Update NEWS about RBS (#3579)

1 files changed, 13 insertions, 0 deletions

diff --git a/NEWS.md b/NEWS.md
index 73ba4948fb..fb8602a97e 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -83,6 +83,8 @@ sufficient information, see the ChangeLog file or Redmine
 * Interpolated String literals are no longer frozen when
   `# frozen-string-literal: true` is used. [[Feature #17104]]
 
+* RBS is introduced. It is a type definition languaged for Ruby programs.
+
 ## Command line options
 
 ### `--help` option
@@ -390,6 +392,17 @@ Excluding feature bug fixes.
 
 * Optimize C method call a little
 
+## RBS
+
+* RBS is a new language for type definition of Ruby programs.
+  It allows writing types of classes and modules with advanced
+  types including union types, overloading, generics, and 
+  _interface types_ for duck typing.
+
+* Ruby ships with type definitions for core/stdlib classes.
+
+* `rbs` gem is bundled to load and process RBS files.
+
 ## Miscellaneous changes
 
 * Methods using `ruby2_keywords` will no longer keep empty keyword