Upgrading packages/Updating to GHC 7: Difference between revisions
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There is no base 3 now, after being deprecated for several years, so dependencies on base 3 won't compile with GHC 7. | There is no base 3 now, after being deprecated for several years, so dependencies on base 3 won't compile with GHC 7. | ||
== Quasiquotation data constructor modified == | |||
The QuasiQuoter constructor now takes four arguments instead of 2. (quoteType and quoteDec were added). One solution: use record syntax to set only the quoters you provide. This allows code to remain backwards compatible. | |||
Revision as of 12:51, 29 September 2010
A list of common problems upgrading packages to GHC 7.
If you maintain packages, this is for you.
-XMonoLocalBinds
If you use -XGADTs or -XTypeFamilies (or -fglasgow-exts, which is deprecated) you get -XMonoLocalBinds, which says that local let/where bindings are not auto-generalised. There's an extensive discussion of the reason for this decision in our paper "Let should not be generalised" and the journal version
* http://haskell.org/haskellwiki/Simonpj/Talk:OutsideIn
base 3 goes away
There is no base 3 now, after being deprecated for several years, so dependencies on base 3 won't compile with GHC 7.
Quasiquotation data constructor modified
The QuasiQuoter constructor now takes four arguments instead of 2. (quoteType and quoteDec were added). One solution: use record syntax to set only the quoters you provide. This allows code to remain backwards compatible.