Don't crash if we produce bad data in document generation

Author: davidwengier

src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/Formatting/FormattingUtilities.cs

@@ -407,7 +407,11 @@ public static void GetOriginalDocumentChangesFromLineInfo(FormattingContext cont
                         ? originalLine.End - originalStart
                         : lineInfo.FormattedLength;
                     var formattedStart = formattedLine.Start + formattedIndentation + lineInfo.FormattedOffset;
-                    formattingChanges.Add(new TextChange(new TextSpan(originalStart, length), formattedText.ToString(TextSpan.FromBounds(formattedStart, formattedLine.End - lineInfo.FormattedOffsetFromEndOfLine))));
+                    var formattedEnd = formattedLine.End - lineInfo.FormattedOffsetFromEndOfLine;
+                    if (formattedEnd > formattedStart)
+                    {
+                        formattingChanges.Add(new TextChange(new TextSpan(originalStart, length), formattedText.ToString(TextSpan.FromBounds(formattedStart, formattedEnd))));
+                    }
 
                     if (lineInfo.CheckForNewLines)
                     {

src/Razor/test/Microsoft.VisualStudio.LanguageServices.Razor.Test/Cohost/Formatting/FormattingLogTest.cs

@@ -88,6 +88,22 @@ public async Task RanOutOfOriginalLines()
         await GetFormattingEditsAsync(contents, htmlChangesFile);
     }
 
+    [Fact]
+    [WorkItem("https://developercommunity.visualstudio.com/t/Razor-Formatting-Feature-internal-error/11041869#T-ND11043454")]
+    public async Task MultiLineLambda()
+    {
+        var contents = GetResource("InitialDocument.txt");
+
+        var document = CreateProjectAndRazorDocument(contents);
+
+        var options = new RazorFormattingOptions();
+
+        var formattingService = (RazorFormattingService)OOPExportProvider.GetExportedValue<IRazorFormattingService>();
+        formattingService.GetTestAccessor().SetFormattingLoggerFactory(new TestFormattingLoggerFactory(TestOutputHelper));
+
+        await GetFormattingEditsAsync(document, [], span: default, options.CodeBlockBraceOnNextLine, options.AttributeIndentStyle, options.InsertSpaces, options.TabSize, RazorCSharpSyntaxFormattingOptions.Default);
+    }
+
     private async Task<TextEdit[]?> GetFormattingEditsAsync(string contents, string htmlChangesFile)
     {
         var document = CreateProjectAndRazorDocument(contents);

src/Razor/test/Microsoft.VisualStudio.LanguageServices.Razor.Test/TestFiles/FormattingLog/MultiLineLambda/InitialDocument.txt

@@ -0,0 +1,3 @@
+<button @onclick="()=>{
+StateHasChanged();}">
+</button>