diff --git a/include/ruby/internal/intern/proc.h b/include/ruby/internal/intern/proc.h
index 003e6a04420c6a..d6f77cbd4d648a 100644
--- a/include/ruby/internal/intern/proc.h
+++ b/include/ruby/internal/intern/proc.h
@@ -50,6 +50,4 @@ VALUE rb_protect(VALUE (*)(VALUE), VALUE, int*);
 
 RBIMPL_SYMBOL_EXPORT_END()
 
-VALUE rb_callable_receiver(VALUE);
-
 #endif /* RBIMPL_INTERN_PROC_H */