(*
 * Copyright (c) Meta Platforms, Inc. and affiliates.
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 *)

module Ast = Flow_ast
module Type = Ast.Type
open Flow_ast_differ
open Utils_js
open OUnit2

let parse_options =
  Some
    {
      Parser_env.components = false;
      enums = true;
      esproposal_decorators = true;
      types = true;
      use_strict = false;
      module_ref_prefix = None;
      module_ref_prefix_LEGACY_INTEROP = None;
    }

class useless_mapper =
  object (this)
    inherit [Loc.t] Flow_ast_mapper.mapper as super

    method! number_literal _loc (lit : Loc.t Ast.NumberLiteral.t) =
      let open Ast.NumberLiteral in
      match lit.value with
      | 4.0 -> { value = 5.0; raw = "5"; comments = None }
      | _ -> lit

    method! string_literal _loc (lit : Loc.t Ast.StringLiteral.t) =
      let open Ast.StringLiteral in
      let { value; comments; _ } = lit in
      if String.equal "RenameSL" value then
        { value = "GotRenamedSL"; raw = "\"GotRenamedSL\""; comments }
      else
        lit

    method! logical loc (expr : (Loc.t, Loc.t) Ast.Expression.Logical.t) =
      let open Ast.Expression.Logical in
      let expr = super#logical loc expr in
      let { operator; _ } = expr in
      match operator with
      | NullishCoalesce -> { expr with operator = Or }
      | _ -> expr

    method! binary loc (expr : (Loc.t, Loc.t) Ast.Expression.Binary.t) =
      let open Ast.Expression.Binary in
      let expr = super#binary loc expr in
      let { operator; _ } = expr in
      match operator with
      | Plus -> { expr with operator = Minus }
      | Mult -> { expr with operator = Plus }
      | _ -> expr

    method! unary_expression loc (expr : (Loc.t, Loc.t) Ast.Expression.Unary.t) =
      let open Ast.Expression.Unary in
      let expr = super#unary_expression loc expr in
      let { operator; _ } = expr in
      match operator with
      | Minus -> expr
      | _ -> { expr with operator = Minus }

    method! identifier id =
      let (loc, { Ast.Identifier.name; comments = _ }) = id in
      match name with
      | "rename" -> Flow_ast_utils.ident_of_source (loc, "gotRenamed")
      | "Rename" -> Flow_ast_utils.ident_of_source (loc, "GotRenamed")
      | "RENAME" -> Flow_ast_utils.ident_of_source (loc, "GOT_RENAMED")
      | _ -> id

    method! variable_declaration loc (decl : (Loc.t, Loc.t) Ast.Statement.VariableDeclaration.t) =
      let open Ast.Variable in
      let open Ast.Statement.VariableDeclaration in
      let decl = super#variable_declaration loc decl in
      let { declarations; kind; comments } = decl in
      if kind = Var then
        { declarations; kind = Const; comments }
      else
        decl

    method! template_literal_element (elem : 'loc Ast.Expression.TemplateLiteral.Element.t) =
      let open Ast.Expression.TemplateLiteral.Element in
      let (loc, { value; tail }) = elem in
      if value.raw = "rename" then
        (loc, { value = { raw = "gotRenamed"; cooked = "gotRenamed" }; tail })
      else
        elem

    method! type_ (annot : (Loc.t, Loc.t) Type.t) =
      let open Ast.NumberLiteral in
      let annot = super#type_ annot in
      let (loc, typ) = annot in
      match typ with
      | Type.Number comments -> (loc, Type.String comments)
      | Type.NumberLiteral _ ->
        (loc, Type.NumberLiteral { value = 4.0; raw = "4.0"; comments = None })
      | _ -> annot

    method! jsx_element _loc (elem : (Loc.t, Loc.t) Ast.JSX.element) =
      let open Ast.JSX in
      let {
        opening_element = (_, open_elem) as opening_element;
        closing_element;
        children;
        comments;
      } =
        elem
      in
      let opening_element' = this#jsx_opening_element opening_element in
      let closing_element' =
        let (loc, open_elem') = opening_element' in
        if open_elem'.Opening.self_closing then
          None
        (* if self_closing changed from true to false, construct a closing element *)
        else if open_elem.Opening.self_closing then
          Some (loc, { Closing.name = open_elem'.Opening.name })
        else
          Flow_ast_mapper.map_opt super#jsx_closing_element closing_element
      in
      let children' = this#jsx_children children in
      if
        opening_element == opening_element'
        && closing_element == closing_element'
        && children == children'
      then
        elem
      else
        {
          opening_element = opening_element';
          closing_element = closing_element';
          children = children';
          comments;
        }

    method! jsx_opening_element (elem : (Loc.t, Loc.t) Ast.JSX.Opening.t) =
      let open Ast.JSX.Opening in
      let (loc, { name; targs; self_closing; attributes }) = elem in
      let name' = this#jsx_element_name name in
      let self_closing' =
        match name' with
        | Ast.JSX.Identifier (_, { Ast.JSX.Identifier.name = id_name; comments = _ }) ->
          if id_name = "selfClosing" then
            true
          else if id_name = "notSelfClosing" then
            false
          else
            self_closing
        | _ -> self_closing
      in
      let attributes' = ListUtils.ident_map super#jsx_opening_attribute attributes in
      if name == name' && self_closing == self_closing' && attributes == attributes' then
        elem
      else
        (loc, { name = name'; targs; self_closing = self_closing'; attributes = attributes' })

    method! jsx_identifier (id : (Loc.t, Loc.t) Ast.JSX.Identifier.t) =
      let open Ast.JSX.Identifier in
      let (loc, { name; comments }) = id in
      match name with
      | "rename" -> (loc, { name = "gotRenamed"; comments })
      | "Rename" -> (loc, { name = "GotRenamed"; comments })
      | "RENAME" -> (loc, { name = "GOT_RENAMED"; comments })
      | _ -> id

    method! jsx_attribute (attr : (Loc.t, Loc.t) Ast.JSX.Attribute.t) =
      let open Ast.JSX.Attribute in
      let (loc, { name; value }) = attr in
      let name' =
        match name with
        | Identifier id -> Identifier (this#jsx_identifier id)
        | _ -> name
      in
      let value' = Flow_ast_mapper.map_opt super#jsx_attribute_value value in
      if name == name' && value == value' then
        attr
      else
        (loc, { name = name'; value = value' })

    method! jsx_child (child : (Loc.t, Loc.t) Ast.JSX.child) =
      let open Ast.JSX in
      match child with
      | (loc, Text txt) ->
        let { Text.value; _ } = txt in
        if value = "rename" then
          (loc, Text { Text.value = "gotRenamed"; Text.raw = "gotRenamed" })
        else
          child
      | _ -> super#jsx_child child

    method! variance (variance : Loc.t Ast.Variance.t) =
      let open Ast.Variance in
      match variance with
      | (loc, { kind = Minus; comments }) -> (loc, { kind = Plus; comments })
      | _ -> variance

    method! call_type_args (loc, targs) =
      let open Ast.Expression.CallTypeArgs in
      let { arguments; comments } = targs in
      let f targ =
        let open Ast.Expression.CallTypeArg in
        match targ with
        | Explicit targ' -> Explicit (this#type_ targ')
        | Implicit (loc, _) -> Explicit (loc, Ast.Type.Any None)
      in
      (loc, { arguments = Base.List.map ~f arguments; comments })

    method! function_param_type (fpt : (Loc.t, Loc.t) Ast.Type.Function.Param.t) =
      let open Ast.Type.Function.Param in
      let ((loc, fpt') as fpt) = super#function_param_type fpt in
      let { name; _ } = fpt' in
      let name' = Flow_ast_mapper.map_opt this#identifier name in
      if name' == name then
        fpt
      else
        (loc, { fpt' with name = name' })

    method! update_expression loc (expr : (Loc.t, Loc.t) Ast.Expression.Update.t) =
      let open Ast.Expression.Update in
      let expr = super#update_expression loc expr in
      let { operator; _ } = expr in
      match operator with
      | Increment -> expr
      | _ -> { expr with operator = Increment }

    method! object_property_type (opt : (Loc.t, Loc.t) Ast.Type.Object.Property.t) =
      let open Ast.Type.Object.Property in
      let ((loc, opt') as opt) = super#object_property_type opt in
      let { key; variance; _ } = opt' in
      let key' = this#object_key key in
      let variance' = this#variance_opt variance in
      if key' == key && variance' == variance then
        opt
      else
        (loc, { opt' with key = key'; variance = variance' })

    method! enum_defaulted_member (member : Loc.t Ast.Statement.EnumDeclaration.DefaultedMember.t) =
      let open Ast.Statement.EnumDeclaration.DefaultedMember in
      let (loc, { id }) = member in
      match id with
      | (loc', { Ast.Identifier.name = "On"; comments }) ->
        (loc, { id = (loc', Ast.Identifier.{ name = "Enabled"; comments }) })
      | _ -> member

    method! enum_string_member
        (member :
          (Loc.t Ast.StringLiteral.t, Loc.t) Ast.Statement.EnumDeclaration.InitializedMember.t
          ) =
      let open Ast.Statement.EnumDeclaration.InitializedMember in
      let (loc, { id; init }) = member in
      match init with
      | (loc', Ast.StringLiteral.{ value; raw = _; comments }) when String.equal "on" value ->
        ( loc,
          {
            id;
            init = (loc', Ast.StringLiteral.{ value = "enabled"; raw = "\"enabled\""; comments });
          }
        )
      | _ -> member

    method! enum_number_member
        (member :
          (Loc.t Ast.NumberLiteral.t, Loc.t) Ast.Statement.EnumDeclaration.InitializedMember.t
          ) =
      let open Ast.Statement.EnumDeclaration.InitializedMember in
      let (loc, { id; init }) = member in
      match init with
      | (loc', Ast.NumberLiteral.{ value = 1.0; raw; comments = None }) ->
        ( loc,
          {
            id;
            init =
              ( loc',
                Ast_builder.number_literal
                  ~comments:
                    {
                      Ast.Syntax.leading = [];
                      trailing = [Ast_builder.Comments.line " a comment"];
                      internal = ();
                    }
                  1.0
                  raw
              );
          }
        )
      | _ -> member
  end

(* TODO: add test for RegExp case? *)
class literal_mapper =
  object
    inherit [Loc.t] Flow_ast_mapper.mapper as super

    method! expression (loc, expr) =
      match expr with
      | Ast.Expression.NullLiteral _ ->
        let lit = { Ast.StringLiteral.value = "wasNull"; raw = "wasNull"; comments = None } in
        (loc, Ast.Expression.StringLiteral lit)
      | _ -> super#expression (loc, expr)

    method! string_literal _loc lit =
      let open Ast.StringLiteral in
      match lit.value with
      | "rename" -> { value = "gotRenamed"; raw = "gotRenamed"; comments = None }
      | _ -> lit

    method! boolean_literal _loc lit =
      let open Ast.BooleanLiteral in
      match lit.value with
      | false -> { value = true; comments = None }
      | _ -> lit

    method! number_literal _loc lit =
      let open Ast.NumberLiteral in
      match lit.value with
      | 4.0 -> { value = 5.0; raw = "5"; comments = None }
      | _ -> lit
  end

class insert_variance_mapper =
  object (this)
    inherit useless_mapper as super

    method! type_param (tparam : (Loc.t, Loc.t) Ast.Type.TypeParam.t) =
      let open Ast.Type.TypeParam in
      let ((loc, tparam') as orig) = super#type_param tparam in
      let { variance; _ } = tparam' in
      let variance' = this#variance_opt_ loc variance in
      if variance == variance' then
        orig
      else
        (loc, { tparam' with variance = variance' })

    (* New variance method with a different type signature that allows us to insert a loc *)
    method variance_opt_ (loc : Loc.t) (variance : Loc.t Ast.Variance.t option) =
      let open Ast.Variance in
      match variance with
      | None -> Some (loc, { kind = Plus; comments = None })
      | _ -> variance
  end

class delete_variance_mapper =
  object
    inherit [Loc.t] Flow_ast_mapper.mapper

    method! variance_opt (variance : Loc.t Ast.Variance.t option) =
      let open Ast.Variance in
      match variance with
      | Some (_loc, { kind = Minus; comments = _ }) -> None
      | _ -> variance
  end

class insert_end_mapper =
  object
    inherit [Loc.t] Flow_ast_mapper.mapper

    method! statement_list stmts =
      let stmt = List.nth stmts (List.length stmts - 1) in
      stmts @ [stmt]
  end

class insert_begin_mapper =
  object
    inherit [Loc.t] Flow_ast_mapper.mapper

    method! statement_list stmts =
      let stmt = List.nth stmts (List.length stmts - 1) in
      stmt :: stmts
  end

class insert_dup_mapper =
  object
    inherit [Loc.t] Flow_ast_mapper.mapper

    method! statement_list stmts =
      let rec dup = function
        | [] -> []
        | h :: t -> h :: h :: dup t
      in
      dup stmts
  end

class first_last_dup_mapper =
  object
    inherit [Loc.t] Flow_ast_mapper.mapper

    method! statement_list stmts = (List.hd stmts :: stmts) @ [List.hd (List.rev stmts)]
  end

class insert_import_mapper =
  object
    inherit useless_mapper as super

    method! statement_list stmts =
      if List.length stmts > 0 then
        let open Ast.Statement.ImportDeclaration in
        let stmts = super#statement_list stmts in
        let (loc, _) = List.hd stmts in
        let imp =
          ( loc,
            Ast.Statement.ImportDeclaration
              {
                import_kind = Ast.Statement.ImportDeclaration.ImportValue;
                source = (loc, { Ast.StringLiteral.value = "baz"; raw = "\"baz\""; comments = None });
                default = None;
                specifiers =
                  Some
                    (Ast.Statement.ImportDeclaration.ImportNamedSpecifiers
                       [
                         {
                           kind = None;
                           local = None;
                           remote = Flow_ast_utils.ident_of_source (loc, "baz");
                           remote_name_def_loc = None;
                         };
                       ]
                    );
                comments = None;
              }
          )
        in
        imp :: stmts
      else
        super#statement_list stmts
  end

class insert_second_import_mapper =
  object
    inherit useless_mapper as super

    method! statement_list stmts =
      if List.length stmts > 0 then
        let open Ast.Statement.ImportDeclaration in
        let stmts = super#statement_list stmts in
        let (loc, _) = List.hd stmts in
        let imp =
          ( loc,
            Ast.Statement.ImportDeclaration
              {
                import_kind = Ast.Statement.ImportDeclaration.ImportValue;
                source = (loc, { Ast.StringLiteral.value = "baz"; raw = "\"baz\""; comments = None });
                default = None;
                specifiers =
                  Some
                    (Ast.Statement.ImportDeclaration.ImportNamedSpecifiers
                       [
                         {
                           kind = None;
                           local = None;
                           remote = Flow_ast_utils.ident_of_source (loc, "baz");
                           remote_name_def_loc = None;
                         };
                       ]
                    );
                comments = None;
              }
          )
        in
        List.hd stmts :: imp :: List.tl stmts
      else
        super#statement_list stmts
  end

