Improve generics

Gemfile

@@ -16,4 +16,4 @@ group :development, optional: true do
   gem "majo"
 end
 
-gem "rbs"
+# gem "rbs", path: "../rbs"

Gemfile.lock

@@ -12,7 +12,7 @@ PATH
       logger (>= 1.3.0)
       parser (>= 3.1)
       rainbow (>= 2.2.2, < 4.0)
-      rbs (>= 3.5.0.pre)
+      rbs (~> 3.6.0.dev)
       securerandom (>= 0.1)
       strscan (>= 1.0.0)
       terminal-table (>= 2, < 4)
@@ -73,7 +73,7 @@ GEM
     rb-fsevent (0.11.2)
     rb-inotify (0.11.1)
       ffi (~> 1.0)
-    rbs (3.5.2)
+    rbs (3.6.0.dev.1)
       logger
     rdoc (6.7.0)
       psych (>= 4.0.0)
@@ -101,7 +101,6 @@ DEPENDENCIES
   minitest-hooks
   minitest-slow_test
   rake
-  rbs
   stackprof
   steep!
   vernier (~> 1.0)

lib/steep.rb

@@ -164,6 +164,11 @@ def self.ui_logger
   def self.new_logger(output, prev_level)
     logger = Logger.new(output)
     logger.formatter = proc do |severity, datetime, progname, msg|
+      # @type var severity: String
+      # @type var datetime: Time
+      # @type var progname: untyped
+      # @type var msg: untyped
+      # @type block: String
       "#{datetime.strftime('%Y-%m-%d %H:%M:%S.%L')}: #{severity}: #{msg}\n"
     end
     ActiveSupport::TaggedLogging.new(logger).tap do |logger|

lib/steep/ast/types/factory.rb

@@ -36,6 +36,29 @@ def type_1_opt(type)
           end
         end
 
+        def normalize_args(type_name, args)
+          case
+          when type_name.class?
+            if entry = env.normalized_module_class_entry(type_name)
+              type_params = entry.type_params
+            end
+          when type_name.interface?
+            if entry = env.interface_decls.fetch(type_name, nil)
+              type_params = entry.decl.type_params
+            end
+          when type_name.alias?
+            if entry = env.type_alias_decls.fetch(type_name, nil)
+              type_params = entry.decl.type_params
+            end
+          end
+
+          if type_params && !type_params.empty?
+            RBS::AST::TypeParam.normalize_args(type_params, args)
+          else
+            args
+          end
+        end
+
         def type(type)
           if ty = type_cache[type]
             return ty
@@ -68,15 +91,15 @@ def type(type)
               Name::Singleton.new(name: type_name)
             when RBS::Types::ClassInstance
               type_name = type.name
-              args = type.args.map {|arg| type(arg) }
+              args = normalize_args(type_name, type.args).map {|arg| type(arg) }
               Name::Instance.new(name: type_name, args: args)
             when RBS::Types::Interface
               type_name = type.name
-              args = type.args.map {|arg| type(arg) }
+              args = normalize_args(type_name, type.args).map {|arg| type(arg) }
               Name::Interface.new(name: type_name, args: args)
             when RBS::Types::Alias
               type_name = type.name
-              args = type.args.map {|arg| type(arg) }
+              args = normalize_args(type_name, type.args).map {|arg| type(arg) }
               Name::Alias.new(name: type_name, args: args)
             when RBS::Types::Union
               Union.build(types: type.types.map {|ty| type(ty) })
@@ -245,9 +268,10 @@ def params(type)
         def type_param(type_param)
           Interface::TypeParam.new(
             name: type_param.name,
-            upper_bound: type_opt(type_param.upper_bound),
+            upper_bound: type_opt(type_param.upper_bound_type),
             variance: type_param.variance,
-            unchecked: type_param.unchecked?
+            unchecked: type_param.unchecked?,
+            default_type: type_opt(type_param.default_type)
           )
         end
 

lib/steep/interface/builder.rb

@@ -50,7 +50,7 @@ def validate_fvs(name, type)
         end
 
         def upper_bound(a)
-          variable_bounds.fetch(a, nil)
+          variable_bounds.fetch(a, Interface::TypeParam::IMPLICIT_UPPER_BOUND)
         end
       end
 
