Add singleton(X)[Y] type support

Gemfile.lock

@@ -3,7 +3,7 @@ PATH
   specs:
     rbi (0.3.9)
       prism (~> 1.0)
-      rbs (>= 3.4.4)
+      rbs (>= 4.0.1)
 
 GEM
   remote: https://rubygems.org/
@@ -29,13 +29,14 @@ GEM
     parser (3.3.10.0)
       ast (~> 2.4.1)
       racc
-    prism (1.6.0)
+    prism (1.9.0)
     racc (1.8.1)
     rainbow (3.1.1)
     rake (13.3.1)
-    rbs (4.0.0.dev.4)
+    rbs (4.0.1)
       logger
-      prism (>= 1.3.0)
+      prism (>= 1.6.0)
+      tsort
     regexp_parser (2.11.3)
     require-hooks (0.2.2)
     rexml (3.4.4)
@@ -87,6 +88,7 @@ GEM
       thor (>= 1.2.0)
       yard-sorbet
     thor (1.4.0)
+    tsort (0.2.0)
     unicode-display_width (3.2.0)
       unicode-emoji (~> 4.1)
     unicode-emoji (4.1.0)

lib/rbi/rbs/type_translator.rb

@@ -54,7 +54,8 @@ def translate(type)
           when ::RBS::Types::Bases::Void
             Type.void
           when ::RBS::Types::ClassSingleton
-            Type.class_of(Type.simple(type.name.to_s))
+            type_parameter = type.args.first ? translate(type.args.first) : nil
+            Type.class_of(Type.simple(type.name.to_s), type_parameter)
           when ::RBS::Types::ClassInstance
             translate_class_instance(type)
           when ::RBS::Types::Function

lib/rbi/rbs_printer.rb

@@ -1106,6 +1106,11 @@ def visit_class_of(type)
       @string << "singleton("
       visit(type.type)
       @string << ")"
+      if (type_parameter = type.type_parameter)
+        @string << "["
+        visit(type_parameter)
+        @string << "]"
+      end
     end
 
     #: (Type::All type) -> void

rbi.gemspec

@@ -25,7 +25,7 @@ Gem::Specification.new do |spec|
   ]
 
   spec.add_dependency("prism", "~> 1.0")
-  spec.add_dependency("rbs", ">= 3.4.4")
+  spec.add_dependency("rbs", ">= 4.0.1")
 
   spec.required_ruby_version = ">= 3.1"
 end