merge revision(s) 56747,56754,56777: [Backport #12923] [Backport #12930] [Backport #13238]

	class.c: no fstring singleton class

	* class.c (singleton_class_of): prohibit fstrings from creating
	  singleton classes.
	  temporary measure for [ruby-dev:49867] [Bug #12923]
	test_fstring.rb: fix exception

	* test/-ext-/string/test_fstring.rb (test_singleton_class): fix
	  expected exception class.  [ruby-dev:49867] [Bug #12923]
	vm_eval.c: fstring instance_eval

	* vm_eval.c (singleton_class_for_eval): enable fstring singleton
	  class for instance_eval.  [ruby-core:78116] [Bug #12930]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_3@58157 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 2 insertions, 0 deletions

diff --git a/vm_eval.c b/vm_eval.c
index d275b8e6e8..138cc2fd54 100644
--- a/vm_eval.c
+++ b/vm_eval.c
@@ -1667,6 +1667,8 @@ singleton_class_for_eval(VALUE self)
     switch (BUILTIN_TYPE(self)) {
       case T_FLOAT: case T_BIGNUM: case T_SYMBOL:
 	return Qnil;
+      case T_STRING:
+	if (FL_TEST_RAW(self, RSTRING_FSTR)) return Qnil;
       default:
 	return rb_singleton_class(self);
     }