Also solve the issue for interpolations.

Author: josevalim

src/elixir_transform.erl

@@ -339,9 +339,8 @@ transform({bin_element, Line, Expr, Type, Specifiers }, S) ->
 % = Variables
 %
 % No variables can be defined in a string without interpolation.
-transform({string, Line, String }, S) ->
-  CharList = [{integer,Line,Integer} || Integer <- String],
-  { elixir_tree_helpers:build_simple_bin(Line, CharList), S };
+transform({string, Line, String } = Expr, S) ->
+  { elixir_tree_helpers:build_simple_bin(Line, [Expr]), S };
 
 % Handle interpolated strings declarations.
 %

src/elixir_tree_helpers.erl

@@ -44,7 +44,15 @@ build_bin_each(Fun, [], Line, S, Acc) ->
 
 build_bin_each(Fun, [H|T], Line, S, Acc) ->
   { Expr, NS, Format } = Fun(H, S),
-  build_bin_each(Fun, T, Line, NS, [{ bin_element, Line, Expr, default, Format }|Acc]).
+  case Expr of
+    {string, _, String} ->
+      Final = lists:foldl(fun(Integer, FinalAcc) ->
+        [{bin_element,Line,{integer,Line,Integer},default,Format}|FinalAcc]
+      end, Acc, String),
+      build_bin_each(Fun, T, Line, NS, Final);
+    _ ->
+      build_bin_each(Fun, T, Line, NS, [{ bin_element, Line, Expr, default, Format }|Acc])
+  end.
 
 % Build simple binaries
 build_simple_bin(Line, Exprs) ->