class insert_second_cjsimport_mapper =
  object
    inherit useless_mapper as super

    method! statement_list stmts =
      if List.length stmts > 0 then
        let open Ast.Statement.Expression in
        let stmts = super#statement_list stmts in
        let (loc, _) = List.hd stmts in
        let imp =
          ( loc,
            Ast.Statement.Expression
              {
                expression =
                  ( loc,
                    Ast.Expression.Call
                      {
                        Ast.Expression.Call.callee =
                          ( loc,
                            Ast.Expression.Identifier
                              (Flow_ast_utils.ident_of_source (loc, "require"))
                          );
                        targs = None;
                        arguments =
                          ( loc,
                            {
                              Ast.Expression.ArgList.arguments =
                                [
                                  Ast.Expression.Expression
                                    ( loc,
                                      Ast.Expression.StringLiteral
                                        {
                                          Ast.StringLiteral.value = "baz";
                                          raw = "\"baz\"";
                                          comments = None;
                                        }
                                    );
                                ];
                              comments = None;
                            }
                          );
                        comments = None;
                      }
                  );
                directive = None;
                comments = None;
              }
          )
        in
        List.hd stmts :: imp :: List.tl stmts
      else
        super#statement_list stmts
  end

class add_body_mapper =
  object
    inherit useless_mapper as super

    method! statement_list stmts =
      if List.length stmts > 0 then
        let open Ast.Statement.Expression in
        let stmts = super#statement_list stmts in
        let (loc, _) = List.rev stmts |> List.hd in
        let imp =
          ( loc,
            Ast.Statement.Expression
              {
                expression =
                  ( loc,
                    Ast.Expression.Call
                      {
                        Ast.Expression.Call.callee =
                          ( loc,
                            Ast.Expression.Identifier (Flow_ast_utils.ident_of_source (loc, "foo"))
                          );
                        targs = None;
                        arguments =
                          ( loc,
                            {
                              Ast.Expression.ArgList.arguments =
                                [
                                  Ast.Expression.Expression
                                    ( loc,
                                      Ast.Expression.StringLiteral
                                        {
                                          Ast.StringLiteral.value = "baz";
                                          raw = "\"baz\"";
                                          comments = None;
                                        }
                                    );
                                ];
                              comments = None;
                            }
                          );
                        comments = None;
                      }
                  );
                directive = None;
                comments = None;
              }
          )
        in
        stmts @ [imp]
      else
        super#statement_list stmts
  end

class delete_mapper =
  object
    inherit [Loc.t] Flow_ast_mapper.mapper

    method! statement_list = List.tl
  end

class delete_end_mapper =
  object
    inherit [Loc.t] Flow_ast_mapper.mapper

    method! statement_list stmt = List.rev stmt |> List.tl |> List.rev
  end

class delete_annot_mapper =
  object
    inherit [Loc.t] Flow_ast_mapper.mapper as super

    method! pattern ?kind expr =
      let open Ast.Pattern in
      let open Ast.Pattern.Identifier in
      let expr = super#pattern ?kind expr in
      let (loc, patt) = expr in
      match patt with
      | Identifier id -> (loc, Identifier { id with annot = Type.Missing Loc.none })
      | _ -> expr

    method! type_annotation_hint return =
      match super#type_annotation_hint return with
      | Type.Available (loc, _) -> Type.Missing loc
      | Type.Missing _ -> return

    method! function_return_annotation return =
      let open Ast.Function in
      match super#function_return_annotation return with
      | ReturnAnnot.Missing _loc
      | ReturnAnnot.TypeGuard (_loc, _) ->
        return
      | ReturnAnnot.Available (loc, _) -> ReturnAnnot.Missing loc
  end

class insert_annot_mapper =
  object
    inherit [Loc.t] Flow_ast_mapper.mapper as super

    method! pattern ?kind expr =
      let open Ast.Pattern in
      let open Ast.Pattern.Identifier in
      let expr = super#pattern ?kind expr in
      let (loc, patt) = expr in
      match patt with
      | Identifier id ->
        (loc, Identifier { id with annot = Type.Available (loc, (loc, Type.Number None)) })
      | _ -> expr

    method! type_annotation_hint return =
      match super#type_annotation_hint return with
      | Type.Available _ -> return
      | Type.Missing _loc -> Type.Available (_loc, (_loc, Type.Number None))

    method! function_return_annotation return =
      let open Ast.Function in
      match super#function_return_annotation return with
      | ReturnAnnot.Available _
      | ReturnAnnot.TypeGuard _ ->
        return
      | ReturnAnnot.Missing _loc -> ReturnAnnot.Available (_loc, (_loc, Type.Number None))
  end

class insert_function_annot_mapper =
  object
    inherit [Loc.t] Flow_ast_mapper.mapper as super

    method! type_annotation_hint return =
      match super#type_annotation_hint return with
      | Type.Available _ -> return
      | Type.Missing loc ->
        Type.Available
          ( loc,
            ( loc,
              Type.Function
                {
                  Type.Function.tparams = None;
                  params =
                    ( loc,
                      {
                        Type.Function.Params.this_ = None;
                        params = [];
                        rest = None;
                        comments = None;
                      }
                    );
                  return = Ast.Type.Function.TypeAnnotation (loc, Type.Number None);
                  comments = None;
                }
            )
          )

    method! function_return_annotation return =
      let open Ast.Function in
      match super#function_return_annotation return with
      | ReturnAnnot.Available _
      | ReturnAnnot.TypeGuard _ ->
        return
      | ReturnAnnot.Missing loc ->
        ReturnAnnot.Available
          ( loc,
            ( loc,
              Type.Function
                {
                  Type.Function.tparams = None;
                  params =
                    ( loc,
                      {
                        Type.Function.Params.this_ = None;
                        params = [];
                        rest = None;
                        comments = None;
                      }
                    );
                  return = Ast.Type.Function.TypeAnnotation (loc, Type.Number None);
                  comments = None;
                }
            )
          )
  end

class insert_import_and_annot_mapper =
  object
    inherit [Loc.t] Flow_ast_mapper.mapper as super

    method! type_annotation_hint return =
      match super#type_annotation_hint return with
      | Type.Available _ -> return
      | Type.Missing loc ->
        Type.Available
          ( loc,
            ( loc,
              Type.Function
                {
                  Type.Function.tparams = None;
                  params =
                    ( loc,
                      {
                        Type.Function.Params.this_ = None;
                        params = [];
                        rest = None;
                        comments = None;
                      }
                    );
                  return = Ast.Type.Function.TypeAnnotation (loc, Type.Number None);
                  comments = None;
                }
            )
          )

    method! function_return_annotation return =
      let open Ast.Function in
      match super#function_return_annotation return with
      | ReturnAnnot.Available _
      | ReturnAnnot.TypeGuard _ ->
        return
      | ReturnAnnot.Missing loc ->
        ReturnAnnot.Available
          ( loc,
            ( loc,
              Type.Function
                {
                  Type.Function.tparams = None;
                  params =
                    ( loc,
                      {
                        Type.Function.Params.this_ = None;
                        params = [];
                        rest = None;
                        comments = None;
                      }
                    );
                  return = Ast.Type.Function.TypeAnnotation (loc, Type.Number None);
                  comments = None;
                }
            )
          )

    method! program prog =
      let (loc, { Ast.Program.statements = stmts; interpreter; comments; all_comments }) =
        super#program prog
      in
      let import num =
        let imp = Printf.sprintf "new_import%d" num in
        let open Ast.Statement in
        ( Loc.none,
          ImportDeclaration
            {
              ImportDeclaration.import_kind = ImportDeclaration.ImportType;
              source = (Loc.none, { Ast.StringLiteral.value = imp; raw = imp; comments = None });
              default = None;
              specifiers =
                Some
                  ImportDeclaration.(
                    ImportNamedSpecifiers
                      [
                        {
                          kind = None;
                          local = Some (Flow_ast_utils.ident_of_source (Loc.none, "here"));
                          remote = Flow_ast_utils.ident_of_source (Loc.none, "there");
                          remote_name_def_loc = None;
                        };
                      ]
                  );
              comments = None;
            }
        )
      in

      ( loc,
        {
          Ast.Program.statements = List.hd stmts :: import 1 :: import 2 :: List.tl stmts;
          interpreter;
          comments;
          all_comments;
        }
      )
  end

class prop_annot_mapper =
  object
    inherit [Loc.t] Flow_ast_mapper.mapper as super

    method! class_property _loc (prop : (Loc.t, Loc.t) Ast.Class.Property.t') =
      let open Ast.Class.Property in
      let prop = super#class_property _loc prop in
      let { annot; _ } = prop in
      let annot' =
        match annot with
        | Type.Available _ -> annot
        | Type.Missing _ -> Type.Available (Loc.none, (Loc.none, Type.Number None))
      in
      { prop with annot = annot' }
  end

class func_return_annot_mapper =
  object
    inherit [Loc.t] Flow_ast_mapper.mapper

    method! function_ _ f =
      let open Ast.Function in
      let return' =
        match f.return with
        | ReturnAnnot.Available _
        | ReturnAnnot.TypeGuard _ ->
          f.return
        | ReturnAnnot.Missing _ -> ReturnAnnot.Available (Loc.none, (Loc.none, Type.Number None))
      in
      { f with return = return' }
  end

class insert_typecast_mapper =
  object
    inherit [Loc.t] Flow_ast_mapper.mapper

    method! expression expression =
      let (loc, _) = expression in
      ( loc,
        Ast.Expression.TypeCast
          {
            Ast.Expression.TypeCast.annot = (loc, (loc, Type.Any None));
            expression;
            comments = None;
          }
      )
  end

class insert_call_type_args =
  object
    inherit [Loc.t] Flow_ast_mapper.mapper

    method! call_type_args (loc, { Ast.Expression.CallTypeArgs.arguments; comments }) =
      ( loc,
        {
          Ast.Expression.CallTypeArgs.arguments =
            Ast.Expression.CallTypeArg.Explicit (loc, Ast.Type.Any None) :: arguments;
          comments;
        }
      )
  end

class add_comment_mapper =
  object
    inherit [Loc.t] Flow_ast_mapper.mapper

    method! identifier (loc, i) =
      ( loc,
        {
          i with
          Flow_ast.Identifier.comments =
            Some
              {
                Flow_ast.Syntax.leading = [Ast_builder.Comments.block "hello"];
                trailing = [Ast_builder.Comments.block "bye"];
                internal = ();
              };
        }
      )
  end

class true_to_false_mapper =
  object
    inherit [Loc.t] Flow_ast_mapper.mapper

    method! boolean_literal _loc (expr : Loc.t Ast.BooleanLiteral.t) =
      let open Ast.BooleanLiteral in
      match expr.value with
      | true -> { value = false; comments = None }
      | _ -> expr

    method! type_annotation (annot : (Loc.t, Loc.t) Ast.Type.annotation) =
      let (t1, a) = annot in
      let (t2, right_var) = a in
      match right_var with
      | Ast.Type.BooleanLiteral { Ast.BooleanLiteral.value = true; comments } ->
        (t1, (t2, Ast.Type.BooleanLiteral { Ast.BooleanLiteral.value = false; comments }))
      | _ -> annot
  end

class remove_annotation_rest_mapper =
  object
    inherit [Loc.t] Flow_ast_mapper.mapper as super

    method! type_ (annot : (Loc.t, Loc.t) Type.t) =
      let annot = super#type_ annot in
      let (loc, typ) = annot in
      match typ with
      | Type.Intersection { Type.Intersection.types = (t, t', _); comments } ->
        (loc, Type.Intersection { Type.Intersection.types = (t, t', []); comments })
      | Type.Union { Type.Union.types = (t, t', _); comments } ->
        (loc, Type.Union { Type.Union.types = (t, t', []); comments })
      | _ -> annot
  end

class double_sequence_mapper =
  object
    inherit [Loc.t] Flow_ast_mapper.mapper

    method! sequence _loc { Ast.Expression.Sequence.expressions; comments } =
      { Ast.Expression.Sequence.expressions = expressions @ expressions; comments }
  end

let edits_of_source source mapper =
  let (ast, _) = Parser_flow.program source ~parse_options in
  let new_ast = mapper#program ast in
  let edits = program ast new_ast |> Ast_diff_printer.edits_of_changes in
  (* Extract columns from the locs *)
  Base.List.map ~f:(fun (loc, text) -> Loc.((loc.start.column, loc._end.column), text)) edits

let debug_string_of_edit ((start, end_), text) = Printf.sprintf "((%d, %d), %s)" start end_ text

let debug_string_of_edits = Base.List.map ~f:debug_string_of_edit %> String.concat ", "

let debug_string_of_change (i, chg) =
  match chg with
  | Replace (ol, ne) -> Printf.sprintf "Replace %s with %s at %d" ol ne i
  | Insert { items = ins; _ } -> Printf.sprintf "Insert %s at %d" (String.concat ", " ins) i
  | Delete d -> Printf.sprintf "Delete %s at %d" d i

let debug_string_of_script script =
  match script with
  | None -> "no script"
  | Some sc -> Base.List.map ~f:debug_string_of_change sc |> String.concat "\n"

let mk_insert ~sep ?(leading_sep = false) items =
  Insert { items; separator = sep; leading_separator = leading_sep }

let apply_edits source edits =
  let apply_edit acc ((_begin, _end), str) =
    let before = Str.string_before acc _begin in
    let after = Str.string_after acc _end in
    before ^ str ^ after
  in
  List.fold_left apply_edit source (List.rev edits)

let assert_edits_equal ctxt ~edits ~source ~expected ~mapper =
  let edits' = edits_of_source source mapper in
  assert_equal ~ctxt ~printer:debug_string_of_edits ~msg:"Edits" edits edits';
  assert_equal ~ctxt ~printer:(fun s -> s) ~msg:"Edits applied" expected (apply_edits source edits')

let assert_edits_differ ctxt ~edits ~source ~expected ~mapper =
  let edits' = edits_of_source source mapper in
  assert_equal ~ctxt ~printer:debug_string_of_edits ~msg:"Edits" edits edits';
  assert_equal ~ctxt ~printer:(fun s -> s) ~msg:"Edits applied" expected (apply_edits source edits')

