Class: Steep::TypeConstruction

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

Defined Under Namespace

Modules: Types Classes: BlockContext, BreakContext, MethodContext, ModuleContext

Constant Summary collapse

NOTHING = 
::Object.new

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(checker:, source:, annotations:, type_env:, typing:, self_type:, method_context:, block_context:, module_context:, break_context:) ⇒ TypeConstruction 



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# File 'lib/steep/type_construction.rb', line 112

def initialize(checker:, source:, annotations:, type_env:, typing:, self_type:, method_context:, block_context:, module_context:, break_context:)
  @checker = checker
  @source = source
  @annotations = annotations
  @typing = typing
  @self_type = self_type
  @block_context = block_context
  @method_context = method_context
  @module_context = module_context
  @break_context = break_context
  @type_env = type_env
end

Instance Attribute Details

#annotations ⇒ Object (readonly)

Returns the value of attribute annotations.



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# File 'lib/steep/type_construction.rb', line 103

def annotations
  @annotations
end

#block_context ⇒ Object (readonly)

Returns the value of attribute block_context.



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# File 'lib/steep/type_construction.rb', line 106

def block_context
  @block_context
end

#break_context ⇒ Object (readonly)

Returns the value of attribute break_context.



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# File 'lib/steep/type_construction.rb', line 109

def break_context
  @break_context
end

#checker ⇒ Object (readonly)

Returns the value of attribute checker.



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# File 'lib/steep/type_construction.rb', line 101

def checker
  @checker
end

#method_context ⇒ Object (readonly)

Returns the value of attribute method_context.



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# File 'lib/steep/type_construction.rb', line 105

def method_context
  @method_context
end

#module_context ⇒ Object (readonly)

Returns the value of attribute module_context.



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# File 'lib/steep/type_construction.rb', line 107

def module_context
  @module_context
end

#self_type ⇒ Object (readonly)

Returns the value of attribute self_type.



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# File 'lib/steep/type_construction.rb', line 108

def self_type
  @self_type
end

#source ⇒ Object (readonly)

Returns the value of attribute source.



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# File 'lib/steep/type_construction.rb', line 102

def source
  @source
end

#type_env ⇒ Object (readonly)

Returns the value of attribute type_env.



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# File 'lib/steep/type_construction.rb', line 110

def type_env
  @type_env
end

#typing ⇒ Object (readonly)

Returns the value of attribute typing.



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# File 'lib/steep/type_construction.rb', line 104

def typing
  @typing
end

Class Method Details

.argument_typing_pairs(params:, arguments:) ⇒ Object 



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# File 'lib/steep/type_construction.rb', line 1853

def self.argument_typing_pairs(params:, arguments:)
  keywords = {}
  unless params.required_keywords.empty? && params.optional_keywords.empty? && !params.rest_keywords
    # has keyword args
    last_arg = arguments.last
    if last_arg&.type == :hash
      arguments.pop

      last_arg.children.each do |elem|
        case elem.type
        when :pair
          key, value = elem.children
          if key.type == :sym
            name = key.children[0]

            keywords[name] = value
          end
        end
      end
    end
  end

  pairs = []

  params.flat_unnamed_params.each do |param_type|
    arg = arguments.shift
    pairs << [param_type.last, arg] if arg
  end

  if params.rest
    arguments.each do |arg|
      pairs << [params.rest, arg]
    end
  end

  params.flat_keywords.each do |name, type|
    arg = keywords.delete(name)
    if arg
      pairs << [type, arg]
    end
  end

  if params.rest_keywords
    keywords.each_value do |arg|
      pairs << [params.rest_keywords, arg]
    end
  end

  pairs
end

.block_param_typing_pairs(param_types:, param_nodes:) ⇒ Object 



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# File 'lib/steep/type_construction.rb', line 1841

def self.block_param_typing_pairs(param_types: , param_nodes:)
  pairs = []

  param_types.required.each.with_index do |type, index|
    if (param = param_nodes[index])
      pairs << [param, type]
    end
  end

  pairs
end

.parameter_types(nodes, type) ⇒ Object 



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# File 'lib/steep/type_construction.rb', line 1904

def self.parameter_types(nodes, type)
  nodes = nodes.dup

  env = {}

  type.params.required.each do |type|
    a = nodes.first
    if a&.type == :arg
      env[a.children.first] = type
      nodes.shift
    else
      break
    end
  end

  type.params.optional.each do |type|
    a = nodes.first

    if a&.type == :optarg
      env[a.children.first] = type
      nodes.shift
    else
      break
    end
  end

  if type.params.rest
    a = nodes.first
    if a&.type == :restarg
      env[a.children.first] = Types.array_instance(type.params.rest)
      nodes.shift
    end
  end

  nodes.each do |node|
    if node.type == :kwarg
      name = node.children[0]
      ty = type.params.required_keywords[name.name]
      env[name] = ty if ty
    end

    if node.type == :kwoptarg
      name = node.children[0]
      ty = type.params.optional_keywords[name.name]
      env[name] = ty if ty
    end

    if node.type == :kwrestarg
      ty = type.params.rest_keywords
      if ty
        env[node.children[0]] = Types.hash_instance(Types.symbol_instance, ty)
      end
    end
  end

  env
end

.truthy_variables(node) ⇒ Object 



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# File 'lib/steep/type_construction.rb', line 2130

def self.truthy_variables(node)
  case node&.type
  when :lvar
    Set.new([node.children.first.name])
  when :lvasgn
    Set.new([node.children.first.name]) + truthy_variables(node.children[1])
  when :and
    truthy_variables(node.children[0]) + truthy_variables(node.children[1])
  when :begin
    truthy_variables(node.children.last)
  else
    Set.new()
  end
end

.unwrap(type) ⇒ Object 



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# File 'lib/steep/type_construction.rb', line 2120

def self.unwrap(type)
  case
  when type.is_a?(AST::Types::Union)
    types = type.types.reject {|type| type.is_a?(AST::Types::Name) && type.name == TypeName::Instance.new(name: ModuleName.parse("::NilClass")) }
    AST::Types::Union.build(types: types)
  else
    type
  end
end

.valid_parameter_env?(env, nodes, params) ⇒ Boolean 



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# File 'lib/steep/type_construction.rb', line 1962

def self.valid_parameter_env?(env, nodes, params)
  env.size == nodes.size && env.size == params.size
end

.value_variables(node) ⇒ Object 



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# File 'lib/steep/type_construction.rb', line 2145

def self.value_variables(node)
  case node&.type
  when :lvar
    Set.new([node.children.first.name])
  when :lvasgn
    Set.new([node.children.first.name]) + value_variables(node.children[1])
  when :begin
    value_variables(node.children.last)
  else
    Set.new
  end
end

Instance Method Details

#absolute_name(module_name) ⇒ Object 



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# File 'lib/steep/type_construction.rb', line 1981

def absolute_name(module_name)
  if current_namespace
    current_namespace + module_name
  else
    module_name.absolute!
  end
end

#absolute_type(type) ⇒ Object 



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# File 'lib/steep/type_construction.rb', line 1989

def absolute_type(type)
  if type
    checker.builder.absolute_type(type, current: current_namespace)
  end
end

