Single AST node should contain trivia

[nojaf]

Issue created from fantomas-online

Code

// This file is automatically generated by FAKE
// This file is needed for IDE support only
#if !FAKE
#load "intellisense_lazy.fsx"
#endif

Error

System.ArgumentException: The input sequence was empty. (Parameter 'list')
   at Fantomas.Trivia.findLastNode(FSharpList`1 nodes) in /home/runner/work/fantomas-tools/fantomas-tools/.deps/fantomas/src/Fantomas/Trivia.fs:line 61
   at Fantomas.Trivia.addTriviaToTriviaNode(FSharpFunc`2 triviaBetweenAttributeAndParentBinding, Boolean hasAnonModulesAndOpenStatements, Int32 startOfSourceCode, FSharpList`1 triviaNodes, Trivia trivia) in /home/runner/work/fantomas-tools/fantomas-tools/.deps/fantomas/src/Fantomas/Trivia.fs:line 381
   at Fantomas.Trivia.collectTrivia@422-1.Invoke(FSharpList`1 triviaNodes, Trivia trivia) in /home/runner/work/fantomas-tools/fantomas-tools/.deps/fantomas/src/Fantomas/Trivia.fs:line 414
   at Microsoft.FSharp.Collections.ListModule.Fold[T,TState](FSharpFunc`2 folder, TState state, FSharpList`1 list) in F:\workspace\_work\1\s\src\fsharp\FSharp.Core\list.fs:line 222
   at Fantomas.Trivia.collectTrivia(FSharpList`1 tokens, Int32 lineCount, ParsedInput ast)
   at Fantomas.Context.Context.Create(FormatConfig config, FSharpList`1 defines, String content, FSharpOption`1 maybeAst)
   at Fantomas.CodeFormatterImpl.formatWith(ParsedInput ast, FSharpList`1 defines, FormatContext formatContext, FormatConfig config) in /home/runner/work/fantomas-tools/fantomas-tools/.deps/fantomas/src/Fantomas/CodeFormatterImpl.fs:line 395
   at Fantomas.CodeFormatterImpl.format@412-1.Invoke(Tuple`2[] _arg1) in /home/runner/work/fantomas-tools/fantomas-tools/.deps/fantomas/src/Fantomas/CodeFormatterImpl.fs:line 414
   at Microsoft.FSharp.Control.AsyncPrimitives.CallThenInvokeNoHijackCheck[a,b](AsyncActivation`1 ctxt, FSharpFunc`2 userCode, b result1) in F:\workspace\_work\1\s\src\fsharp\FSharp.Core\async.fs:line 416
   at Microsoft.FSharp.Control.Trampoline.Execute(FSharpFunc`2 firstAction) in F:\workspace\_work\1\s\src\fsharp\FSharp.Core\async.fs:line 109

Problem description

Bug in Trivia.fs

let private findLastNode (nodes: TriviaNodeAssigner list) : TriviaNodeAssigner option =
    match nodes with
    | [] -> None
    | nodes ->
        nodes
        |> List.filter isMainNodeButNotAnonModule
        |> List.maxBy (fun tn -> tn.Range.EndLine)
        |> Some

where there is only one trivia node.

Extra information

• The formatted result breaks by code.
• The formatted result gives compiler warnings.
• I or my company would be willing to help fix this.

Options

Fantomas Master at 08/27/2020 15:33:58 - 5d3a411

Default Fantomas configuration