val mutable in signature loses 'mutable'

[dsyme]

Issue created from fantomas-online

Code

/// For extra diagnostics 
val mutable showParserStackOnParseError: bool

Result

/// For extra diagnostics
val showParserStackOnParseError: bool

Problem description

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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.

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Fantomas 4.6 branch at 11/03/2021 17:27:28 - 10f599c

Default Fantomas configuration

Signature file

_{Did you know that you can ignore files when formatting from fantomas-tool or the FAKE targets by using a .fantomasignore file?}

[nojaf]

Hello, thank you for reporting this issue.
The mutable information is not captured in:

fantomas/src/Fantomas/SourceParser.fs

Lines 1555 to 1568 in 3e077f5

	let (|Val|)
	(SynValSig (ats,
	(IdentOrKeyword (OpNameFullInPattern (s, _)) as ident),
	SynValTyparDecls (typars, _),
	t,
	vi,
	isInline,
	_,
	px,
	ao,
	_,
	range))
	=
	(ats, px, ao, s, ident.idRange, t, vi, isInline, typars, range)

and then not printed in

fantomas/src/Fantomas/CodePrinter.fs

Lines 923 to 941 in abd2358

	and genVal astContext (Val (ats, px, ao, s, identRange, t, vi, isInline, tds, range)) =
	let typeName = genTypeAndParam astContext s tds []
	let (FunType namedArgs) = (t, vi)
	let hasGenerics = Option.isSome tds
	genPreXmlDoc px
	+> genAttributes astContext ats
	+> (!- "val "
	+> onlyIf isInline (!- "inline ")
	+> opt sepSpace ao genAccess
	+> typeName
	|> genTriviaFor Ident_ identRange)
	+> ifElse hasGenerics sepColonWithSpacesFixed sepColon
	+> ifElse
	(List.isNotEmpty namedArgs)
	(autoIndentAndNlnIfExpressionExceedsPageWidth (genTypeList astContext namedArgs))
	(genConstraints astContext t vi)
	|> genTriviaFor SynValSig_ range

Something like onlyIf isMutable (!- "mutable ") is missing.

This is a good first issue for newcomers to get their feet wet.