From a29330f69c8550befb63d56530c97c74f7f4eead Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jos=C3=A9=20Valim?= <jose.valim@plataformatec.com.br>
Date: Sun, 16 Dec 2018 12:48:00 +0100
Subject: [PATCH 1/2] No longer wrap expression in binary as Erlang/OTP 20+
 does it by default

---
 lib/elixir/src/elixir_erl_for.erl | 24 +++++++-----------------
 1 file changed, 7 insertions(+), 17 deletions(-)

diff --git a/lib/elixir/src/elixir_erl_for.erl b/lib/elixir/src/elixir_erl_for.erl
index 8c044a764eb..cb876ac1971 100644
--- a/lib/elixir/src/elixir_erl_for.erl
+++ b/lib/elixir/src/elixir_erl_for.erl
@@ -19,11 +19,9 @@ translate(Meta, Args, Return, S) ->
   {TExpr, SE}  = elixir_erl_pass:translate(wrap_expr(Expr, TInto), SC),
   SF = elixir_erl_var:mergec(SI, SE),
 
-  case comprehension_expr(TInto, TExpr) of
-    {inline, TIntoExpr} ->
-      build_inline(Ann, TCases, TIntoExpr, TInto, TUniq, SF);
-    {into, TIntoExpr} ->
-      build_into(Ann, TCases, TIntoExpr, TInto, TUniq, SF)
+  case inline_or_into(TInto, TExpr) of
+    inline -> build_inline(Ann, TCases, TExpr, TInto, TUniq, SF);
+    into -> build_into(Ann, TCases, TExpr, TInto, TUniq, SF)
   end.
 
 %% In case we have no return, we wrap the expression
@@ -88,7 +86,6 @@ collect_filters([H | T], Acc) ->
 collect_filters([], Acc) ->
   {Acc, []}.
 
-
 build_inline(Ann, Clauses, Expr, Into, Uniq, S) ->
   case not Uniq and lists:all(fun(Clause) -> element(1, Clause) == bin end, Clauses) of
     true  -> {build_comprehension(Ann, Clauses, Expr, Into), S};
@@ -313,17 +310,10 @@ comprehension_kind({bin, _, []}) -> bc.
 comprehension_generator(enum) -> generate;
 comprehension_generator(bin) -> b_generate.
 
-comprehension_expr({bin, _, []}, {bin, _, _} = Expr) ->
-  {inline, Expr};
-comprehension_expr({bin, Ann, []}, Expr) ->
-  BinExpr = {bin, Ann, [{bin_element, Ann, Expr, default, [bitstring]}]},
-  {inline, BinExpr};
-comprehension_expr({nil, _}, Expr) ->
-  {inline, Expr};
-comprehension_expr(false, Expr) ->
-  {inline, Expr};
-comprehension_expr(_, Expr) ->
-  {into, Expr}.
+inline_or_into({bin, _, []}) -> inline;
+inline_or_into({nil, _}) -> inline;
+inline_or_into(false) -> inline;
+inline_or_into(_) -> into.
 
 comprehension_filter(Ann, Filters) ->
   [join_filter(Ann, Filter, {atom, Ann, true}, {atom, Ann, false}) ||

From 72729ec856007f1c8b45dbc4d4fc1f53a3fcd854 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jos=C3=A9=20Valim?= <jose.valim@plataformatec.com.br>
Date: Sun, 16 Dec 2018 13:35:40 +0100
Subject: [PATCH 2/2] fixup!

---
 lib/elixir/src/elixir_erl_for.erl | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/lib/elixir/src/elixir_erl_for.erl b/lib/elixir/src/elixir_erl_for.erl
index cb876ac1971..3e7ae73fd42 100644
--- a/lib/elixir/src/elixir_erl_for.erl
+++ b/lib/elixir/src/elixir_erl_for.erl
@@ -19,7 +19,7 @@ translate(Meta, Args, Return, S) ->
   {TExpr, SE}  = elixir_erl_pass:translate(wrap_expr(Expr, TInto), SC),
   SF = elixir_erl_var:mergec(SI, SE),
 
-  case inline_or_into(TInto, TExpr) of
+  case inline_or_into(TInto) of
     inline -> build_inline(Ann, TCases, TExpr, TInto, TUniq, SF);
     into -> build_into(Ann, TCases, TExpr, TInto, TUniq, SF)
   end.
@@ -291,8 +291,6 @@ no_var_expr(Ann, _) -> [{var, Ann, '_'}].
 no_var_size({var, _, _}) -> throw(unbound_size);
 no_var_size(Size) -> Size.
 
-build_comprehension(Ann, Clauses, Expr, false) ->
-  {lc, Ann, Expr, comprehension_clause(Clauses)};
 build_comprehension(Ann, Clauses, Expr, Into) ->
   {comprehension_kind(Into), Ann, Expr, comprehension_clause(Clauses)}.
 
@@ -304,6 +302,7 @@ comprehension_clause([{Kind, Meta, Left, Right, Filters} | T]) ->
 comprehension_clause([]) ->
   [].
 
+comprehension_kind(false) -> lc;
 comprehension_kind({nil, _}) -> lc;
 comprehension_kind({bin, _, []}) -> bc.