Class: Steep::Subtyping::Check

Inherits:
Object
  • Object
show all
Defined in:
lib/steep/subtyping/check.rb

Defined Under Namespace

Classes: CannotResolveError

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(builder:) ⇒ Check

Returns a new instance of Check.



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# File 'lib/steep/subtyping/check.rb', line 7

def initialize(builder:)
  @builder = builder
  @cache = {}
end

Instance Attribute Details

#builder ⇒ Object (readonly)

Returns the value of attribute builder.



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# File 'lib/steep/subtyping/check.rb', line 4

def builder
  @builder
end

#cache ⇒ Object (readonly)

Returns the value of attribute cache.



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# File 'lib/steep/subtyping/check.rb', line 5

def cache
  @cache
end

Instance Method Details

#alias?(type) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/steep/subtyping/check.rb', line 42

def alias?(type)
  type.is_a?(AST::Types::Name::Alias)
end

#cacheable?(relation) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/steep/subtyping/check.rb', line 46

def cacheable?(relation)
  relation.sub_type.free_variables.empty? && relation.super_type.free_variables.empty?
end

#check(relation, constraints:, assumption: Set.new, trace: Trace.new) ⇒ Object 



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# File 'lib/steep/subtyping/check.rb', line 12

def check(relation, constraints:, assumption: Set.new, trace: Trace.new)
  Steep.logger.tagged "#{relation.sub_type} <: #{relation.super_type}" do
    prefix = trace.size
    cached = cache[relation]
    if cached && constraints.empty?
      if cached.success?
        cached
      else
        cached.merge_trace(trace)
      end
    else
      if assumption.member?(relation)
        success(constraints: constraints)
      else
        trace.add(relation.sub_type, relation.super_type) do
          assumption = assumption + Set.new([relation])
          check0(relation, assumption: assumption, trace: trace, constraints: constraints).tap do |result|
            result = result.else do |failure|
              failure.drop(prefix)
            end

            Steep.logger.debug "result=#{result.class}"
            cache[relation] = result if cacheable?(relation)
          end
        end
      end
    end
  end
end

#check0(relation, assumption:, trace:, constraints:) ⇒ Object 



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# File 'lib/steep/subtyping/check.rb', line 58

def check0(relation, assumption:, trace:, constraints:)
  case
  when same_type?(relation, assumption: assumption)
    success(constraints: constraints)

  when relation.sub_type.is_a?(AST::Types::Any) || relation.super_type.is_a?(AST::Types::Any)
    success(constraints: constraints)

  when relation.super_type.is_a?(AST::Types::Void)
    success(constraints: constraints)

  when relation.super_type.is_a?(AST::Types::Top)
    success(constraints: constraints)

  when relation.sub_type.is_a?(AST::Types::Bot)
    success(constraints: constraints)

  when relation.super_type.is_a?(AST::Types::Boolean)
    success(constraints: constraints)

  when alias?(relation.sub_type)
    check0(
      Relation.new(sub_type: expand_alias(relation.sub_type), super_type: relation.super_type),
      assumption: assumption,
      trace: trace,
      constraints: constraints
    )

  when alias?(relation.super_type)
    check0(
      Relation.new(super_type: expand_alias(relation.super_type), sub_type: relation.sub_type),
      assumption: assumption,
      trace: trace,
      constraints: constraints
    )

  when relation.sub_type.is_a?(AST::Types::Literal)
    check0(
      Relation.new(sub_type: relation.sub_type.back_type, super_type: relation.super_type),
      assumption: assumption,
      trace: trace,
      constraints: constraints
    )

  when relation.sub_type.is_a?(AST::Types::Union)
    results = relation.sub_type.types.map do |sub_type|
      check0(Relation.new(sub_type: sub_type, super_type: relation.super_type),
             assumption: assumption,
             trace: trace,
             constraints: constraints)
    end

    if results.all?(&:success?)
      results.first
    else
      results.find(&:failure?)
    end

