diff options
| -rw-r--r-- | compiler/cmm/CmmLex.x | 6 | ||||
| -rw-r--r-- | compiler/parser/Lexer.x | 42 | ||||
| -rw-r--r-- | utils/genprimopcode/Lexer.x | 6 |
3 files changed, 37 insertions, 17 deletions
diff --git a/compiler/cmm/CmmLex.x b/compiler/cmm/CmmLex.x index fca5a1eee8..89ae796c70 100644 --- a/compiler/cmm/CmmLex.x +++ b/compiler/cmm/CmmLex.x @@ -11,16 +11,12 @@ ----------------------------------------------------------------------------- { +-- See Note [Warnings in code generated by Alex] in compiler/parser/Lexer.x {-# OPTIONS_GHC -fno-warn-unused-matches #-} {-# OPTIONS_GHC -fno-warn-unused-binds #-} {-# OPTIONS_GHC -fno-warn-unused-imports #-} {-# OPTIONS_GHC -fno-warn-tabs #-} {-# OPTIONS_GHC -fno-warn-missing-signatures #-} --- The above warning suppression flags are a temporary kludge. --- While working on this module you are encouraged to remove it and fix --- any warnings in the module. See --- http://ghc.haskell.org/trac/ghc/wiki/Commentary/CodingStyle#Warnings --- for details module CmmLex ( CmmToken(..), cmmlex, diff --git a/compiler/parser/Lexer.x b/compiler/parser/Lexer.x index 98d167d4dd..01e7de3efd 100644 --- a/compiler/parser/Lexer.x +++ b/compiler/parser/Lexer.x @@ -41,20 +41,16 @@ -- Alex "Haskell code fragment top" { --- XXX The above flags turn off warnings in the generated code: {-# LANGUAGE BangPatterns #-} + +-- See Note [Warnings in code generated by Alex] in compiler/parser/Lexer.x {-# OPTIONS_GHC -fno-warn-unused-matches #-} {-# OPTIONS_GHC -fno-warn-unused-binds #-} {-# OPTIONS_GHC -fno-warn-unused-imports #-} {-# OPTIONS_GHC -fno-warn-tabs #-} {-# OPTIONS_GHC -fno-warn-missing-signatures #-} -{-# OPTIONS_GHC -fno-warn-overlapping-patterns #-} --- The above warning suppression flags are a temporary kludge. --- While working on this module you are encouraged to remove it and fix --- any warnings in the module. See --- http://ghc.haskell.org/trac/ghc/wiki/Commentary/CodingStyle#Warnings --- for details +{-# OPTIONS_GHC -fno-warn-overlapping-patterns #-} {-# OPTIONS_GHC -funbox-strict-fields #-} module Lexer ( @@ -2695,4 +2691,36 @@ isDocComment (ITdocSection _ _) = True isDocComment (ITdocOptions _) = True isDocComment (ITdocOptionsOld _) = True isDocComment _ = False + +{- Note [Warnings in code generated by Alex] + +We add the following warning suppression flags to all code generated by Alex: + +{-# OPTIONS_GHC -fno-warn-unused-matches #-} +{-# OPTIONS_GHC -fno-warn-unused-binds #-} +{-# OPTIONS_GHC -fno-warn-unused-imports #-} +{-# OPTIONS_GHC -fno-warn-tabs #-} +{-# OPTIONS_GHC -fno-warn-missing-signatures #-} + +Without these flags, current versions of Alex will generate code that is not +warning free. Note that this is the result of Alex' internals, not of the way +we have have written our (Lexer).x files. + +As always, we need code to be warning free when validating with -Werror. + +The list of flags is as short as possible (at the time of writing), to try to +avoid suppressing warnings for bugs in our own code. + +TODO. Reevaluate this situation once Alex >3.1.4 is released. Hopefully you +can remove these flags from all (Lexer).x files in the repository, and also +delete this Note. Don't forget to update aclocal.m4, and send a HEADS UP +message to ghc-devs. + +The first release of Alex after 3.1.4 will either suppress all warnings itself +[1] (bad), or most warnings will be fixed and only a few select ones will be +suppressed by default [2] (better). + +[1] https://github.com/simonmar/alex/commit/1eefcde22ba1bb9b51d523814415714e20f0761e +[2] https://github.com/simonmar/alex/pull/69 +-} } diff --git a/utils/genprimopcode/Lexer.x b/utils/genprimopcode/Lexer.x index 3ec6c2ef6e..ad2590bcb8 100644 --- a/utils/genprimopcode/Lexer.x +++ b/utils/genprimopcode/Lexer.x @@ -1,15 +1,11 @@ { +-- See Note [Warnings in code generated by Alex] in compiler/parser/Lexer.x {-# OPTIONS_GHC -fno-warn-unused-matches #-} {-# OPTIONS_GHC -fno-warn-unused-binds #-} {-# OPTIONS_GHC -fno-warn-tabs #-} {-# OPTIONS_GHC -fno-warn-missing-signatures #-} {-# OPTIONS_GHC -fno-warn-unused-imports #-} --- The above warning suppression flags are a temporary kludge. --- While working on this module you are encouraged to remove it and fix --- any warnings in the module. See --- http://ghc.haskell.org/trac/ghc/wiki/Commentary/CodingStyle#Warnings --- for details module Lexer (lex_tok) where |