#applicable_args?(params:, arguments:) ⇒ Boolean 



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# File 'lib/steep/type_construction.rb', line 1807

def applicable_args?(params:, arguments:)
  params.each_missing_argument arguments do |_|
    return false
  end

  params.each_extra_argument arguments do |_|
    return false
  end

  params.each_missing_keyword arguments do |_|
    return false
  end

  params.each_extra_keyword arguments do |_|
    return false
  end

  all_args = arguments.dup

  self.class.argument_typing_pairs(params: params, arguments: arguments.dup).each do |(param_type, argument)|
    all_args.delete_if {|a| a.equal?(argument) }

    check(argument, param_type) do |_, _|
      return false
    end
  end

  all_args.each do |arg|
    synthesize(arg)
  end

  true
end

#assign_type_to_variable(var, type, node) ⇒ Object 



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# File 'lib/steep/type_construction.rb', line 1388

def assign_type_to_variable(var, type, node)
  name = var.name
  type_env.assign(lvar: name, type: type) do |result|
    var_type = type_env.get(lvar: name)
    typing.add_error(Errors::IncompatibleAssignment.new(node: node,
                                                        lhs_type: var_type,
                                                        rhs_type: type,
                                                        result: result))
  end
end

#check(node, type) ⇒ Object 



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# File 'lib/steep/type_construction.rb', line 1354

def check(node, type)
  type_ = synthesize(node)

  result = checker.check(
    Subtyping::Relation.new(sub_type: type_,
                            super_type: type),
    constraints: Subtyping::Constraints.empty
  )
  if result.failure?
    yield(type, type_, result)
  end
end

#current_namespace ⇒ Object 



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# File 'lib/steep/type_construction.rb', line 1966

def current_namespace
  module_context&.current_namespace
end

#each_child_node(node) ⇒ Object 



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# File 'lib/steep/type_construction.rb', line 1775

def each_child_node(node)
  if block_given?
    node.children.each do |child|
      if child.is_a?(::AST::Node)
        yield child
      end
    end
  else
    enum_for :each_child_node, node
  end
end

#fallback_any_rec(node) ⇒ Object 



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# File 'lib/steep/type_construction.rb', line 2110

def fallback_any_rec(node)
  fallback_to_any(node) unless typing.has_type?(node)

  each_child_node(node) do |child|
    fallback_any_rec(child)
  end

  typing.type_of(node: node)
end

#fallback_to_any(node) ⇒ Object 



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# File 'lib/steep/type_construction.rb', line 2079

def fallback_to_any(node)
  if block_given?
    typing.add_error yield
  else
    typing.add_error Errors::FallbackAny.new(node: node)
  end

  typing.add_typing node, Types.any
end

#flatten_const_name(node) ⇒ Object 



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# File 'lib/steep/type_construction.rb', line 2060

def flatten_const_name(node)
  path = []

  while node
    case node.type
    when :const, :casgn
      path.unshift(node.children[1])
      node = node.children[0]
    when :cbase
      path.unshift("")
      break
    else
      return nil
    end
  end

  path.join("::").to_sym
end

#for_branch(node, truthy_vars: Set.new, type_case_override: nil) ⇒ Object 



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# File 'lib/steep/type_construction.rb', line 374

def for_branch(node, truthy_vars: Set.new, type_case_override: nil)
  annots = source.annotations(block: node)

  type_env = self.type_env

  lvar_types = self.type_env.lvar_types.each.with_object({}) do |(var, type), env|
    if truthy_vars.member?(var)
      env[var] = TypeConstruction.unwrap(type)
    else
      env[var] = type
    end
  end
  type_env = type_env.with_annotations(lvar_types: lvar_types) do |var, relation, result|
    raise "Unexpected annotate failure: #{relation}"
  end

  if type_case_override
    type_env = type_env.with_annotations(lvar_types: type_case_override) do |var, relation, result|
      typing.add_error(
        Errors::IncompatibleTypeCase.new(node: node,
                                         var_name: var,
                                         relation: relation,
                                         result: result)
      )
    end
  end

  type_env = type_env.with_annotations(
    lvar_types: annots.var_types.transform_values {|a| absolute_type(a.type) },
    ivar_types: annots.ivar_types.transform_values {|ty| absolute_type(ty) },
    const_types: annots.const_types.transform_values {|ty| absolute_type(ty) },
    gvar_types: {}
  ) do |var, relation, result|
    typing.add_error(
      Errors::IncompatibleAnnotation.new(node: node,
                                         var_name: var,
                                         relation: relation,
                                         result: result)
    )
  end

  with(type_env: type_env)
end

#for_class(node) ⇒ Object 



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# File 'lib/steep/type_construction.rb', line 315

def for_class(node)
  annots = source.annotations(block: node)
  new_class_name = ModuleName.from_node(node.children.first) or raise "Unexpected class name: #{node.children.first}"

  implement_module_name =
    if annots.implement_module
      annots.implement_module.name
    else
      absolute_name(new_class_name).yield_self do |name|
        if checker.builder.signatures.class_name?(name)
          signature = checker.builder.signatures.find_class(name)
          AST::Annotation::Implements::Module.new(name: name,
                                                  args: signature.params&.variables || [])
        end
      end
    end

  if implement_module_name
    class_name = implement_module_name.name
    class_args = implement_module_name.args.map {|x| AST::Types::Var.new(name: x) }

    _ = checker.builder.build(TypeName::Instance.new(name: class_name))

    instance_type = AST::Types::Name.new_instance(name: class_name, args: class_args)
    module_type = AST::Types::Name.new_class(name: class_name, args: [], constructor: nil)
  end

  new_namespace = nested_namespace(new_class_name)
  class_const_env = TypeInference::ConstantEnv.new(builder: checker.builder, current_namespace: new_namespace)

  module_context = ModuleContext.new(
    instance_type: annots.instance_type || instance_type,
    module_type: annots.module_type || module_type,
    implement_name: implement_module_name,
    current_namespace: new_namespace,
    const_env: class_const_env
  )

  class_type_env = TypeInference::TypeEnv.build(
    annotations: annots,
    const_env: class_const_env,
    signatures: checker.builder.signatures,
    subtyping: checker
  )

  self.class.new(
    checker: checker,
    source: source,
    annotations: annots,
    type_env: class_type_env,
    typing: typing,
    method_context: nil,
    block_context: nil,
    module_context: module_context,
    self_type: module_context.module_type,
    break_context: nil
  )
end

#for_module(node) ⇒ Object 



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# File 'lib/steep/type_construction.rb', line 236

def for_module(node)
  annots = source.annotations(block: node)
  new_module_name = ModuleName.from_node(node.children.first) or raise "Unexpected module name: #{node.children.first}"

  module_type = AST::Types::Name.new_instance(name: "::Module")

  implement_module_name =
    if annots.implement_module
      annots.implement_module.name
    else
      absolute_name(new_module_name).yield_self do |module_name|
        if checker.builder.signatures.module_name?(module_name)
          signature = checker.builder.signatures.find_module(module_name)
          AST::Annotation::Implements::Module.new(name: module_name,
                                                  args: signature.params&.variables || [])
        end
      end
    end

  if implement_module_name
    module_name = implement_module_name.name
    module_args = implement_module_name.args.map {|x| AST::Types::Var.new(name: x) }

    abstract = checker.builder.build(TypeName::Instance.new(name: module_name))

    instance_type = absolute_type(
      AST::Types::Name.new_instance(name: module_name, args: module_args)
    )

    unless abstract.supers.empty?
      instance_type = AST::Types::Intersection.build(
        types: [instance_type, AST::Types::Name.new_instance(name: "::Object")] + abstract.supers.map {|x| absolute_type(x) }
      )
    end

    module_type = AST::Types::Intersection.build(types: [
      AST::Types::Name.new_instance(name: "::Module"),
      absolute_type(AST::Types::Name.new_module(name: module_name, args: module_args))
    ])
  end

  if annots.instance_type
    instance_type = absolute_type(annots.instance_type)
  end

  if annots.module_type
    module_type = absolute_type(annots.module_type)
  end

  new_namespace = nested_namespace(new_module_name)
  module_const_env = TypeInference::ConstantEnv.new(builder: checker.builder, current_namespace: new_namespace)

  module_context_ = ModuleContext.new(
    instance_type: instance_type,
    module_type: module_type,
    implement_name: implement_module_name,
    current_namespace: new_namespace,
    const_env: module_const_env
  )

  module_type_env = TypeInference::TypeEnv.build(annotations: annots,
                                                 subtyping: checker,
                                                 const_env: module_const_env,
                                                 signatures: checker.builder.signatures)

  self.class.new(
    checker: checker,
    source: source,
    annotations: annots,
    type_env: module_type_env,
    typing: typing,
    method_context: nil,
    block_context: nil,
    module_context: module_context_,
    self_type: module_context_.module_type,
    break_context: nil
  )
end

