Moves comments when reformatting data, only if neces... | lspitzner/brittany

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Given an ill-formed data declaration, Brittany will fix it, but messes up the comments in the process:

Before:

data Example
  = Example
  { example :: Int
  -- ^ Comment
  , example :: Int
  -- ^ Comment
  , example :: Int
  }

After:

data Example = Example
  { example :: Int
             -- ^ Comment
  , example :: Int
             -- ^ Comment
  , example :: Int
  }

However, if the declaration is already well-formed:

data Example = Example
  { example :: Int
  -- ^ Comment
  , example :: Int
  -- ^ Comment
  , example :: Int
  }

The comments don't move.

Our configuration

---
conf_debug:
  dconf_roundtrip_exactprint_only: false
  dconf_dump_bridoc_simpl_par: false
  dconf_dump_ast_unknown: false
  dconf_dump_bridoc_simpl_floating: false
  dconf_dump_config: false
  dconf_dump_bridoc_raw: false
  dconf_dump_bridoc_final: false
  dconf_dump_bridoc_simpl_alt: false
  dconf_dump_bridoc_simpl_indent: false
  dconf_dump_annotations: false
  dconf_dump_bridoc_simpl_columns: false
  dconf_dump_ast_full: false
conf_forward:
  options_ghc:
    - -XBangPatterns
    - -XDataKinds
    - -XDeriveAnyClass
    - -XDeriveFoldable
    - -XDeriveFunctor
    - -XDeriveGeneric
    - -XDeriveLift
    - -XDeriveTraversable
    - -XDerivingStrategies
    - -XFlexibleContexts
    - -XFlexibleInstances
    - -XGADTs
    - -XGeneralizedNewtypeDeriving
    - -XLambdaCase
    - -XMultiParamTypeClasses
    - -XNoImplicitPrelude
    - -XNoMonomorphismRestriction
    - -XOverloadedStrings
    - -XRankNTypes
    - -XRecordWildCards
    - -XScopedTypeVariables
    - -XStandaloneDeriving
    - -XTypeApplications
    - -XTypeFamilies
conf_errorHandling:
  econf_ExactPrintFallback: ExactPrintFallbackModeInline
  econf_Werror: false
  econf_omit_output_valid_check: false
  econf_produceOutputOnErrors: false
conf_preprocessor:
  ppconf_CPPMode: CPPModeAbort
  ppconf_hackAroundIncludes: false
conf_obfuscate: false
conf_roundtrip_exactprint_only: false
conf_version: 1
conf_layout:
  lconfig_reformatModulePreamble: true
  lconfig_altChooser:
    tag: AltChooserBoundedSearch
    contents: 3
  lconfig_allowSingleLineExportList: false
  lconfig_importColumn: 60
  lconfig_hangingTypeSignature: false
  lconfig_importAsColumn: 50
  lconfig_alignmentLimit: 1
  lconfig_indentListSpecial: true
  lconfig_indentAmount: 2
  lconfig_alignmentBreakOnMultiline: true
  lconfig_cols: 80
  lconfig_indentPolicy: IndentPolicyLeft
  lconfig_indentWhereSpecial: true
  lconfig_columnAlignMode:
    tag: ColumnAlignModeDisabled
    contents: 0.7

% stack exec brittany -- --version
brittany version 0.13.1.0
Copyright (C) 2016-2019 Lennart Spitzner
Copyright (C) 2019 PRODA LTD
There is NO WARRANTY, to the extent permitted by law.

Reproduce the issue with the ill-formed and well-formed data declarations shown in the report using Brittany 0.13.1.0 and the supplied configuration. Trace the formatter's comment handling during reformatting; done means comments remain aligned with their fields when the declaration is repaired, without changing the already well-formed case.

Written by the indexing model from the issue text.

Moves comments when reformatting data, only if necessary

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