F# Interactive displays enums unnecessarily verbosely.

[teo-tsirpanis]

On .NET 6 SDK Preview 7, .NET SDK 5.0.400 and .NET Core SDK 3.1.412, writing something like

System.Char.GetUnicodeCategory 'a';;

will display

val it : System.Globalization.UnicodeCategory = LowercaseLetter {value__ = 1;}

while it could display

val it : System.Globalization.UnicodeCategory = LowercaseLetter

I persume it is a side-effect of #5002. It does not happen when using sprintf "%A".

[smoothdeveloper]

I personally find the additional information useful, maybe it could pretty printed while retaining the actual value, keeping how it behaves when displayed in FSI versus what "%A" does.

[dsyme]

This should be fixed, we don't intend to show value__

[joshuapassos]

@dsyme, if I change the pattern matching by adding the enum type check, can maybe I resolve the problem?

fsharp/src/fsharp/utils/sformat.fs

Lines 1247 to 1272 in c50b294

	| ObjectValue obj ->
	let ty = obj.GetType()
	match obj with
	| :? string as s ->
	stringValueL s
	| :? Array as arr ->
	arrayValueL depthLim arr
	| _ when isSetOrMapType ty ->
	mapSetValueL depthLim prec ty obj
	| :? System.Collections.IEnumerable as ie ->
	sequenceValueL showMode depthLim prec ie
	| _ when showMode = ShowTopLevelBinding && typeUsesSystemObjectToString ty ->
	emptyL
	| _ when opts.ShowProperties ->
	countNodes 1
	objectValueWithPropertiesL depthLim (ty: Type) (obj: obj)
	| _ ->
	countNodes 1
	// This buries an obj in the layout, rendered at squash time via a leafFormatter.
	Layout.objL obj

  | :? Enum -> 
    countNodes 1
    Layout.objL obj

[dsyme]

Yes! :)