diff --git a/gems/parser/3.2/_test/test.rb b/gems/parser/3.2/_test/test.rb
index c41269383..65ece5019 100644
--- a/gems/parser/3.2/_test/test.rb
+++ b/gems/parser/3.2/_test/test.rb
@@ -75,3 +75,29 @@
   node.loc.begin
   node.loc.end
 end
+
+parser = Parser::CurrentRuby.new
+parser.version + 1
+parser.diagnostics.all_errors_are_fatal = true
+parser.diagnostics.ignore_warnings = true
+parser.diagnostics.consumer = ->(diagnostic) { diagnostic.render.join("\n") }
+source_buffer = Parser::Source::Buffer.new("(string)", source: "foo(1)")
+parser.parse(source_buffer)&.type
+ast, ast_comments = parser.parse_with_comments(source_buffer)
+ast&.type
+ast_comments.map(&:text)
+Parser::CurrentRuby.parse("1", "(file)", 1)
+Parser::CurrentRuby.parse_with_comments("1", "(file)", 1)
+
+begin
+  Parser::CurrentRuby.parse("foo(")
+rescue Parser::SyntaxError => error
+  error.diagnostic.level.to_s
+  error.diagnostic.reason.to_s
+  error.diagnostic.message.upcase
+  error.diagnostic.location.source
+  error.diagnostic.highlights.map(&:source)
+  error.diagnostic.arguments.keys
+rescue Parser::UnknownEncodingInMagicComment => error
+  error.message
+end
diff --git a/gems/parser/3.2/parser.rbs b/gems/parser/3.2/parser.rbs
index 7f7aea348..a386951a9 100644
--- a/gems/parser/3.2/parser.rbs
+++ b/gems/parser/3.2/parser.rbs
@@ -1,9 +1,47 @@
 module Parser
-  CurrentRuby: Parser::Base
+  CurrentRuby: singleton(Parser::Base)
 
   class Base < Racc::Parser
-    def parse: (String string, ?String file, ?Integer line) -> Parser::AST::Node?
-    def parse_with_comments: (String string, ?String file, ?Integer line) -> [Parser::AST::Node?, Array[Source::Comment]]
+    def self.parse: (String string, ?String file, ?Integer line) -> Parser::AST::Node?
+    def self.parse_with_comments: (String string, ?String file, ?Integer line) -> [Parser::AST::Node?, Array[Source::Comment]]
+
+    attr_reader diagnostics: Diagnostic::Engine
+
+    def version: () -> Integer
+    def parse: (Source::Buffer source_buffer) -> Parser::AST::Node?
+    def parse_with_comments: (Source::Buffer source_buffer) -> [Parser::AST::Node?, Array[Source::Comment]]
+  end
+
+  class SyntaxError < StandardError
+    attr_reader diagnostic: Diagnostic
+
+    def initialize: (Diagnostic diagnostic) -> void
+  end
+
+  class UnknownEncodingInMagicComment < ArgumentError
+  end
+
+  class Diagnostic
+    LEVELS: Array[Symbol]
+
+    attr_reader level: Symbol
+    attr_reader reason: Symbol
+    attr_reader arguments: Hash[Symbol, untyped]
+    attr_reader location: Source::Range
+    attr_reader highlights: Array[Source::Range]
+
+    def initialize: (Symbol level, Symbol reason, Hash[Symbol, untyped]? arguments, Source::Range location, ?Array[Source::Range] highlights) -> void
+    def message: () -> String
+    def render: () -> Array[String]
+
+    class Engine
+      attr_accessor consumer: (^(Diagnostic) -> void)?
+      attr_accessor all_errors_are_fatal: bool
+      attr_accessor ignore_warnings: bool
+
+      def initialize: (?(^(Diagnostic) -> void)? consumer) -> void
+      def process: (Diagnostic diagnostic) -> self
+    end
   end
 
   class Ruby18 < Base