  when relation.super_type.is_a?(AST::Types::Union)
    results = relation.super_type.types.map do |super_type|
      check0(Relation.new(sub_type: relation.sub_type, super_type: super_type),
             assumption: assumption,
             trace: trace,
             constraints: constraints)
    end

    results.find(&:success?) || results.first

  when relation.sub_type.is_a?(AST::Types::Intersection)
    results = relation.sub_type.types.map do |sub_type|
      check0(Relation.new(sub_type: sub_type, super_type: relation.super_type),
             assumption: assumption,
             trace: trace,
             constraints: constraints)
    end

    results.find(&:success?) || results.first

  when relation.super_type.is_a?(AST::Types::Intersection)
    results = relation.super_type.types.map do |super_type|
      check0(Relation.new(sub_type: relation.sub_type, super_type: super_type),
             assumption: assumption,
             trace: trace,
             constraints: constraints)
    end

    if results.all?(&:success?)
      results.first
    else
      results.find(&:failure?)
    end

  when relation.super_type.is_a?(AST::Types::Var) && constraints.unknown?(relation.super_type.name)
    constraints.add(relation.super_type.name, sub_type: relation.sub_type)
    success(constraints: constraints)

  when relation.sub_type.is_a?(AST::Types::Var) && constraints.unknown?(relation.sub_type.name)
    constraints.add(relation.sub_type.name, super_type: relation.super_type)
    success(constraints: constraints)

  when relation.super_type.is_a?(AST::Types::Var) || relation.sub_type.is_a?(AST::Types::Var)
    failure(error: Result::Failure::UnknownPairError.new(relation: relation),
            trace: trace)

  when relation.sub_type.is_a?(AST::Types::Name::Base) && relation.super_type.is_a?(AST::Types::Name::Base)
    if (pairs = extract_nominal_pairs(relation))
      results = pairs.flat_map do |(sub, sup)|
        Relation.new(sub_type: sub, super_type: sup).yield_self do |rel|
          [rel, rel.flip]
        end
      end.map do |relation|
        check0(relation,
               assumption: assumption,
               trace: trace,
               constraints: constraints)
      end

      if results.all?(&:success?)
        results.first
      else
        results.find(&:failure?)
      end
    else
      sub_interface = resolve(relation.sub_type)
      super_interface = resolve(relation.super_type)

      check_interface(sub_interface, super_interface, assumption: assumption, trace: trace, constraints: constraints)
    end

  when relation.sub_type.is_a?(AST::Types::Proc) && relation.super_type.is_a?(AST::Types::Proc)
    check_method_params(:__proc__,
                        relation.sub_type.params, relation.super_type.params,
                        assumption: assumption,
                        trace: trace,
                        constraints: constraints).then do
      check0(Relation.new(sub_type: relation.sub_type.return_type, super_type: relation.super_type.return_type),
             assumption: assumption,
             trace: trace,
             constraints: constraints)
    end

  when relation.sub_type.is_a?(AST::Types::Tuple) && relation.super_type.is_a?(AST::Types::Tuple)
    if relation.sub_type.types.size >= relation.super_type.types.size
      pairs = relation.sub_type.types.take(relation.super_type.types.size).zip(relation.super_type.types)
      results = pairs.flat_map do |t1, t2|
        relation = Relation.new(sub_type: t1, super_type: t2)
        [check0(relation, assumption: assumption, trace: trace, constraints: constraints),
         check0(relation.flip, assumption: assumption, trace: trace, constraints: constraints)]
      end

      if results.all?(&:success?)
        success(constraints: constraints)
      else
        results.find(&:failure?)
      end
    else
      failure(error: Result::Failure::UnknownPairError.new(relation: relation),
              trace: trace)
    end

  when relation.sub_type.is_a?(AST::Types::Tuple)
    sub_interface = resolve(relation.sub_type)
    super_interface = resolve(relation.super_type)

    check_interface(sub_interface,
                    super_interface,
                    assumption: assumption,
                    trace: trace,
                    constraints: constraints)

