Merge pull request #1 from sharwell/pr-1961

Eliminate boxing in SyntaxTriviaList.LastOrDefault

Author: nbarbettini

StyleCop.Analyzers/StyleCop.Analyzers.CodeFixes/ReadabilityRules/SA1127CodeFixProvider.cs

@@ -92,8 +92,7 @@ private static string GetParentIndentation(SyntaxToken token)
             var parentTrivia = token.Parent.Parent.GetLeadingTrivia();
 
             return parentTrivia
-                .Where(t => t.IsKind(SyntaxKind.WhitespaceTrivia))
-                .LastOrDefault()
+                .LastOrDefault(SyntaxKind.WhitespaceTrivia)
                 .ToString();
         }
 

StyleCop.Analyzers/StyleCop.Analyzers/LinqHelpers/SyntaxTriviaListEnumerable.cs

@@ -5,6 +5,7 @@ namespace System.Linq
 {
     using Collections.Generic;
     using Microsoft.CodeAnalysis;
+    using Microsoft.CodeAnalysis.CSharp;
 
     /// <summary>
     /// This class supports a subset of LINQ operations on <see cref="SyntaxTriviaList"/> without requiring boxing of
@@ -93,5 +94,26 @@ internal static bool All(this SyntaxTriviaList list, Func<SyntaxTrivia, bool> pr
 
             return true;
         }
+
+        /// <summary>
+        /// Returns the last trivia of a specified kind in a trivia list.
+        /// </summary>
+        /// <param name="list">The trivia list.</param>
+        /// <param name="kind">The syntax kind.</param>
+        /// <returns>The last <see cref="SyntaxTrivia"/> in <paramref name="list"/> with the specified
+        /// <paramref name="kind"/>; otherwise, a default <see cref="SyntaxTrivia"/> instance if no matching trivia was
+        /// found.</returns>
+        internal static SyntaxTrivia LastOrDefault(this SyntaxTriviaList list, SyntaxKind kind)
+        {
+            foreach (var trivia in list.Reverse())
+            {
+                if (trivia.IsKind(kind))
+                {
+                    return trivia;
+                }
+            }
+
+            return default(SyntaxTrivia);
+        }
     }
 }