The ru_local field of a CoreRule is False for implicit Ids

	MERGE to 6.6.1

For class-ops, record selectors, data constructors, we want the ru_local
field of the Rule to be False.  We do not attach the rule to the binding
for the Id, because there simply isn't a binding until the code gen stage.

(NB: the ru_local field is different to the orphan-hood of the rule.)

This fixes a bug that meant that RULES on class ops were never exported.

3 files changed, 11 insertions, 5 deletions

diff --git a/compiler/coreSyn/CoreSyn.lhs b/compiler/coreSyn/CoreSyn.lhs
index 09e41aaeb9..9b9d8faefd 100644
--- a/compiler/coreSyn/CoreSyn.lhs
+++ b/compiler/coreSyn/CoreSyn.lhs
@@ -218,6 +218,10 @@ data CoreRule
 	-- Locality
 	ru_local :: Bool	-- The fn at the head of the rule is
 				-- defined in the same module as the rule
+				-- and is not an implicit Id (like a record sel
+				-- class op, or data con)
+		-- NB: ru_local is *not* used to decide orphan-hood
+		--	c.g. MkIface.coreRuleToIfaceRule
     }
 
   | BuiltinRule {		-- Built-in rules are used for constant folding
diff --git a/compiler/deSugar/Desugar.lhs b/compiler/deSugar/Desugar.lhs
index 99be1b0a46..0801b1c663 100644
--- a/compiler/deSugar/Desugar.lhs
+++ b/compiler/deSugar/Desugar.lhs
@@ -293,9 +293,10 @@ dsRule mod in_scope (L loc (HsRule name act vars lhs tv_lhs rhs fv_rhs))
 	
 	-- Substitute the dict bindings eagerly,
 	-- and take the body apart into a (f args) form
-	{ let local_rule = nameIsLocalOrFrom mod fn_name
-		-- NB we can't use isLocalId in the orphan test, 
-		-- because isLocalId isn't true of class methods
+	{ let local_rule = isLocalId fn_id
+		-- NB: isLocalId is False of implicit Ids.  This is good becuase
+		-- we don't want to attach rules to the bindings of implicit Ids, 
+		-- because they don't show up in the bindings until just before code gen
 	      fn_name   = idName fn_id
 
 	      rule = Rule { ru_name = name, ru_fn = fn_name, ru_act = act,
diff --git a/compiler/iface/TcIface.lhs b/compiler/iface/TcIface.lhs
index d5cc5fde5e..b6f1f484f2 100644
--- a/compiler/iface/TcIface.lhs
+++ b/compiler/iface/TcIface.lhs
@@ -547,12 +547,13 @@ tcIfaceRule (IfaceRule {ifRuleName = name, ifActivation = act, ifRuleBndrs = bnd
 		   ; return (bndrs', args', rhs') }
 	; let mb_tcs = map ifTopFreeName args
         ; lcl <- getLclEnv
-        ; let this_module = if_mod lcl
 	; returnM (Rule { ru_name = name, ru_fn = fn, ru_act = act, 
 			  ru_bndrs = bndrs', ru_args = args', 
 			  ru_rhs = rhs', 
 			  ru_rough = mb_tcs,
-			  ru_local = nameModule fn == this_module }) }
+			  ru_local = False }) }	-- An imported RULE is never for a local Id
+						-- or, even if it is (module loop, perhaps)
+						-- we'll just leave it in the non-local set
   where
 	-- This function *must* mirror exactly what Rules.topFreeName does
 	-- We could have stored the ru_rough field in the iface file