  when relation.sub_type.is_a?(AST::Types::Record) && relation.super_type.is_a?(AST::Types::Record)
    if Set.new(relation.sub_type.elements.keys).superset?(Set.new(relation.super_type.elements.keys))
      keys = relation.super_type.elements.keys
      type_pairs = keys.map {|key| [relation.sub_type.elements[key], relation.super_type.elements[key]] }
      results = type_pairs.flat_map do |t1, t2|
        relation = Relation.new(sub_type: t1, super_type: t2)
        [check0(relation, assumption: assumption, trace: trace, constraints: constraints),
         check0(relation.flip, assumption: assumption, trace: trace, constraints: constraints)]
      end

      if results.all?(&:success?)
        success(constraints: constraints)
      else
        results.find(&:failure?)
      end
    else
      failure(error: Result::Failure::UnknownPairError.new(relation: relation),
              trace: trace)
    end
  else
    failure(error: Result::Failure::UnknownPairError.new(relation: relation),
            trace: trace)
  end
end

#check_block_given(name, sub_block, super_block, trace:, constraints:) ⇒ Object 



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# File 'lib/steep/subtyping/check.rb', line 422

def check_block_given(name, sub_block, super_block, trace:, constraints:)
  case
  when !super_block && !sub_block
    success(constraints: constraints)
  when super_block && sub_block && super_block.optional? == sub_block.optional?
    success(constraints: constraints)
  when sub_block&.optional?
    success(constraints: constraints)
  else
    failure(
      error: Result::Failure::BlockMismatchError.new(name: name),
      trace: trace
    )
  end
end

#check_block_params(name, sub_block, super_block, assumption:, trace:, constraints:) ⇒ Object 



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# File 'lib/steep/subtyping/check.rb', line 574

def check_block_params(name, sub_block, super_block, assumption:, trace:, constraints:)
  if sub_block && super_block
    check_method_params(name,
                        super_block.type.params,
                        sub_block.type.params,
                        assumption: assumption,
                        trace: trace,
                        constraints: constraints)
  else
    success(constraints: constraints)
  end
end

#check_block_return(sub_block, super_block, assumption:, trace:, constraints:) ⇒ Object 



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# File 'lib/steep/subtyping/check.rb', line 587

def check_block_return(sub_block, super_block, assumption:, trace:, constraints:)
  if sub_block && super_block
    relation = Relation.new(sub_type: super_block.type.return_type,
                                super_type: sub_block.type.return_type)
    check(relation, assumption: assumption, trace: trace, constraints: constraints)
  else
    success(constraints: constraints)
  end
end

#check_interface(sub_type, super_type, assumption:, trace:, constraints:) ⇒ Object 



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# File 'lib/steep/subtyping/check.rb', line 302

def check_interface(sub_type, super_type, assumption:, trace:, constraints:)
  method_pairs = []

  super_type.methods.each do |name, sup_method|
    sub_method = sub_type.methods[name]

    if sub_method
      method_pairs << [sub_method, sup_method]
    else
      return failure(error: Result::Failure::MethodMissingError.new(name: name),
                     trace: trace)
    end
  end

  method_pairs.each do |(sub_method, sup_method)|
    result = check_method(sub_method.name, sub_method, sup_method, assumption: assumption, trace: trace, constraints: constraints)
    return result if result.failure?
  end

  success(constraints: constraints)
end

#check_method(name, sub_method, super_method, assumption:, trace:, constraints:) ⇒ Object 



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# File 'lib/steep/subtyping/check.rb', line 324

def check_method(name, sub_method, super_method, assumption:, trace:, constraints:)
  trace.add(sub_method, super_method) do
    all_results = super_method.types.map do |super_type|
      sub_method.types.map do |sub_type|
        trace.add(sub_type, super_type) do
          case
          when super_type.type_params.empty? && sub_type.type_params.empty?
            check_method_type(name,
                              sub_type,
                              super_type,
                              assumption: assumption,
                              trace: trace,
                              constraints: constraints)

          when super_type.type_params.empty?
            yield_self do
              sub_args = sub_type.type_params.map {|x| AST::Types::Var.fresh(x) }
              sub_type = sub_type.instantiate(Interface::Substitution.build(sub_type.type_params,
                                                                            sub_args))