let tests =
  "ast_differ"
  >::: [
         ( "literal_number" >:: fun ctxt ->
           let source = "4" in
           assert_edits_equal
             ctxt
             ~edits:[((0, 1), "5")]
             ~source
             ~expected:"5"
             ~mapper:(new literal_mapper)
         );
         ( "literal_string" >:: fun ctxt ->
           let source = "\"rename\"" in
           assert_edits_equal
             ctxt
             ~edits:[((0, 8), "\"gotRenamed\"")]
             ~source
             ~expected:"\"gotRenamed\""
             ~mapper:(new literal_mapper)
         );
         ( "literal_bool" >:: fun ctxt ->
           let source = "false" in
           assert_edits_equal
             ctxt
             ~edits:[((0, 5), "true")]
             ~source
             ~expected:"true"
             ~mapper:(new literal_mapper)
         );
         ( "literal_null" >:: fun ctxt ->
           let source = "null" in
           assert_edits_equal
             ctxt
             ~edits:[((0, 4), "\"wasNull\"")]
             ~source
             ~expected:"\"wasNull\""
             ~mapper:(new literal_mapper)
         );
         ( "string_literal_type" >:: fun ctxt ->
           let source = "(foo: \"RenameSL\")" in
           assert_edits_equal
             ctxt
             ~edits:[((6, 16), "\"GotRenamedSL\"")]
             ~source
             ~expected:"(foo: \"GotRenamedSL\")"
             ~mapper:(new useless_mapper)
         );
         ( "simple" >:: fun ctxt ->
           let source = "function foo() { (5 - 3); 4; (6 + 4); }" in
           assert_edits_equal
             ctxt
             ~edits:[((26, 27), "5"); ((30, 35), "6 - 5")]
             ~source
             ~expected:"function foo() { (5 - 3); 5; (6 - 5); }"
             ~mapper:(new useless_mapper)
         );
         ( "class" >:: fun ctxt ->
           let source = "class Foo { bar() { 4; } }" in
           assert_edits_equal
             ctxt
             ~edits:[((20, 21), "5")]
             ~source
             ~expected:"class Foo { bar() { 5; } }"
             ~mapper:(new useless_mapper)
         );
         ( "class2" >:: fun ctxt ->
           let source = "class Foo { bar = 4; }" in
           assert_edits_equal
             ctxt
             ~edits:[((18, 19), "5")]
             ~source
             ~expected:"class Foo { bar = 5; }"
             ~mapper:(new useless_mapper)
         );
         ( "class_prop_annot" >:: fun ctxt ->
           let source = "class A { f = (x: string) => x; }" in
           assert_edits_equal
             ctxt
             ~edits:[((11, 11), ": number")]
             ~source
             ~expected:"class A { f: number = (x: string) => x; }"
             ~mapper:(new prop_annot_mapper)
         );
         ( "class_extends" >:: fun ctxt ->
           let source = "class A extends rename<rename, dontrename> { }" in
           assert_edits_equal
             ctxt
             ~edits:[((16, 22), "gotRenamed"); ((23, 29), "gotRenamed")]
             ~source
             ~expected:"class A extends gotRenamed<gotRenamed, dontrename> { }"
             ~mapper:(new useless_mapper)
         );
         ( "class_extends_integration" >:: fun ctxt ->
           let source = "class A extends rename { bar = 4 }" in
           assert_edits_equal
             ctxt
             ~edits:[((16, 22), "gotRenamed"); ((31, 32), "5")]
             ~source
             ~expected:"class A extends gotRenamed { bar = 5 }"
             ~mapper:(new useless_mapper)
         );
         ( "interface_id" >:: fun ctxt ->
           let source = "interface Rename { }" in
           assert_edits_equal
             ctxt
             ~edits:[((10, 16), "GotRenamed")]
             ~source
             ~expected:"interface GotRenamed { }"
             ~mapper:(new useless_mapper)
         );
         ( "interface_tparams" >:: fun ctxt ->
           let source = "interface Foo<RENAME> { }" in
           assert_edits_equal
             ctxt
             ~edits:[((14, 20), "GOT_RENAMED")]
             ~source
             ~expected:"interface Foo<GOT_RENAMED> { }"
             ~mapper:(new useless_mapper)
         );
         ( "interface_extends_id" >:: fun ctxt ->
           let source = "interface Foo extends Rename { }" in
           assert_edits_equal
             ctxt
             ~edits:[((22, 28), "GotRenamed")]
             ~source
             ~expected:"interface Foo extends GotRenamed { }"
             ~mapper:(new useless_mapper)
         );
         ( "interface_extends_targ_simple" >:: fun ctxt ->
           let source = "interface Foo extends Bar<RENAME> { }" in
           assert_edits_equal
             ctxt
             ~edits:[((26, 32), "GOT_RENAMED")]
             ~source
             ~expected:"interface Foo extends Bar<GOT_RENAMED> { }"
             ~mapper:(new useless_mapper)
         );
         ( "interface_extends_targs" >:: fun ctxt ->
           let source = "interface Foo extends Bar<RENAME, RENAME> { }" in
           assert_edits_equal
             ctxt
             ~edits:[((26, 32), "GOT_RENAMED"); ((34, 40), "GOT_RENAMED")]
             ~source
             ~expected:"interface Foo extends Bar<GOT_RENAMED, GOT_RENAMED> { }"
             ~mapper:(new useless_mapper)
         );
         ( "interface_combo" >:: fun ctxt ->
           let source = "interface Rename extends Rename<RENAME> { }" in
           assert_edits_equal
             ctxt
             ~edits:[((10, 16), "GotRenamed"); ((25, 31), "GotRenamed"); ((32, 38), "GOT_RENAMED")]
             ~source
             ~expected:"interface GotRenamed extends GotRenamed<GOT_RENAMED> { }"
             ~mapper:(new useless_mapper)
         );
         ( "interface_body_object_property_key" >:: fun ctxt ->
           let source = "interface Foo { rename: string }" in
           assert_edits_equal
             ctxt
             ~edits:[((16, 22), "gotRenamed")]
             ~source
             ~expected:"interface Foo { gotRenamed: string }"
             ~mapper:(new useless_mapper)
         );
         ( "interface_body_object_property_value_init" >:: fun ctxt ->
           let source = "interface Foo { bar: number }" in
           assert_edits_equal
             ctxt
             ~edits:[((21, 27), "string")]
             ~source
             ~expected:"interface Foo { bar: string }"
             ~mapper:(new useless_mapper)
         );
         ( "obj_prop" >:: fun ctxt ->
           let source = "let x = { rename : 4 }" in
           assert_edits_equal
             ctxt
             ~edits:[((10, 16), "gotRenamed"); ((19, 20), "5")]
             ~source
             ~expected:"let x = { gotRenamed : 5 }"
             ~mapper:(new useless_mapper)
         );
         ( "obj_prop2" >:: fun ctxt ->
           let source = "let x = { bar() { rename; } }" in
           assert_edits_equal
             ctxt
             ~edits:[((18, 24), "gotRenamed")]
             ~source
             ~expected:"let x = { bar() { gotRenamed; } }"
             ~mapper:(new useless_mapper)
         );
         ( "obj_prop3" >:: fun ctxt ->
           let source = "let x = { 4 : 3 }" in
           assert_edits_equal
             ctxt
             ~edits:[((10, 11), "5")]
             ~source
             ~expected:"let x = { 5 : 3 }"
             ~mapper:(new useless_mapper)
         );
         ( "obj_spread_prop" >:: fun ctxt ->
           let source = "let x = { ...rename, x : 4}" in
           assert_edits_equal
             ctxt
             ~edits:[((13, 19), "gotRenamed"); ((25, 26), "5")]
             ~source
             ~expected:"let x = { ...gotRenamed, x : 5}"
             ~mapper:(new useless_mapper)
         );
         ( "precedence" >:: fun ctxt ->
           let source = "5 - 3 * 3" in
           (* It is mandatory to insert the parens here *)
           assert_edits_equal
             ctxt
             ~edits:[((4, 9), "(3 + 3)")]
             ~source
             ~expected:"5 - (3 + 3)"
             ~mapper:(new useless_mapper)
         );
         ( "tuple" >:: fun ctxt ->
           let source = "type Foo = [number, number];" in
           assert_edits_equal
             ctxt
             ~edits:[((12, 18), "string"); ((20, 26), "string")]
             ~source
             ~expected:"type Foo = [string, string];"
             ~mapper:(new useless_mapper)
         );
         ( "identifier" >:: fun ctxt ->
           let source = "5 - rename" in
           assert_edits_equal
             ctxt
             ~edits:[((4, 10), "gotRenamed")]
             ~source
             ~expected:"5 - gotRenamed"
             ~mapper:(new useless_mapper)
         );
         ( "interface_type" >:: fun ctxt ->
           let source = "type Foo = interface { rename() : string }" in
           assert_edits_equal
             ctxt
             ~edits:[((23, 29), "gotRenamed")]
             ~source
             ~expected:"type Foo = interface { gotRenamed() : string }"
             ~mapper:(new useless_mapper)
         );
         ( "new" >:: fun ctxt ->
           let source = "new rename()" in
           assert_edits_equal
             ctxt
             ~edits:[((4, 10), "gotRenamed")]
             ~source
             ~expected:"new gotRenamed()"
             ~mapper:(new useless_mapper)
         );
         ( "typeof_type" >:: fun ctxt ->
           let source = "type Foo = typeof rename" in
           assert_edits_equal
             ctxt
             ~edits:[((18, 24), "gotRenamed")]
             ~source
             ~expected:"type Foo = typeof gotRenamed"
             ~mapper:(new useless_mapper)
         );
         ( "new_type_param" >:: fun ctxt ->
           let source = "new foo<RENAME>()" in
           assert_edits_equal
             ctxt
             ~edits:[((8, 14), "GOT_RENAMED")]
             ~source
             ~expected:"new foo<GOT_RENAMED>()"
             ~mapper:(new useless_mapper)
         );
         ( "new_type_param_2" >:: fun ctxt ->
           let source = "new rename<RENAME>(rename)" in
           assert_edits_equal
             ctxt
             ~edits:[((4, 10), "gotRenamed"); ((11, 17), "GOT_RENAMED"); ((19, 25), "gotRenamed")]
             ~source
             ~expected:"new gotRenamed<GOT_RENAMED>(gotRenamed)"
             ~mapper:(new useless_mapper)
         );
         ( "new_type_param_3" >:: fun ctxt ->
           let source = "new foo<FOO>(rename)" in
           assert_edits_equal
             ctxt
             ~edits:[((13, 19), "gotRenamed")]
             ~source
             ~expected:"new foo<FOO>(gotRenamed)"
             ~mapper:(new useless_mapper)
         );
         ( "new_type_param_multiple" >:: fun ctxt ->
           let source = "new foo<RENAME, RENAME>()" in
           assert_edits_equal
             ctxt
             ~edits:[((8, 14), "GOT_RENAMED"); ((16, 22), "GOT_RENAMED")]
             ~source
             ~expected:"new foo<GOT_RENAMED, GOT_RENAMED>()"
             ~mapper:(new useless_mapper)
         );
         ( "new_type_param_insert" >:: fun ctxt ->
           let source = "new foo<>()" in
           assert_edits_equal
             ctxt
             ~edits:[((0, 11), "new foo<any>()")]
             ~source
             ~expected:"new foo<any>()"
             ~mapper:(new insert_call_type_args)
         );
         ( "new_type_param_implicit" >:: fun ctxt ->
           let source = "new foo<_>()" in
           assert_edits_equal
             ctxt
             ~edits:[((0, 12), "new foo<any>()")]
             ~source
             ~expected:"new foo<any>()"
             ~mapper:(new useless_mapper)
         );
         ( "member" >:: fun ctxt ->
           let source = "rename.a" in
           assert_edits_equal
             ctxt
             ~edits:[((0, 6), "gotRenamed")]
             ~source
             ~expected:"gotRenamed.a"
             ~mapper:(new useless_mapper)
         );
         ( "member_identifier" >:: fun ctxt ->
           let source = "rename.rename" in
           assert_edits_equal
             ctxt
             ~edits:[((0, 6), "gotRenamed"); ((7, 13), "gotRenamed")]
             ~source
             ~expected:"gotRenamed.gotRenamed"
             ~mapper:(new useless_mapper)
         );
         ( "member_expression" >:: fun ctxt ->
           let source = "obj[4]" in
           assert_edits_equal
             ctxt
             ~edits:[((4, 5), "5")]
             ~source
             ~expected:"obj[5]"
             ~mapper:(new useless_mapper)
         );
         ( "unary_same_op" >:: fun ctxt ->
           let source = "-rename" in
           assert_edits_equal
             ctxt
             ~edits:[((1, 7), "gotRenamed")]
             ~source
             ~expected:"-gotRenamed"
             ~mapper:(new useless_mapper)
         );
         ( "unary_diff_op" >:: fun ctxt ->
           let source = "+rename" in
           assert_edits_equal
             ctxt
             ~edits:[((0, 7), "-gotRenamed")]
             ~source
             ~expected:"-gotRenamed"
             ~mapper:(new useless_mapper)
         );
         ( "block" >:: fun ctxt ->
           let source = "{ 2; 4; 10; rename; }" in
           assert_edits_equal
             ctxt
             ~edits:[((5, 6), "5"); ((12, 18), "gotRenamed")]
             ~source
             ~expected:"{ 2; 5; 10; gotRenamed; }"
             ~mapper:(new useless_mapper)
         );
         ( "if_nochange" >:: fun ctxt ->
           let source = "if (true) { false; } else { true; }" in
           assert_edits_equal
             ctxt
             ~edits:[]
             ~source
             ~expected:"if (true) { false; } else { true; }"
             ~mapper:(new useless_mapper)
         );
         ( "if_noblock" >:: fun ctxt ->
           let source = "if (4) rename;" in
           assert_edits_equal
             ctxt
             ~edits:[((4, 5), "5"); ((7, 13), "gotRenamed")]
             ~source
             ~expected:"if (5) gotRenamed;"
             ~mapper:(new useless_mapper)
         );
         ( "if_partial" >:: fun ctxt ->
           let source = "if (4) { rename; }" in
           assert_edits_equal
             ctxt
             ~edits:[((4, 5), "5"); ((9, 15), "gotRenamed")]
             ~source
             ~expected:"if (5) { gotRenamed; }"
             ~mapper:(new useless_mapper)
         );
         ( "if_full" >:: fun ctxt ->
           let source = "if (4) { 4; } else { rename }" in
           assert_edits_equal
             ctxt
             ~edits:[((4, 5), "5"); ((9, 10), "5"); ((21, 27), "gotRenamed")]
             ~source
             ~expected:"if (5) { 5; } else { gotRenamed }"
             ~mapper:(new useless_mapper)
         );
         ( "conditional_nochange" >:: fun ctxt ->
           let source = "1 > 0 ? false : true" in
           assert_edits_equal
             ctxt
             ~edits:[]
             ~source
             ~expected:"1 > 0 ? false : true"
             ~mapper:(new useless_mapper)
         );
         ( "conditional_test" >:: fun ctxt ->
           let source = "rename ? false : true" in
           assert_edits_equal
             ctxt
             ~edits:[((0, 6), "gotRenamed")]
             ~source
             ~expected:"gotRenamed ? false : true"
             ~mapper:(new useless_mapper)
         );
         ( "conditional_consequent" >:: fun ctxt ->
           let source = "1 > 0 ? rename : true" in
           assert_edits_equal
             ctxt
             ~edits:[((8, 14), "gotRenamed")]
             ~source
             ~expected:"1 > 0 ? gotRenamed : true"
             ~mapper:(new useless_mapper)
         );