@@ -494,7 +494,7 @@ def tuple_shape(tuple)
                   block: nil
                 ),
                 MethodType.new(
-                  type_params: [TypeParam.new(name: :T, upper_bound: nil, variance: :invariant, unchecked: false)],
+                  type_params: [TypeParam.new(name: :T, upper_bound: nil, variance: :invariant, unchecked: false, default_type: nil)],
                   type: Function.new(
                     params: Function::Params.build(
                       required: [
@@ -508,7 +508,7 @@ def tuple_shape(tuple)
                   block: nil
                 ),
                 MethodType.new(
-                  type_params: [TypeParam.new(name: :T, upper_bound: nil, variance: :invariant, unchecked: false)],
+                  type_params: [TypeParam.new(name: :T, upper_bound: nil, variance: :invariant, unchecked: false, default_type: nil)],
                   type: Function.new(
                     params: Function::Params.build(required: [AST::Types::Literal.new(value: index)]),
                     return_type: AST::Types::Union.build(types: [elem_type, AST::Types::Var.new(name: :T)]),
@@ -658,7 +658,7 @@ def record_shape(record)
                   block: nil
                 ),
                 MethodType.new(
-                  type_params: [TypeParam.new(name: :T, upper_bound: nil, variance: :invariant, unchecked: false)],
+                  type_params: [TypeParam.new(name: :T, upper_bound: nil, variance: :invariant, unchecked: false, default_type: nil)],
                   type: Function.new(
                     params: Function::Params.build(required: [key_type, AST::Types::Var.new(name: :T)]),
                     return_type: AST::Types::Union.build(types: [value_type, AST::Types::Var.new(name: :T)]),
@@ -667,7 +667,7 @@ def record_shape(record)
                   block: nil
                 ),
                 MethodType.new(
-                  type_params: [TypeParam.new(name: :T, upper_bound: nil, variance: :invariant, unchecked: false)],
+                  type_params: [TypeParam.new(name: :T, upper_bound: nil, variance: :invariant, unchecked: false, default_type: nil)],
                   type: Function.new(
                     params: Function::Params.build(required: [key_type]),
                     return_type: AST::Types::Union.build(types: [value_type, AST::Types::Var.new(name: :T)]),

lib/steep/interface/type_param.rb

@@ -1,32 +1,37 @@
 module Steep
   module Interface
     class TypeParam
+      IMPLICIT_UPPER_BOUND = AST::Builtin.optional(AST::Builtin::Object.instance_type)
+
       attr_reader :name
       attr_reader :upper_bound
       attr_reader :variance
       attr_reader :unchecked
       attr_reader :location
+      attr_reader :default_type
 
-      def initialize(name:, upper_bound:, variance:, unchecked:, location: nil)
+      def initialize(name:, upper_bound:, variance:, unchecked:, location: nil, default_type:)
         @name = name
         @upper_bound = upper_bound
         @variance = variance
         @unchecked = unchecked
         @location = location
+        @default_type = default_type
       end
 
       def ==(other)
         other.is_a?(TypeParam) &&
           other.name == name &&
           other.upper_bound == upper_bound &&
           other.variance == variance &&
-          other.unchecked == unchecked
+          other.unchecked == unchecked &&
+          other.default_type == default_type
       end
 
       alias eql? ==
 
       def hash
-        name.hash ^ upper_bound.hash ^ variance.hash ^ unchecked.hash
+        name.hash ^ upper_bound.hash ^ variance.hash ^ unchecked.hash ^ default_type.hash
       end
 
       def self.rename(params, conflicting_names = params.map(&:name), new_names = conflicting_names.map {|n| AST::Types::Var.fresh_name(n) })
@@ -44,7 +49,8 @@ def self.rename(params, conflicting_names = params.map(&:name), new_names = conf
                   upper_bound: param.upper_bound&.subst(subst),
                   variance: param.variance,
                   unchecked: param.unchecked,
-                  location: param.location
+                  location: param.location,
+                  default_type: param.default_type&.subst(subst)
                 )
               else
                 param
@@ -80,19 +86,28 @@ def to_s
         buf
       end
 
