Fix eol handling on the last token in a file when formatting code actions

src/Analyzers/CSharp/Tests/ImplementInterface/ImplementInterfaceCodeFixTests.cs

@@ -10,6 +10,7 @@
 using Microsoft.CodeAnalysis.CSharp.Shared.Extensions;
 using Microsoft.CodeAnalysis.Editor.UnitTests.CodeActions;
 using Microsoft.CodeAnalysis.Editor.UnitTests.Diagnostics.NamingStyles;
+using Microsoft.CodeAnalysis.Formatting;
 using Microsoft.CodeAnalysis.ImplementType;
 using Microsoft.CodeAnalysis.Test.Utilities;
 using Microsoft.CodeAnalysis.Testing;
@@ -11900,4 +11901,27 @@ class C1 : I1
             ReferenceAssemblies = ReferenceAssemblies.Net.Net80,
             LanguageVersion = LanguageVersionExtensions.CSharpNext,
         }.RunAsync();
+
+    [Fact]
+    public Task TestImplementIDisposable_DisposePattern_LF_EndOfLine()
+         => new VerifyCS.Test
+         {
+             TestCode = """
+                using System;
+                class C : {|CS0535:IDisposable|}{|CS1513:|}{|CS1514:|}
+                """.Replace("\r\n", "\n"),
+             FixedCode = $$"""
+                using System;
+                class C : IDisposable
+                {
+                    private bool disposedValue;
+
+                {{DisposePattern("protected virtual ", "C", "public void ")}}
+                }
+                """.Replace("\r\n", "\n"),
+             CodeActionIndex = 1,
+             ReferenceAssemblies = ReferenceAssemblies.Net.Net80,
+             LanguageVersion = LanguageVersionExtensions.CSharpNext,
+             Options = { { FormattingOptions2.NewLine, "\n" } },
+         }.RunAsync();
 }

src/Workspaces/SharedUtilitiesAndExtensions/Compiler/Core/Formatting/FormattingExtensions.cs

@@ -281,31 +281,34 @@ static IEnumerable<TextSpan> EnumerateAnnotatedSpans(SyntaxNode node, SyntaxAnno
                 var (firstToken, lastToken) = nodeOrToken.AsNode(out var childNode)
                     ? (childNode.GetFirstToken(includeZeroWidth: true), childNode.GetLastToken(includeZeroWidth: true))
                     : (nodeOrToken.AsToken(), nodeOrToken.AsToken());
-                yield return GetSpan(firstToken, lastToken);
+                yield return GetSpanIncludingPreviousAndNextTokens(firstToken, lastToken);
             }
         }
     }
 
-    internal static TextSpan GetSpan(SyntaxToken firstToken, SyntaxToken lastToken)
+    /// <summary>
+    /// Attempt to get a span that encompassed these tokens, but is expanded to go from the normal start of the
+    /// token that precedes them to the normal end of the token that follows.  If there is no token that precedes
+    /// or follows, then we expand to consume at least the full span of the <paramref name="firstToken"/> and 
+    /// <paramref name="lastToken"/> so that we at least will try to format any trivia on them.
+    /// </summary>
+    internal static TextSpan GetSpanIncludingPreviousAndNextTokens(SyntaxToken firstToken, SyntaxToken lastToken)
     {
         var previousToken = firstToken.GetPreviousToken();
-        var nextToken = lastToken.GetNextToken();
-
-        if (previousToken.RawKind != 0)
-        {
-            firstToken = previousToken;
-        }
+        var start = previousToken.RawKind != 0
+            ? previousToken.SpanStart
+            : firstToken.FullSpan.Start;
 
-        if (nextToken.RawKind != 0)
-        {
-            lastToken = nextToken;
-        }
+        var nextToken = lastToken.GetNextToken();
+        var end = nextToken.RawKind != 0
+            ? nextToken.Span.End
+            : lastToken.FullSpan.End;
 
-        return TextSpan.FromBounds(firstToken.SpanStart, lastToken.Span.End);
+        return TextSpan.FromBounds(start, end);
     }
 
     internal static TextSpan GetElasticSpan(SyntaxToken token)
-        => GetSpan(token, token);
+        => GetSpanIncludingPreviousAndNextTokens(token, token);
 
     private static IEnumerable<TextSpan> AggregateSpans(IEnumerable<TextSpan> spans)
     {