for review: polymorphic unification not (in, in)

[David Glen JEFFERY]

Hi Fergus,

How does this look?
--------------------------------------------------------------

Estimated hours taken: 2

compiler/polymorphism.m:
	Abort if there is a polymorphic unification that is in
	a partially instantiated mode. This error should be
	caught earlier (probably during mode analysis), but it's
	best to abort rather than just go ahead and generate
	bad code.

tests/invalid/polymorphic_unification.m:
tests/invalid/polymorphic_unification.err_exp:
	A test case for the above change.

tests/invalid/Mmakefile:
	Turn this test case on.

Index: polymorphism.m
===================================================================
RCS file: /home/staff/zs/imp/mercury/compiler/polymorphism.m,v
retrieving revision 1.153
diff -u -t -r1.153 polymorphism.m
--- polymorphism.m	1998/10/15 09:25:11	1.153
+++ polymorphism.m	1998/11/09 05:22:33
@@ -947,10 +947,11 @@
                         ;
                                 error("polymorphism.m: can't find `builtin:unify/2'")
                         },
-                        % XXX Bug! - we should check that the mode is (in, in),
-                        %     and report an error (e.g. "unification of
-                        %     polymorphically typed variables in partially
-                        %     instantiated mode") if it isn't
+                        { Mode = XMode - YMode },
+                        { require(mode_is_fully_input(ModuleInfo, XMode),
+                                "Sorry, not implemented: polymorphic unification in mode other than (in, in)") },
+                        { require(mode_is_fully_input(ModuleInfo, YMode),
+                                "Sorry, not implemented: polymorphic unification in mode other than (in, in)") },
                         { hlds_pred__in_in_unification_proc_id(ProcId) },
                         { map__lookup(TypeInfoMap, TypeVar, TypeInfoLocn) },
                         { SymName = unqualified("unify") },



cvs diff: Diffing .
Index: Mmakefile
===================================================================
RCS file: /home/staff/zs/imp/tests/invalid/Mmakefile,v
retrieving revision 1.35
diff -u -t -r1.35 Mmakefile
--- Mmakefile	1998/10/29 14:59:12	1.35
+++ Mmakefile	1998/11/09 05:16:14
@@ -34,6 +34,7 @@
         no_exports.m \
         nullary_ho_func_error.m \
         occurs.m \
+        polymorphic_unification.m \
         pragma_c_code_and_clauses1.m \
         pragma_c_code_and_clauses2.m \
         pragma_c_code_no_det.m \
@@ -85,6 +86,13 @@
 
 %.err: %.m
         if $(MC) $(ALL_MCFLAGS) --errorcheck-only $* > $*.err 2>&1; \
+        then false; else true; fi
+
+# We need a hard-coded rule for polymorphic_unification because we need to
+# do more than error check it: the error case we are checking for only
+# gets caught during polymorphism.
+polymorphic_unification.err: polymorphic_unification.m
+        if $(MC) $(ALL_MCFLAGS) polymorphic_unification > polymorphic_unification.err 2>&1; \
         then false; else true; fi
 
 # Some tests have more than one possible valid output, so
cvs diff: polymorphic_unification.err_exp is a new entry, no comparison available
cvs diff: polymorphic_unification.m is a new entry, no comparison available

--------------------------------------------------------------

New file: polymorphic_unification.m:

:- module polymorphic_unification.

:- interface.

:- import_module io.

:- pred main(io__state::di, io__state::uo) is det.

:- implementation.

main -->
	[].

:- import_module list.

:- pred p(T, T).
:- mode p(in, list_skel->dead).

p(X, X).

--------------------------------------------------------------
New file: polymorphic_unification.err_exp:

Software error: Sorry, not implemented: polymorphic unification in mode other than (in, in)
Stack dump not available in this grade.
--------------------------------------------------------------


dgj
-- 
David Jeffery (dgj at cs.mu.oz.au) |  Marge: Did you just call everyone "chicken"?
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