<div dir="ltr">When compiling code with Generalized Newtype Deriving and the -fwarn-unsafe flag, I get<div><br></div><div><p style="margin:0px"><font face="Menlo"><span style="font-size:12px">-XGeneralizedNewtypeDeriving is not allowed in Safe Haskell</span></font><br></p><p style="margin:0px"><font face="Menlo"><span style="font-size:12px"><br></span></font></p><p style="margin:0px"><font face="Menlo"><span style="font-size:12px">This happens both in GHC 7.8 and GHC 7.10.</span></font></p><p style="margin:0px"><font face="Menlo"><span style="font-size:12px"><br></span></font></p><p style="margin:0px"><font face="Menlo"><span style="font-size:12px">I thought I remembered reading somewhere that GNTD is now part of the safe language?  The GHC manual used to state that GNTD is not allowed in Safe Haskell:</span></font></p><p style="margin:0px"><font face="Menlo"><span style="font-size:12px"><br></span></font></p><p style="margin:0px"><a href="https://downloads.haskell.org/~ghc/7.6.3/docs/html/users_guide/safe-haskell.html#safe-language">https://downloads.haskell.org/~ghc/7.6.3/docs/html/users_guide/safe-haskell.html#safe-language</a><font face="Menlo"><span style="font-size:12px"><br></span></font></p><p style="margin:0px"><br></p><p style="margin:0px">But this language on GNTD not being part of the safe language was removed in the 7.8 manual:</p><p style="margin:0px"><br></p><p style="margin:0px"><a href="https://downloads.haskell.org/~ghc/7.8.2/docs/html/users_guide/safe-haskell.html#safe-language">https://downloads.haskell.org/~ghc/7.8.2/docs/html/users_guide/safe-haskell.html#safe-language</a><br></p><p style="margin:0px"><br></p><p style="margin:0px">The GHC release notes don't say anything about this one way or the other.  Thoughts?</p></div></div>