From: simonpj <unknown>
Date: Thu, 3 May 2001 09:01:50 +0000 (+0000)
Subject: [project @ 2001-05-03 09:01:50 by simonpj]
X-Git-Tag: Approximately_9120_patches~2018
X-Git-Url: http://git.megacz.com/?a=commitdiff_plain;ds=sidebyside;h=9708f9d95c6f882996ce1b0cba0366802f244c1e;p=ghc-hetmet.git

[project @ 2001-05-03 09:01:50 by simonpj]
Improve error message
---

diff --git a/ghc/compiler/typecheck/TcInstDcls.lhs b/ghc/compiler/typecheck/TcInstDcls.lhs
index 9b478e0..d4dd386 100644
--- a/ghc/compiler/typecheck/TcInstDcls.lhs
+++ b/ghc/compiler/typecheck/TcInstDcls.lhs
@@ -13,7 +13,7 @@ import CmdLineOpts	( DynFlag(..), dopt )
 
 import HsSyn		( HsDecl(..), InstDecl(..), TyClDecl(..), HsType(..),
 			  MonoBinds(..), HsExpr(..),  HsLit(..), Sig(..), 
-			  andMonoBindList, collectMonoBinders, isClassDecl
+			  andMonoBindList, collectMonoBinders, isClassDecl, toHsType
 			)
 import RnHsSyn		( RenamedHsBinds, RenamedInstDecl, RenamedHsDecl, 
 			  RenamedMonoBinds, RenamedTyClDecl, RenamedHsType, 
@@ -512,8 +512,9 @@ tcInstDecl2 :: InstInfo -> NF_TcM (LIE, TcMonoBinds)
 tcInstDecl2 (InstInfo { iDFunId = dfun_id, 
 			iBinds = monobinds, iPrags = uprags })
   =	 -- Prime error recovery
-    recoverNF_Tc (returnNF_Tc (emptyLIE, EmptyMonoBinds))  $
-    tcAddSrcLoc (getSrcLoc dfun_id)			   $
+    recoverNF_Tc (returnNF_Tc (emptyLIE, EmptyMonoBinds))	$
+    tcAddSrcLoc (getSrcLoc dfun_id)			   	$
+    tcAddErrCtxt (instDeclCtxt (toHsType (idType dfun_id)))	$
 
 	-- Instantiate the instance decl with tc-style type variables
     tcInstType (idType dfun_id)		`thenNF_Tc` \ (inst_tyvars', dfun_theta', dict_ty') ->