              constraints.add_var(*sub_args)

              match_method_type(name, sub_type, super_type, trace: trace).yield_self do |pairs|
                case pairs
                when Array
                  subst = pairs.each.with_object(Interface::Substitution.empty) do |(sub, sup), subst|
                    case
                    when sub.is_a?(AST::Types::Var) && sub_args.include?(sub)
                      subst.add!(sub.name, sup)
                    when sup.is_a?(AST::Types::Var) && sub_args.include?(sup)
                      subst.add!(sup.name, sub)
                    end
                  end

                  check_method_type(name,
                                    sub_type.subst(subst),
                                    super_type,
                                    assumption: assumption,
                                    trace: trace,
                                    constraints: constraints)
                else
                  pairs
                end
              end
            end

          when super_type.type_params.size == sub_type.type_params.size
            yield_self do
              args = sub_type.type_params.map {|x| AST::Types::Var.fresh(x) }

              sub_type_ = sub_type.instantiate(Interface::Substitution.build(sub_type.type_params, args))
              super_type_ = super_type.instantiate(Interface::Substitution.build(super_type.type_params, args))

              constraints.add_var(*args)

              check_method_type(name,
                                sub_type_,
                                super_type_,
                                assumption: assumption,
                                trace: trace,
                                constraints: constraints)
            end
          else
            failure(error: Result::Failure::PolyMethodSubtyping.new(name: name),
                    trace: trace)
          end
        end
      end
    end

    all_results.each do |results|
      if results.any?(&:success?)
        #ok
      else
        return results.find(&:failure?)
      end
    end

    success(constraints: constraints)
  end
end

#check_method_params(name, sub_params, super_params, assumption:, trace:, constraints:) ⇒ Object 



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# File 'lib/steep/subtyping/check.rb', line 438

def check_method_params(name, sub_params, super_params, assumption:, trace:, constraints:)
  match_params(name, sub_params, super_params, trace: trace).yield_self do |pairs|
    case pairs
    when Array
      pairs.each do |(sub_type, super_type)|
        relation = Relation.new(super_type: sub_type, sub_type: super_type)

        result = check(relation, assumption: assumption, trace: trace, constraints: constraints)
        return result if result.failure?
      end

      success(constraints: constraints)
    else
      pairs
    end
  end
end

#check_method_type(name, sub_type, super_type, assumption:, trace:, constraints:) ⇒ Object 



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# File 'lib/steep/subtyping/check.rb', line 406

def check_method_type(name, sub_type, super_type, assumption:, trace:, constraints:)
  Steep.logger.tagged("#{name}: #{sub_type} <: #{super_type}") do
    check_method_params(name, sub_type.params, super_type.params, assumption: assumption, trace: trace, constraints: constraints).then do
      check_block_given(name, sub_type.block, super_type.block, trace: trace, constraints: constraints).then do
        check_block_params(name, sub_type.block, super_type.block, assumption: assumption, trace: trace, constraints: constraints).then do
          check_block_return(sub_type.block, super_type.block, assumption: assumption, trace: trace, constraints:constraints).then do
            relation = Relation.new(super_type: super_type.return_type,
                                    sub_type: sub_type.return_type)
            check(relation, assumption: assumption, trace: trace, constraints: constraints)
          end
        end
      end
    end
  end
end

#expand_alias(type) ⇒ Object 



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# File 'lib/steep/subtyping/check.rb', line 951

def expand_alias(type)
  expanded = case type
             when AST::Types::Union
               AST::Types::Union.build(
                 types: type.types.map {|ty| expand_alias(ty) },
                 location: type.location
               )
             when AST::Types::Intersection
               AST::Types::Intersection.build(
                 types: type.types.map {|ty| expand_alias(ty) },
                 location: type.location
               )
             when AST::Types::Name::Alias
               alias_sig = builder.signatures.find_alias(type.name, namespace: AST::Namespace.root)
               expanded_alias = builder.absolute_type(alias_sig.type, current: alias_sig.name.namespace)
               args = type.args.map {|ty| expand_alias(ty) }
               s = Interface::Substitution.build(alias_sig.params&.variables || [], args)
               expand_alias(expanded_alias.subst(s))
             else
               type
             end

