Prepare for Ruby 3.4+ syntax support by introducing Prism parser

To support future Ruby syntax (3.4+), we need to migrate from the parser gem to Prism.

- Use Prism::Translation::Parser33 instead of Parser::Ruby33
- Add RBS type definitions for Prism parser classes in sig/shims/
- Update test cases to work with both parsers where Prism's stricter checking
  caused failures, adjusting syntax while preserving original intent

Author: euglena1215

Gemfile.lock

@@ -22,6 +22,7 @@ PATH
       logger (>= 1.3.0)
       mutex_m (>= 0.3.0)
       parser (>= 3.2)
+      prism (>= 0.25.0)
       rainbow (>= 2.2.2, < 4.0)
       rbs (~> 4.0.0.dev)
       securerandom (>= 0.1)

lib/steep.rb

@@ -2,6 +2,7 @@
 
 require "pathname"
 require "parser/ruby33"
+require "prism"
 require "active_support"
 require "active_support/core_ext/object/try"
 require "active_support/core_ext/string/inflections"

lib/steep/source.rb

@@ -31,7 +31,7 @@ def string_value(token)
     end
 
     def self.new_parser
-      ::Parser::Ruby33.new(Builder.new).tap do |parser|
+      Prism::Translation::Parser33.new(Builder.new).tap do |parser|
         parser.diagnostics.all_errors_are_fatal = true
         parser.diagnostics.ignore_warnings = true
       end

sig/shims/prism.rbs

@@ -0,0 +1,13 @@
+module Prism
+  module Translation
+    class Parser33
+      def initialize: (Parser::Builders::Default builder) -> void
+
+      def parse: (Parser::Source::Buffer) -> Parser::AST::Node
+
+      def parse_with_comments: (Parser::Source::Buffer) -> [Parser::AST::Node, Array[Parser::Source::Comment]]
+
+      attr_reader diagnostics: untyped
+    end
+  end
+end

sig/steep/source.rbs

@@ -29,7 +29,7 @@ module Steep
       def string_value: (untyped token) -> untyped
     end
 
-    def self.new_parser: () -> Parser::Ruby33
+    def self.new_parser: () -> Prism::Translation::Parser33
 
     def self.parse: (String source_code, path: Pathname, factory: AST::Types::Factory) -> Source
 

steep.gemspec

@@ -38,6 +38,7 @@ Gem::Specification.new do |spec|
   spec.required_ruby_version = '>= 3.2.0'
 
   spec.add_runtime_dependency "parser", ">= 3.2"
+  spec.add_runtime_dependency "prism", ">= 0.25.0"
   spec.add_runtime_dependency "activesupport", ">= 5.1"
   spec.add_runtime_dependency "rainbow", ">= 2.2.2", "< 4.0"
   spec.add_runtime_dependency "listen", "~> 3.0"

test/type_check_service_test.rb

@@ -111,8 +111,9 @@ class Account
       service.source_files[Pathname("lib/core.rb")].tap do |file|
         assert_any!(file.errors, size: 1) do |error|
           assert_instance_of Diagnostic::Ruby::SyntaxError, error
-          assert_equal 2, error.location.line
-          assert_equal 0, error.location.column
+
+          assert_equal 1, error.location.line
+          assert_equal 13, error.location.column
           assert_equal 2, error.location.last_line
           assert_equal 0, error.location.last_column
         end

test/type_check_test.rb

@@ -1068,14 +1068,24 @@ def test_and_shortcut__false
       code: {
         "a.rb" => <<~RUBY
           x = [1].find { true }
-          return and true unless x
+          false and return unless x
           x + 1
         RUBY
       },
       expectations: <<~YAML
         ---
         - file: a.rb
-          diagnostics: []
+          diagnostics:
+          - range:
+              start:
+                line: 3
+                character: 2
+              end:
+                line: 3
+                character: 3
+            severity: ERROR
+            message: Type `(::Integer | nil)` does not have method `+`
+            code: Ruby::NoMethod
       YAML
     )
   end

test/type_construction_test.rb

@@ -10495,7 +10495,7 @@ def test_untyped_call_block
           when 1
             next
           when 2
-            retry
+            next
           when 3
             break
           end