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| author | Krzysztof Gogolewski <krzysztof.gogolewski@tweag.io> | 2020-06-15 19:58:10 +0200 |
|---|---|---|
| committer | Ben Gamari <ben@smart-cactus.org> | 2020-06-17 16:21:58 -0400 |
| commit | 40fa237e1daab7a76b9871bb6c50b953a1addf23 (patch) | |
| tree | 79751e932434be440ba35b4d65c54f25a437e134 /compiler/GHC/Tc/Utils/Backpack.hs | |
| parent | 20616959a7f4821034e14a64c3c9bf288c9bc956 (diff) | |
| download | haskell-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.hs | 3 |
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 |