diff --git a/vsintegration/src/FSharp.Editor/Diagnostics/DocumentDiagnosticAnalyzer.fs b/vsintegration/src/FSharp.Editor/Diagnostics/DocumentDiagnosticAnalyzer.fs
index c3fd80b8d8b..d7667baf2c9 100644
--- a/vsintegration/src/FSharp.Editor/Diagnostics/DocumentDiagnosticAnalyzer.fs
+++ b/vsintegration/src/FSharp.Editor/Diagnostics/DocumentDiagnosticAnalyzer.fs
@@ -81,23 +81,24 @@ type internal FSharpDocumentDiagnosticAnalyzer() =
                 }
             
             let results = 
-              (errors |> Seq.choose(fun error ->
-                if error.StartLineAlternate = 0 || error.EndLineAlternate = 0 then
-                    // F# error line numbers are one-based. Compiler returns 0 for global errors (reported by ProjectDiagnosticAnalyzer)
-                    None
-                else
-                    // Roslyn line numbers are zero-based
-                    let linePositionSpan = LinePositionSpan(LinePosition(error.StartLineAlternate - 1, error.StartColumn),LinePosition(error.EndLineAlternate - 1, error.EndColumn))
-                    let textSpan = sourceText.Lines.GetTextSpan(linePositionSpan)
-                    
-                    // F# compiler report errors at end of file if parsing fails. It should be corrected to match Roslyn boundaries
-                    let correctedTextSpan = 
-                        if textSpan.End < sourceText.Length then textSpan 
-                        else TextSpan.FromBounds(max 0 (sourceText.Length - 1), sourceText.Length)
-                    
-                    let location = Location.Create(filePath, correctedTextSpan , linePositionSpan)
-                    Some(CommonRoslynHelpers.ConvertError(error, location)))
-              ).ToImmutableArray()
+              (HashSet(errors, errorInfoEqualityComparer)
+               |> Seq.choose(fun error ->
+                    if error.StartLineAlternate = 0 || error.EndLineAlternate = 0 then
+                        // F# error line numbers are one-based. Compiler returns 0 for global errors (reported by ProjectDiagnosticAnalyzer)
+                        None
+                    else
+                        // Roslyn line numbers are zero-based
+                        let linePositionSpan = LinePositionSpan(LinePosition(error.StartLineAlternate - 1, error.StartColumn), LinePosition(error.EndLineAlternate - 1, error.EndColumn))
+                        let textSpan = sourceText.Lines.GetTextSpan(linePositionSpan)
+                        
+                        // F# compiler report errors at end of file if parsing fails. It should be corrected to match Roslyn boundaries
+                        let correctedTextSpan =
+                            if textSpan.End < sourceText.Length then textSpan 
+                            else TextSpan.FromBounds(max 0 (sourceText.Length - 1), sourceText.Length)
+                        
+                        let location = Location.Create(filePath, correctedTextSpan , linePositionSpan)
+                        Some(CommonRoslynHelpers.ConvertError(error, location)))
+                  ).ToImmutableArray()
             return results
         }