         ( "conditional_alternate" >:: fun ctxt ->
           let source = "1 > 0 ? false : rename" in
           assert_edits_equal
             ctxt
             ~edits:[((16, 22), "gotRenamed")]
             ~source
             ~expected:"1 > 0 ? false : gotRenamed"
             ~mapper:(new useless_mapper)
         );
         ( "conditional_cons_and_alt" >:: fun ctxt ->
           let source = "1 > 0 ? 4 : rename" in
           assert_edits_equal
             ctxt
             ~edits:[((8, 9), "5"); ((12, 18), "gotRenamed")]
             ~source
             ~expected:"1 > 0 ? 5 : gotRenamed"
             ~mapper:(new useless_mapper)
         );
         ( "with_nochange" >:: fun ctxt ->
           let source = "with (object) { foo = true; }" in
           assert_edits_equal
             ctxt
             ~edits:[]
             ~source
             ~expected:"with (object) { foo = true; }"
             ~mapper:(new useless_mapper)
         );
         ( "with_object" >:: fun ctxt ->
           let source = "with (rename) { foo = true; };" in
           assert_edits_equal
             ctxt
             ~edits:[((6, 12), "gotRenamed")]
             ~source
             ~expected:"with (gotRenamed) { foo = true; };"
             ~mapper:(new useless_mapper)
         );
         ( "with_body" >:: fun ctxt ->
           let source = "with (objct) { rename; };" in
           assert_edits_equal
             ctxt
             ~edits:[((15, 21), "gotRenamed")]
             ~source
             ~expected:"with (objct) { gotRenamed; };"
             ~mapper:(new useless_mapper)
         );
         ( "function_expression" >:: fun ctxt ->
           let source = "(function() { 4; })" in
           assert_edits_equal
             ctxt
             ~edits:[((14, 15), "5")]
             ~source
             ~expected:"(function() { 5; })"
             ~mapper:(new useless_mapper)
         );
         ( "function_id" >:: fun ctxt ->
           let source = "(function rename() { return; })" in
           assert_edits_equal
             ctxt
             ~edits:[((10, 16), "gotRenamed")]
             ~source
             ~expected:"(function gotRenamed() { return; })"
             ~mapper:(new useless_mapper)
         );
         ( "function_rest" >:: fun ctxt ->
           let source = "(function(...rename) { return; })" in
           assert_edits_equal
             ctxt
             ~edits:[((13, 19), "gotRenamed")]
             ~source
             ~expected:"(function(...gotRenamed) { return; })"
             ~mapper:(new useless_mapper)
         );
         ( "function_param" >:: fun ctxt ->
           let source = "(function(rename, ...dontRename) { return; })" in
           assert_edits_equal
             ctxt
             ~edits:[((10, 16), "gotRenamed")]
             ~source
             ~expected:"(function(gotRenamed, ...dontRename) { return; })"
             ~mapper:(new useless_mapper)
         );
         ( "function_params" >:: fun ctxt ->
           let source = "(function(rename, dontRename, rename) { return; })" in
           assert_edits_equal
             ctxt
             ~source
             ~edits:[((10, 16), "gotRenamed"); ((30, 36), "gotRenamed")]
             ~expected:"(function(gotRenamed, dontRename, gotRenamed) { return; })"
             ~mapper:(new useless_mapper)
         );
         ( "function_type_params" >:: fun ctxt ->
           let source = "(function<RENAME>() { return; })" in
           assert_edits_equal
             ctxt
             ~edits:[((10, 16), "GOT_RENAMED")]
             ~source
             ~expected:"(function<GOT_RENAMED>() { return; })"
             ~mapper:(new useless_mapper)
         );
         ( "function_combo" >:: fun ctxt ->
           let source = "(function rename<RENAME>(rename): Rename { return 4; })" in
           assert_edits_equal
             ctxt
             ~source
             ~edits:
               [
                 ((10, 16), "gotRenamed");
                 ((17, 23), "GOT_RENAMED");
                 ((25, 31), "gotRenamed");
                 ((34, 40), "GotRenamed");
                 ((50, 51), "5");
               ]
             ~expected:"(function gotRenamed<GOT_RENAMED>(gotRenamed): GotRenamed { return 5; })"
             ~mapper:(new useless_mapper)
         );
         ( "arrow_function" >:: fun ctxt ->
           let source = "let bar = (x) => 4;" in
           assert_edits_equal
             ctxt
             ~edits:[((17, 18), "5")]
             ~source
             ~expected:"let bar = (x) => 5;"
             ~mapper:(new useless_mapper)
         );
         ( "call" >:: fun ctxt ->
           let source = "rename()" in
           assert_edits_equal
             ctxt
             ~edits:[((0, 6), "gotRenamed")]
             ~source
             ~expected:"gotRenamed()"
             ~mapper:(new useless_mapper)
         );
         ( "call_type_param" >:: fun ctxt ->
           let source = "rename<RENAME>()" in
           assert_edits_equal
             ctxt
             ~edits:[((0, 6), "gotRenamed"); ((7, 13), "GOT_RENAMED")]
             ~source
             ~expected:"gotRenamed<GOT_RENAMED>()"
             ~mapper:(new useless_mapper)
         );
         ( "variable_declaration_kind" >:: fun ctxt ->
           let source = "var x = 5;" in
           assert_edits_equal
             ctxt
             ~edits:[((0, 10), "const x = 5;")]
             ~source
             ~expected:"const x = 5;"
             ~mapper:(new useless_mapper)
         );
         ( "variable_declaration_expression" >:: fun ctxt ->
           let source = "let x = 4;" in
           assert_edits_equal
             ctxt
             ~edits:[((8, 9), "5")]
             ~source
             ~expected:"let x = 5;"
             ~mapper:(new useless_mapper)
         );
         ( "variable_declaration_kind_expression" >:: fun ctxt ->
           let source = "var x = 4;" in
           assert_edits_equal
             ctxt
             ~edits:[((0, 10), "const x = 5;")]
             ~source
             ~expected:"const x = 5;"
             ~mapper:(new useless_mapper)
         );
         ( "for" >:: fun ctxt ->
           let source = "for (i = 7; i < rename; i++) {}" in
           assert_edits_equal
             ctxt
             ~edits:[((16, 22), "gotRenamed")]
             ~source
             ~expected:"for (i = 7; i < gotRenamed; i++) {}"
             ~mapper:(new useless_mapper)
         );
         ( "for_init" >:: fun ctxt ->
           let source = "for (let i = 4; i < 10; i++) {}" in
           assert_edits_equal
             ctxt
             ~edits:[((13, 14), "5")]
             ~source
             ~expected:"for (let i = 5; i < 10; i++) {}"
             ~mapper:(new useless_mapper)
         );
         ( "for_body" >:: fun ctxt ->
           let source = "for (i = 7; i < top; i++) { rename; }" in
           assert_edits_equal
             ctxt
             ~edits:[((28, 34), "gotRenamed")]
             ~source
             ~expected:"for (i = 7; i < top; i++) { gotRenamed; }"
             ~mapper:(new useless_mapper)
         );
         ( "for_in_left" >:: fun ctxt ->
           let source = "for (var x in xs) { continue; }" in
           assert_edits_equal
             ctxt
             ~edits:[((0, 31), "for (const x in xs) {\n  continue;\n}")]
             ~source
             ~expected:"for (const x in xs) {\n  continue;\n}"
             ~mapper:(new useless_mapper)
         );
         ( "for_in_right" >:: fun ctxt ->
           let source = "for (let x in rename) { continue; }" in
           assert_edits_equal
             ctxt
             ~edits:[((14, 20), "gotRenamed")]
             ~source
             ~expected:"for (let x in gotRenamed) { continue; }"
             ~mapper:(new useless_mapper)
         );
         ( "for_in_body" >:: fun ctxt ->
           let source = "for (let x in xs) { rename; }" in
           assert_edits_equal
             ctxt
             ~edits:[((20, 26), "gotRenamed")]
             ~source
             ~expected:"for (let x in xs) { gotRenamed; }"
             ~mapper:(new useless_mapper)
         );
         ( "while_test" >:: fun ctxt ->
           let source = "while (rename) { break; };" in
           assert_edits_equal
             ctxt
             ~edits:[((7, 13), "gotRenamed")]
             ~source
             ~expected:"while (gotRenamed) { break; };"
             ~mapper:(new useless_mapper)
         );
         ( "while_body" >:: fun ctxt ->
           let source = "while (true) { rename; };" in
           assert_edits_equal
             ctxt
             ~edits:[((15, 21), "gotRenamed")]
             ~source
             ~expected:"while (true) { gotRenamed; };"
             ~mapper:(new useless_mapper)
         );
         ( "for_of_left" >:: fun ctxt ->
           let source = "for (var x of xs) { continue; }" in
           assert_edits_equal
             ctxt
             ~edits:[((0, 31), "for (const x of xs) {\n  continue;\n}")]
             ~source
             ~expected:"for (const x of xs) {\n  continue;\n}"
             ~mapper:(new useless_mapper)
         );
         ( "for_of_right" >:: fun ctxt ->
           let source = "for (let x of rename) { continue; }" in
           assert_edits_equal
             ctxt
             ~edits:[((14, 20), "gotRenamed")]
             ~source
             ~expected:"for (let x of gotRenamed) { continue; }"
             ~mapper:(new useless_mapper)
         );
         ( "for_of_body" >:: fun ctxt ->
           let source = "for (let x of xs) { rename; }" in
           assert_edits_equal
             ctxt
             ~edits:[((20, 26), "gotRenamed")]
             ~source
             ~expected:"for (let x of xs) { gotRenamed; }"
             ~mapper:(new useless_mapper)
         );
         ( "do_while_body" >:: fun ctxt ->
           let source = "do { rename; } while (true);" in
           assert_edits_equal
             ctxt
             ~edits:[((5, 11), "gotRenamed")]
             ~source
             ~expected:"do { gotRenamed; } while (true);"
             ~mapper:(new useless_mapper)
         );
         ( "do_while_condition" >:: fun ctxt ->
           let source = "do { continue; } while (rename);" in
           assert_edits_equal
             ctxt
             ~edits:[((24, 30), "gotRenamed")]
             ~source
             ~expected:"do { continue; } while (gotRenamed);"
             ~mapper:(new useless_mapper)
         );
         ( "try_stmt_body" >:: fun ctxt ->
           let source = "try { rename; } catch(e) { other; };" in
           assert_edits_equal
             ctxt
             ~edits:[((6, 12), "gotRenamed")]
             ~source
             ~expected:"try { gotRenamed; } catch(e) { other; };"
             ~mapper:(new useless_mapper)
         );
         ( "try_stmt_catch" >:: fun ctxt ->
           let source = "try { thing; } catch(rename) { other; };" in
           assert_edits_equal
             ctxt
             ~edits:[((21, 27), "gotRenamed")]
             ~source
             ~expected:"try { thing; } catch(gotRenamed) { other; };"
             ~mapper:(new useless_mapper)
         );
         ( "try_stmt_handler" >:: fun ctxt ->
           let source = "try { thing; } catch(e) { rename; };" in
           assert_edits_equal
             ctxt
             ~edits:[((26, 32), "gotRenamed")]
             ~source
             ~expected:"try { thing; } catch(e) { gotRenamed; };"
             ~mapper:(new useless_mapper)
         );
         ( "try_stmt_finalizer" >:: fun ctxt ->
           let source = "try { thing; } finally { rename; };" in
           assert_edits_equal
             ctxt
             ~edits:[((25, 31), "gotRenamed")]
             ~source
             ~expected:"try { thing; } finally { gotRenamed; };"
             ~mapper:(new useless_mapper)
         );
         ( "labeled_label" >:: fun ctxt ->
           let source = "rename: while (true) { }" in
           assert_edits_equal
             ctxt
             ~edits:[((0, 6), "gotRenamed")]
             ~source
             ~expected:"gotRenamed: while (true) { }"
             ~mapper:(new useless_mapper)
         );
         ( "labeled_body" >:: fun ctxt ->
           let source = "foo: while (rename) { }" in
           assert_edits_equal
             ctxt
             ~edits:[((12, 18), "gotRenamed")]
             ~source
             ~expected:"foo: while (gotRenamed) { }"
             ~mapper:(new useless_mapper)
         );
         ( "switch_discriminant" >:: fun ctxt ->
           let source = "switch (rename) { case true: break; }" in
           assert_edits_equal
             ctxt
             ~edits:[((8, 14), "gotRenamed")]
             ~source
             ~expected:"switch (gotRenamed) { case true: break; }"
             ~mapper:(new useless_mapper)
         );
         ( "switch_case_test" >:: fun ctxt ->
           let source = "switch (true) { case rename: break; }" in
           assert_edits_equal
             ctxt
             ~edits:[((21, 27), "gotRenamed")]
             ~source
             ~expected:"switch (true) { case gotRenamed: break; }"
             ~mapper:(new useless_mapper)
         );
         ( "switch_case_consequent" >:: fun ctxt ->
           let source = "switch (true) { case true: rename; }" in
           assert_edits_equal
             ctxt
             ~edits:[((27, 33), "gotRenamed")]
             ~source
             ~expected:"switch (true) { case true: gotRenamed; }"
             ~mapper:(new useless_mapper)
         );
         ( "algo_diff_end_insert" >:: fun ctxt ->
           let source = "var x = 5; var y = 6;" in
           assert_edits_differ
             ctxt
             ~edits:[((21, 21), "var y = 6;")]
             ~source
             ~expected:"var x = 5; var y = 6;var y = 6;"
             ~mapper:(new insert_end_mapper)
         );
         ( "algo_diff_delete" >:: fun ctxt ->
           let source = "var x = 5; var y = 6; var z = 7;" in
           assert_edits_differ
             ctxt
             ~edits:[((0, 10), "")]
             ~source
             ~expected:" var y = 6; var z = 7;"
             ~mapper:(new delete_mapper)
         );
         ( "algo_diff_begin_insert" >:: fun ctxt ->
           let source = "var x = 5; var y = 6;" in
           assert_edits_differ
             ctxt
             ~edits:[((0, 0), "var y = 6;")]
             ~source
             ~expected:"var y = 6;var x = 5; var y = 6;"
             ~mapper:(new insert_begin_mapper)
         );
         ( "algo_diff_middle_insert" >:: fun ctxt ->
           let source = "var x = 5; var y = 6;" in
           assert_edits_differ
             ctxt
             ~edits:[((10, 10), "var x = 5;"); ((21, 21), "var y = 6;")]
             ~source
             ~expected:"var x = 5;var x = 5; var y = 6;var y = 6;"
             ~mapper:(new insert_dup_mapper)
         );
         ( "algo_diff_empty" >:: fun ctxt ->
           let source = "" in
           let (ast_empty, _) = Parser_flow.program source in
           let (ast_var, _) = Parser_flow.program "var x = 6;" in
           let edits =
             program ast_empty ast_var
             |> Ast_diff_printer.edits_of_changes
             |> Base.List.map ~f:(fun (loc, text) -> Loc.((loc.start.column, loc._end.column), text))
           in
           assert_equal ~ctxt edits [((0, 0), "var x = 6;")];
           assert_equal ~ctxt (apply_edits source edits) "var x = 6;"
         );
         ( "unnamed_class_expression" >:: fun ctxt ->
           let source = "(class { method() { rename; } })" in
           assert_edits_equal
