Deriving Bug?

[davorak]

ghci -XDeriveDataTypeable > import Data.Typeable > data S = S deriving (typeable) ghc: panic! (the 'impossible' happened)

(GHC version 7.4.2 for x86_64-unknown-linux):

nameModule typeable{tv av8}

Please report ...

data S = S deriving typeable causes a parse error and The following work just fine:

data S = S deriving Typeable data S = S deriving (Typeable)

data S = S deriving (show) causes a similar error the only change being:

nameModule show{tv av8}

The same problem exists outside of ghci when trying to compile with GHC.

The ascii tree for the dependancies of the ghc install produced with

nix-store -q --tree $(which ghc)

/nix/store/gzb4pca6nnb16lw2mbmr68kx2vwx8q56-ghc-7.4.2-wrapper
+---/nix/store/043zrsanirjh8nbc5vqpjn93hhrf107f-bash-4.2-p24
| +---/nix/store/cj7a81wsm1ijwwpkks3725661h3263p5-glibc-2.13
| | +---/nix/store/jfcs9xnfbmiwqs224sb0qqsybbfl3sab-linux-headers-2.6.35.14
| | | +---/nix/store/jfcs9xnfbmiwqs224sb0qqsybbfl3sab-linux-headers-2.6.35.14 [...]
| | +---/nix/store/cj7a81wsm1ijwwpkks3725661h3263p5-glibc-2.13 [...]
| +---/nix/store/043zrsanirjh8nbc5vqpjn93hhrf107f-bash-4.2-p24 [...]
+---/nix/store/858ww5lrjxca5asa79vwq5rm6m1h3q6k-ghc-7.4.2
| +---/nix/store/cj7a81wsm1ijwwpkks3725661h3263p5-glibc-2.13 [...]
| +---/nix/store/043zrsanirjh8nbc5vqpjn93hhrf107f-bash-4.2-p24 [...]
| +---/nix/store/1iigiim5855m8j7pmwf5xrnpf705s4dh-binutils-2.21.1a
| | +---/nix/store/cj7a81wsm1ijwwpkks3725661h3263p5-glibc-2.13 [...]
| | +---/nix/store/i3mqzy76lf51v5zqxjxyvf11j25iwycd-zlib-1.2.7
| | | +---/nix/store/cj7a81wsm1ijwwpkks3725661h3263p5-glibc-2.13 [...]
| | | +---/nix/store/i3mqzy76lf51v5zqxjxyvf11j25iwycd-zlib-1.2.7 [...]
| | +---/nix/store/1iigiim5855m8j7pmwf5xrnpf705s4dh-binutils-2.21.1a [...]
| +---/nix/store/a9jvlnrva7vr1szbg6shpw6nr5xz898p-gmp-5.0.5
| | +---/nix/store/cj7a81wsm1ijwwpkks3725661h3263p5-glibc-2.13 [...]
| | +---/nix/store/4gv9gby4bn1y0rlw3k0d5lyqy0yfkrc6-gcc-4.6.3
| | | +---/nix/store/jfcs9xnfbmiwqs224sb0qqsybbfl3sab-linux-headers-2.6.35.14 [...]
| | | +---/nix/store/cj7a81wsm1ijwwpkks3725661h3263p5-glibc-2.13 [...]
| | | +---/nix/store/i3mqzy76lf51v5zqxjxyvf11j25iwycd-zlib-1.2.7 [...]
| | | +---/nix/store/4gv9gby4bn1y0rlw3k0d5lyqy0yfkrc6-gcc-4.6.3 [...]
| | +---/nix/store/a9jvlnrva7vr1szbg6shpw6nr5xz898p-gmp-5.0.5 [...]
| +---/nix/store/ahg5mlj2mlp7yfl3x875pq95ar763vgj-ncurses-5.9
| | +---/nix/store/cj7a81wsm1ijwwpkks3725661h3263p5-glibc-2.13 [...]
| | +---/nix/store/043zrsanirjh8nbc5vqpjn93hhrf107f-bash-4.2-p24 [...]
| | +---/nix/store/ahg5mlj2mlp7yfl3x875pq95ar763vgj-ncurses-5.9 [...]
| +---/nix/store/v4m3gahx1iz53v51rdinh0lcmipn1p4j-perl-5.14.2
| | +---/nix/store/cj7a81wsm1ijwwpkks3725661h3263p5-glibc-2.13 [...]
| | +---/nix/store/4gv9gby4bn1y0rlw3k0d5lyqy0yfkrc6-gcc-4.6.3 [...]
| | +---/nix/store/vpp6h8l3mzjdn5paziz31vk52pg73635-coreutils-8.15
| | | +---/nix/store/cj7a81wsm1ijwwpkks3725661h3263p5-glibc-2.13 [...]
| | | +---/nix/store/qh3l8f8369kvbhnkbwwnpaxayvnvi55v-acl-2.2.51
| | | | +---/nix/store/cj7a81wsm1ijwwpkks3725661h3263p5-glibc-2.13 [...]
| | | | +---/nix/store/jaabnv7dgxzvyhg0nxzk7xqs2qxp5rcy-attr-2.4.46
| | | | | +---/nix/store/cj7a81wsm1ijwwpkks3725661h3263p5-glibc-2.13 [...]
| | | | | +---/nix/store/jaabnv7dgxzvyhg0nxzk7xqs2qxp5rcy-attr-2.4.46 [...]
| | | | +---/nix/store/qh3l8f8369kvbhnkbwwnpaxayvnvi55v-acl-2.2.51 [...]
| | | +---/nix/store/vpp6h8l3mzjdn5paziz31vk52pg73635-coreutils-8.15 [...]
| | +---/nix/store/v4m3gahx1iz53v51rdinh0lcmipn1p4j-perl-5.14.2 [...]
| +---/nix/store/xl3kqxs68gzs4h309wjyd32im9n6cnyr-gcc-wrapper-4.6.3
| | +---/nix/store/cj7a81wsm1ijwwpkks3725661h3263p5-glibc-2.13 [...]
| | +---/nix/store/043zrsanirjh8nbc5vqpjn93hhrf107f-bash-4.2-p24 [...]
| | +---/nix/store/1iigiim5855m8j7pmwf5xrnpf705s4dh-binutils-2.21.1a [...]
| | +---/nix/store/4gv9gby4bn1y0rlw3k0d5lyqy0yfkrc6-gcc-4.6.3 [...]
| | +---/nix/store/vpp6h8l3mzjdn5paziz31vk52pg73635-coreutils-8.15 [...]
| | +---/nix/store/xl3kqxs68gzs4h309wjyd32im9n6cnyr-gcc-wrapper-4.6.3 [...]
| +---/nix/store/858ww5lrjxca5asa79vwq5rm6m1h3q6k-ghc-7.4.2 [...]
+---/nix/store/gzb4pca6nnb16lw2mbmr68kx2vwx8q56-ghc-7.4.2-wrapper [...]

OS: nixos 1.1 GHC: 7.4.2

[monoidal]

Thanks for the report, the bug is already fixed in GHC 7.6 - bug #5961.