Properly format functions without the Tfun type.

Summary: There are some functions (like `idx`) which are special-cased by the typechecker, which means that even though its type is Function it doesn't have a Tfun. Right now we fall back to displaying these as if they were class members, due to a faulty match expression.

Differential Revision: D7418540

fbshipit-source-id: 01ff338788230187be2203deebdccecdcd2aed3e

hphp/hack/src/typing/typing_print.ml

@@ -595,30 +595,27 @@ module Full = struct
    in
    let body =
      let open SymbolOccurrence in
      match occurrence with
      | { type_ = Class; name; _ } -> Concat [text "class "; text_strip_ns name]

      | { type_ = Function; name; _ }
      | { type_ = Method (_, name); _ }
      | { type_ = Property (_, name); _ }
      | { type_ = ClassConst (_, name); _ }
      | { type_ = GConst; name; _ } ->
      match occurrence, x with
      | { type_ = Class; name; _ }, _ -> Concat [text "class "; text_strip_ns name]

      | { type_ = Function; name; _ }, (_, Tfun ft)
      | { type_ = Method (_, name); _ }, (_, Tfun ft) ->
        (* Use short names for function types since they display a lot more
           information to the user. *)
        begin match x with
        | (_, Tfun ft) ->
          Concat [
            text "function ";
            text_strip_ns name;
            fun_type text_strip_ns ISet.empty env ft;
          ]
        | _ ->
          Concat [
            ty text_strip_ns ISet.empty env x;
            Space;
            text_strip_ns (occurrence.name);
          ]
        end
         Concat [
           text "function ";
           text_strip_ns name;
           fun_type text_strip_ns ISet.empty env ft;
         ]

      | { type_ = Property _; name; _ }, _
      | { type_ = ClassConst _; name; _ }, _
      | { type_ = GConst; name; _ }, _ ->
        Concat [
          ty text_strip_ns ISet.empty env x;
          Space;
          text_strip_ns name;
        ]

      | _ -> ty text_strip_ns ISet.empty env x
    in

hphp/hack/test/integration_ml/test_server_hover.ml

@@ -19,8 +19,13 @@ let pos_at (line1, column1) (line2, column2) =
    (File_pos.of_line_column_offset line1 (column1 - 1) 0)
    (File_pos.of_line_column_offset line2 column2 0))

let builtins = "<?hh // strict
class Awaitable<T> {}"
let builtins = "<?hh // decl
class Awaitable<T> {}
interface Traversable<+Tv> {}
interface KeyedTraversable<+Tk, +Tv> extends Traversable<Tv> {}
interface Container<+Tv> extends Traversable<Tv> {}
interface KeyedContainer<+Tk, +Tv> extends Container<Tv>, KeyedTraversable<Tk, Tv> {}
function idx<Tk, Tv>(?KeyedContainer<Tk, Tv> $collection, Tk $index, $default = null): ?Tv {}"

let class_members = "<?hh // strict
abstract class ClassMembers {
@@ -424,17 +429,38 @@ the other stars."; "Full name: `DocBlock::leadingStarsAndMDList`"];
  ]
]

let special_cases = "<?hh // strict
function special_cases(): void {
  idx(array(1, 2, 3), 1);
//^3:3
}
"

let special_cases_cases = [
  ("special_cases.php", 3, 3), [
    {
      (* Without the `ft` corresponding to the `Tfun`, we can't give any useful
         information here :/ *)
      snippet = "?int";
      addendum = [];
      pos = pos_at (3, 3) (3, 24);
    }
  ]
]

let files = [
  "builtins.php", builtins;
  "class_members.php", class_members;
  "classname_call.php", classname_call;
  "chained_calls.php", chained_calls;
  "classname_variable.php", classname_variable;
  "docblock.php", docblock;
  "special_cases.php", special_cases;
]

let cases =
  docblockCases
  special_cases_cases
  @ docblockCases
  @ class_members_cases
  @ classname_call_cases
  @ chained_calls_cases