#for_new_method(method_name, node, args:, self_type:) ⇒ Object 



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# File 'lib/steep/type_construction.rb', line 125

def for_new_method(method_name, node, args:, self_type:)
  annots = source.annotations(block: node)
  type_env = TypeInference::TypeEnv.new(subtyping: checker,
                                        const_env: module_context&.const_env || self.type_env.const_env)

  self.type_env.const_types.each do |name, type|
    type_env.set(const: name, type: type)
  end

  self_type = annots.self_type || self_type

  self_interface = self_type && (self_type != Types.any || nil) && checker.resolve(self_type, with_initialize: true)
  interface_method = self_interface&.yield_self {|interface| interface.methods[method_name] }
  annotation_method = annotations.lookup_method_type(method_name)&.yield_self do |method_type|
    Interface::Method.new(type_name: nil,
                          name: method_name,
                          types: [checker.builder.method_type_to_method_type(method_type,
                                                                             current: current_namespace)],
                          super_method: interface_method&.super_method,
                          attributes: [])
  end

  if interface_method && annotation_method
    result = checker.check_method(method_name,
                                  annotation_method,
                                  interface_method,
                                  assumption: Set.new,
                                  trace: Subtyping::Trace.new,
                                  constraints: Subtyping::Constraints.empty)

    if result.failure?
      typing.add_error Errors::IncompatibleMethodTypeAnnotation.new(
        node: node,
        annotation_method: annotation_method,
        interface_method: interface_method,
        result: result
      )
    end
  end

  method = annotation_method || interface_method

  case
  when method && method.types.size == 1
    method_type = method.types.first
    return_type = method_type.return_type
    var_types = TypeConstruction.parameter_types(args, method_type).transform_values {|type| absolute_type(type) }
    unless TypeConstruction.valid_parameter_env?(var_types, args.reject {|arg| arg.type == :blockarg }, method_type.params)
      typing.add_error Errors::MethodArityMismatch.new(node: node)
    end
  when method
    typing.add_error Errors::MethodDefinitionWithOverloading.new(node: node, method: method)
    return_type = union_type(*method.types.map(&:return_type))
    var_types = {}
  else
    var_types = {}
  end

  if annots.return_type && return_type
    return_type_relation = Subtyping::Relation.new(sub_type: annots.return_type,
                                                   super_type: return_type)
    checker.check(return_type_relation, constraints: Subtyping::Constraints.empty).else do |result|
      typing.add_error Errors::MethodReturnTypeAnnotationMismatch.new(node: node,
                                                                      method_type: return_type,
                                                                      annotation_type: annots.return_type,
                                                                      result: result)
    end
  end

  constructor_method = method&.attributes&.include?(:constructor)

  method_context = MethodContext.new(
    name: method_name,
    method: method,
    method_type: method_type,
    return_type: annots.return_type || return_type,
    constructor: constructor_method
  )

  var_types.each do |name, type|
    type_env.set(lvar: name, type: type)
  end

  ivar_types = {}
  ivar_types.merge!(self_interface.ivars) if self_interface
  ivar_types.merge!(annots.ivar_types)

  ivar_types.each do |name, type|
    type_env.set(ivar: name, type: type)
  end

  type_env = type_env.with_annotations(
    lvar_types: annots.var_types.transform_values {|annot| absolute_type(annot.type) },
    ivar_types: annots.ivar_types,
    const_types: annots.const_types.transform_values {|type| absolute_type(type) }
  )

  self.class.new(
    checker: checker,
    source: source,
    annotations: annots,
    type_env: type_env,
    block_context: nil,
    self_type: self_type,
    method_context: method_context,
    typing: typing,
    module_context: module_context,
    break_context: nil
  )
end

#namespace_module?(node) ⇒ Boolean 



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# File 'lib/steep/type_construction.rb', line 2093

def namespace_module?(node)
  nodes = case node.type
          when :class, :module
            node.children.last&.yield_self {|child|
              if child.type == :begin
                child.children
              else
                [child]
              end
            } || []
          else
            return false
          end

  !nodes.empty? && nodes.all? {|child| child.type == :class || child.type == :module }
end

#nested_namespace(new) ⇒ Object 



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# File 'lib/steep/type_construction.rb', line 1970

def nested_namespace(new)
  case
  when !new.simple?
    current_namespace
  when current_namespace
    current_namespace + new
  else
    new.absolute!
  end
end

#self_class?(node) ⇒ Boolean 



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# File 'lib/steep/type_construction.rb', line 2089

def self_class?(node)
  node.type == :send && node.children[0]&.type == :self && node.children[1] == :class
end

#synthesize(node) ⇒ Object 



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# File 'lib/steep/type_construction.rb', line 435

def synthesize(node)
  Steep.logger.tagged "synthesize:(#{node.location.expression.to_s.split(/:/, 2).last})" do
    Steep.logger.debug node.type
    case node.type
    when :begin, :kwbegin
      yield_self do
        type = each_child_node(node).map do |child|
          synthesize(child)
        end.last

        typing.add_typing(node, type)
      end

    when :lvasgn
      yield_self do
        var = node.children[0]
        rhs = node.children[1]

        if var.name == :_
          typing.add_typing(node, Types.any)
        else
          type_assignment(var, rhs, node)
        end
      end

    when :lvar
      yield_self do
        var = node.children[0]
        type = type_env.get(lvar: var.name) do
          fallback_to_any node
        end

        typing.add_typing node, type
      end

    when :ivasgn
      name = node.children[0]
      value = node.children[1]

      type_ivasgn(name, value, node)

    when :ivar
      yield_self do
        name = node.children[0]
        type = type_env.get(ivar: name) do
          fallback_to_any node
        end
        typing.add_typing(node, type)
      end

    when :send
      yield_self do
        if self_class?(node)
          module_type = module_context.module_type
          type = if module_type.is_a?(AST::Types::Name) && module_type.name.is_a?(TypeName::Class)
                   AST::Types::Name.new(name: module_type.name.updated(constructor: method_context.constructor),
                                        args: module_type.args)
                 else
                   module_type
                 end
          typing.add_typing(node, type)
        else
          type_send(node, send_node: node, block_params: nil, block_body: nil)
        end
      end

    when :csend
      yield_self do
        type = if self_class?(node)
                 module_type = module_context.module_type
                 type = if module_type.is_a?(AST::Types::Name)
                          AST::Types::Name.new(name: module_type.name.updated(constructor: method_context.constructor),
                                               args: module_type.args)
                        else
                          module_type
                        end
                 typing.add_typing(node, type)
               else
                 type_send(node, send_node: node, block_params: nil, block_body: nil, unwrap: true)
               end

        union_type(type, Types.nil_instance)
      end

    when :match_with_lvasgn
      each_child_node(node) do |child|
        synthesize(child)
      end
      typing.add_typing(node, Types.any)

