From b3912ef355dee6a459d2839e804a71632d52772c Mon Sep 17 00:00:00 2001
From: quintela <unknown>
Date: Tue, 2 Dec 1997 18:11:33 +0000
Subject: [PATCH] [project @ 1997-12-02 18:11:33 by quintela] data types with
one constructor doesn't need WildCadr cases
---
ghc/compiler/typecheck/TcGenDeriv.lhs | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/ghc/compiler/typecheck/TcGenDeriv.lhs b/ghc/compiler/typecheck/TcGenDeriv.lhs
index dde873ef589f..c2e2cf501f89 100644
--- a/ghc/compiler/typecheck/TcGenDeriv.lhs
+++ b/ghc/compiler/typecheck/TcGenDeriv.lhs
@@ -286,6 +286,9 @@ cmp_eq _ _ = EQ
\end{verbatim}
\end{itemize}
+If there is only one constructor in the Data Type we don't need the WildCard Patern.
+JJQC-30-Nov-1997
+
\begin{code}
gen_Ord_binds :: TyCon -> RdrNameMonoBinds
@@ -320,7 +323,10 @@ gen_Ord_binds tycon
cmp_eq
= mk_FunMonoBind tycon_loc cmp_eq_RDR (map pats_etc nonnullary_cons ++
- [([WildPatIn, WildPatIn], default_rhs)])
+ if ((length nonnullary_cons + length nullary_cons) == 1)
+ then []
+ else [([WildPatIn, WildPatIn],
+ default_rhs)])
where
pats_etc data_con
= ([con1_pat, con2_pat],
--
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