             ctxt
             ~edits:[((20, 26), "gotRenamed")]
             ~source
             ~expected:"(class { method() { gotRenamed; } })"
             ~mapper:(new useless_mapper)
         );
         ( "named_class_expression" >:: fun ctxt ->
           let source = "(class Foo { method() { rename; } })" in
           assert_edits_equal
             ctxt
             ~edits:[((24, 30), "gotRenamed")]
             ~source
             ~expected:"(class Foo { method() { gotRenamed; } })"
             ~mapper:(new useless_mapper)
         );
         ( "return_statement_with_expression" >:: fun ctxt ->
           let source = "function foo() { return rename; }" in
           assert_edits_equal
             ctxt
             ~edits:[((24, 30), "gotRenamed")]
             ~source
             ~expected:"function foo() { return gotRenamed; }"
             ~mapper:(new useless_mapper)
         );
         ( "type_annotation_delete" >:: fun ctxt ->
           let source = "let x : number = 3;" in
           assert_edits_equal
             ctxt
             ~edits:[((6, 14), "")]
             ~source
             ~expected:"let x  = 3;"
             ~mapper:(new delete_annot_mapper)
         );
         ( "type_annotation_insert" >:: fun ctxt ->
           let source = "let x = 3;" in
           assert_edits_equal
             ctxt
             ~edits:[((5, 5), ": number")]
             ~source
             ~expected:"let x: number = 3;"
             ~mapper:(new insert_annot_mapper)
         );
         ( "type_annotation_replace" >:: fun ctxt ->
           let source = "let x : number = 3;" in
           assert_edits_equal
             ctxt
             ~edits:[((8, 14), "string")]
             ~source
             ~expected:"let x : string = 3;"
             ~mapper:(new useless_mapper)
         );
         ( "type_annotation_rename_type_arg" >:: fun ctxt ->
           let source = "(foo: bar<rename>);" in
           assert_edits_equal
             ctxt
             ~edits:[((10, 16), "gotRenamed")]
             ~source
             ~expected:"(foo: bar<gotRenamed>);"
             ~mapper:(new useless_mapper)
         );
         ( "type_annotation_rename_type" >:: fun ctxt ->
           let source = "(foo: rename<bar>);" in
           assert_edits_equal
             ctxt
             ~edits:[((6, 12), "gotRenamed")]
             ~source
             ~expected:"(foo: gotRenamed<bar>);"
             ~mapper:(new useless_mapper)
         );
         ( "type_annotation_rename_type_and_typearg" >:: fun ctxt ->
           let source = "(foo: rename<rename>);" in
           assert_edits_equal
             ctxt
             ~edits:[((6, 12), "gotRenamed"); ((13, 19), "gotRenamed")]
             ~source
             ~expected:"(foo: gotRenamed<gotRenamed>);"
             ~mapper:(new useless_mapper)
         );
         ( "type_annotation_rename_qualified_type" >:: fun ctxt ->
           let source = "(foo: Foo.rename<Bar>);" in
           assert_edits_equal
             ctxt
             ~edits:[((10, 16), "gotRenamed")]
             ~source
             ~expected:"(foo: Foo.gotRenamed<Bar>);"
             ~mapper:(new useless_mapper)
         );
         ( "type_annotation_rename_qualified_typearg" >:: fun ctxt ->
           let source = "(foo: Foo.Bar<rename>);" in
           assert_edits_equal
             ctxt
             ~edits:[((14, 20), "gotRenamed")]
             ~source
             ~expected:"(foo: Foo.Bar<gotRenamed>);"
             ~mapper:(new useless_mapper)
         );
         ( "type_annotation_rename_qualified_type_and_typearg" >:: fun ctxt ->
           let source = "(foo: Foo.rename<rename>);" in
           assert_edits_equal
             ctxt
             ~edits:[((10, 16), "gotRenamed"); ((17, 23), "gotRenamed")]
             ~source
             ~expected:"(foo: Foo.gotRenamed<gotRenamed>);"
             ~mapper:(new useless_mapper)
         );
         ( "return_type_replace" >:: fun ctxt ->
           let source = "function foo() : number { return 1; }" in
           assert_edits_equal
             ctxt
             ~edits:[((17, 23), "string")]
             ~source
             ~expected:"function foo() : string { return 1; }"
             ~mapper:(new useless_mapper)
         );
         ( "return_type_delete" >:: fun ctxt ->
           let source = "function foo() : number { return 1; }" in
           assert_edits_equal
             ctxt
             ~edits:[((15, 23), "")]
             ~source
             ~expected:"function foo()  { return 1; }"
             ~mapper:(new delete_annot_mapper)
         );
         ( "return_type_insert" >:: fun ctxt ->
           let source = "function foo() { return 1; }" in
           assert_edits_equal
             ctxt
             ~edits:[((14, 14), ": number")]
             ~source
             ~expected:"function foo(): number { return 1; }"
             ~mapper:(new insert_annot_mapper)
         );
         ( "comments" >:: fun ctxt ->
           let source = "function foo() { /* comment */ (5 - 3); 4; (6 + 4); /* comment */}" in
           assert_edits_equal
             ctxt
             ~edits:[((40, 41), "5"); ((44, 49), "6 - 5")]
             ~source
             ~expected:"function foo() { /* comment */ (5 - 3); 5; (6 - 5); /* comment */}"
             ~mapper:(new useless_mapper)
         );
         ( "fn_default_export" >:: fun ctxt ->
           let source = "export default function foo() { let x = rename; }" in
           assert_edits_equal
             ctxt
             ~edits:[((40, 46), "gotRenamed")]
             ~source
             ~expected:"export default function foo() { let x = gotRenamed; }"
             ~mapper:(new useless_mapper)
         );
         ( "fn_export_named" >:: fun ctxt ->
           let source = "export function foo() { let x = rename; }" in
           assert_edits_equal
             ctxt
             ~edits:[((32, 38), "gotRenamed")]
             ~source
             ~expected:"export function foo() { let x = gotRenamed; }"
             ~mapper:(new useless_mapper)
         );
         ( "assignment_left" >:: fun ctxt ->
           let source = "rename = 6;" in
           assert_edits_equal
             ctxt
             ~edits:[((0, 6), "gotRenamed")]
             ~source
             ~expected:"gotRenamed = 6;"
             ~mapper:(new useless_mapper)
         );
         ( "assignment_right" >:: fun ctxt ->
           let source = "x = rename;" in
           assert_edits_equal
             ctxt
             ~edits:[((4, 10), "gotRenamed")]
             ~source
             ~expected:"x = gotRenamed;"
             ~mapper:(new useless_mapper)
         );
         ( "list_diff_simple" >:: fun ctxt ->
           let a = "a" in
           let b = "b" in
           let old_list = [a] in
           let new_list = [b] in
           let edits = [(0, Replace (a, b))] in
           let script = list_diff old_list new_list in
           assert_equal ~ctxt (Some edits) script
         );
         ( "list_diff_simple2" >:: fun ctxt ->
           let a = "a" in
           let b = "b" in
           let old_list = [a; a] in
           let new_list = [b; b] in
           let edits = [(0, Replace (a, b)); (1, Replace (a, b))] in
           let script = list_diff old_list new_list in
           assert_equal ~ctxt (Some edits) script
         );
         ( "list_diff_simple3" >:: fun ctxt ->
           let a = "a" in
           let b = "b" in
           let old_list = [a; a] in
           let new_list = [b; b; b; b] in
           let edits =
             [
               (0, Replace (a, b));
               (1, Replace (a, b));
               (1, mk_insert ~sep:None ~leading_sep:true [b; b]);
             ]
           in
           let script = list_diff old_list new_list in
           assert_equal ~ctxt (Some edits) script
         );
         ( "list_diff_simple4" >:: fun ctxt ->
           let a = "a" in
           let b = "b" in
           let old_list = [a; a; a; a] in
           let new_list = [b; b] in
           let edits = [(0, Replace (a, b)); (1, Replace (a, b)); (2, Delete a); (3, Delete a)] in
           let script = list_diff old_list new_list in
           assert_equal ~ctxt (Some edits) script
         );
         ( "list_diff_paper" >:: fun ctxt ->
           let a = "a" in
           let b = "b" in
           let c = "c" in
           let old_list = [a; b; c; a; b; b; a] in
           let new_list = [c; b; a; b; a; c] in
           let edits =
             [
               (0, Delete a);
               (1, Delete b);
               (3, Delete a);
               (4, mk_insert ~sep:None [a]);
               (6, mk_insert ~sep:None [c]);
             ]
           in
           let script = list_diff old_list new_list in
           assert_equal ~ctxt (Some edits) script
         );
         ( "list_diff_flip" >:: fun ctxt ->
           let x = "x" in
           let y = "y" in
           let old_list = [x; x; x; y; y; y] in
           let new_list = [y; y; y; x; x; x] in
           let edits =
             [(0, Delete x); (1, Delete x); (2, Delete x); (5, mk_insert ~sep:None [x; x; x])]
           in
           let script = list_diff old_list new_list in
           assert_equal ~ctxt (Some edits) script
         );
         ( "list_diff_sentence" >:: fun ctxt ->
           let (t', h, i, s, space, e, n, t, c, o, pd, d) =
             ("T", "h", "i", "s", " ", "e", "n", "t", "c", "o", ".", "d")
           in
           (*"This is sentence one."*)
           let old_list =
             [t'; h; i; s; space; i; s; space; s; e; n; t; e; n; c; e; space; o; n; e; pd]
           in
           (*"This is the second sentence"*)
           let new_list =
             [
               t';
               h;
               i;
               s;
               space;
               i;
               s;
               space;
               t;
               h;
               e;
               space;
               s;
               e;
               c;
               o;
               n;
               d;
               space;
               s;
               e;
               n;
               t;
               e;
               n;
               c;
               e;
               pd;
             ]
           in
           let edits =
             [
               (7, mk_insert ~sep:None [t; h; e; space]);
               (9, mk_insert ~sep:None [c; o]);
               (11, Replace (t, d));
               (11, mk_insert ~sep:None ~leading_sep:true [space; s]);
               (14, Replace (c, t));
               (16, Delete space);
               (17, Delete o);
               (18, mk_insert ~sep:None [c]);
             ]
           in
           let script = list_diff old_list new_list in
           assert_equal ~ctxt ~printer:debug_string_of_script (Some edits) script
         );
         ( "list_diff_simple5" >:: fun ctxt ->
           let a = "a" in
           let b = "b" in
           let old_list = [a; b] in
           let new_list = [b] in
           let edits = [(0, Delete a)] in
           let script = list_diff old_list new_list in
           assert_equal ~ctxt (Some edits) script
         );
         ( "pattern_identifier" >:: fun ctxt ->
           let source = "let rename = 0" in
           assert_edits_equal
             ctxt
             ~edits:[((4, 10), "gotRenamed")]
             ~source
             ~expected:"let gotRenamed = 0"
             ~mapper:(new useless_mapper)
         );
         ( "pattern_array" >:: fun ctxt ->
           let source = "let [rename,rename] = [0]" in
           assert_edits_equal
             ctxt
             ~edits:[((5, 11), "gotRenamed"); ((12, 18), "gotRenamed")]
             ~source
             ~expected:"let [gotRenamed,gotRenamed] = [0]"
             ~mapper:(new useless_mapper)
         );
         ( "pattern_array_nested" >:: fun ctxt ->
           let source = "let [[[rename]]] = 0" in
           assert_edits_equal
             ctxt
             ~edits:[((7, 13), "gotRenamed")]
             ~source
             ~expected:"let [[[gotRenamed]]] = 0"
             ~mapper:(new useless_mapper)
         );
         ( "pattern_array_rest" >:: fun ctxt ->
           let source = "let [a,b,...rename] = 0" in
           assert_edits_equal
             ctxt
             ~edits:[((12, 18), "gotRenamed")]
             ~source
             ~expected:"let [a,b,...gotRenamed] = 0"
             ~mapper:(new useless_mapper)
         );
         ( "pattern_array_annot" >:: fun ctxt ->
           let source = "let [foo,bar]: rename = [0]" in
           assert_edits_equal
             ctxt
             ~edits:[((15, 21), "gotRenamed")]
             ~source
             ~expected:"let [foo,bar]: gotRenamed = [0]"
             ~mapper:(new useless_mapper)
         );
         ( "pattern_object_longhand" >:: fun ctxt ->
           let source = "let {rename: rename} = 0" in
           assert_edits_equal
             ctxt
             ~edits:[((5, 11), "gotRenamed"); ((13, 19), "gotRenamed")]
             ~source
             ~expected:"let {gotRenamed: gotRenamed} = 0"
             ~mapper:(new useless_mapper)
         );
         ( "pattern_object_rest" >:: fun ctxt ->
           let source = "let {a,b,...rename} = 0" in
           assert_edits_equal
             ctxt
             ~edits:[((12, 18), "gotRenamed")]
             ~source
             ~expected:"let {a,b,...gotRenamed} = 0"
             ~mapper:(new useless_mapper)
         );
         ( "pattern_object_annot" >:: fun ctxt ->
           let source = "let {foo: bar}: rename = 0" in
           assert_edits_equal
             ctxt
             ~edits:[((16, 22), "gotRenamed")]
             ~source
             ~expected:"let {foo: bar}: gotRenamed = 0"
             ~mapper:(new useless_mapper)
         );
         ( "pattern_assignment" >:: fun ctxt ->
           let source = "let [a=rename] = 0" in
           assert_edits_equal
             ctxt
             ~edits:[((7, 13), "gotRenamed")]
             ~source
             ~expected:"let [a=gotRenamed] = 0"
             ~mapper:(new useless_mapper)
         );
         ( "type_cast_expr" >:: fun ctxt ->
           let source = "(rename: string)" in
           assert_edits_equal
             ctxt
             ~edits:[((1, 7), "gotRenamed")]
             ~source
             ~expected:"(gotRenamed: string)"
             ~mapper:(new useless_mapper)
         );
         ( "type_cast_type" >:: fun ctxt ->
           let source = "(dontrename: number)" in
           assert_edits_equal
             ctxt
             ~edits:[((13, 19), "string")]
             ~source
             ~expected:"(dontrename: string)"
             ~mapper:(new useless_mapper)
         );
         ( "type_cast_assign" >:: fun ctxt ->
           let source = "const x : number = (dontrename: number)" in
           assert_edits_equal
             ctxt
             ~edits:[((10, 16), "string"); ((32, 38), "string")]
             ~source
             ~expected:"const x : string = (dontrename: string)"
             ~mapper:(new useless_mapper)
         );
         ( "type_cast_add" >:: fun ctxt ->
           let source = "const dontrename = call( /* preserve spaces */  )" in
           assert_edits_equal
             ctxt
             ~edits:[((19, 19), "("); ((49, 49), ": any)")]
             ~source
             ~mapper:(new insert_typecast_mapper)
             ~expected:"const dontrename = (call( /* preserve spaces */  ): any)"
         );
         ( "class_type_param_instantiation" >:: fun ctxt ->
           let source = "class A extends B<{}> { m(): rename {} }" in