  if block_given?
    yield expanded
  else
    expanded
  end
end

#extract_nominal_pairs(relation) ⇒ Object 



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# File 'lib/steep/subtyping/check.rb', line 253

def extract_nominal_pairs(relation)
  sub_type = relation.sub_type
  super_type = relation.super_type
  
  case
  when sub_type.is_a?(AST::Types::Name::Instance) && super_type.is_a?(AST::Types::Name::Instance)
    if sub_type.name == super_type.name && sub_type.args.size == super_type.args.size
      sub_type.args.zip(super_type.args)
    end
  when sub_type.is_a?(AST::Types::Name::Interface) && super_type.is_a?(AST::Types::Name::Interface)
    if sub_type.name == super_type.name && sub_type.args.size == super_type.args.size
      sub_type.args.zip(super_type.args)
    end
  when sub_type.is_a?(AST::Types::Name::Alias) && super_type.is_a?(AST::Types::Name::Alias)
    if sub_type.name == super_type.name && sub_type.args.size == super_type.args.size
      sub_type.args.zip(super_type.args)
    end
  when sub_type.is_a?(AST::Types::Name::Class) && super_type.is_a?(AST::Types::Name::Class)
    if sub_type.name == super_type.name
      []
    end
  when sub_type.is_a?(AST::Types::Name::Module) && super_type.is_a?(AST::Types::Name::Module)
    if sub_type.name == super_type.name
      []
    end
  end
end

#failure(error:, trace:) ⇒ Object 



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# File 'lib/steep/subtyping/check.rb', line 54

def failure(error:, trace:)
  Result::Failure.new(error: error, trace: trace)
end

#match_method_type(name, sub_type, super_type, trace:) ⇒ Object 



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# File 'lib/steep/subtyping/check.rb', line 456

def match_method_type(name, sub_type, super_type, trace:)
  [].tap do |pairs|
    match_params(name, sub_type.params, super_type.params, trace: trace).yield_self do |result|
      return result unless result.is_a?(Array)
      pairs.push(*result)
      pairs.push [sub_type.return_type, super_type.return_type]

      case
      when !super_type.block && !sub_type.block
        # No block required and given

      when super_type.block && sub_type.block
        match_params(name, super_type.block.type.params, sub_type.block.type.params, trace: trace).yield_self do |block_result|
          return block_result unless block_result.is_a?(Array)
          pairs.push(*block_result)
          pairs.push [super_type.block.type.return_type, sub_type.block.type.return_type]
        end

      else
        return failure(error: Result::Failure::BlockMismatchError.new(name: name),
                       trace: trace)
      end
    end
  end
end

#match_params(name, sub_params, super_params, trace:) ⇒ Object 



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# File 'lib/steep/subtyping/check.rb', line 482

def match_params(name, sub_params, super_params, trace:)
  pairs = []

  sub_flat = sub_params.flat_unnamed_params
  sup_flat = super_params.flat_unnamed_params

  failure = failure(error: Result::Failure::ParameterMismatchError.new(name: name),
                    trace: trace)

  case
  when super_params.rest
    return failure unless sub_params.rest

    while sub_flat.size > 0
      sub_type = sub_flat.shift
      sup_type = sup_flat.shift

      if sup_type
        pairs << [sub_type.last, sup_type.last]
      else
        pairs << [sub_type.last, super_params.rest]
      end
    end

    if sub_params.rest
      pairs << [sub_params.rest, super_params.rest]
    end

  when sub_params.rest
    while sub_flat.size > 0
      sub_type = sub_flat.shift
      sup_type = sup_flat.shift

      if sup_type
        pairs << [sub_type.last, sup_type.last]
      else
        break
      end
    end

