modelbuilder: resolve_mtype does not crash when the class is incomplete

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

diff --git a/src/modelbuilder_base.nit b/src/modelbuilder_base.nit
index 9995338..f01fbd8 100644 (file)
--- a/src/modelbuilder_base.nit
+++ b/src/modelbuilder_base.nit
@@ -305,7 +305,9 @@ class ModelBuilder
                if mtype isa MGenericType then
                        var mclass = mtype.mclass
                        for i in [0..mclass.arity[ do
-                               var bound = mclass.intro.bound_mtype.arguments[i]
+                               var intro = mclass.try_intro
+                               if intro == null then return null # skip error
+                               var bound = intro.bound_mtype.arguments[i]
                                var nt = ntype.n_types[i]
                                var mt = resolve_mtype(mmodule, mclassdef, nt)
                                if mt == null then return null # forward error