Added Symbol#name

https://bugs.ruby-lang.org/issues/16150#change-87446

NEWS.md

@@ -165,6 +165,12 @@ Outstanding ones only.
         * Symbol#to_proc now returns a lambda Proc.
           [[Feature #16260]]
 
+    * New method
+
+        * Symbol#name, which returns the name of the symbol if it is
+          named.  The returned string cannot be modified.
+          [[Feature #16150]]
+
 * Warning
 
     * Modified method
@@ -343,6 +349,7 @@ Excluding feature bug fixes.
 [Feature #16378]: https://bugs.ruby-lang.org/issues/16378
 [Feature #16828]: https://bugs.ruby-lang.org/issues/16828
 [Bug #14541]:     https://bugs.ruby-lang.org/issues/14541
+[Feature #16150]: https://bugs.ruby-lang.org/issues/16150
 [Feature #16175]: https://bugs.ruby-lang.org/issues/16175
 [Feature #15973]: https://bugs.ruby-lang.org/issues/15973
 [Feature #16614]: https://bugs.ruby-lang.org/issues/16614

string.c

@@ -11539,6 +11539,7 @@ Init_String(void)
     rb_define_method(rb_cSymbol, "inspect", sym_inspect, 0);
     rb_define_method(rb_cSymbol, "to_s", rb_sym_to_s, 0);
     rb_define_method(rb_cSymbol, "id2name", rb_sym_to_s, 0);
+    rb_define_method(rb_cSymbol, "name", rb_sym2str, 0);
     rb_define_method(rb_cSymbol, "intern", sym_to_sym, 0);
     rb_define_method(rb_cSymbol, "to_sym", sym_to_sym, 0);
     rb_define_method(rb_cSymbol, "to_proc", rb_sym_to_proc, 0);

test/ruby/test_symbol.rb

@@ -105,6 +105,12 @@ def test_inspect
     end
   end
 
+  def test_name
+    assert_equal("foo", :foo.name)
+    assert_same(:foo.name, :foo.name)
+    assert_predicate(:foo.name, :frozen?)
+  end
+
   def test_to_proc
     assert_equal %w(1 2 3), (1..3).map(&:to_s)
     [