    if sub_params.rest && !sup_flat.empty?
      sup_flat.each do |sup_type|
        pairs << [sub_params.rest, sup_type.last]
      end
    end
  when sub_params.required.size + sub_params.optional.size >= super_params.required.size + super_params.optional.size
    while sub_flat.size > 0
      sub_type = sub_flat.shift
      sup_type = sup_flat.shift

      if sup_type
        pairs << [sub_type.last, sup_type.last]
      else
        if sub_type.first == :required
          return failure
        else
          break
        end
      end
    end
  else
    return failure
  end

  sub_flat_kws = sub_params.flat_keywords
  sup_flat_kws = super_params.flat_keywords

  sup_flat_kws.each do |name, _|
    if sub_flat_kws.key?(name)
      pairs << [sub_flat_kws[name], sup_flat_kws[name]]
    else
      if sub_params.rest_keywords
        pairs << [sub_params.rest_keywords, sup_flat_kws[name]]
      else
        return failure
      end
    end
  end

  sub_params.required_keywords.each do |name, _|
    unless super_params.required_keywords.key?(name)
      return failure
    end
  end

  if sub_params.rest_keywords && super_params.rest_keywords
    pairs << [sub_params.rest_keywords, super_params.rest_keywords]
  end

  pairs
end

#resolve(type, self_type: type, instance_type: nil, module_type: nil, with_private: false) ⇒ Object 



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# File 'lib/steep/subtyping/check.rb', line 624

def resolve(type, self_type: type, instance_type: nil, module_type: nil, with_private: false)
  Steep.logger.debug("Check#resolve: type=#{type}")
  case type
  when AST::Types::Any, AST::Types::Var, AST::Types::Class, AST::Types::Instance
    raise CannotResolveError.new(type: type)

  when AST::Types::Nil, AST::Types::Literal, AST::Types::Boolean
    resolve(type.back_type,
            self_type: self_type,
            instance_type: instance_type,
            module_type: module_type,
            with_private: with_private)

  when AST::Types::Name::Instance
    resolve_instance(type,
                     self_type: self_type,
                     instance_type: instance_type,
                     module_type: module_type,
                     with_private: with_private)

  when AST::Types::Name::Class
    yield_self do
      abstract_interface = builder.build_class(type.name, constructor: type.constructor).without_private(!with_private)

      unless instance_type
        type_params = builder.signatures.find_class(type.name).params&.variables || []
        instance_type = AST::Types::Name::Instance.new(name: type.name,
                                                       args: type_params.map {|var| AST::Types::Var.new(name: var) })
      end

      interface = abstract_interface.instantiate(
        type: self_type,
        args: [],
        instance_type: instance_type,
        module_type: AST::Builtin::Class.class_type
      )

      if type_params
        interface.subst(Interface::Substitution.build(type_params, type_params.map { AST::Builtin.any_type }))
      else
        interface
      end
    end

  when AST::Types::Name::Module
    yield_self do
      abstract_interface = builder.build_module(type.name).without_private(!with_private)

      unless instance_type
        type_params = builder.signatures.find_module(type.name).params&.variables || []
        instance_type = AST::Types::Name::Instance.new(name: type.name,
                                                       args: type_params.map {|var| AST::Types::Var.new(name: var) })
      end

      interface = abstract_interface.instantiate(
        type: self_type,
        args: [],
        instance_type: instance_type,
        module_type: AST::Builtin::Module.class_type
      )

      if type_params
        interface.subst(Interface::Substitution.build(type_params, type_params.map { AST::Builtin.any_type }))
      else
        interface
      end
    end

  when AST::Types::Name::Interface
    yield_self do
      abstract_interface = builder.build_interface(type.name)

      abstract_interface.instantiate(
        type: self_type,
        args: type.args,
        instance_type: nil,
        module_type: nil
      )
    end

  when AST::Types::Name::Alias
    resolve(expand_alias(type),
            self_type: self_type,
            instance_type: instance_type,
            module_type: module_type,
            with_private: with_private)

  when AST::Types::Union
    interfaces = type.types.map do |member_type|
      fresh = AST::Types::Var.fresh(:___)