    when :op_asgn
      yield_self do
        lhs, op, rhs = node.children

        synthesize(rhs)

        lhs_type = case lhs.type
                   when :lvasgn
                     type_env.get(lvar: lhs.children.first.name) do
                       break
                     end
                   when :ivasgn
                     type_env.get(ivar: lhs.children.first) do
                       break
                     end
                   else
                     Steep.logger.error("Unexpected op_asgn lhs: #{lhs.type}")
                     nil
                   end

        case
        when lhs_type == Types.any
          typing.add_typing(node, lhs_type)
        when !lhs_type
          fallback_to_any(node)
        else
          lhs_interface = checker.resolve(lhs_type, with_initialize: false)
          op_method = lhs_interface.methods[op]

          if op_method
            args = TypeInference::SendArgs.from_nodes([rhs])
            return_type_or_error = type_method_call(node,
                                                    receiver_type: lhs_type,
                                                    method: op_method,
                                                    args: args,
                                                    block_params: nil,
                                                    block_body: nil)

            if return_type_or_error.is_a?(Errors::Base)
              typing.add_error return_type_or_error
            else
              result = checker.check(
                Subtyping::Relation.new(sub_type: return_type_or_error, super_type: lhs_type),
                constraints: Subtyping::Constraints.empty
              )
              if result.failure?
                typing.add_error(
                  Errors::IncompatibleAssignment.new(
                    node: node,
                    lhs_type: lhs_type,
                    rhs_type: return_type_or_error,
                    result: result
                  )
                )
              end
            end
          else
            typing.add_error Errors::NoMethod.new(node: node, method: op, type: lhs_type)
          end

          typing.add_typing(node, lhs_type)
        end
      end

    when :super
      yield_self do
        if self_type && method_context&.method
          if method_context.super_method
            each_child_node(node) do |child| synthesize(child) end

            super_method = method_context.super_method
            args = TypeInference::SendArgs.from_nodes(node.children.dup)

            return_type_or_error = type_method_call(node,
                                                    receiver_type: self_type,
                                                    method: super_method,
                                                    args: args,
                                                    block_params: nil,
                                                    block_body: nil)

            if return_type_or_error.is_a?(Errors::Base)
              fallback_to_any node do
                return_type_or_error
              end
            else
              typing.add_typing node, return_type_or_error
            end
          else
            fallback_to_any node do
              Errors::UnexpectedSuper.new(node: node, method: method_context.name)
            end
          end
        else
          typing.add_typing node, Types.any
        end
      end

    when :block
      yield_self do
        send_node, params, body = node.children
        type_send(node, send_node: send_node, block_params: params, block_body: body)
      end

    when :def
      new = for_new_method(node.children[0],
                           node,
                           args: node.children[1].children,
                           self_type: module_context&.instance_type)

      each_child_node(node.children[1]) do |arg|
        new.synthesize(arg)
      end

      if node.children[2]
        return_type = new.method_context&.return_type
        if return_type && !return_type.is_a?(AST::Types::Void)
          new.check(node.children[2], return_type) do |_, actual_type, result|
            typing.add_error(Errors::MethodBodyTypeMismatch.new(node: node,
                                                                expected: return_type,
                                                                actual: actual_type,
                                                                result: result))
          end
        else
          new.synthesize(node.children[2])
        end
      else
        return_type = new.method_context&.return_type
        if return_type && !return_type.is_a?(AST::Types::Void)
          result = checker.check(
            Subtyping::Relation.new(sub_type: Types.nil_instance, super_type: return_type),
            constraints: Subtyping::Constraints.empty
          )
          if result.failure?
            typing.add_error(Errors::MethodBodyTypeMismatch.new(node: node,
                                                                expected: return_type,
                                                                actual: Types.nil_instance,
                                                                result: result))
          end
        end            
      end

      if module_context
        module_context.defined_instance_methods << node.children[0]
      end

      typing.add_typing(node, Types.any)

    when :defs
      synthesize(node.children[0]).tap do |self_type|
        new = for_new_method(node.children[1],
                             node,
                             args: node.children[2].children,
                             self_type: self_type)

        each_child_node(node.children[2]) do |arg|
          new.synthesize(arg)
        end

        if node.children[3]
          return_type = new.method_context&.return_type
          if return_type && !return_type.is_a?(AST::Types::Void)
            new.check(node.children[3], return_type) do |return_type, actual_type, result|
              typing.add_error(Errors::MethodBodyTypeMismatch.new(node: node,
                                                                  expected: return_type,
                                                                  actual: actual_type,
                                                                  result: result))
            end
          else
            new.synthesize(node.children[3])
          end
        end
      end

      if module_context
        if node.children[0].type == :self
          module_context.defined_module_methods << node.children[1]
        end
      end

      typing.add_typing(node, Types.symbol_instance)

    when :return
      yield_self do
        if node.children.size > 0
          return_types = node.children.map do |value|
            synthesize(value)
          end

          value_type = if return_types.size == 1
                         return_types.first
                       else
                         Types.array_instance(union_type(*return_types))
                       end

          if method_context&.return_type && !method_context.return_type.is_a?(AST::Types::Void)
            result = checker.check(
              Subtyping::Relation.new(sub_type: value_type,
                                      super_type: method_context.return_type),
              constraints: Subtyping::Constraints.empty
            )

            if result.failure?
              typing.add_error(Errors::ReturnTypeMismatch.new(node: node,
                                                              expected: method_context.return_type,
                                                              actual: value_type,
                                                              result: result))
            end
          end
        end

        typing.add_typing(node, Types.any)
      end

    when :break
      value = node.children[0]

      if break_context
        case
        when value && break_context.break_type
          check(value, break_context.break_type) do |break_type, actual_type, result|
            typing.add_error Errors::BreakTypeMismatch.new(node: node,
                                                           expected: break_type,
                                                           actual: actual_type,
                                                           result: result)
          end
        when !value
          # ok
        else
          synthesize(value) if value
          typing.add_error Errors::UnexpectedJumpValue.new(node: node)
        end
      else
        synthesize(value)
        typing.add_error Errors::UnexpectedJump.new(node: node)
      end

      typing.add_typing(node, Types.any)

    when :next
      value = node.children[0]

      if break_context
        case
        when value && break_context.next_type
          check(value, break_context.next_type) do |break_type, actual_type, result|
            typing.add_error Errors::BreakTypeMismatch.new(node: node,
                                                           expected: break_type,
                                                           actual: actual_type,
                                                           result: result)
          end
        when !value
          # ok
        else
          synthesize(value) if value
          typing.add_error Errors::UnexpectedJumpValue.new(node: node)
        end
      else
        synthesize(value)
        typing.add_error Errors::UnexpectedJump.new(node: node)
      end

      typing.add_typing(node, Types.any)

    when :retry
      unless break_context
        typing.add_error Errors::UnexpectedJump.new(node: node)
      end
      typing.add_typing(node, Types.any)

    when :arg, :kwarg, :procarg0
      yield_self do
        var = node.children[0]
        type = type_env.get(lvar: var.name) do
          fallback_to_any node
        end
        typing.add_typing(node, type)
      end

    when :optarg, :kwoptarg
      yield_self do
        var = node.children[0]
        rhs = node.children[1]
        type_assignment(var, rhs, node)
      end

    when :restarg
      yield_self do
        var = node.children[0]
        type = type_env.get(lvar: var.name) do
          typing.add_error Errors::FallbackAny.new(node: node)
          Types.array_instance(Types.any)
        end

