Raise proper error on invalid function in quoted expressions, closes #2020

Author: José Valim

lib/elixir/src/elixir_exp.erl

@@ -396,7 +396,7 @@ expand_many(Args, E) ->
 %%   3
 %%
 %% However, lexical information is.
-expand_arg(Arg, Acc) when is_number(Arg); is_atom(Arg); is_binary(Arg); is_pid(Arg); is_function(Arg) ->
+expand_arg(Arg, Acc) when is_number(Arg); is_atom(Arg); is_binary(Arg); is_pid(Arg) ->
   { Arg, Acc };
 expand_arg(Arg, { Acc1, Acc2 }) ->
   { EArg, EAcc } = expand(Arg, Acc1),

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

@@ -389,6 +389,10 @@ defmodule Kernel.ExpansionTest do
     assert_raise CompileError, %r"invalid quoted expression: {1, 2, 3}", fn ->
       expand(quote do: unquote({ 1, 2, 3 }))
     end
+
+    assert_raise CompileError, %r"invalid quoted expression: #Function<", fn ->
+      expand(quote do: unquote({ :sample, fn -> end }))
+    end
   end
 
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