diff --git a/src/FsAutoComplete/CodeFixes/NegateBooleanExpression.fs b/src/FsAutoComplete/CodeFixes/NegateBooleanExpression.fs
index 133f53f12..f96de4eee 100644
--- a/src/FsAutoComplete/CodeFixes/NegateBooleanExpression.fs
+++ b/src/FsAutoComplete/CodeFixes/NegateBooleanExpression.fs
@@ -85,6 +85,9 @@ let fix (getParseResultsForFile: GetParseResultsForFile) : CodeFix =
                   Path = path
                   NeedsParensAfterNot = true }
 
+            // X.Y()
+            | SynExpr.App(funcExpr = SynExpr.LongIdent(longDotId = LastIdentFromSynLongIdent ident))
+
             // X().Y()
             | SynExpr.App(funcExpr = SynExpr.DotGet(longDotId = LastIdentFromSynLongIdent ident))
 
diff --git a/test/FsAutoComplete.Tests.Lsp/CodeFixTests/NegateBooleanExpressionTests.fs b/test/FsAutoComplete.Tests.Lsp/CodeFixTests/NegateBooleanExpressionTests.fs
index b493f0e4f..16be05b69 100644
--- a/test/FsAutoComplete.Tests.Lsp/CodeFixTests/NegateBooleanExpressionTests.fs
+++ b/test/FsAutoComplete.Tests.Lsp/CodeFixTests/NegateBooleanExpressionTests.fs
@@ -180,4 +180,24 @@ type X() =
 
 let b = not (X().Y())"
 
+        testCaseAsync "negate instance member invocation"
+        <| CodeFix.check
+          server
+          "
+open System.Collections.Generic
+
+let foo () =
+    let dict = dict []
+    dict.TryAdd$0(\"foo\", \"bar\")
+    ()"
+          Diagnostics.acceptAll
+          selectCodeFix
+          "
+open System.Collections.Generic
+
+let foo () =
+    let dict = dict []
+    (not (dict.TryAdd(\"foo\", \"bar\")))
+    ()"
+
         ])