        typing.add_typing(node, type)
      end

    when :kwrestarg
      yield_self do
        var = node.children[0]
        type = type_env.get(lvar: var.name) do
          typing.add_error Errors::FallbackAny.new(node: node)
          Types.hash_instance(Types.symbol_instance, Types.any)
        end

        typing.add_typing(node, type)
      end

    when :int
      typing.add_typing(node, AST::Types::Name.new_instance(name: "::Integer"))

    when :float
      typing.add_typing(node, AST::Types::Name.new_instance(name: "::Float"))

    when :nil
      typing.add_typing(node, Types.nil_instance)

    when :sym
      typing.add_typing(node, Types.symbol_instance)

    when :str
      typing.add_typing(node, Types.string_instance)

    when :true, :false
      typing.add_typing(node, AST::Types::Name.new_interface(name: :_Boolean))

    when :hash
      yield_self do
        key_types = []
        value_types = []

        each_child_node(node) do |child|
          case child.type
          when :pair
            key, value = child.children
            key_types << synthesize(key)
            value_types << synthesize(value)
          when :kwsplat
            splat_type = synthesize(child.children[0])

            if splat_type.is_a?(AST::Types::Name) && splat_type.name == TypeName::Instance.new(name: ModuleName.parse("::Hash"))
              key_types << splat_type.args[0]
              value_types << splat_type.args[1]
            else
              typing.add_error Errors::UnexpectedSplat.new(node: child, type: splat_type)
              key_types << Types.any
              value_types << Types.any
            end
          else
            raise "Unexpected non pair: #{child.inspect}" unless child.type == :pair
          end
        end

        key_type = key_types.empty? ? Types.any : AST::Types::Union.build(types: key_types)
        value_type = value_types.empty? ? Types.any : AST::Types::Union.build(types: value_types)

        typing.add_typing(node, Types.hash_instance(key_type, value_type))
      end

    when :dstr
      each_child_node(node) do |child|
        synthesize(child)
      end

      typing.add_typing(node, Types.string_instance)

    when :dsym
      each_child_node(node) do |child|
        synthesize(child)
      end

      typing.add_typing(node, Types.symbol_instance)

    when :class
      yield_self do
        for_class(node).tap do |constructor|
          constructor.synthesize(node.children[2]) if node.children[2]

          if constructor.module_context&.implement_name && !namespace_module?(node)
            constructor.validate_method_definitions(node, constructor.module_context.implement_name)
          end
        end

        typing.add_typing(node, Types.nil_instance)
      end

    when :module
      yield_self do
        for_module(node).yield_self do |constructor|
          constructor.synthesize(node.children[1]) if node.children[1]

          if constructor.module_context&.implement_name && !namespace_module?(node)
            constructor.validate_method_definitions(node, constructor.module_context.implement_name)
          end
        end

        typing.add_typing(node, Types.nil_instance)
      end

    when :self
      if self_type
        typing.add_typing(node, self_type)
      else
        fallback_to_any node
      end

    when :const
      const_name = ModuleName.from_node(node)
      if const_name
        type = type_env.get(const: const_name) do
          fallback_to_any node
        end
        typing.add_typing node, type
      else
        fallback_to_any node
      end

    when :casgn
      yield_self do
        const_name = ModuleName.from_node(node)
        if const_name
          value_type = synthesize(node.children.last)
          type = type_env.assign(const: const_name, type: value_type) do |error|
            case error
            when Subtyping::Result::Failure
              const_type = type_env.get(const: const_name)
              typing.add_error(Errors::IncompatibleAssignment.new(node: node,
                                                                  lhs_type: const_type,
                                                                  rhs_type: value_type,
                                                                  result: error))
            when nil
              typing.add_error(Errors::UnknownConstantAssigned.new(node: node, type: value_type))
            end
          end

          typing.add_typing(node, type)
        else
          synthesize(node.children.last)
          fallback_to_any(node)
        end
      end

    when :yield
      if method_context&.method_type
        if method_context.block_type
          block_type = method_context.block_type
          block_type.params.flat_unnamed_params.map(&:last).zip(node.children).each do |(type, node)|
            if node && type
              check(node, type) do |_, rhs_type, result|
                typing.add_error(Errors::IncompatibleAssignment.new(node: node,
                                                                    lhs_type: type,
                                                                    rhs_type: rhs_type,
                                                                    result: result))
              end
            end
          end

          typing.add_typing(node, block_type.return_type)
        else
          typing.add_error(Errors::UnexpectedYield.new(node: node))
          fallback_to_any node
        end
      else
        fallback_to_any node
      end

    when :zsuper
      yield_self do
        if method_context&.method
          if method_context.super_method
            types = method_context.super_method.types.map(&:return_type)
            typing.add_typing(node, union_type(*types))
          else
            typing.add_error(Errors::UnexpectedSuper.new(node: node, method: method_context.name))
            fallback_to_any node
          end
        else
          fallback_to_any node
        end
      end

    when :array
      yield_self do
        if node.children.empty?
          typing.add_typing(node, Types.array_instance(Types.any))
        else
          types = node.children.flat_map do |e|
            if e.type == :splat
              Steep.logger.info "Typing of splat in array is incompatible with Ruby; it does not use #to_a method"
              synthesize(e.children.first).yield_self do |type|
                case type
                when AST::Types::Union
                  type.types
                else
                  [type]
                end
              end.map do |type|
                case
                when type.is_a?(AST::Types::Name) && type.name.is_a?(TypeName::Instance) && type.name.name == ModuleName.new(name: "Array", absolute: true)
                  type.args.first
                when type.is_a?(AST::Types::Name) && type.name.is_a?(TypeName::Instance) && type.name.name == ModuleName.new(name: "Range", absolute: true)
                  type.args.first
                else
                  type
                end
              end
            else
              [synthesize(e)]
            end
          end

          typing.add_typing(node, Types.array_instance(AST::Types::Union.build(types: types)))
        end
      end

    when :and
      yield_self do
        left, right = node.children
        left_type = synthesize(left)

        truthy_vars = TypeConstruction.truthy_variables(left)
        right_type, right_env = for_branch(right, truthy_vars: truthy_vars).yield_self do |constructor|
          type = constructor.synthesize(right)
          [type, constructor.type_env]
        end

        type_env.join!([right_env, TypeInference::TypeEnv.new(subtyping: checker,
                                                              const_env: nil)])

        if Types.boolean?(left_type)
          typing.add_typing(node, union_type(left_type, right_type))
        else
          typing.add_typing(node, union_type(right_type, Types.nil_instance))
        end
      end

    when :or
      types = each_child_node(node).map {|child| synthesize(child) }
      type = union_type(*types)
      typing.add_typing(node, type)

    when :if
      cond, true_clause, false_clause = node.children
      synthesize cond

      truthy_vars = TypeConstruction.truthy_variables(cond)

      if true_clause
        true_type, true_env = for_branch(true_clause, truthy_vars: truthy_vars).yield_self do |constructor|
          type = constructor.synthesize(true_clause)
          [type, constructor.type_env]
        end
      end
      if false_clause
        false_type, false_env = for_branch(false_clause).yield_self do |constructor|
          type = constructor.synthesize(false_clause)
          [type, constructor.type_env]
        end
      end

      type_env.join!([true_env, false_env].compact)
      typing.add_typing(node, union_type(true_type, false_type))

    when :case
      yield_self do
        cond, *whens = node.children

        if cond
          cond_type = synthesize(cond)
          if cond_type.is_a?(AST::Types::Union)
            var_names = TypeConstruction.value_variables(cond)
            var_types = cond_type.types.dup
          end
        end

        pairs = whens.each.with_object([]) do |clause, pairs|
          if clause&.type == :when
            test_types = clause.children.take(clause.children.size - 1).map do |child|
              synthesize(child)
            end

