Inherit max_iv_count from superclass

In 274870bd5434ab64ac3a3c9db9aa27d262c1d6d6 we gained the ability to
make an educated guess at the max_iv_count of a class based on its
initialize method. This commit makes subclasses inherit their super's
max_iv_count, which makes the estimate work in cases that the subclass
does not have an initialize method.

1 files changed, 7 insertions, 1 deletions

diff --git a/class.c b/class.c
index b9d62c18b1..87ebabef32 100644
--- a/class.c
+++ b/class.c
@@ -326,7 +326,13 @@ rb_class_new(VALUE super)
 {
     Check_Type(super, T_CLASS);
     rb_check_inheritable(super);
-    return rb_class_boot(super);
+    VALUE klass = rb_class_boot(super);
+
+    if (super != rb_cObject && super != rb_cBasicObject) {
+        RCLASS_EXT(klass)->max_iv_count = RCLASS_EXT(super)->max_iv_count;
+    }
+
+    return klass;
 }
 
 VALUE