diff --git a/src/FSharp.Analyzers/PartialAppAnalyzer.fs b/src/FSharp.Analyzers/PartialAppAnalyzer.fs
index f4394ce..05d4178 100644
--- a/src/FSharp.Analyzers/PartialAppAnalyzer.fs
+++ b/src/FSharp.Analyzers/PartialAppAnalyzer.fs
@@ -33,16 +33,23 @@ module PartialAppAnalyzer =
             visitExpr handler argExpr
         | SynExpr.App (funcExpr = SynExpr.Ident i) -> handler (i.idText, i.idRange, 1 + depth)
         | SynExpr.App (funcExpr = SynExpr.LongIdent (longDotId = longDotId) ; argExpr = argExpr) ->
-            let (SynIdent.SynIdent (ident = ident)) = longDotId.IdentsWithTrivia |> Seq.last
-            handler (ident.idText, longDotId.Range, 1 + depth)
+            longDotId.IdentsWithTrivia
+            |> Seq.tryLast
+            |> Option.iter (fun (SynIdent.SynIdent (ident = ident)) ->
+                handler (ident.idText, longDotId.Range, 1 + depth)
+            )
+
             visitApp handler depth argExpr
         | SynExpr.App (funcExpr = SynExpr.App _ as funcExpr ; argExpr = argExpr) ->
             visitApp handler (1 + depth) funcExpr
             visitApp handler depth argExpr
         | SynExpr.App (funcExpr = SynExpr.TypeApp (expr = SynExpr.Ident i)) -> handler (i.idText, i.idRange, 1 + depth)
         | SynExpr.App (funcExpr = SynExpr.TypeApp (expr = SynExpr.LongIdent (longDotId = longDotId))) ->
-            let (SynIdent.SynIdent (ident = ident)) = longDotId.IdentsWithTrivia |> Seq.last
-            handler (ident.idText, longDotId.Range, 1 + depth)
+            longDotId.IdentsWithTrivia
+            |> Seq.tryLast
+            |> Option.iter (fun (SynIdent.SynIdent (ident = ident)) ->
+                handler (ident.idText, longDotId.Range, 1 + depth)
+            )
         | SynExpr.IfThenElse (ifExpr = ifExpr ; thenExpr = thenExpr ; elseExpr = elseExpr) ->
             visitApp handler depth ifExpr
             visitApp handler depth thenExpr