diff options
Diffstat (limited to 'compiler/GHC/Core/Opt/WorkWrap.hs')
| -rw-r--r-- | compiler/GHC/Core/Opt/WorkWrap.hs | 9 |
1 files changed, 5 insertions, 4 deletions
diff --git a/compiler/GHC/Core/Opt/WorkWrap.hs b/compiler/GHC/Core/Opt/WorkWrap.hs index 35d818d814..1c7a728d12 100644 --- a/compiler/GHC/Core/Opt/WorkWrap.hs +++ b/compiler/GHC/Core/Opt/WorkWrap.hs @@ -679,10 +679,11 @@ is there only to generate used-once info for single-entry thunks. Note [Don't eta expand in w/w] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -A binding where the manifestArity of the RHS is less than idArity of the binder -means GHC.Core.Opt.Arity didn't eta expand that binding. When this happens, it does so -for a reason (see Note [exprArity invariant] in GHC.Core.Opt.Arity) and we probably have -a PAP, cast or trivial expression as RHS. +A binding where the manifestArity of the RHS is less than idArity of +the binder means GHC.Core.Opt.Arity didn't eta expand that binding +When this happens, it does so for a reason (see Note [Arity invariants for bindings] +in GHC.Core.Opt.Arity) and we probably have a PAP, cast or trivial expression +as RHS. Below is a historical account of what happened when w/w still did eta expansion. Nowadays, it doesn't do that, but will simply w/w for the wrong arity, unleashing |