-      def update(name: self.name, upper_bound: self.upper_bound, variance: self.variance, unchecked: self.unchecked, location: self.location)
+      def update(name: self.name, upper_bound: self.upper_bound, variance: self.variance, unchecked: self.unchecked, location: self.location, default_type: self.default_type)
         TypeParam.new(
           name: name,
           upper_bound: upper_bound,
           variance: variance,
           unchecked: unchecked,
-          location: location
+          location: location,
+          default_type: default_type
         )
       end
 
       def subst(s)
         if u = upper_bound
-          update(upper_bound: u.subst(s))
+          ub = u.subst(s)
+        end
+
+        if d = default_type
+          dt = d.subst(s)
+        end
+
+        if ub || dt
+          update(upper_bound: ub, default_type: dt)
         else
           self
         end

lib/steep/server/lsp_formatter.rb

@@ -375,8 +375,8 @@ def name_and_params(name, params)
             end
             s << param.name.to_s
 
-            if param.upper_bound
-              s << " < #{param.upper_bound.to_s}"
+            if param.upper_bound_type
+              s << " < #{param.upper_bound_type.to_s}"
             end
 
             s

lib/steep/signature/validator.rb

@@ -79,8 +79,8 @@ def validate_type_application_constraints(type_name, type_params, type_args, loc
           type_params.zip(type_args).each do |param, arg|
             arg or raise
 
-            if param.upper_bound
-              upper_bound_type = factory.type(param.upper_bound).subst(subst)
+            if param.upper_bound_type
+              upper_bound_type = factory.type(param.upper_bound_type).subst(subst)
               arg_type = factory.type(arg)
 
               constraints = Subtyping::Constraints.empty
@@ -101,7 +101,8 @@ def validate_type_application_constraints(type_name, type_params, type_args, loc
                     name: param.name,
                     upper_bound: upper_bound_type,
                     variance: param.variance,
-                    unchecked: param.unchecked?
+                    unchecked: param.unchecked?,
+                    default_type: factory.type_opt(param.default_type)
                   ),
                   location: location
                 )
@@ -236,7 +237,7 @@ def each_variable_type(definition)
       def validate_definition_type(definition)
         each_method_type(definition) do |method_type|
           upper_bounds = method_type.type_params.each.with_object({}) do |param, hash|
-            hash[param.name] = factory.type_opt(param.upper_bound)
+            hash[param.name] = factory.type_opt(param.upper_bound_type)
           end
 
           checker.push_variable_bounds(upper_bounds) do
@@ -264,7 +265,7 @@ def validate_one_class_decl(name, entry)
           Steep.logger.tagged "#{name}" do
             builder.build_instance(name).tap do |definition|
               upper_bounds = definition.type_params_decl.each.with_object({}) do |param, bounds|
-                bounds[param.name] = factory.type_opt(param.upper_bound)
+                bounds[param.name] = factory.type_opt(param.upper_bound_type)
               end
 
               self_type = AST::Types::Name::Instance.new(
@@ -480,7 +481,7 @@ def validate_one_interface(name)
             definition = builder.build_interface(name)
 
             upper_bounds = definition.type_params_decl.each.with_object({}) do |param, bounds|
-              bounds[param.name] = factory.type_opt(param.upper_bound)
+              bounds[param.name] = factory.type_opt(param.upper_bound_type)
             end
 
             self_type = AST::Types::Name::Interface.new(
@@ -575,7 +576,7 @@ def validate_one_alias(name, entry = env.type_alias_decls[name])
             end
 
             upper_bounds = entry.decl.type_params.each.with_object({}) do |param, bounds|
-              bounds[param.name] = factory.type_opt(param.upper_bound)
+              bounds[param.name] = factory.type_opt(param.upper_bound_type)
             end
 
             validator.validate_type_alias(entry: entry) do |type|