      resolve(member_type, self_type: type, instance_type: fresh, module_type: fresh, with_private: with_private).select_method_type do |method_type|
        !method_type.each_type.include?(fresh)
      end
    end

    methods = interfaces.inject(nil) do |methods, i|
      if methods
        intersection = {}
        i.methods.each do |name, new_method|
          existing_method = methods[name]

          if existing_method
            case
            when new_method == existing_method
              intersection[name] = new_method
            when check_method(name, new_method, existing_method,
                              assumption: Set.new,
                              trace: Trace.new,
                              constraints: Constraints.empty).success?
              intersection[name] = existing_method
            when check_method(name, existing_method, new_method,
                              assumption: Set.new,
                              trace: Trace.new,
                              constraints: Constraints.empty).success?
              intersection[name] = new_method
            else
              merged_method_types = []

              existing_method.types.each do |existing_method_type|
                new_method.types.each do |new_method_type|
                  if existing_method_type.params == new_method_type.params &&
                    existing_method_type.block == new_method_type.block &&
                    existing_method_type.type_params == new_method_type.type_params
                    merged_method_types << existing_method_type.with(
                      return_type: AST::Types::Union.build(
                        types: [
                          existing_method_type.return_type,
                          new_method_type.return_type
                        ]
                      ),
                      location: nil
                    )
                  end
                end
              end

              unless merged_method_types.empty?
                intersection[name] = Interface::Method.new(
                  type_name: nil,
                  name: name,
                  types: merged_method_types,
                  super_method: nil,
                  attributes: []
                )
              end
            end
          end
        end
        intersection
      else
        i.methods
      end
    end

    Interface::Instantiated.new(type: type,
                                methods: methods,
                                ivar_chains: {})

  when AST::Types::Intersection
    interfaces = type.types.map do |type|
      resolve(type, with_private: with_private)
    end

    methods = interfaces.inject(nil) do |methods, i|
      if methods
        i.methods.each do |name, method|
          if methods.key?(name)
            case
            when method == methods[name]
            when check_method(name, method, methods[name],
                              assumption: Set.new,
                              trace: Trace.new,
                              constraints: Constraints.empty).success?
              methods[name] = method
            when check_method(name, methods[name], method,
                              assumption: Set.new,
                              trace: Trace.new,
                              constraints: Constraints.empty).success?
              methods[name] = methods[name]
            else
              methods[name] = Interface::Method.new(
                type_name: nil,
                name: name,
                types: methods[name].types + method.types,
                super_method: nil,
                attributes: []
              )
            end
          else
            methods[name] = i.methods[name]
          end
        end
        methods
      else
        i.methods
      end
    end

    ivar_chains = interfaces.each.with_object({}) do |interface, chains|
      chains.merge!(interface.ivar_chains)
    end

    Interface::Instantiated.new(type: type,
                                methods: methods,
                                ivar_chains: ivar_chains)
  when AST::Types::Void
    Interface::Instantiated.new(type: type,
                                methods: {},
                                ivar_chains: {})

  when AST::Types::Tuple
    yield_self do
      element_type = AST::Types::Union.build(types: type.types)
      array_type = AST::Builtin::Array.instance_type(element_type)
      array_interface = resolve(array_type, self_type: self_type, with_private: with_private)

      array_interface.methods[:[]] = array_interface.methods[:[]].yield_self do |aref|
        types = type.types.map.with_index {|elem_type, index|
          Interface::MethodType.new(
            type_params: [],
            params: Interface::Params.new(required: [AST::Types::Literal.new(value: index)],
                                          optional: [],
                                          rest: nil,
                                          required_keywords: {},
                                          optional_keywords: {},
                                          rest_keywords: nil),
            block: nil,
            return_type: elem_type,
            location: nil
          )
        } + aref.types
        aref.with_types(types)
      end