            if (body = clause.children.last)
              if var_names && var_types && test_types.all? {|type| type.is_a?(AST::Types::Name) && type.name.is_a?(TypeName::Class) && type.args.empty? }
                var_types_in_body = test_types.flat_map {|test_type|
                  filtered_types = var_types.select {|var_type| var_type.name.name == test_type.name.name }
                  if filtered_types.empty?
                    test_type.instance_type
                  else
                    filtered_types
                  end
                }
                var_types.reject! {|type|
                  var_types_in_body.any? {|test_type|
                    test_type.name.name == type.name.name
                  }
                }

                type_case_override = var_names.each.with_object({}) do |var_name, hash|
                  hash[var_name] = union_type(*var_types_in_body)
                end
              else
                type_case_override = nil
              end

              for_branch(body, type_case_override: type_case_override).yield_self do |body_construction|
                type = body_construction.synthesize(body)
                pairs << [type, body_construction.type_env]
              end
            else
              pairs << [Types.nil_instance, nil]
            end
          else
            if clause
              if var_types
                if !var_types.empty?
                  type_case_override = var_names.each.with_object({}) do |var_name, hash|
                    hash[var_name] = union_type(*var_types)
                  end
                  var_types.clear
                else
                  typing.add_error Errors::ElseOnExhaustiveCase.new(node: node, type: cond_type)
                  type_case_override = var_names.each.with_object({}) do |var_name, hash|
                    hash[var_name] = Types.any
                  end
                end
              end

              for_branch(clause, type_case_override: type_case_override).yield_self do |body_construction|
                type = body_construction.synthesize(clause)
                pairs << [type, body_construction.type_env]
              end
            end
          end
        end

        types = pairs.map(&:first)
        envs = pairs.map(&:last)

        if var_types
          unless var_types.empty? || whens.last
            types.push Types.nil_instance
          end
        end

        type_env.join!(envs.compact)
        typing.add_typing(node, union_type(*types))
      end

    when :rescue
      yield_self do
        body, *resbodies, else_node = node.children
        body_type = synthesize(body) if body

        resbody_pairs = resbodies.map do |resbody|
          exn_classes, assignment, body = resbody.children

          if exn_classes
            case exn_classes.type
            when :array
              exn_types = exn_classes.children.map {|child| synthesize(child) }
            else
              Steep.logger.error "Unexpected exception list: #{exn_classes.type}"
            end
          end

          if assignment
            case assignment.type
            when :lvasgn
              var_name = assignment.children[0].name
            else
              Steep.logger.error "Unexpected rescue variable assignment: #{assignment.type}"
            end
          end

          type_override = {}

          case
          when exn_classes && var_name
            instance_types = exn_types.map do |type|
              case
              when type.is_a?(AST::Types::Name) && type.name.is_a?(TypeName::Class)
                type.instance_type
              else
                Types.any
              end
            end
            type_override[var_name] = AST::Types::Union.build(types: instance_types)
          when var_name
            type_override[var_name] = Types.any
          end

          resbody_construction = for_branch(resbody, type_case_override: type_override)

          type = if body
                   resbody_construction.synthesize(body)
                 else
                   Types.nil_instance
                 end
          [type, resbody_construction.type_env]
        end
        resbody_types, resbody_envs = resbody_pairs.transpose

        if else_node
          else_construction = for_branch(else_node)
          else_type = else_construction.synthesize(else_node)
          else_env = else_construction.type_env
        end

        type_env.join!([*resbody_envs, else_env].compact)

        types = [body_type, *resbody_types, else_type].compact
        typing.add_typing(node, union_type(*types))
      end

    when :resbody
      yield_self do
        klasses, asgn, body = node.children
        synthesize(klasses) if klasses
        synthesize(asgn) if asgn
        body_type = synthesize(body) if body
        typing.add_typing(node, body_type)
      end

    when :ensure
      yield_self do
        body, ensure_body = node.children
        body_type = synthesize(body) if body
        synthesize(ensure_body) if ensure_body
        typing.add_typing(node, union_type(body_type))
      end

    when :masgn
      type_masgn(node)

    when :while, :while_post, :until, :until_post
      yield_self do
        cond, body = node.children

        synthesize(cond)
        truthy_vars = node.type == :while ? TypeConstruction.truthy_variables(cond) : Set.new

        if body
          for_loop = for_branch(body, truthy_vars: truthy_vars).with(break_context: BreakContext.new(break_type: nil, next_type: nil))
          for_loop.synthesize(body)
          type_env.join!([for_loop.type_env])
        end

        typing.add_typing(node, Types.any)
      end

    when :irange, :erange
      types = node.children.map {|n| synthesize(n) }
      type = Types.range_instance(union_type(*types))
      typing.add_typing(node, type)

    when :regexp
      each_child_node(node) do |child|
        synthesize(child)
      end

      typing.add_typing(node, AST::Types::Name.new_instance(name: "::Regexp"))

    when :regopt
      # ignore
      typing.add_typing(node, Types.any)

    when :nth_ref, :back_ref
      typing.add_typing(node, Types.string_instance)

    when :or_asgn, :and_asgn
      yield_self do
        _, rhs = node.children
        rhs_type = synthesize(rhs)
        typing.add_typing(node, rhs_type)
      end

    when :defined?
      each_child_node(node) do |child|
        synthesize(child)
      end

      typing.add_typing(node, Types.any)

    when :gvasgn
      yield_self do
        name, rhs = node.children
        type = checker.builder.signatures.find_gvar(name)&.type

        if type
          check(rhs, type) do |_, rhs_type, result|
            typing.add_error(Errors::IncompatibleAssignment.new(node: node,
                                                                lhs_type: type,
                                                                rhs_type: rhs_type,
                                                                result: result))
          end
        else
          synthesize(rhs)
          fallback_to_any node
        end
      end

    when :gvar
      yield_self do
        name = node.children.first
        type = checker.builder.signatures.find_gvar(name)&.type

        if type
          typing.add_typing(node, type)
        else
          fallback_to_any node
        end
      end

    when :splat, :block_pass, :blockarg, :sclass
      yield_self do
        Steep.logger.error "Unsupported node #{node.type}"

        each_child_node node do |child|
          synthesize(child)
        end

        typing.add_typing node, Types.any
      end

    else
      raise "Unexpected node: #{node.inspect}, #{node.location.expression}"
    end
  end
end

#test_args(params:, arguments:) ⇒ Object 



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# File 'lib/steep/type_construction.rb', line 1787

def test_args(params:, arguments:)
  params.each_missing_argument arguments do |_|
    return nil
  end

  params.each_extra_argument arguments do |_|
    return nil
  end

  params.each_missing_keyword arguments do |_|
    return nil
  end

  params.each_extra_keyword arguments do |_|
    return nil
  end

  self.class.argument_typing_pairs(params: params, arguments: arguments.dup)
end

#try_method_type(node, receiver_type:, method_type:, arg_pairs:, block_params:, block_body:) ⇒ Object 



