fsprojects#776 test

src/Fantomas.Tests/FunctionDefinitionTests.fs

@@ -81,6 +81,33 @@ let ``should keep identifiers with + in double backticks``() =
     |> should equal """let ``Foo+Bar`` () = x
 """
 
+[<Test>]
+let ``double backticks with non-alphanum character, 776``() =
+    formatSourceString false """let ``!foo hoo`` () = ()
+let ``@foo hoo`` () = ()
+let ``$foo hoo`` () = ()
+let ``%foo hoo`` () = ()
+let ``^foo hoo`` () = ()
+let ``&foo hoo`` () = ()
+let ``*foo hoo`` () = ()
+let ``<foo hoo`` () = ()
+let ``>foo hoo`` () = ()
+let ``=foo hoo`` () = ()
+let ``-foo hoo`` () = ()
+    """ config
+    |> should equal """let ``!foo hoo`` () = ()
+let ``@foo hoo`` () = ()
+let ``$foo hoo`` () = ()
+let ``%foo hoo`` () = ()
+let ``^foo hoo`` () = ()
+let ``&foo hoo`` () = ()
+let ``*foo hoo`` () = ()
+let ``<foo hoo`` () = ()
+let ``>foo hoo`` () = ()
+let ``=foo hoo`` () = ()
+let ``-foo hoo`` () = ()
+"""
+
 [<Test>]
 let ``let bindings with return types``() =
     formatSourceString false """