rta: fast fix to avoid resolving illegal types.

This requires a more in-depth work to improve the model.
Another improvement can also to teach RTA the context of object mechanism
so that only legal receivers are attempted.

Signed-off-by: Jean Privat <jean@pryen.org>

diff --git a/src/rapid_type_analysis.nit b/src/rapid_type_analysis.nit
index 88e2b7e..c5ddc4a 100644 (file)
--- a/src/rapid_type_analysis.nit
+++ b/src/rapid_type_analysis.nit
@@ -313,6 +313,7 @@ class RapidTypeAnalysis
                                if not ot.can_resolve_for(t, t, mainmodule) then continue
                                var rt = ot.anchor_to(mainmodule, t)
                                if live_types.has(rt) then continue
+                               if not is_valid_type(rt) then continue
                                if not check_depth(rt) then continue
                                #print "{ot}/{t} -> {rt}"
                                live_types.add(rt)
@@ -329,6 +330,7 @@ class RapidTypeAnalysis
                        for t in live_types do
                                if not ot.can_resolve_for(t, t, mainmodule) then continue
                                var rt = ot.anchor_to(mainmodule, t)
+                               if not is_valid_type(rt) then continue
                                live_cast_types.add(rt)
                                #print "  {ot}/{t} -> {rt}"
                        end
@@ -336,6 +338,16 @@ class RapidTypeAnalysis
                #print "cast MType {live_cast_types.length}: {live_cast_types.join(", ")}"
        end
 
+       # Quick and dirty check that a forced type resolution gives a legal type
+       # TODO: move up in the model and kill `can_resolve_for`
+       private fun is_valid_type(mtype: MType): Bool
+       do
+               if mtype isa MGenericType then
+                       return mtype.is_subtype(mainmodule, null, mtype.mclass.intro.bound_mtype)
+               end
+               return true
+       end
+
        private fun check_depth(mtype: MClassType): Bool
        do
                var d = mtype.length