merge revision(s) 60980,60984: [Backport #14070]

	Modules should not have subclasses.

	When refining a module, the module was set to the superclass of its refinement,
	and a segmentation fault occurred.
	The superclass of the refinement should be an iclass of the module.
	[ruby-core:83617] [Bug #14070]

	The superclass of a refinement should have BasicObject as its ancestor.

	Otherwise, VM_ASSERT(callable_method_entry_p(cme)) in
	prepare_callable_method_entry() fails if VM_CHECK_MODE is 2.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_4@62233 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 16 insertions, 1 deletions

diff --git a/eval.c b/eval.c
index 8a839ced7d..617cb6f1be 100644
--- a/eval.c
+++ b/eval.c
@@ -1144,6 +1144,18 @@ hidden_identity_hash_new(void)
     return hash;
 }
 
+static VALUE
+refinement_superclass(VALUE superclass)
+{
+    if (RB_TYPE_P(superclass, T_MODULE)) {
+	/* FIXME: Should ancestors of superclass be used here? */
+	return rb_include_class_new(superclass, rb_cBasicObject);
+    }
+    else {
+	return superclass;
+    }
+}
+
 void
 rb_using_refinement(rb_cref_t *cref, VALUE klass, VALUE module)
 {
@@ -1171,6 +1183,7 @@ rb_using_refinement(rb_cref_t *cref, VALUE klass, VALUE module)
 	}
     }
     FL_SET(module, RMODULE_IS_OVERLAID);
+    superclass = refinement_superclass(superclass);
     c = iclass = rb_include_class_new(module, superclass);
     RCLASS_REFINED_CLASS(c) = klass;
 
@@ -1260,6 +1273,7 @@ add_activated_refinement(VALUE activated_refinements,
 	}
     }
     FL_SET(refinement, RMODULE_IS_OVERLAID);
+    superclass = refinement_superclass(superclass);
     c = iclass = rb_include_class_new(refinement, superclass);
     RCLASS_REFINED_CLASS(c) = klass;
     refinement = RCLASS_SUPER(refinement);
@@ -1314,8 +1328,9 @@ rb_mod_refine(VALUE module, VALUE klass)
     }
     refinement = rb_hash_lookup(refinements, klass);
     if (NIL_P(refinement)) {
+	VALUE superclass = refinement_superclass(klass);
 	refinement = rb_module_new();
-	RCLASS_SET_SUPER(refinement, klass);
+	RCLASS_SET_SUPER(refinement, superclass);
 	FL_SET(refinement, RMODULE_IS_REFINEMENT);
 	CONST_ID(id_refined_class, "__refined_class__");
 	rb_ivar_set(refinement, id_refined_class, klass);