Backport OTP 24 compatibility patches to v1.11 (#10743)

* Update Erlang warnings translation (#10694)

Since erlang/otp@8ecc648
instead of `{eval_failure, Reason}` we'd get `{eval_failure, Call, Reason}`

* Fix translating erl compiler errors to diagnostics on OTP 24 (#10719)

The compiler previously emitted just `line` and now emits `{line,
column}`.

The diagnostic struct accepts as position either:

    nil
    line
    {start_line, start_col, end_line, end_col}

so we could have used the `column` to create the 4-tuple but we don't
have enough information to do that correctly, we don't know where the
line ends.

* Fix remaining warning translations for OTP 24 (#10720)

Yecc error message changed so we need to loosen up our assertion:

OTP 23

    iex> iex
    Erlang/OTP 23 [erts-11.1.7] [source] [64-bit] [smp:8:8] [ds:8:8:10] [async-threads:1]

    Interactive Elixir (1.11.3) - press Ctrl+C to exit (type h() ENTER for help)
    iex(1)> :yecc.file('f.yrl')
    f.yrl:1: syntax error before: '.'
    :error

OTP 24

    iex> iex
    Erlang/OTP 24 [DEVELOPMENT] [erts-11.1.7] [source-802d2c5083] [64-bit] [smp:8:8] [ds:8:8:10] [async-threads:1]

    Interactive Elixir (1.12.0-dev) - press Ctrl+C to exit (type h() ENTER for help)
    iex(1)> :yecc.file('f.yrl')
    f.yrl:1:5: syntax error before: .

    :error

* Support 16bit floats in bitstrings (#10740)

On OTP 24:

    iex> <<x::float-16>> = <<60, 0>>
    iex> x
    1.0
    iex> <<x::float-16>>
    <<60, 0>>

Before OTP 24 we'd get errors or wouldn't match:

    iex> <<1.0::float-16>>
    ** (ArgumentError) argument error while evaluating iex at line 1

    <<x::float-16>> = <<60, 0>>
    ** (MatchError) no match of right hand side value: <<60, 0>>

    iex> (fn <<x::float-16>> -> x; _ -> :nomatch end).(<<60, 0>>)
    :nomatch

* Handle :compile.file/2 returning :error on OTP 24 (#10742)

Before OTP 24 when given invalid args, :compile.file/2 would return:

    iex(1)> :compile.file('a.erl', [{:d, 'foo', 'bar'}, :report])
    {:error, :badarg}

On OTP 24:

    iex(1)> :compile.file('a.erl', [{:d, 'foo', 'bar'}, :report])

    *** Internal compiler error ***
    exception error: bad argument
      in function  io_lib:format/2
         called as io_lib:format("badly formed '~s'",[{"foo","bar"}])
      in call from sys_messages:list_errors/3 (sys_messages.erl, line 53)
      in call from lists:foreach/2 (lists.erl, line 1342)
      in call from compile:comp_ret_err/1 (compile.erl, line 546)
      in call from compile:'-internal_fun/2-anonymous-0-'/2 (compile.erl, line 229)
      in call from compile:'-do_compile/2-anonymous-0-'/1 (compile.erl, line 219)
    :error

Author: wojtekmach

lib/elixir/lib/kernel/special_forms.ex

@@ -233,9 +233,9 @@ defmodule Kernel.SpecialForms do
 
   Sizes for types are a bit more nuanced. The default size for integers is 8.
 
-  For floats, it is 64. For floats, `size * unit` must result in 32 or 64,
+  For floats, it is 64. For floats, `size * unit` must result in 16, 32, or 64,
   corresponding to [IEEE 754](https://en.wikipedia.org/wiki/IEEE_floating_point)
-  binary32 and binary64, respectively.
+  binary16, binary32, and binary64, respectively.
 
   For binaries, the default is the size of the binary. Only the last binary in a
   match can use the default size. All others must have their size specified

lib/elixir/src/elixir_bitstring.erl

@@ -319,8 +319,13 @@ build_spec(Meta, _Size, Unit, Type, _Endianness, Sign, Spec, E) when Type == bin
 build_spec(Meta, Size, Unit, Type, Endianness, Sign, Spec, E) when Type == integer; Type == float ->
   NumberSize = number_size(Size, Unit),
   if
-    Type == float, is_integer(NumberSize), NumberSize /= 32, NumberSize /= 64 ->
-      form_error(Meta, E, ?MODULE, {bittype_float_size, NumberSize});
+    Type == float, is_integer(NumberSize) ->
+      case valid_float_size(NumberSize) of
+        true ->
+          add_spec(Type, add_spec(Endianness, add_spec(Sign, Spec)));
+        false ->
+          form_error(Meta, E, ?MODULE, {bittype_float_size, NumberSize})
+      end;
     Size == default, Unit /= default ->
       form_error(Meta, E, ?MODULE, bittype_unit);
     true ->
@@ -331,6 +336,12 @@ number_size(Size, default) when is_integer(Size) -> Size;
 number_size(Size, Unit) when is_integer(Size) -> Size * Unit;
 number_size(Size, _) -> Size.
 
