Fix binary typespecs

  * Removes <<_::size*unit>>
  * Adds <<_::size, _::_*unit>>

Signed-off-by: José Valim <jose.valim@plataformatec.com.br>

Author: ericmj

lib/elixir/lib/kernel/typespec.ex

@@ -580,13 +580,13 @@ defmodule Kernel.Typespec do
 
   defp typespec_to_ast({:type, line, :binary, [arg1, arg2]}) do
     [arg1, arg2] = for arg <- [arg1, arg2], do: typespec_to_ast(arg)
-    cond do
-      arg2 == 0 ->
+    case {typespec_to_ast(arg1), typespec_to_ast(arg2)} do
+      {arg1, 0} ->
         quote line: line, do: <<_ :: unquote(arg1)>>
-      arg1 == 0 ->
+      {0, arg2} ->
         quote line: line, do: <<_ :: _ * unquote(arg2)>>
-      true ->
-        quote line: line, do: <<_ :: unquote(arg1) * unquote(arg2)>>
+      {arg1, arg2} ->
+        quote line: line, do: <<_ :: unquote(arg1), _ :: _ * unquote(arg2)>>
     end
   end
 
@@ -707,16 +707,16 @@ defmodule Kernel.Typespec do
     {:type, line(meta), :binary, [{:integer, line(meta), 0}, {:integer, line(unit_meta), unit}]}
   end
 
-  defp typespec({:<<>>, meta, [{:::, shared_meta, [{:_, _, ctx}, {:*, _, [size, unit]}]}]}, _, _)
-      when is_atom(ctx) and is_integer(unit) and is_integer(size) do
-    {:type, line(meta), :binary, [{:integer, line(shared_meta), size}, {:integer, line(shared_meta), unit}]}
-  end
-
   defp typespec({:<<>>, meta, [{:::, size_meta, [{:_, _, ctx}, size]}]}, _, _)
       when is_atom(ctx) and is_integer(size) do
     {:type, line(meta), :binary, [{:integer, line(size_meta), size}, {:integer, line(meta), 0}]}
   end
 
+  defp typespec({:<<>>, meta, [{:::, size_meta, [{:_, _, ctx1}, size]}, {:::, unit_meta, [{:_, _, ctx2}, {:*, _, [{:_, _, ctx3}, unit]}]}]}, _, _)
+      when is_atom(ctx1) and is_atom(ctx2) and is_atom(ctx3) and is_integer(size) and is_integer(unit) do
+    {:type, line(meta), :binary, [{:integer, line(size_meta), size}, {:integer, line(unit_meta), unit}]}
+  end
+
   ## Handle maps and structs
   defp typespec({:map, meta, args}, _vars, _caller) when args == [] or is_atom(args) do
     {:type, line(meta), :map, :any}

lib/elixir/pages/Typespecs.md

@@ -58,9 +58,9 @@ The following literals are also supported in typespecs:
           | 1.0                           ## Floats
 
           | <<>>                          ## Bitstrings
-          | <<_::size>>                 # size is 0 or a positive integer
-          | <<_::_ * unit>>             # unit is an integer from 1 to 256
-          | <<_::size * unit>>
+          | <<_::size>>                   # size is 0 or a positive integer
+          | <<_::_*unit>>                 # unit is an integer from 1 to 256
+          | <<_::size, _::_*unit>>
 
           | [type]                        ## Lists
           | []                            # empty list

lib/elixir/test/elixir/kernel/typespec_test.exs

@@ -144,7 +144,7 @@ defmodule Kernel.TypespecTest do
 
   test "@type with a binary with a base size" do
     module = test_module do
-      @type mytype :: <<_ :: 3>>
+      @type mytype :: <<_::3>>
     end
 
     assert [type: {:mytype, {:type, _, :binary, [{:integer, _, 3}, {:integer, _, 0}]}, []}] =
@@ -160,6 +160,23 @@ defmodule Kernel.TypespecTest do
            types(module)
   end
 
+  test "@type with a binary with a size and unit size" do
+    module = test_module do
+      @type mytype :: <<_::3, _::_*8>>
+    end
+
+    assert [type: {:mytype, {:type, _, :binary, [{:integer, _, 3}, {:integer, _, 8}]}, []}] =
+           types(module)
+  end
+
+  test "@type with invalid binary spec" do
+    assert_raise CompileError, fn ->
+      test_module do
+        @type mytype :: <<_::3*8>>
+      end
+    end
+  end
+
   test "@type with a range op" do
     module = test_module do
       @type mytype :: 1..10
@@ -545,9 +562,9 @@ defmodule Kernel.TypespecTest do
       (quote do: @type simple_type() :: integer()),
       (quote do: @type param_type(p) :: [p]),
       (quote do: @type union_type() :: integer() | binary() | boolean()),
-      (quote do: @type binary_type1() :: <<_ :: _ * 8>>),
-      (quote do: @type binary_type2() :: <<_ :: 3 * 8>>),
-      (quote do: @type binary_type3() :: <<_ :: 3>>),
+      (quote do: @type binary_type1() :: <<_::_*8>>),
+      (quote do: @type binary_type2() :: <<_::3>>),
+      (quote do: @type binary_type3() :: <<_::3, _::_*8>>),
       (quote do: @type tuple_type() :: {integer()}),
       (quote do: @type ftype() :: (() -> any()) | (() -> integer()) | ((integer() -> integer()))),
       (quote do: @type cl() :: char_list()),