summaryrefslogtreecommitdiff
path: root/compiler/GHC/Tc/Utils/Backpack.hs
diff options
context:
space:
mode:
authorKrzysztof Gogolewski <krzysztof.gogolewski@tweag.io>2020-06-15 19:58:10 +0200
committerBen Gamari <ben@smart-cactus.org>2020-06-17 16:21:58 -0400
commit40fa237e1daab7a76b9871bb6c50b953a1addf23 (patch)
tree79751e932434be440ba35b4d65c54f25a437e134 /compiler/GHC/Tc/Utils/Backpack.hs
parent20616959a7f4821034e14a64c3c9bf288c9bc956 (diff)
downloadhaskell-40fa237e1daab7a76b9871bb6c50b953a1addf23.tar.gz
Linear types (#15981)
This is the first step towards implementation of the linear types proposal (https://github.com/ghc-proposals/ghc-proposals/pull/111). It features * A language extension -XLinearTypes * Syntax for linear functions in the surface language * Linearity checking in Core Lint, enabled with -dlinear-core-lint * Core-to-core passes are mostly compatible with linearity * Fields in a data type can be linear or unrestricted; linear fields have multiplicity-polymorphic constructors. If -XLinearTypes is disabled, the GADT syntax defaults to linear fields The following items are not yet supported: * a # m -> b syntax (only prefix FUN is supported for now) * Full multiplicity inference (multiplicities are really only checked) * Decent linearity error messages * Linear let, where, and case expressions in the surface language (each of these currently introduce the unrestricted variant) * Multiplicity-parametric fields * Syntax for annotating lambda-bound or let-bound with a multiplicity * Syntax for non-linear/multiple-field-multiplicity records * Linear projections for records with a single linear field * Linear pattern synonyms * Multiplicity coercions (test LinearPolyType) A high-level description can be found at https://ghc.haskell.org/trac/ghc/wiki/LinearTypes/Implementation Following the link above you will find a description of the changes made to Core. This commit has been authored by * Richard Eisenberg * Krzysztof Gogolewski * Matthew Pickering * Arnaud Spiwack With contributions from: * Mark Barbone * Alexander Vershilov Updates haddock submodule.
Diffstat (limited to 'compiler/GHC/Tc/Utils/Backpack.hs')
-rw-r--r--compiler/GHC/Tc/Utils/Backpack.hs3
1 files changed, 2 insertions, 1 deletions
diff --git a/compiler/GHC/Tc/Utils/Backpack.hs b/compiler/GHC/Tc/Utils/Backpack.hs
index 1f6090c7b7..72a1aee55d 100644
--- a/compiler/GHC/Tc/Utils/Backpack.hs
+++ b/compiler/GHC/Tc/Utils/Backpack.hs
@@ -50,6 +50,7 @@ import GHC.Types.SrcLoc
import GHC.Driver.Types
import GHC.Utils.Outputable
import GHC.Core.Type
+import GHC.Core.Multiplicity
import GHC.Data.FastString
import GHC.Rename.Fixity ( lookupFixityRn )
import GHC.Data.Maybe
@@ -216,7 +217,7 @@ check_inst sig_inst = do
(substTy skol_subst pred)
givens <- forM theta $ \given -> do
loc <- getCtLocM origin (Just TypeLevel)
- let given_pred = substTy skol_subst given
+ let given_pred = substTy skol_subst (scaledThing given)
new_ev <- newEvVar given_pred
return CtGiven { ctev_pred = given_pred
-- Doesn't matter, make something up