[commit: ghc] ghc-8.6: configure: Fail when bootstrapping with GHC 8.2.1 (d1c7239)

[git at git.haskell.org]

Repository : ssh://git@git.haskell.org/ghc

On branch  : ghc-8.6
Link       : http://ghc.haskell.org/trac/ghc/changeset/d1c7239c037e267873658160b5c290f08f0d6502/ghc

>---------------------------------------------------------------

commit d1c7239c037e267873658160b5c290f08f0d6502
Author: Ben Gamari <ben at smart-cactus.org>
Date:   Sun Jun 17 09:54:18 2018 -0400

    configure: Fail when bootstrapping with GHC 8.2.1
    
    See #15281


>---------------------------------------------------------------

d1c7239c037e267873658160b5c290f08f0d6502
 configure.ac | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/configure.ac b/configure.ac
index 2e6e644..09889ab 100644
--- a/configure.ac
+++ b/configure.ac
@@ -132,6 +132,11 @@ AC_ARG_VAR(CC_STAGE0, [C compiler command (bootstrap)])
 if test "$WithGhc" != ""; then
   FPTOOLS_GHC_VERSION([GhcVersion], [GhcMajVersion], [GhcMinVersion], [GhcPatchLevel])dnl
 
+  # See #15281
+  if test "$GhcMajVersion" = "8" && test "$GhcMinVersion" = "2" && test "$GhcPatchLevel" = "1"; then
+     AC_MSG_ERROR([GHC 8.2.1 is known to be buggy and cannot bootstrap this GHC release (See Trac 15281); please use GHC 8.2.2 or later.])
+  fi
+
   if test "$GhcMajVersion" = "unknown" || test "$GhcMinVersion" = "unknown"; then
      AC_MSG_ERROR([Cannot determine the version of $WithGhc.  Is it really GHC?])
   fi