      array_interface.methods[:[]=] = array_interface.methods[:[]=].yield_self do |aref|
        types = type.types.map.with_index {|elem_type, index|
          Interface::MethodType.new(
            type_params: [],
            params: Interface::Params.new(required: [AST::Types::Literal.new(value: index), elem_type],
                                          optional: [],
                                          rest: nil,
                                          required_keywords: {},
                                          optional_keywords: {},
                                          rest_keywords: nil),
            block: nil,
            return_type: elem_type,
            location: nil
          )
        } + aref.types
        aref.with_types(types)
      end

      array_interface
    end

  when AST::Types::Record
    yield_self do
      key_type = AST::Types::Union.build(types: type.elements.keys.map {|val| AST::Types::Literal.new(value: val) })
      value_type = AST::Types::Union.build(types: type.elements.values)
      hash_interface = resolve(AST::Builtin::Hash.instance_type(key_type, value_type), self_type: self_type, with_private: with_private)

      hash_interface.methods[:[]] = hash_interface.methods[:[]].yield_self do |ref|
        types = type.elements.map do |key, value_type|
          Interface::MethodType.new(
            type_params: [],
            params: Interface::Params.new(required: [AST::Types::Literal.new(value: key)],
                                          optional: [],
                                          rest: nil,
                                          required_keywords: {},
                                          optional_keywords: {},
                                          rest_keywords: nil),
            return_type: value_type,
            block: nil,
            location: nil
          )
        end

        ref.with_types(types + ref.types)
      end

      hash_interface.methods[:[]=] = hash_interface.methods[:[]=].yield_self do |method|
        types = type.elements.map do |key, value_type|
          Interface::MethodType.new(
            type_params: [],
            params: Interface::Params.new(required: [AST::Types::Literal.new(value: key), value_type],
                                          optional: [],
                                          rest: nil,
                                          required_keywords: {},
                                          optional_keywords: {},
                                          rest_keywords: nil),
            return_type: value_type,
            block: nil,
            location: nil
          )
        end

        method.with_types(types + method.types)
      end

      hash_interface
    end

  when AST::Types::Proc
    yield_self do
      proc_interface = resolve(type.back_type, self_type: self_type, with_private: with_private)
      apply_type = Interface::MethodType.new(
        type_params: [],
        params: type.params,
        block: nil,
        return_type: type.return_type,
        location: nil
      )

      proc_interface.methods[:[]] = proc_interface.methods[:[]].yield_self do |aref|
        aref.with_types([apply_type])
      end
      proc_interface.methods[:call] = proc_interface.methods[:call].yield_self do |aref|
        aref.with_types([apply_type])
      end

      proc_interface
    end

  end
end

#resolve_instance(type, self_type:, instance_type:, module_type:, with_private: false) ⇒ Object 



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# File 'lib/steep/subtyping/check.rb', line 606

def resolve_instance(type, self_type:, instance_type:, module_type:, with_private: false)
  abstract_interface = builder.build_instance(type.name).without_private(!with_private)

  module_type = module_type || case builder.signatures.find_class_or_module(type.name)
                               when AST::Signature::Class
                                 AST::Types::Name::Class.new(name: type.name, constructor: nil)
                               when AST::Signature::Module
                                 AST::Types::Name::Module.new(name: type.name)
                               end

  abstract_interface.instantiate(
    type: self_type,
    args: type.args,
    instance_type: instance_type || type,
    module_type: module_type
  )
end

#same_type?(relation, assumption:) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/steep/subtyping/check.rb', line 281

def same_type?(relation, assumption:)
  if assumption.include?(relation) && assumption.include?(relation.flip)
    return true
  end

  case
  when relation.sub_type == relation.super_type
    true
  when relation.sub_type.is_a?(AST::Types::Name::Base) && relation.super_type.is_a?(AST::Types::Name::Base)
    if (pairs = extract_nominal_pairs(relation))
      pairs.all? do |(s, t)|
        same_type?(Relation.new(sub_type: s, super_type: t), assumption: assumption)
      end
    else
      false
    end
  else
    false
  end
end

#success(constraints:) ⇒ Object 



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# File 'lib/steep/subtyping/check.rb', line 50

def success(constraints:)
  Result::Success.new(constraints: constraints)
end