+%% TODO: Simplify when we require OTP 24
+valid_float_size(16) -> erlang:system_info(otp_release) >= "24";
+valid_float_size(32) -> true;
+valid_float_size(64) -> true;
+valid_float_size(_) -> false.
+
 add_spec(default, Spec) -> Spec;
 add_spec(Key, Spec) -> [{Key, [], []} | Spec].
 
@@ -372,7 +383,12 @@ format_error(bittype_signed) ->
 format_error(bittype_unit) ->
   "integer and float types require a size specifier if the unit specifier is given";
 format_error({bittype_float_size, Other}) ->
-  io_lib:format("float requires size*unit to be 32 or 64 (default), got: ~p", [Other]);
+  Message =
+    case erlang:system_info(otp_release) >= "24" of
+      true -> "16, 32, or 64";
+      false -> "32 or 64"
+    end,
+  io_lib:format("float requires size*unit to be ~s (default), got: ~p", [Message, Other]);
 format_error({invalid_literal, Literal}) ->
   io_lib:format("invalid literal ~ts in <<>>", ['Elixir.Macro':to_string(Literal)]);
 format_error({undefined_bittype, Expr}) ->

lib/elixir/src/elixir_erl_compiler.erl

@@ -132,6 +132,17 @@ custom_format(sys_core_fold, nomatch_guard) ->
   "this check/guard will always yield the same result";
 
 %% Handle literal eval failures
+custom_format(sys_core_fold, {eval_failure, {Mod, Name, Arity}, Error}) ->
+  #{'__struct__' := Struct} = 'Elixir.Exception':normalize(error, Error),
+  {ExMod, ExName, ExArgs} = elixir_rewrite:erl_to_ex(Mod, Name, lists:duplicate(Arity, nil)),
+  Call = 'Elixir.Exception':format_mfa(ExMod, ExName, length(ExArgs)),
+  Trimmed = case Call of
+              <<"Kernel.", Rest/binary>> -> Rest;
+              _ -> Call
+            end,
+  ["the call to ", Trimmed, " will fail with ", elixir_aliases:inspect(Struct)];
+
+%% TODO: remove when we require OTP 24
 custom_format(sys_core_fold, {eval_failure, Error}) ->
   #{'__struct__' := Struct} = 'Elixir.Exception':normalize(error, Error),
   ["this expression will fail with ", elixir_aliases:inspect(Struct)];

lib/elixir/test/elixir/kernel/expansion_test.exs

@@ -2387,17 +2387,49 @@ defmodule Kernel.ExpansionTest do
       end
     end
 
-    test "raises for invalid size * unit for floats" do
-      message = ~r"float requires size\*unit to be 32 or 64 \(default\), got: 128"
+    # TODO: Simplify when we require OTP 24
+    if System.otp_release() >= "24" do
+      test "16-bit floats" do
+        import Kernel, except: [-: 2]
 
-      assert_raise CompileError, message, fn ->
-        expand(quote(do: <<12.3::32*4>>))
+        assert expand(quote(do: <<12.3::float-16>>)) |> clean_meta([:alignment]) ==
+                 quote(do: <<12.3::float()-size(16)>>)
       end
 
-      message = ~r"float requires size\*unit to be 32 or 64 \(default\), got: 256"
+      test "raises for invalid size * unit for floats" do
+        message = ~r"float requires size\*unit to be 16, 32, or 64 \(default\), got: 128"
 
-      assert_raise CompileError, message, fn ->
-        expand(quote(do: <<12.3::256>>))
+        assert_raise CompileError, message, fn ->
+          expand(quote(do: <<12.3::32*4>>))
+        end
+
+        message = ~r"float requires size\*unit to be 16, 32, or 64 \(default\), got: 256"
+
+        assert_raise CompileError, message, fn ->
+          expand(quote(do: <<12.3::256>>))
+        end
+      end
+    else
+      test "16-bit floats" do
+        message = ~r"float requires size\*unit to be 32 or 64 \(default\), got: 16"
+
+        assert_raise CompileError, message, fn ->
+          expand(quote(do: <<12.3::16>>))
+        end
+      end
+
+      test "raises for invalid size * unit for floats" do
+        message = ~r"float requires size\*unit to be 32 or 64 \(default\), got: 128"
+
+        assert_raise CompileError, message, fn ->
+          expand(quote(do: <<12.3::32*4>>))
+        end
+
+        message = ~r"float requires size\*unit to be 32 or 64 \(default\), got: 256"
+
+        assert_raise CompileError, message, fn ->
+          expand(quote(do: <<12.3::256>>))
+        end
       end
     end
 

