unknownFlagsErr :: [String] -> a
unknownFlagsErr fs = throwGhcException $ UsageError $ concatMap oneError fs
  where
    oneError f =
        "unrecognised flag: " ++ f ++ "\n" ++
        (case fuzzyMatch f (nub allFlags) of
            [] -> ""
            suggs -> "did you mean one of:\n" ++ unlines (map ("  " ++) suggs))

{- Note [-Bsymbolic and hooks]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-Bsymbolic is a flag that prevents the binding of references to global
symbols to symbols outside the shared library being compiled (see `man
ld`). When dynamically linking, we don't use -Bsymbolic on the RTS
package: that is because we want hooks to be overridden by the user,
we don't want to constrain them to the RTS package.

Unfortunately this seems to have broken somehow on OS X: as a result,
defaultHooks (in hschooks.c) is not called, which does not initialize
the GC stats. As a result, this breaks things like `:set +s` in GHCi
(#8754). As a hacky workaround, we instead call 'defaultHooks'
directly to initalize the flags in the RTS.

A byproduct of this, I believe, is that hooks are likely broken on OS
X when dynamically linking. But this probably doesn't affect most
people since we're linking GHC dynamically, but most things themselves
link statically.
-}
unknownFlagsErr :: [String] -> a
unknownFlagsErr fs = throwGhcException $ UsageError $ concatMap oneError fs
  where
    oneError f =
        "unrecognised flag: " ++ f ++ "\n" ++
        (case fuzzyMatch f (nub allFlags) of
            [] -> ""
            suggs -> "did you mean one of:\n" ++ unlines (map ("  " ++) suggs))

{- Note [-Bsymbolic and hooks]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-Bsymbolic is a flag that prevents the binding of references to global
symbols to symbols outside the shared library being compiled (see `man
ld`). When dynamically linking, we don't use -Bsymbolic on the RTS
package: that is because we want hooks to be overridden by the user,
we don't want to constrain them to the RTS package.

Unfortunately this seems to have broken somehow on OS X: as a result,
defaultHooks (in hschooks.c) is not called, which does not initialize
the GC stats. As a result, this breaks things like `:set +s` in GHCi
(#8754). As a hacky workaround, we instead call 'defaultHooks'
directly to initalize the flags in the RTS.

A byproduct of this, I believe, is that hooks are likely broken on OS
X when dynamically linking. But this probably doesn't affect most
people since we're linking GHC dynamically, but most things themselves
link statically.
-}
unknownFlagsErr fs = throwGhcException $ UsageError $ concatMap oneError fs
  where
    oneError f =
        "unrecognised flag: " ++ f ++ "\n" ++
        (case fuzzyMatch f (nub allFlags) of
            [] -> ""
            suggs -> "did you mean one of:\n" ++ unlines (map ("  " ++) suggs))

{- Note [-Bsymbolic and hooks]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-Bsymbolic is a flag that prevents the binding of references to global
symbols to symbols outside the shared library being compiled (see `man
ld`). When dynamically linking, we don't use -Bsymbolic on the RTS
package: that is because we want hooks to be overridden by the user,
we don't want to constrain them to the RTS package.

Unfortunately this seems to have broken somehow on OS X: as a result,
defaultHooks (in hschooks.c) is not called, which does not initialize
the GC stats. As a result, this breaks things like `:set +s` in GHCi
(#8754). As a hacky workaround, we instead call 'defaultHooks'
directly to initalize the flags in the RTS.

A byproduct of this, I believe, is that hooks are likely broken on OS
X when dynamically linking. But this probably doesn't affect most
people since we're linking GHC dynamically, but most things themselves
link statically.
-}