Do not crash on imports inside nested quotes, closes #13575

Author: josevalim

lib/elixir/src/elixir_quote.erl

@@ -399,14 +399,14 @@ do_quote(Other, _, _) ->
 import_meta(Meta, Name, Arity, Q, E) ->
   case (keyfind(imports, Meta) == false) andalso
       elixir_dispatch:find_imports(Meta, Name, E) of
-    [] ->
+    [_ | _] = Imports ->
+      keystore(imports, keystore(context, Meta, Q#elixir_quote.context), Imports);
+
+    _ ->
       case (Arity == 1) andalso keyfind(ambiguous_op, Meta) of
         {ambiguous_op, nil} -> keystore(ambiguous_op, Meta, Q#elixir_quote.context);
         _ -> Meta
-      end;
-
-    Imports ->
-      keystore(imports, keystore(context, Meta, Q#elixir_quote.context), Imports)
+      end
   end.
 
 %% do_quote_*

lib/elixir/test/elixir/kernel/quote_test.exs

@@ -120,6 +120,12 @@ defmodule Kernel.QuoteTest do
     assert {:quote, _, [[do: {:unquote, _, _}]]} = quote(do: quote(do: unquote(x)))
   end
 
+  test "import inside nested quote" do
+    # Check that we can evaluate imports from quote inside quote
+    assert {{:to_string, meta, [123]}, _} = Code.eval_quoted(quote(do: quote(do: to_string(123))))
+    assert meta[:imports] == [{1, Kernel}]
+  end
+
   defmacrop nested_quote_in_macro do
     x = 1