diff options
Diffstat (limited to 'compiler/main/TidyPgm.hs')
| -rw-r--r-- | compiler/main/TidyPgm.hs | 16 |
1 files changed, 8 insertions, 8 deletions
diff --git a/compiler/main/TidyPgm.hs b/compiler/main/TidyPgm.hs index e9f3f85317..6e84530193 100644 --- a/compiler/main/TidyPgm.hs +++ b/compiler/main/TidyPgm.hs @@ -486,7 +486,7 @@ extendTypeEnvWithPatSyns tidy_patsyns type_env Note [Don't attempt to trim data types] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ For some time GHC tried to avoid exporting the data constructors -of a data type if it wasn't strictly necessary to do so; see Trac #835. +of a data type if it wasn't strictly necessary to do so; see #835. But "strictly necessary" accumulated a longer and longer list of exceptions, and finally I gave up the battle: @@ -501,7 +501,7 @@ of exceptions, and finally I gave up the battle: there are a lot of exceptions, notably when Template Haskell is involved or, more recently, DataKinds. - However Trac #7445 shows that even without TemplateHaskell, using + However #7445 shows that even without TemplateHaskell, using the Data class and invoking Language.Haskell.TH.Quote.dataToExpQ is enough to require us to expose the data constructors. @@ -528,7 +528,7 @@ Then the unfolding looks like This generates bad code unless it's first simplified a bit. That is why CoreUnfold.mkImplicitUnfolding uses simpleOptExpr to do a bit of optimisation first. (Only matters when the selector is used curried; -eg map x ys.) See Trac #2070. +eg map x ys.) See #2070. [Oct 09: in fact, record selectors are no longer implicit Ids at all, because we really do want to optimise them properly. They are treated @@ -541,7 +541,7 @@ because GlobalIds are supposed to have *fixed* IdInfo, but the simplifier and other core-to-core passes mess with IdInfo all the time. The straw that broke the camels back was when a class selector got the wrong arity -- ie the simplifier gave it arity 2, whereas -importing modules were expecting it to have arity 1 (Trac #2844). +importing modules were expecting it to have arity 1 (#2844). It's much safer just to inject them right at the end, after tidying. Oh: two other reasons for injecting them late: @@ -1251,7 +1251,7 @@ tidyTopIdInfo dflags rhs_tidy_env name orig_rhs tidy_rhs idinfo show_unfold caf_ -- marked NOINLINE or something like that -- This is important: if you expose the worker for a loop-breaker -- then you can make the simplifier go into an infinite loop, because - -- in effect the unfolding is exposed. See Trac #1709 + -- in effect the unfolding is exposed. See #1709 -- -- You might think that if show_unfold is False, then the thing should -- not be w/w'd in the first place. But a legitimate reason is this: @@ -1371,7 +1371,7 @@ not exported, to reduce the size of interface files, at least without -O. But that is not always possible: see the old Note [When we can't trim types] below for exceptions. -Then (Trac #7445) I realised that the TH problem arises for any data type +Then (#7445) I realised that the TH problem arises for any data type that we have deriving( Data ), because we can invoke Language.Haskell.TH.Quote.dataToExpQ to get a TH Exp representation of a value built from that data type. @@ -1396,7 +1396,7 @@ now. But there are some times we can't do that, indicated by the 'no_trim_types' flag. -First, Template Haskell. Consider (Trac #2386) this +First, Template Haskell. Consider (#2386) this module M(T, makeOne) where data T = Yay String makeOne = [| Yay "Yep" |] @@ -1405,7 +1405,7 @@ A module that splices in $(makeOne) will then look for a declaration of Yay, so it'd better be there. Hence, brutally but simply, we switch off type constructor trimming if TH is enabled in this module. -Second, data kinds. Consider (Trac #5912) +Second, data kinds. Consider (#5912) {-# LANGUAGE DataKinds #-} module M() where data UnaryTypeC a = UnaryDataC a |