Make sure we have meaningful scom when dealing with exception class dependencies

src/filters/exception/exceptions.ml

@@ -20,21 +20,25 @@ type context = {
 
 let haxe_exception_class ctx =
 	let cls = snd (Lazy.force ctx.haxe_exception) in
+	assert (ctx.scom.curclass != null_class);
 	add_dependency ctx.scom.curclass.cl_module cls.cl_module MDepFromTyping;
 	cls
 
 let haxe_exception_type ctx =
 	let t,cls = Lazy.force ctx.haxe_exception in
+	assert (ctx.scom.curclass != null_class);
 	add_dependency ctx.scom.curclass.cl_module cls.cl_module MDepFromTyping;
 	t
 
 let value_exception_class ctx =
 	let cls = snd (Lazy.force ctx.value_exception) in
+	assert (ctx.scom.curclass != null_class);
 	add_dependency ctx.scom.curclass.cl_module cls.cl_module MDepFromTyping;
 	cls
 
 let value_exception_type ctx =
 	let t,cls = Lazy.force ctx.value_exception in
+	assert (ctx.scom.curclass != null_class);
 	add_dependency ctx.scom.curclass.cl_module cls.cl_module MDepFromTyping;
 	t