           assert_edits_equal
             ctxt
             ~edits:[((29, 35), "gotRenamed")]
             ~source
             ~expected:"class A extends B<{}> { m(): gotRenamed {} }"
             ~mapper:(new useless_mapper)
         );
         ( "logical_operator_left" >:: fun ctxt ->
           let source = "rename && b" in
           assert_edits_equal
             ctxt
             ~edits:[((0, 6), "gotRenamed")]
             ~source
             ~expected:"gotRenamed && b"
             ~mapper:(new useless_mapper)
         );
         ( "logical_operator_right" >:: fun ctxt ->
           let source = "a || rename" in
           assert_edits_equal
             ctxt
             ~edits:[((5, 11), "gotRenamed")]
             ~source
             ~expected:"a || gotRenamed"
             ~mapper:(new useless_mapper)
         );
         ( "logical_operator_changed" >:: fun ctxt ->
           let source = "a ?? b" in
           assert_edits_equal
             ctxt
             ~edits:[((0, 6), "a || b")]
             ~source
             ~expected:"a || b"
             ~mapper:(new useless_mapper)
         );
         ( "insert_import_split" >:: fun ctxt ->
           let source = "5 - (2 + 2)" in
           assert_edits_equal
             ctxt
             ~edits:[((0, 0), "import { baz } from \"baz\";"); ((5, 10), "(2 - 2)")]
             ~source
             ~expected:"import { baz } from \"baz\";5 - ((2 - 2))"
             ~mapper:(new insert_import_mapper)
         );
         ( "insert_import_existing_split" >:: fun ctxt ->
           let source = "foo; 5 - (2 + 2)" in
           assert_edits_equal
             ctxt
             ~edits:[((0, 0), "import { baz } from \"baz\";"); ((10, 15), "(2 - 2)")]
             ~source
             ~expected:"import { baz } from \"baz\";foo; 5 - ((2 - 2))"
             ~mapper:(new insert_import_mapper)
         );
         ( "insert_import_second_split" >:: fun ctxt ->
           let source = "import bing from 'bing'; 5 - (2 + 2)" in
           assert_edits_equal
             ctxt
             ~edits:[((24, 24), "import { baz } from \"baz\";"); ((30, 35), "(2 - 2)")]
             ~source
             ~expected:"import bing from 'bing';import { baz } from \"baz\"; 5 - ((2 - 2))"
             ~mapper:(new insert_second_import_mapper)
         );
         ( "existing_cjs_import_split" >:: fun ctxt ->
           let source = "const x = require('bing'); 5 - (2 + 2)" in
           assert_edits_equal
             ctxt
             ~edits:[((26, 26), "import { baz } from \"baz\";"); ((32, 37), "(2 - 2)")]
             ~source
             ~expected:"const x = require('bing');import { baz } from \"baz\"; 5 - ((2 - 2))"
             ~mapper:(new insert_second_import_mapper)
         );
         ( "insert_cjs_import_split" >:: fun ctxt ->
           let source = "import 'bing'; 5 - (2 + 2)" in
           assert_edits_equal
             ctxt
             ~edits:[((14, 14), "require(\"baz\");"); ((20, 25), "(2 - 2)")]
             ~source
             ~expected:"import 'bing';require(\"baz\"); 5 - ((2 - 2))"
             ~mapper:(new insert_second_cjsimport_mapper)
         );
         ( "pathological_import_split" >:: fun ctxt ->
           let source = "import 'baz'; import 'bing'; 5 - (2 + 2);" in
           assert_edits_equal
             ctxt
             ~edits:[((0, 0), "5 - (2 + 2);")]
             ~source
             ~expected:"5 - (2 + 2);import 'baz'; import 'bing'; 5 - (2 + 2);"
             ~mapper:(new insert_begin_mapper)
         );
         ( "remove_import_split" >:: fun ctxt ->
           let source = "import 'baz';5 - (2 + 2);" in
           assert_edits_equal
             ctxt
             ~edits:[((0, 13), "")]
             ~source
             ~expected:"5 - (2 + 2);"
             ~mapper:(new delete_mapper)
         );
         ( "add_body_split" >:: fun ctxt ->
           let source = "import 'baz';" in
           assert_edits_equal
             ctxt
             ~edits:[((13, 13), "foo(\"baz\");")]
             ~source
             ~expected:"import 'baz';foo(\"baz\");"
             ~mapper:(new add_body_mapper)
         );
         ( "add_to_body_split" >:: fun ctxt ->
           let source = "import 'baz'; bar(qux);" in
           assert_edits_equal
             ctxt
             ~edits:[((23, 23), "foo(\"baz\");")]
             ~source
             ~expected:"import 'baz'; bar(qux);foo(\"baz\");"
             ~mapper:(new add_body_mapper)
         );
         ( "remove_body_split" >:: fun ctxt ->
           let source = "import 'baz';5 - (2 + 2);" in
           assert_edits_equal
             ctxt
             ~edits:[((13, 25), "")]
             ~source
             ~expected:"import 'baz';"
             ~mapper:(new delete_end_mapper)
         );
         ( "spread_simple" >:: fun ctxt ->
           let source = "[...rename]" in
           assert_edits_equal
             ctxt
             ~edits:[((4, 10), "gotRenamed")]
             ~source
             ~expected:"[...gotRenamed]"
             ~mapper:(new useless_mapper)
         );
         ( "tagged_template_tag" >:: fun ctxt ->
           let source = "rename`dontRename`" in
           assert_edits_equal
             ctxt
             ~edits:[((0, 6), "gotRenamed")]
             ~source
             ~expected:"gotRenamed`dontRename`"
             ~mapper:(new useless_mapper)
         );
         ( "tagged_template_literal" >:: fun ctxt ->
           let source = "dontRename`rename`" in
           assert_edits_equal
             ctxt
             ~edits:[((10, 18), "`gotRenamed`")]
             ~source
             ~expected:"dontRename`gotRenamed`"
             ~mapper:(new useless_mapper)
         );
         ( "template_literal_simple" >:: fun ctxt ->
           let source = "`rename`" in
           assert_edits_equal
             ctxt
             ~edits:[((0, 8), "`gotRenamed`")]
             ~source
             ~expected:"`gotRenamed`"
             ~mapper:(new useless_mapper)
         );
         ( "template_literal_expr" >:: fun ctxt ->
           let source = "`foo ${rename} bar`" in
           assert_edits_equal
             ctxt
             ~edits:[((7, 13), "gotRenamed")]
             ~source
             ~expected:"`foo ${gotRenamed} bar`"
             ~mapper:(new useless_mapper)
         );
         ( "template_literal_expr_multiple" >:: fun ctxt ->
           let source = "let test = `${rename} ${foo} bar ${rename}`" in
           assert_edits_equal
             ctxt
             ~edits:[((14, 20), "gotRenamed"); ((35, 41), "gotRenamed")]
             ~source
             ~expected:"let test = `${gotRenamed} ${foo} bar ${gotRenamed}`"
             ~mapper:(new useless_mapper)
         );
         ( "jsx_element_self_closing_simple" >:: fun ctxt ->
           let source = "<rename />" in
           assert_edits_equal
             ctxt
             ~edits:[((1, 7), "gotRenamed")]
             ~source
             ~expected:"<gotRenamed />"
             ~mapper:(new useless_mapper)
         );
         ( "jsx_element_self_closing_namespaced_namespace" >:: fun ctxt ->
           let source = "<RENAME:dontRename />" in
           assert_edits_equal
             ctxt
             ~edits:[((1, 7), "GOT_RENAMED")]
             ~source
             ~expected:"<GOT_RENAMED:dontRename />"
             ~mapper:(new useless_mapper)
         );
         ( "jsx_element_self_closing_namespaced_name" >:: fun ctxt ->
           let source = "<DONT_RENAME:rename />" in
           assert_edits_equal
             ctxt
             ~edits:[((13, 19), "gotRenamed")]
             ~source
             ~expected:"<DONT_RENAME:gotRenamed />"
             ~mapper:(new useless_mapper)
         );
         ( "jsx_element_self_closing_member_expr_object" >:: fun ctxt ->
           let source = "<Rename.dontRename />" in
           assert_edits_equal
             ctxt
             ~edits:[((1, 7), "GotRenamed")]
             ~source
             ~expected:"<GotRenamed.dontRename />"
             ~mapper:(new useless_mapper)
         );
         ( "jsx_element_self_closing_member_expr_name" >:: fun ctxt ->
           let source = "<DontRename.rename />" in
           assert_edits_equal
             ctxt
             ~edits:[((12, 18), "gotRenamed")]
             ~source
             ~expected:"<DontRename.gotRenamed />"
             ~mapper:(new useless_mapper)
         );
         ( "jsx_element_self_closing_member_expr_nested_object" >:: fun ctxt ->
           let source = "<Rename.DontRename.Rename.dontRename />" in
           assert_edits_equal
             ctxt
             ~edits:[((1, 7), "GotRenamed"); ((19, 25), "GotRenamed")]
             ~source
             ~expected:"<GotRenamed.DontRename.GotRenamed.dontRename />"
             ~mapper:(new useless_mapper)
         );
         ( "jsx_element_simple" >:: fun ctxt ->
           let source = "<rename></rename>" in
           assert_edits_equal
             ctxt
             ~edits:[((1, 7), "gotRenamed"); ((10, 16), "gotRenamed")]
             ~source
             ~expected:"<gotRenamed></gotRenamed>"
             ~mapper:(new useless_mapper)
         );
         ( "jsx_element_member_expr_nested" >:: fun ctxt ->
           let source = "<Rename.DontRename.rename></Rename.DontRename.rename>" in
           assert_edits_equal
             ctxt
             ~edits:
               [
                 ((1, 7), "GotRenamed");
                 ((19, 25), "gotRenamed");
                 ((28, 34), "GotRenamed");
                 ((46, 52), "gotRenamed");
               ]
             ~source
             ~expected:"<GotRenamed.DontRename.gotRenamed></GotRenamed.DontRename.gotRenamed>"
             ~mapper:(new useless_mapper)
         );
         ( "jsx_element_to_self_closing" >:: fun ctxt ->
           let source = "<selfClosing></selfClosing>" in
           assert_edits_equal
             ctxt
             ~edits:[((0, 27), "<selfClosing />")]
             ~source
             ~expected:"<selfClosing />"
             ~mapper:(new useless_mapper)
         );
         ( "jsx_element_from_self_closing" >:: fun ctxt ->
           let source = "<notSelfClosing />" in
           assert_edits_equal
             ctxt
             ~edits:[((0, 18), "<notSelfClosing></notSelfClosing>")]
             ~source
             ~expected:"<notSelfClosing></notSelfClosing>"
             ~mapper:(new useless_mapper)
         );
         ( "jsx_element_attribute_name" >:: fun ctxt ->
           let source = "<Component rename={1} />" in
           assert_edits_equal
             ctxt
             ~edits:[((11, 17), "gotRenamed")]
             ~source
             ~expected:"<Component gotRenamed={1} />"
             ~mapper:(new useless_mapper)
         );
         ( "jsx_element_attribute_value_expression_literal" >:: fun ctxt ->
           let source = "<Component someProp={4} />" in
           assert_edits_equal
             ctxt
             ~edits:[((21, 22), "5")]
             ~source
             ~expected:"<Component someProp={5} />"
             ~mapper:(new useless_mapper)
         );
         ( "jsx_element_attribute_value_expression_binop" >:: fun ctxt ->
           let source = "<Component someProp={4 + 4} />" in
           assert_edits_equal
             ctxt
             ~edits:[((21, 26), "5 - 5")]
             ~source
             ~expected:"<Component someProp={5 - 5} />"
             ~mapper:(new useless_mapper)
         );
         ( "jsx_element_attribute_name_and_value" >:: fun ctxt ->
           let source = "<Component rename={4} />" in
           assert_edits_equal
             ctxt
             ~edits:[((11, 17), "gotRenamed"); ((19, 20), "5")]
             ~source
             ~expected:"<Component gotRenamed={5} />"
             ~mapper:(new useless_mapper)
         );
         ( "jsx_element_attribute_list_name" >:: fun ctxt ->
           let source = "<Component dontRename={1} rename={2} />" in
           assert_edits_equal
             ctxt
             ~edits:[((26, 32), "gotRenamed")]
             ~source
             ~expected:"<Component dontRename={1} gotRenamed={2} />"
             ~mapper:(new useless_mapper)
         );
         ( "jsx_element_attribute_list_expression_literal" >:: fun ctxt ->
           let source = "<Component someProp={4} anotherProp={4} />" in
           assert_edits_equal
             ctxt
             ~edits:[((21, 22), "5"); ((37, 38), "5")]
             ~source
             ~expected:"<Component someProp={5} anotherProp={5} />"
             ~mapper:(new useless_mapper)
         );
         ( "jsx_element_spread_attribute" >:: fun ctxt ->
           let source = "<Component {...rename} />" in
           assert_edits_equal
             ctxt
             ~edits:[((15, 21), "gotRenamed")]
             ~source
             ~expected:"<Component {...gotRenamed} />"
             ~mapper:(new useless_mapper)
         );
         ( "jsx_element_spread_attribute_list_mixed" >:: fun ctxt ->
           let source = "<Component {...rename} rename={4}/>" in
           assert_edits_equal
             ctxt
             ~edits:[((15, 21), "gotRenamed"); ((23, 29), "gotRenamed"); ((31, 32), "5")]
             ~source
             ~expected:"<Component {...gotRenamed} gotRenamed={5}/>"
             ~mapper:(new useless_mapper)
         );
         ( "jsx_element_attribute_list_name_and_value" >:: fun ctxt ->
           let source = "<Component rename={1} dontRename={4} />" in
           assert_edits_equal
             ctxt
             ~edits:[((11, 17), "gotRenamed"); ((34, 35), "5")]
             ~source
             ~expected:"<Component gotRenamed={1} dontRename={5} />"
             ~mapper:(new useless_mapper)
         );
         ( "jsx_element_child_element" >:: fun ctxt ->
           let source = "<div><rename /></div>" in
           assert_edits_equal
             ctxt
             ~edits:[((6, 12), "gotRenamed")]
             ~source
             ~expected:"<div><gotRenamed /></div>"
             ~mapper:(new useless_mapper)
         );
         ( "jsx_element_child_fragment" >:: fun ctxt ->
           let source = "<div><>rename</></div>" in
           assert_edits_equal
             ctxt
             ~edits:[((7, 13), "gotRenamed")]
             ~source
             ~expected:"<div><>gotRenamed</></div>"
             ~mapper:(new useless_mapper)
         );
         ( "jsx_element_child_expr" >:: fun ctxt ->
           let source = "<div>{rename}</div>" in
           assert_edits_equal
             ctxt
             ~edits:[((6, 12), "gotRenamed")]
             ~source
             ~expected:"<div>{gotRenamed}</div>"
             ~mapper:(new useless_mapper)
         );
         ( "jsx_element_child_spread" >:: fun ctxt ->
           let source = "<div>{...rename}</div>" in
           assert_edits_equal
             ctxt
             ~edits:[((9, 15), "gotRenamed")]
             ~source
             ~expected:"<div>{...gotRenamed}</div>"
             ~mapper:(new useless_mapper)
         );
         ( "jsx_element_child_text" >:: fun ctxt ->
           let source = "<div>rename</div>" in
           assert_edits_equal
             ctxt
             ~edits:[((5, 11), "gotRenamed")]
             ~source
             ~expected:"<div>gotRenamed</div>"
             ~mapper:(new useless_mapper)
         );
         ( "jsx_element_children" >:: fun ctxt ->
           let source = "<div>{rename} <rename /></div>" in
           assert_edits_equal
             ctxt
             ~edits:[((6, 12), "gotRenamed"); ((15, 21), "gotRenamed")]
