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| author | Ryan Scott <ryan.gl.scott@gmail.com> | 2019-10-24 13:52:36 -0400 |
|---|---|---|
| committer | Marge Bot <ben+marge-bot@smart-cactus.org> | 2019-11-07 08:39:36 -0500 |
| commit | 708c60aa144ed68a5b67a61f16539258dbcdb24e (patch) | |
| tree | 1c73dfe7395871f7986eb12701d19b46825f3f39 /compiler/GHC/Hs/Pat.hs | |
| parent | b4fb232892ec420059e767bbf464bd09361aaefa (diff) | |
| download | haskell-708c60aa144ed68a5b67a61f16539258dbcdb24e.tar.gz | |
Clean up TH's treatment of unary tuples (or, #16881 part two)
!1906 left some loose ends in regards to Template Haskell's treatment
of unary tuples. This patch ends to tie up those loose ends:
* In addition to having `TupleT 1` produce unary tuples, `TupE [exp]`
and `TupP [pat]` also now produce unary tuples.
* I have added various special cases in GHC's pretty-printers to
ensure that explicit 1-tuples are printed using the `Unit` type.
See `testsuite/tests/th/T17380`.
* The GHC 8.10.1 release notes entry has been tidied up a little.
Fixes #16881. Fixes #17371. Fixes #17380.
Diffstat (limited to 'compiler/GHC/Hs/Pat.hs')
| -rw-r--r-- | compiler/GHC/Hs/Pat.hs | 10 |
1 files changed, 8 insertions, 2 deletions
diff --git a/compiler/GHC/Hs/Pat.hs b/compiler/GHC/Hs/Pat.hs index 0fa6dca7b8..cae7144a8c 100644 --- a/compiler/GHC/Hs/Pat.hs +++ b/compiler/GHC/Hs/Pat.hs @@ -529,8 +529,14 @@ pprPat (CoPat _ co pat _) = pprHsWrapper co $ \parens else pprPat pat pprPat (SigPat _ pat ty) = ppr pat <+> dcolon <+> ppr ty pprPat (ListPat _ pats) = brackets (interpp'SP pats) -pprPat (TuplePat _ pats bx) = tupleParens (boxityTupleSort bx) - (pprWithCommas ppr pats) +pprPat (TuplePat _ pats bx) + -- Special-case unary boxed tuples so that they are pretty-printed as + -- `Unit x`, not `(x)` + | [pat] <- pats + , Boxed <- bx + = hcat [text (mkTupleStr Boxed 1), pprParendLPat appPrec pat] + | otherwise + = tupleParens (boxityTupleSort bx) (pprWithCommas ppr pats) pprPat (SumPat _ pat alt arity) = sumParens (pprAlternative ppr pat alt arity) pprPat (ConPatIn con details) = pprUserCon (unLoc con) details pprPat (ConPatOut { pat_con = con |