Pipe is removed when DU type name matches record type name

[JonCanning]

Issue created from fantomas-ui

Pipe is removed when DU type name matches record type name

Code

type Record =
    { Name: string }

type DU = | Record

Result

type Record =
    { Name: string }

type DU = Record

Options

Fantomas 3.1.0

Name	Value
IndentOnTryWith	false
IndentSpaceNum	4
KeepNewlineAfter	false
MaxIfThenElseShortWidth	40
PageWidth	120
ReorderOpenDeclaration	false
SemicolonAtEndOfLine	false
SpaceAfterComma	true
SpaceAfterSemicolon	true
SpaceAroundDelimiter	true
SpaceBeforeArgument	true
SpaceBeforeColon	false
StrictMode	false

[nojaf]

This is by design actually. See https://jindraivanek.gitlab.io/fantomas-ui/#?fantomas=preview&code=C4TwDgpgBAIgqlAvFAPlAShAxgewE4AmQA
You don't need the pipe when you only have one clause.

If preferred you can open a new change request to maybe introduce a setting whether the pipe should be there for single case DUs.

[JonCanning]

In my example it becomes a type alias for Record rather than a single case DU

[nojaf]

Apologies, I missed the point of the issue I'm afraid 😅
The AST is indeed different before and after:

ImplFile
  (ParsedImplFileInput
     ("Script.fsx",true,QualifiedNameOfFile Script$fsx,[],[],
      [SynModuleOrNamespace
         ([Script],false,AnonModule,
          [Types
             ([TypeDefn
                 (ComponentInfo
                    ([],[],[],[Record],
                     PreXmlDoc ((1,11),FSharp.Compiler.Ast+XmlDocCollector),
                     false,None,Script.fsx (1,5--1,11) IsSynthetic=false),
                  Simple
                    (Record
                       (None,
                        [Field
                           ([],false,Some Name,
                            LongIdent (LongIdentWithDots ([string],[])),false,
                            PreXmlDoc
                              ((1,20),FSharp.Compiler.Ast+XmlDocCollector),None,
                            Script.fsx (1,16--1,28) IsSynthetic=false)],
                        Script.fsx (1,14--1,30) IsSynthetic=false),
                     Script.fsx (1,14--1,30) IsSynthetic=false),[],
                  Script.fsx (1,5--1,30) IsSynthetic=false)],
              Script.fsx (1,0--1,30) IsSynthetic=false);
           Types
             ([TypeDefn
                 (ComponentInfo
                    ([],[],[],[DU],
                     PreXmlDoc ((2,7),FSharp.Compiler.Ast+XmlDocCollector),false,
                     None,Script.fsx (2,5--2,7) IsSynthetic=false),
                  Simple
                    (Union
                       (None,
                        [UnionCase
                           ([],Record,UnionCaseFields [],
                            PreXmlDoc
                              ((2,11),FSharp.Compiler.Ast+XmlDocCollector),None,
                            Script.fsx (2,12--2,18) IsSynthetic=false)],
                        Script.fsx (2,10--2,18) IsSynthetic=false),
                     Script.fsx (2,10--2,18) IsSynthetic=false),[],
                  Script.fsx (2,5--2,18) IsSynthetic=false)],
              Script.fsx (2,0--2,18) IsSynthetic=false)],PreXmlDocEmpty,[],None,
          Script.fsx (1,0--2,18) IsSynthetic=false)],(true, true)))

after:

ImplFile
  (ParsedImplFileInput
     ("Script.fsx",true,QualifiedNameOfFile Script$fsx,[],[],
      [SynModuleOrNamespace
         ([Script],false,AnonModule,
          [Types
             ([TypeDefn
                 (ComponentInfo
                    ([],[],[],[Record],
                     PreXmlDoc ((1,11),FSharp.Compiler.Ast+XmlDocCollector),
                     false,None,Script.fsx (1,5--1,11) IsSynthetic=false),
                  Simple
                    (Record
                       (None,
                        [Field
                           ([],false,Some Name,
                            LongIdent (LongIdentWithDots ([string],[])),false,
                            PreXmlDoc
                              ((1,20),FSharp.Compiler.Ast+XmlDocCollector),None,
                            Script.fsx (1,16--1,28) IsSynthetic=false)],
                        Script.fsx (1,14--1,30) IsSynthetic=false),
                     Script.fsx (1,14--1,30) IsSynthetic=false),[],
                  Script.fsx (1,5--1,30) IsSynthetic=false)],
              Script.fsx (1,0--1,30) IsSynthetic=false);
           Types
             ([TypeDefn
                 (ComponentInfo
                    ([],[],[],[DU],
                     PreXmlDoc ((2,7),FSharp.Compiler.Ast+XmlDocCollector),false,
                     None,Script.fsx (2,5--2,7) IsSynthetic=false),
                  Simple
                    (TypeAbbrev
                       (Ok,LongIdent (LongIdentWithDots ([Record],[])),
                        Script.fsx (2,10--2,16) IsSynthetic=false),
                     Script.fsx (2,10--2,16) IsSynthetic=false),[],
                  Script.fsx (2,5--2,16) IsSynthetic=false)],
              Script.fsx (2,0--2,16) IsSynthetic=false)],PreXmlDocEmpty,[],None,
          Script.fsx (1,0--2,16) IsSynthetic=false)],(true, true)))

So I guess single case DU without any UnionCaseFields should also have a pipe.

Thanks for this report!