             ~source
             ~expected:"<div>{gotRenamed} <gotRenamed /></div>"
             ~mapper:(new useless_mapper)
         );
         ( "jsx_element_children_nested" >:: fun ctxt ->
           let source = "<div><rename><><rename /></></rename></div>" in
           assert_edits_equal
             ctxt
             ~edits:[((6, 12), "gotRenamed"); ((16, 22), "gotRenamed"); ((30, 36), "gotRenamed")]
             ~source
             ~expected:"<div><gotRenamed><><gotRenamed /></></gotRenamed></div>"
             ~mapper:(new useless_mapper)
         );
         ( "jsx_fragment_expr" >:: fun ctxt ->
           let source = "<>{rename}</>" in
           assert_edits_equal
             ctxt
             ~edits:[((3, 9), "gotRenamed")]
             ~source
             ~expected:"<>{gotRenamed}</>"
             ~mapper:(new useless_mapper)
         );
         ( "declare_type_alias_id" >:: fun ctxt ->
           let source = "declare type Rename = string" in
           assert_edits_equal
             ctxt
             ~edits:[((13, 19), "GotRenamed")]
             ~source
             ~expected:"declare type GotRenamed = string"
             ~mapper:(new useless_mapper)
         );
         ( "type_alias_id" >:: fun ctxt ->
           let source = "type Rename = string" in
           assert_edits_equal
             ctxt
             ~edits:[((5, 11), "GotRenamed")]
             ~source
             ~expected:"type GotRenamed = string"
             ~mapper:(new useless_mapper)
         );
         ( "type_alias_intersection_left" >:: fun ctxt ->
           let source = "type foo = number & bar" in
           assert_edits_equal
             ctxt
             ~edits:[((11, 17), "string")]
             ~source
             ~expected:"type foo = string & bar"
             ~mapper:(new useless_mapper)
         );
         ( "type_alias_intersection_right" >:: fun ctxt ->
           let source = "type foo = bar & number" in
           assert_edits_equal
             ctxt
             ~edits:[((17, 23), "string")]
             ~source
             ~expected:"type foo = bar & string"
             ~mapper:(new useless_mapper)
         );
         ( "type_alias_intersection_rest" >:: fun ctxt ->
           let source = "type foo = bar & baz & number & number" in
           assert_edits_equal
             ctxt
             ~edits:[((23, 29), "string"); ((32, 38), "string")]
             ~source
             ~expected:"type foo = bar & baz & string & string"
             ~mapper:(new useless_mapper)
         );
         ( "type_alias_intersection_argument_mismatch" >:: fun ctxt ->
           let source = "type foo = bar & true & boolean" in
           assert_edits_equal
             ctxt
             ~edits:[((11, 31), "bar & true")]
             ~source
             ~expected:"type foo = bar & true"
             ~mapper:(new remove_annotation_rest_mapper)
         );
         ( "type_alias_nullable" >:: fun ctxt ->
           let source = "type foo = ?number" in
           assert_edits_equal
             ctxt
             ~edits:[((12, 18), "string")]
             ~source
             ~expected:"type foo = ?string"
             ~mapper:(new useless_mapper)
         );
         ( "type_alias_number_literal" >:: fun ctxt ->
           let source = "type foo = 5.0" in
           assert_edits_equal
             ctxt
             ~edits:[((11, 14), "4.0")]
             ~source
             ~expected:"type foo = 4.0"
             ~mapper:(new useless_mapper)
         );
         ( "type_alias_param_name" >:: fun ctxt ->
           let source = "type alias<RENAME> = string" in
           assert_edits_equal
             ctxt
             ~edits:[((11, 17), "GOT_RENAMED")]
             ~source
             ~expected:"type alias<GOT_RENAMED> = string"
             ~mapper:(new useless_mapper)
         );
         ( "type_alias_param_bound" >:: fun ctxt ->
           let source = "type alias<A: number> = string" in
           assert_edits_equal
             ctxt
             ~edits:[((14, 20), "string")]
             ~source
             ~expected:"type alias<A: string> = string"
             ~mapper:(new useless_mapper)
         );
         ( "type_alias_param_variance" >:: fun ctxt ->
           let source = "type alias<-A> = string" in
           assert_edits_equal
             ctxt
             ~edits:[((11, 12), "+")]
             ~source
             ~expected:"type alias<+A> = string"
             ~mapper:(new useless_mapper)
         );
         ( "type_alias_param_insert_variance" >:: fun ctxt ->
           let source = "type alias<A> = string" in
           assert_edits_equal
             ctxt
             ~edits:[((11, 12), "+A")]
             ~source
             ~expected:"type alias<+A> = string"
             ~mapper:(new insert_variance_mapper)
         );
         ( "type_alias_param_bound_insert_variance" >:: fun ctxt ->
           let source = "type alias<A: number> = string" in
           assert_edits_equal
             ctxt
             ~edits:[((11, 20), "+A: string")]
             ~source
             ~expected:"type alias<+A: string> = string"
             ~mapper:(new insert_variance_mapper)
         );
         ( "type_alias_param_delete_variance" >:: fun ctxt ->
           let source = "type alias<-A> = string" in
           assert_edits_equal
             ctxt
             ~edits:[((11, 12), "")]
             ~source
             ~expected:"type alias<A> = string"
             ~mapper:(new delete_variance_mapper)
         );
         ( "type_alias_param_default" >:: fun ctxt ->
           let source = "type alias<A = number> = string" in
           assert_edits_equal
             ctxt
             ~edits:[((15, 21), "string")]
             ~source
             ~expected:"type alias<A = string> = string"
             ~mapper:(new useless_mapper)
         );
         ( "type_alias_param_combo" >:: fun ctxt ->
           let source = "type alias<-RENAME: number = number> = string" in
           assert_edits_equal
             ctxt
             ~edits:
               [
                 ((11, 12), "+");
                 ((12, 18), "GOT_RENAMED");
                 ((20, 26), "string");
                 ((29, 35), "string");
               ]
             ~source
             ~expected:"type alias<+GOT_RENAMED: string = string> = string"
             ~mapper:(new useless_mapper)
         );
         ( "type_alias_param_list" >:: fun ctxt ->
           let source = "type alias<-RENAME, RENAME: number> = string" in
           assert_edits_equal
             ctxt
             ~edits:
               [
                 ((11, 12), "+");
                 ((12, 18), "GOT_RENAMED");
                 ((20, 26), "GOT_RENAMED");
                 ((28, 34), "string");
               ]
             ~source
             ~expected:"type alias<+GOT_RENAMED, GOT_RENAMED: string> = string"
             ~mapper:(new useless_mapper)
         );
         ( "declare_type_alias_right" >:: fun ctxt ->
           let source = "declare type alias = number" in
           assert_edits_equal
             ctxt
             ~edits:[((21, 27), "string")]
             ~source
             ~expected:"declare type alias = string"
             ~mapper:(new useless_mapper)
         );
         ( "type_alias_right" >:: fun ctxt ->
           let source = "type alias = number" in
           assert_edits_equal
             ctxt
             ~edits:[((13, 19), "string")]
             ~source
             ~expected:"type alias = string"
             ~mapper:(new useless_mapper)
         );
         ( "type_alias_right_function_type_params" >:: fun ctxt ->
           let source = "type alias = (rename: string, bar: number, ...rename: string) => string" in
           assert_edits_equal
             ctxt
             ~edits:[((14, 20), "gotRenamed"); ((35, 41), "string"); ((46, 52), "gotRenamed")]
             ~source
             ~expected:
               "type alias = (gotRenamed: string, bar: string, ...gotRenamed: string) => string"
             ~mapper:(new useless_mapper)
         );
         ( "type_alias_right_function_type_tparams" >:: fun ctxt ->
           let source = "type alias = <RENAME>(param: string) => string" in
           assert_edits_equal
             ctxt
             ~edits:[((14, 20), "GOT_RENAMED")]
             ~source
             ~expected:"type alias = <GOT_RENAMED>(param: string) => string"
             ~mapper:(new useless_mapper)
         );
         ( "type_alias_right_function_type_return" >:: fun ctxt ->
           let source = "type alias = string => number" in
           assert_edits_equal
             ctxt
             ~edits:[((23, 29), "string")]
             ~source
             ~expected:"type alias = string => string"
             ~mapper:(new useless_mapper)
         );
         ( "type_alias_right_object_type" >:: fun ctxt ->
           let source = "type alias = { rename: string }" in
           assert_edits_equal
             ctxt
             ~edits:[((15, 21), "gotRenamed")]
             ~source
             ~expected:"type alias = { gotRenamed: string }"
             ~mapper:(new useless_mapper)
         );
         ( "type_alias_right_object_property_value_get" >:: fun ctxt ->
           let source = "type alias = { get rename(): void; }" in
           assert_edits_equal
             ctxt
             ~edits:[((19, 25), "gotRenamed")]
             ~source
             ~expected:"type alias = { get gotRenamed(): void; }"
             ~mapper:(new useless_mapper)
         );
         ( "type_alias_right_object_property_value_set" >:: fun ctxt ->
           let source = "type alias = { set foo(value: number): void; }" in
           assert_edits_equal
             ctxt
             ~edits:[((30, 36), "string")]
             ~source
             ~expected:"type alias = { set foo(value: string): void; }"
             ~mapper:(new useless_mapper)
         );
         ( "type_alias_right_object_variance" >:: fun ctxt ->
           let source = "type alias = { -foo: string }" in
           assert_edits_equal
             ctxt
             ~edits:[((15, 16), "+")]
             ~source
             ~expected:"type alias = { +foo: string }"
             ~mapper:(new useless_mapper)
         );
         ( "opaque_type_id" >:: fun ctxt ->
           let source = "opaque type Rename = string" in
           assert_edits_equal
             ctxt
             ~edits:[((12, 18), "GotRenamed")]
             ~source
             ~expected:"opaque type GotRenamed = string"
             ~mapper:(new useless_mapper)
         );
         ( "opaque_type_param" >:: fun ctxt ->
           let source = "opaque type foo<RENAME> = string" in
           assert_edits_equal
             ctxt
             ~edits:[((16, 22), "GOT_RENAMED")]
             ~source
             ~expected:"opaque type foo<GOT_RENAMED> = string"
             ~mapper:(new useless_mapper)
         );
         ( "opaque_type_impl" >:: fun ctxt ->
           let source = "opaque type foo<A> = number" in
           assert_edits_equal
             ctxt
             ~edits:[((21, 27), "string")]
             ~source
             ~expected:"opaque type foo<A> = string"
             ~mapper:(new useless_mapper)
         );
         ( "opaque_type_super" >:: fun ctxt ->
           let source = "opaque type foo: number = string" in
           assert_edits_equal
             ctxt
             ~edits:[((17, 23), "string")]
             ~source
             ~expected:"opaque type foo: string = string"
             ~mapper:(new useless_mapper)
         );
         ( "opaque_type_combo" >:: fun ctxt ->
           let source = "opaque type Rename<RENAME>: number = number" in
           assert_edits_equal
             ctxt
             ~edits:
               [
                 ((12, 18), "GotRenamed");
                 ((19, 25), "GOT_RENAMED");
                 ((28, 34), "string");
                 ((37, 43), "string");
               ]
             ~source
             ~expected:"opaque type GotRenamed<GOT_RENAMED>: string = string"
             ~mapper:(new useless_mapper)
         );
         ( "call_insert" >:: fun ctxt ->
           let source = "callFunction(class A { f = (x: string) => x; });" in
           assert_edits_equal
             ctxt
             ~edits:[((24, 24), ": number")]
             ~source
             ~expected:"callFunction(class A { f: number = (x: string) => x; });"
             ~mapper:(new prop_annot_mapper)
         );
         ( "new_insert" >:: fun ctxt ->
           let source = "new MyClass(class A { f = (x: string) => x; });" in
           assert_edits_equal
             ctxt
             ~edits:[((23, 23), ": number")]
             ~source
             ~expected:"new MyClass(class A { f: number = (x: string) => x; });"
             ~mapper:(new prop_annot_mapper)
         );
         ( "insert_inside_array" >:: fun ctxt ->
           let source = "[{ render() { class A { f = (x: string) => x; } return new A() } }]" in
           assert_edits_equal
             ctxt
             ~edits:[((25, 25), ": number")]
             ~source
             ~expected:"[{ render() { class A { f: number = (x: string) => x; } return new A() } }]"
             ~mapper:(new prop_annot_mapper)
         );
         ( "update_same_op" >:: fun ctxt ->
           let source = "++rename" in
           assert_edits_equal
             ctxt
             ~edits:[((2, 8), "gotRenamed")]
             ~source
             ~expected:"++gotRenamed"
             ~mapper:(new useless_mapper)
         );
         ( "update_diff_op" >:: fun ctxt ->
           let source = "--rename" in
           assert_edits_equal
             ctxt
             ~edits:[((0, 8), "++gotRenamed")]
             ~source
             ~expected:"++gotRenamed"
             ~mapper:(new useless_mapper)
         );
         ( "update_arrow_function_add_return_annot" >:: fun ctxt ->
           let source = "const x = bla => { return 0; };" in
           assert_edits_equal
             ctxt
             ~edits:[((10, 13), "(bla)"); ((13, 13), ": number")]
             ~source
             ~expected:"const x = (bla): number => { return 0; };"
             ~mapper:(new func_return_annot_mapper)
         );
         ( "update_arrow_function_single_param" >:: fun ctxt ->
           let source = "const x = bla => { return 0; };" in
           assert_edits_equal
             ctxt
             ~edits:[((7, 7), ": number"); ((10, 13), "(bla: number)"); ((13, 13), ": number")]
             ~source
             ~expected:"const x: number = (bla: number): number => { return 0; };"
             ~mapper:(new insert_annot_mapper)
         );
         ( "update_arrow_function_function_return" >:: fun ctxt ->
           let source = "const x = bla => { return 0; };" in
           assert_edits_equal
             ctxt
             ~edits:
               [
                 ((7, 7), ": (() => number)");
                 ((10, 13), "(bla: () => number)");
                 ((13, 13), ": (() => number)");
               ]
             ~source
             ~expected:
               "const x: (() => number) = (bla: () => number): (() => number) => { return 0; };"
             ~mapper:(new insert_function_annot_mapper)
         );
         ( "new_imports_after_directive_dont_reprint_the_file" >:: fun ctxt ->
           let source = "'use strict';const x = bla => { return 0; };" in
           assert_edits_equal
             ctxt
             ~edits:
               [
                 ( (13, 13),
                   "import type { there as here } from \"new_import1\";
