).ConfigureAwait(false);
+        }
+
         /// <inheritdoc/>
         protected override CodeFixProvider GetCSharpCodeFixProvider()
         {

StyleCop.Analyzers/StyleCop.Analyzers/ReadabilityRules/SA1133DoNotCombineAttributes.cs

@@ -50,6 +50,12 @@ private static void HandleAttributeList(SyntaxNodeAnalysisContext context)
         {
             AttributeListSyntax attributeList = (AttributeListSyntax)context.Node;
 
+            if (attributeList.Parent.IsKind(SyntaxKind.Parameter) || attributeList.Parent.IsKind(SyntaxKind.TypeParameter))
+            {
+                // no analysis required for parameters or type (generic) parameters
+                return;
+            }
+
             if (attributeList.Attributes.Count > 1)
             {
                 context.ReportDiagnostic(Diagnostic.Create(Descriptor, attributeList.Attributes[1].Name.GetLocation()));

documentation/SA1133.md

@@ -44,6 +44,22 @@ public class MyCodeFixProvider : CodeFixProvider
 }
 ```
 
+### Exceptions
+
+A violation of this rule will not occur for attributes placed on parameters or type parameters.
+
+For example, the following code will not produce violations:
+
+```csharp
+public class MyClass<[Foo, Bar] T>
+{
+	public T MyMethod([In, MarshalAs(UnmanagedType.LPWStr)] string value)
+	{
+	    ...
+	}
+}
+```
+
 ## How to fix violations
 
 To fix a violation of this rule, place each attribute within its own set of square brackets.

documentation/SA1134.md

@@ -44,6 +44,22 @@ public class MyCodeFixProvider : CodeFixProvider
 }
 ```
 
+### Exceptions
+
+A violation of this rule will not occur for attributes placed on parameters or type parameters.
+
+For example, the following code will not produce violations:
+
+```csharp
+public class MyClass<[Foo][Bar] T>
+{
+	public T MyMethod([In][MarshalAs(UnmanagedType.LPWStr)] string value)
+	{
+	    ...
+	}
+}
+```
+
 ## How to fix violations
 
 To fix a violation of this rule, place each attribute on its own line.