Crash when trying to format indexed property with three arguments.

[gubser]

I tried to create an issue using fantomas-online but GitHub reported 'Your request URL is too long.'.

Here's the link using preview version: fantomas-online

Code

type MyArray3 () = 
    member _.Item
        with get (x: int, y: int, z: int) =
            ()
        and set (x: int, y: int, z: int) v =
            ()

Result

System.ArgumentException: The lists had different lengths.
list1 is 1 element shorter than list2 (Parameter 'list1')
   at Microsoft.FSharp.Core.DetailedExceptions.invalidArgDifferentListLength[?](String arg1, String arg2, Int32 diff) in D:\a\_work\1\s\src\FSharp.Core\local.fs:line 26
   at Microsoft.FSharp.Primitives.Basics.List.zipToFreshConsTail[a,b](FSharpList`1 cons, FSharpList`1 xs1, FSharpList`1 xs2) in D:\a\_work\1\s\src\FSharp.Core\local.fs:line 906
   at Microsoft.FSharp.Primitives.Basics.List.zip[T1,T2](FSharpList`1 xs1, FSharpList`1 xs2) in D:\a\_work\1\s\src\FSharp.Core\local.fs:line 923
   at Microsoft.FSharp.Collections.ListModule.Zip[T1,T2](FSharpList`1 list1, FSharpList`1 list2) in D:\a\_work\1\s\src\FSharp.Core\list.fs:line 598
   at Fantomas.Core.ASTTransformer.mkTuplePat(CreationAide creationAide, FSharpList`1 pats, FSharpList`1 commas, Range m) in /_//src/Fantomas.Core/ASTTransformer.fs:line 1625
   at Fantomas.Core.ASTTransformer.mkPat(CreationAide creationAide, SynPat p) in /_//src/Fantomas.Core/ASTTransformer.fs:line 1709
   at Fantomas.Core.ASTTransformer.pats@2683.Invoke(SynPat p)
   at Microsoft.FSharp.Primitives.Basics.List.map[T,TResult](FSharpFunc`2 mapping, FSharpList`1 x) in D:\a\_work\1\s\src\FSharp.Core\local.fs:line 243
   at Microsoft.FSharp.Collections.ListModule.Map[T,TResult](FSharpFunc`2 mapping, FSharpList`1 list) in D:\a\_work\1\s\src\FSharp.Core\list.fs:line 96
   at Fantomas.Core.ASTTransformer.mkPropertyGetSetBinding(CreationAide creationAide, FSharpOption`1 accessibility, SingleTextNode leadingKeyword, SynBinding binding) in /_//src/Fantomas.Core/ASTTransformer.fs:line 2683
   at Fantomas.Core.ASTTransformer.mkMemberDefn(CreationAide creationAide, SynMemberDefn md) in /_//src/Fantomas.Core/ASTTransformer.fs:line 2893
   at Microsoft.FSharp.Primitives.Basics.List.map[T,TResult](FSharpFunc`2 mapping, FSharpList`1 x) in D:\a\_work\1\s\src\FSharp.Core\local.fs:line 243
   at Fantomas.Core.ASTTransformer.mkTypeDefn(CreationAide creationAide, SynTypeDefn _arg13) in /_//src/Fantomas.Core/ASTTransformer.fs:line 2619
   at Fantomas.Core.ASTTransformer.mkModuleDecls(CreationAide creationAide, FSharpList`1 decls, FSharpFunc`2 finalContinuation) in /_//src/Fantomas.Core/ASTTransformer.fs:line 3052
   at Fantomas.Core.ASTTransformer.mkModuleOrNamespace(CreationAide creationAide, SynModuleOrNamespace mn) in /_//src/Fantomas.Core/ASTTransformer.fs:line 3136
   at Fantomas.Core.ASTTransformer.mds@3146.Invoke(SynModuleOrNamespace mn)
   at Microsoft.FSharp.Primitives.Basics.List.map[T,TResult](FSharpFunc`2 mapping, FSharpList`1 x) in D:\a\_work\1\s\src\FSharp.Core\local.fs:line 243
   at Microsoft.FSharp.Collections.ListModule.Map[T,TResult](FSharpFunc`2 mapping, FSharpList`1 list) in D:\a\_work\1\s\src\FSharp.Core\list.fs:line 96
   at Fantomas.Core.ASTTransformer.mkImplFile(CreationAide creationAide, ParsedImplFileInput _arg15, Range m) in /_//src/Fantomas.Core/ASTTransformer.fs:line 3146
   at Fantomas.Core.ASTTransformer.mkOak(FSharpOption`1 sourceText, ParsedInput ast) in /_//src/Fantomas.Core/ASTTransformer.fs:line 3571
   at Fantomas.Core.CodeFormatterImpl.formatAST(ParsedInput ast, FSharpOption`1 sourceText, FormatConfig config, FSharpOption`1 cursor) in /_//src/Fantomas.Core/CodeFormatterImpl.fs:line 66
   at Fantomas.Core.CodeFormatterImpl.formatDocument@89-3.Invoke(Unit unitVar) in /_//src/Fantomas.Core/CodeFormatterImpl.fs:line 89
   at Microsoft.FSharp.Control.AsyncPrimitives.CallThenInvoke[T,TResult](AsyncActivation`1 ctxt, TResult result1, FSharpFunc`2 part2) in D:\a\_work\1\s\src\FSharp.Core\async.fs:line 508
   at Microsoft.FSharp.Control.Trampoline.Execute(FSharpFunc`2 firstAction) in D:\a\_work\1\s\src\FSharp.Core\async.fs:line 112

Problem description

Fantomas fails to format indexed property with three variables. But it works with two variabels, see fantomas-online

Extra information
[ ] The formatted result breaks my code.
[ ] The formatted result gives compiler warnings.
[x] I or my company would be willing to help fix this.
[x] I would like a release if this problem is solved.

[nojaf]

Hello, thank you for this report.
I took a look and found a solution to this problem.
The short version is that the AST the parser produces is rather misleading.
We had a workaround for this but never considered any cases where there are more than 2 elements in the tuple.

[nojaf]

Fix available in https://www.nuget.org/packages/fantomas/6.2.3