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| author | Simon Peyton Jones <simonpj@microsoft.com> | 2021-05-04 08:45:08 +0100 |
|---|---|---|
| committer | Simon Peyton Jones <simonpj@microsoft.com> | 2021-05-06 23:22:19 +0100 |
| commit | 2aeee2886818fc66cc23a92de2339fc56f5904c3 (patch) | |
| tree | 3b5dae15c959efc50507b6169b715574862bbbb8 /compiler/GHC/Core/SimpleOpt.hs | |
| parent | 30f6923a834ccaca30c3622a0a82421fabcab119 (diff) | |
| download | haskell-wip/T18481.tar.gz | |
Allow visible type application for levity-poly data conswip/T18481
This patch was driven by #18481, to allow visible type application
for levity-polymorphic newtypes. As so often, it started simple
but grew:
* Significant refactor: I removed HsConLikeOut from the
client-independent Language.Haskell.Syntax.Expr, and put it where it
belongs, as a new constructor `ConLikeTc` in the GHC-specific extension
data type for expressions, `GHC.Hs.Expr.XXExprGhcTc`.
That changed touched a lot of files in a very superficial way.
* Note [Typechecking data constructors] explains the main payload.
The eta-expansion part is no longer done by the typechecker, but
instead deferred to the desugarer, via `ConLikeTc`
* A little side benefit is that I was able to restore VTA for
data types with a "stupid theta": #19775. Not very important,
but the code in GHC.Tc.Gen.Head.tcInferDataCon is is much, much
more elegant now.
* I had to refactor the levity-polymorphism checking code in
GHC.HsToCore.Expr, see
Note [Checking for levity-polymorphic functions]
Note [Checking levity-polymorphic data constructors]
Diffstat (limited to 'compiler/GHC/Core/SimpleOpt.hs')
| -rw-r--r-- | compiler/GHC/Core/SimpleOpt.hs | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/compiler/GHC/Core/SimpleOpt.hs b/compiler/GHC/Core/SimpleOpt.hs index 9e3e92d247..53c239426a 100644 --- a/compiler/GHC/Core/SimpleOpt.hs +++ b/compiler/GHC/Core/SimpleOpt.hs @@ -338,11 +338,11 @@ simple_app env e@(Lam {}) as@(_:_) | (bndrs, body) <- collectBinders e , let zapped_bndrs = zapLamBndrs (length as) bndrs -- Be careful to zap the lambda binders if necessary - -- c.f. the Lam caes of simplExprF1 in GHC.Core.Opt.Simplify + -- c.f. the Lam case of simplExprF1 in GHC.Core.Opt.Simplify -- Lacking this zap caused #19347, when we had a redex -- (\ a b. K a b) e1 e2 -- where (as it happens) the eta-expanded K is produced by - -- Note [Linear fields generalization] in GHC.Tc.Gen.Head + -- Note [Typechecking data constructors] in GHC.Tc.Gen.Head = do_beta env zapped_bndrs body as where do_beta env (b:bs) body (a:as) |