import type { there as here } from \"new_import2\";"
                 );
                 ((20, 20), ": (() => number)");
                 ((23, 26), "(bla: () => number)");
                 ((26, 26), ": (() => number)");
               ]
             ~source
             ~expected:
               "'use strict';import type { there as here } from \"new_import1\";
import type { there as here } from \"new_import2\";const x: (() => number) = (bla: () => number): (() => number) => { return 0; };"
             ~mapper:(new insert_import_and_annot_mapper)
         );
         ( "import_renamed_simple" >:: fun ctxt ->
           let source = "import rename from \"foo\";" in
           assert_edits_equal
             ctxt
             ~edits:[((7, 13), "gotRenamed")]
             ~source
             ~expected:"import gotRenamed from \"foo\";"
             ~mapper:(new useless_mapper)
         );
         ( "import_renamed_simple_multiple1" >:: fun ctxt ->
           let source = "import rename, {bar} from \"foo\";" in
           assert_edits_equal
             ctxt
             ~edits:[((7, 13), "gotRenamed")]
             ~source
             ~expected:"import gotRenamed, {bar} from \"foo\";"
             ~mapper:(new useless_mapper)
         );
         ( "import_renamed_simple_multiple2" >:: fun ctxt ->
           let source = "import bar, {rename} from \"foo\";" in
           assert_edits_equal
             ctxt
             ~edits:[((13, 19), "gotRenamed")]
             ~source
             ~expected:"import bar, {gotRenamed} from \"foo\";"
             ~mapper:(new useless_mapper)
         );
         ( "import_renamed_simple1" >:: fun ctxt ->
           let source = "import {rename} from \"foo\";" in
           assert_edits_equal
             ctxt
             ~edits:[((8, 14), "gotRenamed")]
             ~source
             ~expected:"import {gotRenamed} from \"foo\";"
             ~mapper:(new useless_mapper)
         );
         ( "import_renamed_multiple" >:: fun ctxt ->
           let source = "import {rename, bar} from \"foo\";" in
           assert_edits_equal
             ctxt
             ~edits:[((8, 14), "gotRenamed")]
             ~source
             ~expected:"import {gotRenamed, bar} from \"foo\";"
             ~mapper:(new useless_mapper)
         );
         ( "import_renamed_whole_module" >:: fun ctxt ->
           let source = "import * as rename from \"foo\";" in
           assert_edits_equal
             ctxt
             ~edits:[((12, 18), "gotRenamed")]
             ~source
             ~expected:"import * as gotRenamed from \"foo\";"
             ~mapper:(new useless_mapper)
         );
         ( "import_type1" >:: fun ctxt ->
           let source = "import type rename from \"bar\";" in
           assert_edits_equal
             ctxt
             ~edits:[((12, 18), "gotRenamed")]
             ~source
             ~expected:"import type gotRenamed from \"bar\";"
             ~mapper:(new useless_mapper)
         );
         ( "import_type_and_fn2" >:: fun ctxt ->
           let source = "import rename, {type foo} from \"bar\";" in
           assert_edits_equal
             ctxt
             ~edits:[((7, 13), "gotRenamed")]
             ~source
             ~expected:"import gotRenamed, {type foo} from \"bar\";"
             ~mapper:(new useless_mapper)
         );
         ( "import_multiple_names1" >:: fun ctxt ->
           let source = "import rename, {myBar, myBaz} from \"bar\";" in
           assert_edits_equal
             ctxt
             ~edits:[((7, 13), "gotRenamed")]
             ~source
             ~expected:"import gotRenamed, {myBar, myBaz} from \"bar\";"
             ~mapper:(new useless_mapper)
         );
         ( "import_multiple_names2" >:: fun ctxt ->
           let source = "import myBar, {rename, myBaz} from \"bar\";" in
           assert_edits_equal
             ctxt
             ~edits:[((15, 21), "gotRenamed")]
             ~source
             ~expected:"import myBar, {gotRenamed, myBaz} from \"bar\";"
             ~mapper:(new useless_mapper)
         );
         ( "import_type2" >:: fun ctxt ->
           let source = "import type {rename} from \"bar\";" in
           assert_edits_equal
             ctxt
             ~edits:[((13, 19), "gotRenamed")]
             ~source
             ~expected:"import type {gotRenamed} from \"bar\";"
             ~mapper:(new useless_mapper)
         );
         ( "import_fn_and_rename_module1" >:: fun ctxt ->
           let source = "import rename, * as myModule from \"bar\";" in
           assert_edits_equal
             ctxt
             ~edits:[((7, 13), "gotRenamed")]
             ~source
             ~expected:"import gotRenamed, * as myModule from \"bar\";"
             ~mapper:(new useless_mapper)
         );
         ( "import_fn_and_rename_module2" >:: fun ctxt ->
           let source = "import foo, * as rename from \"bar\";" in
           assert_edits_equal
             ctxt
             ~edits:[((17, 23), "gotRenamed")]
             ~source
             ~expected:"import foo, * as gotRenamed from \"bar\";"
             ~mapper:(new useless_mapper)
         );
         ( "import_rename" >:: fun ctxt ->
           let source = "import {rename as bar} from \"foo\";" in
           assert_edits_equal
             ctxt
             ~edits:[((8, 14), "gotRenamed")]
             ~source
             ~expected:"import {gotRenamed as bar} from \"foo\";"
             ~mapper:(new useless_mapper)
         );
         ( "import_type_and_fn1" >:: fun ctxt ->
           let source = "import foo, {type rename} from \"bar\";" in
           assert_edits_equal
             ctxt
             ~edits:[((18, 24), "gotRenamed")]
             ~source
             ~expected:"import foo, {type gotRenamed} from \"bar\";"
             ~mapper:(new useless_mapper)
         );
         ( "import_type3" >:: fun ctxt ->
           let source = "import {type rename} from \"bar\";" in
           assert_edits_equal
             ctxt
             ~edits:[((13, 19), "gotRenamed")]
             ~source
             ~expected:"import {type gotRenamed} from \"bar\";"
             ~mapper:(new useless_mapper)
         );
         ( "import_typeof1" >:: fun ctxt ->
           let source = "import typeof rename from \"bar\";" in
           assert_edits_equal
             ctxt
             ~edits:[((14, 20), "gotRenamed")]
             ~source
             ~expected:"import typeof gotRenamed from \"bar\";"
             ~mapper:(new useless_mapper)
         );
         ( "import_typeof2" >:: fun ctxt ->
           let source = "import typeof {rename} from \"bar\";" in
           assert_edits_equal
             ctxt
             ~edits:[((15, 21), "gotRenamed")]
             ~source
             ~expected:"import typeof {gotRenamed} from \"bar\";"
             ~mapper:(new useless_mapper)
         );
         ( "throw" >:: fun ctxt ->
           let source = "throw \"rename\";" in
           assert_edits_equal
             ctxt
             ~edits:[((6, 14), "\"gotRenamed\"")]
             ~source
             ~expected:"throw \"gotRenamed\";"
             ~mapper:(new literal_mapper)
         );
         ( "bool1" >:: fun ctxt ->
           let source = "rename = true;" in
           assert_edits_equal
             ctxt
             ~edits:[((0, 6), "gotRenamed")]
             ~source
             ~expected:"gotRenamed = true;"
             ~mapper:(new useless_mapper)
         );
         ( "bool2" >:: fun ctxt ->
           let source = "const rename = 0; Boolean(rename);" in
           assert_edits_equal
             ctxt
             ~edits:[((6, 12), "gotRenamed"); ((26, 32), "gotRenamed")]
             ~source
             ~expected:"const gotRenamed = 0; Boolean(gotRenamed);"
             ~mapper:(new useless_mapper)
         );
         ( "bool3" >:: fun ctxt ->
           let source = "const rename = true; Boolean((false || rename));" in
           assert_edits_equal
             ctxt
             ~edits:[((6, 12), "gotRenamed"); ((39, 45), "gotRenamed")]
             ~source
             ~expected:"const gotRenamed = true; Boolean((false || gotRenamed));"
             ~mapper:(new useless_mapper)
         );
         ( "bool_change" >:: fun ctxt ->
           let source = "const x = true; Boolean(true);" in
           assert_edits_equal
             ctxt
             ~edits:[((10, 14), "false"); ((24, 28), "false")]
             ~source
             ~expected:"const x = false; Boolean(false);"
             ~mapper:(new true_to_false_mapper)
         );
         ( "bool_type_change" >:: fun ctxt ->
           let source = "const x: true = 'garbage';" in
           assert_edits_equal
             ctxt
             ~edits:[((9, 13), "false")]
             ~source
             ~expected:"const x: false = 'garbage';"
             ~mapper:(new true_to_false_mapper)
         );
         ( "comment_add" >:: fun ctxt ->
           let source = "bla" in
           assert_edits_equal
             ctxt
             ~edits:[((0, 0), "/*hello*/"); ((3, 3), "/*bye*/")]
             ~source
             ~expected:"/*hello*/bla/*bye*/"
             ~mapper:(new add_comment_mapper)
         );
         ( "comment_modify" >:: fun ctxt ->
           let source = "/*MAL*/bla/*WRONG*/" in
           assert_edits_equal
             ctxt
             ~edits:[((0, 7), "/*hello*/"); ((10, 19), "/*bye*/")]
             ~source
             ~expected:"/*hello*/bla/*bye*/"
             ~mapper:(new add_comment_mapper)
         );
         ( "comment_annot_generic_deep" >:: fun ctxt ->
           let source = "const a: Box<Bla> = {}" in
           assert_edits_equal
             ctxt
             ~source
             ~mapper:(new add_comment_mapper)
             ~edits:
               [
                 ((6, 6), "/*hello*/");
                 ((7, 7), "/*bye*/");
                 ((9, 9), "/*hello*/");
                 ((12, 12), "/*bye*/");
                 ((13, 13), "/*hello*/");
                 ((16, 16), "/*bye*/");
               ]
             ~expected:"const /*hello*/a/*bye*/: /*hello*/Box/*bye*/</*hello*/Bla/*bye*/> = {}"
         );
         ( "let_union_first" >:: fun ctxt ->
           let source = "let x : number | void = 42;" in
           assert_edits_equal
             ctxt
             ~edits:[((8, 14), "string")]
             ~source
             ~expected:"let x : string | void = 42;"
             ~mapper:(new useless_mapper)
         );
         ( "let_union_second" >:: fun ctxt ->
           let source = "let x : boolean | number = 42;" in
           assert_edits_equal
             ctxt
             ~edits:[((18, 24), "string")]
             ~source
             ~expected:"let x : boolean | string = 42;"
             ~mapper:(new useless_mapper)
         );
         ( "let_union_rest" >:: fun ctxt ->
           let source = "let x : boolean | void | number = 42;" in
           assert_edits_equal
             ctxt
             ~edits:[((25, 31), "string")]
             ~source
             ~expected:"let x : boolean | void | string = 42;"
             ~mapper:(new useless_mapper)
         );
         ( "type_alias_union_argument_mismatch" >:: fun ctxt ->
           let source = "type foo = bar | true | boolean" in
           assert_edits_equal
             ctxt
             ~edits:[((11, 31), "bar | true")]
             ~source
             ~expected:"type foo = bar | true"
             ~mapper:(new remove_annotation_rest_mapper)
         );
         ( "array_type" >:: fun ctxt ->
           let source = "let x : rename[] = []" in
           assert_edits_equal
             ctxt
             ~edits:[((8, 14), "gotRenamed")]
             ~source
             ~expected:"let x : gotRenamed[] = []"
             ~mapper:(new useless_mapper)
         );
         ( "sequence1" >:: fun ctxt ->
           let source = "(a, b, c, rename, d)" in
           assert_edits_equal
             ctxt
             ~edits:[((10, 16), "gotRenamed")]
             ~source
             ~expected:"(a, b, c, gotRenamed, d)"
             ~mapper:(new useless_mapper)
         );
         ( "sequence2" >:: fun ctxt ->
           let source = "(a, b, c, d)" in
           assert_edits_equal
             ctxt
             ~edits:[((1, 11), "a, b, c, d, a, b, c, d")]
             ~source
             ~expected:"(a, b, c, d, a, b, c, d)"
             ~mapper:(new double_sequence_mapper)
         );
         ( "declare_class_id" >:: fun ctxt ->
           let source = "declare class rename { }" in
           assert_edits_equal
             ctxt
             ~edits:[((14, 20), "gotRenamed")]
             ~source
             ~expected:"declare class gotRenamed { }"
             ~mapper:(new useless_mapper)
         );
         ( "declare_class_tparam" >:: fun ctxt ->
           let source = "declare class C<rename> { }" in
           assert_edits_equal
             ctxt
             ~edits:[((16, 22), "gotRenamed")]
             ~source
             ~expected:"declare class C<gotRenamed> { }"
             ~mapper:(new useless_mapper)
         );
         ( "declare_class_extends" >:: fun ctxt ->
           let source = "declare class C extends rename { }" in
           assert_edits_equal
             ctxt
             ~edits:[((24, 30), "gotRenamed")]
             ~source
             ~expected:"declare class C extends gotRenamed { }"
             ~mapper:(new useless_mapper)
         );
         ( "declare_class_body" >:: fun ctxt ->
           let source = "declare class C { f: rename }" in
           assert_edits_equal
             ctxt
             ~edits:[((21, 27), "gotRenamed")]
             ~source
             ~expected:"declare class C { f: gotRenamed }"
             ~mapper:(new useless_mapper)
         );
         ( "enum_declaration_unchanged" >:: fun ctxt ->
           let source = "enum Status {On, Off}" in
           (* use an unrelated mapper to ensure enums are not affected *)
           assert_edits_equal
             ctxt
             ~edits:[]
             ~source
             ~expected:"enum Status {On, Off}"
             ~mapper:(new literal_mapper)
         );
         ( "enum_comments_unchanged" >:: fun ctxt ->
           let source = "enum Status {On, Off // internal comment\n}" in
           (* use an unrelated mapper to ensure enums are not affected *)
           assert_edits_equal
             ctxt
             ~edits:[]
             ~source
             ~expected:"enum Status {On, Off // internal comment\n}"
             ~mapper:(new literal_mapper)
         );
         ( "enum_declaration_defaulted_string" >:: fun ctxt ->
           let source = "enum Status {On, Off}" in
           assert_edits_equal
             ctxt
             ~edits:[((13, 15), "Enabled")]
             ~source
             ~expected:"enum Status {Enabled, Off}"
             ~mapper:(new useless_mapper)
         );
         ( "enum_declaration_string" >:: fun ctxt ->
           let source = "enum Status {On = \"on\", Off = \"off\"}" in
           assert_edits_equal
             ctxt
             ~edits:[((18, 22), "\"enabled\"")]
             ~source
             ~expected:"enum Status {On = \"enabled\", Off = \"off\"}"
             ~mapper:(new useless_mapper)
         );
         ( "enum_add_comment" >:: fun ctxt ->
           let source = "enum Status {On = 1, Off = 2}" in
           assert_edits_equal
             ctxt
             ~edits:[((19, 19), "// a comment\n")]
             ~source
             ~expected:"enum Status {On = 1// a comment\n, Off = 2}"
             ~mapper:(new useless_mapper)
         );
       ]