lib/elixir/test/elixir/kernel/warning_test.exs

@@ -931,22 +931,31 @@ defmodule Kernel.WarningTest do
     purge(Sample)
   end
 
+  # TODO: Simplify when we require OTP 24
+  if System.otp_release() >= "24" do
+    @argument_error_message "the call to :erlang.atom_to_binary/2"
+    @arithmetic_error_message "the call to +/2"
+  else
+    @argument_error_message "this expression"
+    @arithmetic_error_message "this expression"
+  end
+
   test "eval failure warning" do
     assert capture_err(fn ->
              Code.eval_string("""
              defmodule Sample1 do
                def foo, do: Atom.to_string "abc"
              end
              """)
-           end) =~ ~r"this expression will fail with ArgumentError\n.*nofile:2"
+           end) =~ "#{@argument_error_message} will fail with ArgumentError\n  nofile:2"
 
     assert capture_err(fn ->
              Code.eval_string("""
              defmodule Sample2 do
                def foo, do: 1 + nil
              end
              """)
-           end) =~ ~r"this expression will fail with ArithmeticError\n.*nofile:2"
+           end) =~ "#{@arithmetic_error_message} will fail with ArithmeticError\n  nofile:2"
   after
     purge([Sample1, Sample2])
   end

lib/mix/lib/mix/compilers/erlang.ex

@@ -271,7 +271,7 @@ defmodule Mix.Compilers.Erlang do
   defp to_diagnostics(warnings_or_errors, severity) do
     for {file, issues} <- warnings_or_errors,
         {line, module, data} <- issues do
-      position = if is_integer(line) and line >= 1, do: line
+      position = line(line)
 
       %Mix.Task.Compiler.Diagnostic{
         file: Path.absname(file),
@@ -288,7 +288,12 @@ defmodule Mix.Compilers.Erlang do
     for {_, warnings} <- entries,
         {file, issues} <- warnings,
         {line, module, message} <- issues do
-      IO.puts("#{file}:#{line}: Warning: #{module.format_error(message)}")
+      IO.puts("#{file}:#{line(line)}: Warning: #{module.format_error(message)}")
     end
   end
+
+  defp line({line, _column}) when is_integer(line) and line >= 1, do: line
+  # TODO: remove when we require OTP 24
+  defp line(line) when is_integer(line) and line >= 1, do: line
+  defp line(_), do: nil
 end

lib/mix/lib/mix/tasks/compile.erlang.ex

@@ -100,9 +100,10 @@ defmodule Mix.Tasks.Compile.Erlang do
       file = Erlang.to_erl_file(Path.rootname(input, ".erl"))
 
       case :compile.file(file, erlc_options) do
-        {:error, :badarg} ->
+        # TODO: Don't handle {:error, :badarg} when we require OTP 24
+        error when error == :error or error == {:error, :badarg} ->
           message =
-            "Compiling Erlang #{inspect(file)} failed with ArgumentError, probably because of invalid :erlc_options"
+            "Compiling Erlang file #{inspect(file)} failed, probably because of invalid :erlc_options"
 
           Mix.raise(message)
 

lib/mix/test/mix/tasks/compile.erlang_test.exs

@@ -14,7 +14,7 @@ defmodule Mix.Tasks.Compile.ErlangTest do
   @tag erlc_options: [{:d, 'foo', 'bar'}]
   test "raises on invalid erlc_options" do
     in_fixture("compile_erlang", fn ->
-      assert_raise Mix.Error, ~r"failed with ArgumentError", fn ->
+      assert_raise Mix.Error, ~r"Compiling Erlang file '.*' failed", fn ->
         capture_io(fn ->
           Mix.Tasks.Compile.Erlang.run([])
         end)

lib/mix/test/mix/tasks/compile.yecc_test.exs

@@ -23,10 +23,12 @@ defmodule Mix.Tasks.Compile.YeccTest do
         assert %Mix.Task.Compiler.Diagnostic{
                  compiler_name: "yecc",
                  file: ^file,
-                 message: "syntax error before: '.'",
+                 message: message,
                  position: 1,
                  severity: :error
                } = diagnostic
+
+        assert message =~ "syntax error before: "
       end)
 
       assert File.regular?("src/test_ok.erl")