[m-rev.] diff: fix bug with type classes & pragma c_code

[Fergus Henderson]

My change to library/store.m happened to trigger a compiler bug...
hence the fix below.  I'm currently running a bootcheck, and I'll
commit both this change and the one to library/store.m if the bootcheck passes.

----------

Estimated hours taken: 2
Branches: main

compiler/polymorphism.m:
	Fix a bug in the handling of pragma c_code / foreign_proc: in
	the case where the procedure had both type class constraints
	and unconstrained type variables, it was getting the arguments
	in the wrong order.

Workspace: /home/venus/fjh/ws-venus4/mercury
Index: compiler/polymorphism.m
===================================================================
RCS file: /home/mercury1/repository/mercury/compiler/polymorphism.m,v
retrieving revision 1.216
diff -u -d -r1.216 polymorphism.m
--- compiler/polymorphism.m	31 Jul 2001 14:29:50 -0000	1.216
+++ compiler/polymorphism.m	6 Aug 2001 03:50:38 -0000
@@ -1634,11 +1634,22 @@
 	require(unify(NEVs, NumExtraVars), 
 		"list length mismatch in polymorphism processing pragma_c"),
 
-	polymorphism__c_code_add_typeinfos(
-			PredTypeVars, PredTypeVarSet, ExistQVars, Impl,
-			ArgInfo0, ArgInfo1),
+%	The argument order is as follows:
+%	first the UnivTypeInfos (for universally quantified type variables)
+% 	then the ExistTypeInfos (for existentially quantified type variables)
+%	then the UnivTypeClassInfos (for universally quantified constraints)
+%	then the ExistTypeClassInfos (for existentially quantified constraints)
+%	and finally the original arguments of the predicate.
+%
+%	But since we're building ArgInfo by starting with the original
+%	arguments and prepending things as we go, we need to do it in
+%	reverse order.
+
 	polymorphism__c_code_add_typeclass_infos(
 			UnivCs, ExistCs, PredTypeVarSet, Impl,
+			ArgInfo0, ArgInfo1),
+	polymorphism__c_code_add_typeinfos(
+			PredTypeVars, PredTypeVarSet, ExistQVars, Impl,
 			ArgInfo1, ArgInfo),
 
 	%

-- 
Fergus Henderson <fjh at cs.mu.oz.au>  |  "I have always known that the pursuit
The University of Melbourne         |  of excellence is a lethal habit"
WWW: <http://www.cs.mu.oz.au/~fjh>  |     -- the last words of T. S. Garp.
--------------------------------------------------------------------------
mercury-reviews mailing list
post:  mercury-reviews at cs.mu.oz.au
administrative address: owner-mercury-reviews at cs.mu.oz.au
unsubscribe: Address: mercury-reviews-request at cs.mu.oz.au Message: unsubscribe
subscribe:   Address: mercury-reviews-request at cs.mu.oz.au Message: subscribe
--------------------------------------------------------------------------