Fail to compile try without else/catch/after/rescue, closes #2797

Signed-off-by: José Valim <[email protected]>

Author: José Valim

lib/elixir/src/elixir_exp_clauses.erl

@@ -101,7 +101,9 @@ do_receive(Meta, {Key, _}, _Acc, E) ->
 %% Try
 
 'try'(Meta, [], E) ->
-  compile_error(Meta, ?m(E, file), "missing do keywords in try");
+  compile_error(Meta, ?m(E, file), "missing do keyword in try");
+'try'(Meta, [{do, _}], E) ->
+  compile_error(Meta, ?m(E, file), "missing catch/rescue/after/else keyword in try");
 'try'(Meta, KV, E) when not is_list(KV) ->
   elixir_errors:compile_error(Meta, ?m(E, file), "invalid arguments for try");
 'try'(Meta, KV, E) ->

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

@@ -392,11 +392,6 @@ defmodule Kernel.ExpansionTest do
 
   ## Try
 
-  test "try: expands do" do
-    assert expand(quote do: (try do x = y end; x)) ==
-           quote do: (try do x = y() end; x())
-  end
-
   test "try: expands catch" do
     assert expand(quote do: (try do x catch x, y -> z = :erlang.+(x, y) end; z)) ==
            quote do: (try do x() catch x, y -> z = :erlang.+(x, y) end; z())
@@ -417,6 +412,12 @@ defmodule Kernel.ExpansionTest do
            quote do: (try do x() rescue unquote(:in)(x, _) -> x; unquote(:in)(_, [:"Elixir.Error"]) -> x() end; x())
   end
 
+  test "try: expects more than do" do
+    assert_raise CompileError, ~r"missing catch/rescue/after/else keyword in try", fn ->
+      expand(quote do: (try do x = y end; x))
+    end
+  end
+
   ## Binaries
 
   test "bitstrings: size * unit" do