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# File 'lib/steep/type_construction.rb', line 1588

def try_method_type(node, receiver_type:, method_type:, arg_pairs:, block_params:, block_body:)
  fresh_types = method_type.type_params.map {|x| AST::Types::Var.fresh(x) }
  fresh_vars = Set.new(fresh_types.map(&:name))
  instantiation = Interface::Substitution.build(method_type.type_params, fresh_types)

  method_type.instantiate(instantiation).yield_self do |method_type|
    constraints = Subtyping::Constraints.new(unknowns: fresh_types.map(&:name))
    variance = Subtyping::VariableVariance.from_method_type(method_type)
    occurence = Subtyping::VariableOccurence.from_method_type(method_type)

    arg_pairs.each do |(arg_node, param_type)|
      relation = Subtyping::Relation.new(
        sub_type: typing.type_of(node: arg_node),
        super_type: param_type.subst(instantiation)
      )

      checker.check(relation, constraints: constraints).else do |result|
        return Errors::ArgumentTypeMismatch.new(
          node: arg_node,
          receiver_type: receiver_type,
          expected: relation.super_type,
          actual: relation.sub_type
        )
      end
    end

    if method_type.block && block_params
      block_annotations = source.annotations(block: node)

      params = TypeInference::BlockParams.from_node(block_params, annotations: block_annotations)
      block_param_pairs = params.zip(method_type.block.params)

      unless block_param_pairs
        return Errors::IncompatibleBlockParameters.new(
          node: node,
          method_type: method_type
        )
      end

      block_param_pairs.each do |param, type|
        if param.type
          relation = Subtyping::Relation.new(
            sub_type: type,
            super_type: absolute_type(param.type)
          )

          checker.check(relation, constraints: constraints).else do |result|
            return Errors::BlockParameterTypeMismatch.new(
              node: param.node,
              expected: type,
              actual: param.type
            )
          end
        end
      end

      if block_annotations.block_type
        relation = Subtyping::Relation.new(
          sub_type: absolute_type(block_annotations.block_type),
          super_type: method_type.block.return_type
        )

        checker.check(relation, constraints: constraints).else do |result|
          typing.add_error Errors::BlockTypeMismatch.new(node: node,
                                                         expected: method_type.block.return_type,
                                                         actual: absolute_type(block_annotations.block_type),
                                                         result: result)
        end
      end
    end

    case
    when method_type.block && block_params && block_body
      Steep.logger.debug "block is okay: method_type=#{method_type}"
      Steep.logger.debug "Constraints = #{constraints}"

      begin
        method_type.subst(constraints.solution(checker, variance: variance, variables: occurence.params)).yield_self do |method_type|
          block_annotations = source.annotations(block: node)

          params = TypeInference::BlockParams.from_node(block_params, annotations: block_annotations)
          block_param_pairs = params.zip(method_type.block.params)

          block_type_env = type_env.dup.yield_self do |env|
            block_param_pairs.each do |param, type|
              if param.type
                env.set(lvar: param.var.name, type: absolute_type(param.type))
              else
                env.set(lvar: param.var.name, type: absolute_type(type))
              end
            end

            env.with_annotations(
              lvar_types: block_annotations.var_types.transform_values {|annot| absolute_type(annot.type) },
              ivar_types: block_annotations.ivar_types.transform_values {|type| absolute_type(type) },
              const_types: block_annotations.const_types.transform_values {|type| absolute_type(type) }
            )
          end

          return_type = if block_annotations.break_type
                          union_type(method_type.return_type, absolute_type(block_annotations.break_type))
                        else
                          method_type.return_type
                        end
          Steep.logger.debug("return_type = #{return_type}")

          block_context = BlockContext.new(body_type: absolute_type(block_annotations.block_type))
          Steep.logger.debug("block_context { body_type: #{block_context.body_type} }")

          break_context = BreakContext.new(
            break_type: absolute_type(block_annotations.break_type) || method_type.return_type,
            next_type: absolute_type(block_annotations.block_type)
          )
          Steep.logger.debug("break_context { type: #{absolute_type(break_context.break_type)} }")

          for_block = self.class.new(
            checker: checker,
            source: source,
            annotations: annotations + block_annotations,
            type_env: block_type_env,
            block_context: block_context,
            typing: typing,
            method_context: method_context,
            module_context: module_context,
            self_type: absolute_type(block_annotations.self_type) || self_type,
            break_context: break_context
          )

          each_child_node(block_params) do |p|
            for_block.synthesize(p)
          end

          block_body_type = for_block.synthesize(block_body)

          unless method_type.block.return_type.is_a?(AST::Types::Void)
            result = checker.check(Subtyping::Relation.new(
              sub_type: block_annotations.block_type || block_body_type,
              super_type: method_type.block.return_type
            ), constraints: constraints)

            if result.success?
              return_type.subst(constraints.solution(checker, variance: variance, variables: fresh_vars))
            else
              typing.add_error Errors::BlockTypeMismatch.new(node: node,
                                                             expected: method_type.block.return_type,
                                                             actual: block_annotations.block_type || block_body_type,
                                                             result: result)
              return_type
            end
          else
            return_type
          end
        end

      rescue Subtyping::Constraints::UnsatisfiableConstraint => exn
        typing.add_error Errors::UnsatisfiableConstraint.new(node: node,
                                                             method_type: method_type,
                                                             var: exn.var,
                                                             sub_type: exn.sub_type,
                                                             super_type: exn.super_type,
                                                             result: exn.result
        )
        fallback_any_rec node
      end

    when !method_type.block && !block_params && !block_body
      # OK, without block
      method_type.subst(constraints.solution(checker, variance: variance, variables: fresh_vars)).return_type

    when !method_type.block && block_params && block_body
      Errors::UnexpectedBlockGiven.new(
        node: node,
        method_type: method_type
      )

    when method_type.block && !block_params && !block_body
      Errors::RequiredBlockMissing.new(
        node: node,
        method_type: method_type
      )

    else
      raise "Unexpected case condition"
    end
  end
end

#type_assignment(var, rhs, node) ⇒ Object 



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# File 'lib/steep/type_construction.rb', line 1367

def type_assignment(var, rhs, node)
  if rhs
    rhs_type = synthesize(rhs)
    node_type = assign_type_to_variable(var, rhs_type, node)
    typing.add_typing(node, node_type)
  else
    raise
    lhs_type = variable_type(var)

    if lhs_type
      typing.add_var_type(var, lhs_type)
      typing.add_typing(node, lhs_type)
      var_types[var] = lhs_type
    else
      typing.add_var_type(var, Types.any)
      fallback_to_any node
      var_types[var] = Types.any
    end
  end
end

#type_ivasgn(name, rhs, node) ⇒ Object 



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# File 'lib/steep/type_construction.rb', line 1399

def type_ivasgn(name, rhs, node)
  rhs_type = synthesize(rhs)
  ivar_type = type_env.assign(ivar: name, type: rhs_type) do |error|
    case error
    when Subtyping::Result::Failure
      type = type_env.get(ivar: name)
      typing.add_error(Errors::IncompatibleAssignment.new(node: node,
                                                          lhs_type: type,
                                                          rhs_type: rhs_type,
                                                          result: error))
    when nil
      fallback_to_any node
    end
  end
  typing.add_typing(node, ivar_type)
end

