Pass correct bitstring meta during expansion

Closes #15244

Author: lukaszsamson

lib/elixir/src/elixir_bitstring.erl

@@ -61,7 +61,7 @@ expand(BitstrMeta, Fun, [H | T], Acc, S, E, Alignment, RequireSize) ->
 
   InferredMeta = [{inferred_bitstring_spec, true} | Meta],
   EAcc = concat_or_prepend_bitstring(InferredMeta, ELeft, ERight, Acc, ES, MatchOrRequireSize),
-  expand(Meta, Fun, T, EAcc, {SS, OriginalS}, ES, Alignment, RequireSize).
+  expand(BitstrMeta, Fun, T, EAcc, {SS, OriginalS}, ES, Alignment, RequireSize).
 
 extract_meta({_, Meta, _}, _) -> Meta;
 extract_meta(_, Meta) -> Meta.

lib/elixir/test/elixir/kernel/errors_test.exs

@@ -267,6 +267,18 @@ defmodule Kernel.ErrorsTest do
     )
   end
 
+  test "invalid literal on bitstring" do
+    assert_compile_error(
+      ["nofile:1:1", "a bitstring only accepts binaries, numbers, and variables inside a match"],
+      ~c"""
+      <<
+        "foo",
+        [1]
+      >> = List.flatten([])
+      """
+    )
+  end
+
   test "literal on map and struct" do
     assert_compile_error(
       ["nofile:1:10", "expected key-value pairs in a map, got: put_in(foo.bar.baz, nil)"],