Fix Trac #3964: view patterns in DsArrows

Just a missing case; I've eliminated the catch-all so
that we get a warning next time we extend HsPat

diff --git a/compiler/deSugar/DsArrows.lhs b/compiler/deSugar/DsArrows.lhs
index b1a4c59..d50aa3e 100644 (file)
--- a/compiler/deSugar/DsArrows.lhs
+++ b/compiler/deSugar/DsArrows.lhs
@@ -1066,5 +1066,6 @@ collectl (L _ pat) bndrs
     go (SigPatOut pat _)          = collectl pat bndrs
     go (TypePat _)                = bndrs
     go (CoPat _ pat _)            = collectl (noLoc pat) bndrs
-    go p                          = pprPanic "collectl/go" (ppr p)
+    go (ViewPat _ pat _)          = collectl pat bndrs
+    go p@(QuasiQuotePat {})       = pprPanic "collectl/go" (ppr p)
 \end{code}