#type_masgn(node) ⇒ Object 



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# File 'lib/steep/type_construction.rb', line 1416

def type_masgn(node)
  lhs, rhs = node.children
  rhs_type = synthesize(rhs)

  case
  when rhs.type == :array && lhs.children.all? {|a| a.type == :lvasgn || a.type == :ivasgn } && lhs.children.size == rhs.children.size
    pairs = lhs.children.zip(rhs.children)
    pairs.each do |(l, r)|
      case
      when l.type == :lvasgn
        type_assignment(l.children.first, r, l)
      when l.type == :ivasgn
        type_ivasgn(l.children.first, r, l)
      end
    end

    typing.add_typing(node, rhs_type)

  when rhs_type.is_a?(AST::Types::Any)
    fallback_to_any(node)

  when rhs_type.is_a?(AST::Types::Name) && rhs_type.name.is_a?(TypeName::Instance) && rhs_type.name.name == ModuleName.new(name: "Array", absolute: true)
    element_type = rhs_type.args.first

    lhs.children.each do |assignment|
      case assignment.type
      when :lvasgn
        assign_type_to_variable(assignment.children.first, element_type, assignment)
      when :ivasgn
        assignment.children.first.yield_self do |ivar|
          type_env.assign(ivar: ivar, type: element_type) do |error|
            case error
            when Subtyping::Result::Failure
              type = type_env.get(ivar: ivar)
              typing.add_error(Errors::IncompatibleAssignment.new(node: assignment,
                                                                  lhs_type: type,
                                                                  rhs_type: element_type,
                                                                  result: error))
            when nil
              fallback_to_any node
            end
          end
        end
      end
    end

    typing.add_typing node, rhs_type

  when rhs_type.is_a?(AST::Types::Union) &&
    rhs_type.types.all? {|type| type.is_a?(AST::Types::Name) && type.name.is_a?(TypeName::Instance) && type.name.name == ModuleName.new(name: "Array", absolute: true) }

    types = rhs_type.types.flat_map do |type|
      type.args.first
    end

    element_type = AST::Types::Union.build(types: types)

    lhs.children.each do |assignment|
      case assignment.type
      when :lvasgn
        assign_type_to_variable(assignment.children.first, element_type, assignment)
      when :ivasgn
        assignment.children.first.yield_self do |ivar|
          type_env.assign(ivar: ivar, type: element_type) do |error|
            case error
            when Subtyping::Result::Failure
              type = type_env.get(ivar: ivar)
              typing.add_error(Errors::IncompatibleAssignment.new(node: assignment,
                                                                  lhs_type: type,
                                                                  rhs_type: element_type,
                                                                  result: error))
            when nil
              fallback_to_any node
            end
          end
        end
      end
    end

    typing.add_typing node, rhs_type

  else
    Steep.logger.error("Unsupported masgn: #{rhs.type} (#{rhs_type})")
    fallback_to_any(node)
  end
end

#type_method_call(node, receiver_type:, method:, args:, block_params:, block_body:) ⇒ Object 



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# File 'lib/steep/type_construction.rb', line 1560

def type_method_call(node, receiver_type:, method:, args:, block_params:, block_body:)
  results = method.types.map do |method_type|
    Steep.logger.tagged method_type.location&.source do
      arg_pairs = args.zip(method_type.params)

      if arg_pairs
        try_method_type(node,
                        receiver_type: receiver_type,
                        method_type: method_type,
                        arg_pairs: arg_pairs,
                        block_params: block_params,
                        block_body: block_body)
      else
        Steep.logger.debug(node.inspect)
        Errors::IncompatibleArguments.new(node: node, receiver_type: receiver_type, method_type: method_type)
      end
    end
  end

  if results.all? {|result| result.is_a?(Errors::Base) }
    results.first
  else
    results.find do |result|
      !result.is_a?(Errors::Base)
    end
  end
end

#type_send(node, send_node:, block_params:, block_body:, unwrap: false) ⇒ Object 



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# File 'lib/steep/type_construction.rb', line 1503

def type_send(node, send_node:, block_params:, block_body:, unwrap: false)
  receiver, method_name, *arguments = send_node.children
  receiver_type = receiver ? synthesize(receiver) : self_type
  arguments.each do |arg|
    if arg.type == :splat
      type = synthesize(arg.children[0])
      typing.add_typing(arg, Types.array_instance(type))
    else
      synthesize(arg)
    end
  end

  if unwrap
    receiver_type = TypeConstruction.unwrap(receiver_type)
  end

  case receiver_type
  when AST::Types::Any
    typing.add_typing node, Types.any

  when nil
    fallback_to_any node

  else
    begin
      interface = checker.resolve(receiver_type, with_initialize: false)
      method = interface.methods[method_name]

      if method
        args = TypeInference::SendArgs.from_nodes(arguments)
        return_type_or_error = type_method_call(node,
                                                method: method,
                                                args: args,
                                                block_params: block_params,
                                                block_body: block_body,
                                                receiver_type: receiver_type)

        if return_type_or_error.is_a?(Errors::Base)
          fallback_to_any node do
            return_type_or_error
          end
        else
          typing.add_typing node, return_type_or_error
        end
      else
        fallback_to_any node do
          Errors::NoMethod.new(node: node, method: method_name, type: receiver_type)
        end
      end
    rescue Subtyping::Check::CannotResolveError
      fallback_to_any node do
        Errors::NoMethod.new(node: node, method: method_name, type: receiver_type)
      end
    end
  end
end

#union_type(*types) ⇒ Object 



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# File 'lib/steep/type_construction.rb', line 1995

def union_type(*types)
  AST::Types::Union.build(types: types)
end

#validate_method_definitions(node, module_name) ⇒ Object 



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# File 'lib/steep/type_construction.rb', line 1999

def validate_method_definitions(node, module_name)
  signature = checker.builder.signatures.find_class_or_module(module_name.name)
  expected_instance_method_names = Set.new()
  expected_module_method_names = Set.new

  signature.members.each do |member|
    case member
    when AST::Signature::Members::Method
      if member.instance_method?
        expected_instance_method_names << member.name
      end
      if member.module_method?
        expected_module_method_names << member.name
      end
    when AST::Signature::Members::Attr
      expected_instance_method_names << member.name
      expected_instance_method_names << "#{member.name}=".to_sym if member.accessor?
    end
  end

  expected_instance_method_names.each do |method_name|
    case
    when module_context.defined_instance_methods.include?(method_name)
      # ok
    when annotations.dynamics[method_name]&.instance_method?
      # ok
    else
      typing.add_error Errors::MethodDefinitionMissing.new(node: node,
                                                           module_name: module_name.name,
                                                           kind: :instance,
                                                           missing_method: method_name)
    end
  end
  expected_module_method_names.each do |method_name|
    case
    when module_context.defined_module_methods.include?(method_name)
      # ok
    when annotations.dynamics[method_name]&.module_method?
      # ok
    else
      typing.add_error Errors::MethodDefinitionMissing.new(node: node,
                                                           module_name: module_name.name,
                                                           kind: :module,
                                                           missing_method: method_name)
    end
  end

  annotations.dynamics.each do |method_name, annotation|
    case
    when annotation.module_method? && expected_module_method_names.member?(method_name)
      # ok
    when annotation.instance_method? && expected_instance_method_names.member?(method_name)
      # ok
    else
      typing.add_error Errors::UnexpectedDynamicMethod.new(node: node,
                                                           module_name: module_name.name,
                                                           method_name: method_name)
    end
  end
end

#with(annotations: NOTHING, type_env: NOTHING, method_context: NOTHING, block_context: NOTHING, module_context: NOTHING, self_type: NOTHING, break_context: NOTHING) ⇒ Object 



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# File 'lib/steep/type_construction.rb', line 420

def with(annotations: NOTHING, type_env: NOTHING, method_context: NOTHING, block_context: NOTHING, module_context: NOTHING, self_type: NOTHING, break_context: NOTHING)
  self.class.new(
    checker: checker,
    source: source,
    annotations: annotations.equal?(NOTHING) ? self.annotations : annotations,
    type_env: type_env.equal?(NOTHING) ? self.type_env : type_env,
    typing: typing,
    method_context: method_context.equal?(NOTHING) ? self.method_context : method_context,
    block_context: block_context.equal?(NOTHING) ? self.block_context : block_context,
    module_context: module_context.equal?(NOTHING) ? self.module_context : module_context,
    self_type: self_type.equal?(NOTHING) ? self.self_type : self_type,
    break_context: break_context.equal?(NOTHING) ? self.break_context : break_context
  )
end