From 730a2163245cf7aaf389458113e6fa338eca7865 Mon Sep 17 00:00:00 2001
From: Alec Theriault <alec.theriault@gmail.com>
Date: Sat, 28 Mar 2020 12:04:16 -0400
Subject: Use TTG empty extensions to remove some `error`'s
None of these error cases should ever have been reachable, so this is
just a matter of leveraging the type system to assert this.
* Use the `NoExtCon` and `noExtCon` to handle case matches for no
extension constructors, instead of throwing an `error`.
* Use the extension field of `HsSpliceTy` to ensure that this variant
of `HsType` cannot exist in an `HsType DocNameI`.
---
haddock-api/src/Haddock/Backends/Xhtml/Decl.hs | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
(limited to 'haddock-api/src/Haddock/Backends/Xhtml')
diff --git a/haddock-api/src/Haddock/Backends/Xhtml/Decl.hs b/haddock-api/src/Haddock/Backends/Xhtml/Decl.hs
index b450dc94..25669ca7 100644
--- a/haddock-api/src/Haddock/Backends/Xhtml/Decl.hs
+++ b/haddock-api/src/Haddock/Backends/Xhtml/Decl.hs
@@ -32,6 +32,7 @@ import Haddock.Doc (combineDocumentation)
import Data.List ( intersperse, sort )
import qualified Data.Map as Map
import Data.Maybe
+import Data.Void ( absurd )
import Text.XHtml hiding ( name, title, p, quote )
import BasicTypes (PromotionFlag(..), isPromoted)
@@ -1215,7 +1216,7 @@ ppr_mono_ty (HsKindSig _ ty kind) u q e =
ppr_mono_ty (HsListTy _ ty) u q _ = brackets (ppr_mono_lty ty u q HideEmptyContexts)
ppr_mono_ty (HsIParamTy _ (L _ n) ty) u q _ =
ppIPName n <+> dcolon u <+> ppr_mono_lty ty u q HideEmptyContexts
-ppr_mono_ty (HsSpliceTy {}) _ _ _ = error "ppr_mono_ty HsSpliceTy"
+ppr_mono_ty (HsSpliceTy v _) _ _ _ = absurd v
ppr_mono_ty (HsRecTy {}) _ _ _ = toHtml "{..}"
-- Can now legally occur in ConDeclGADT, the output here is to provide a
-- placeholder in the signature, which is followed by the field
--
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