Emit leaner code on =

Author: sabiwara

lib/elixir/src/elixir_clauses.erl

@@ -169,11 +169,16 @@ with(Meta, Args, S, E) ->
 
   {{with, Meta, EExprs ++ [[{do, EDo} | EOpts]]}, S3, E}.
 
-expand_with({'<-', Meta, [Left, Right]}, {S, E, _HasMatch}) ->
+expand_with({'<-', Meta, [Left, Right]}, {S, E, HasMatch}) ->
   {ERight, SR, ER} = elixir_expand:expand(Right, S, E),
   SM = elixir_env:reset_read(SR, S),
   {[ELeft], SL, EL} = head([Left], SM, ER),
-  {{'<-', Meta, [ELeft, ERight]}, {SL, EL, true}};
+  case ELeft of
+    {Var, _, Ctx} when is_atom(Var), is_atom(Ctx) ->
+      {{'=', Meta, [ELeft, ERight]}, {SL, EL, HasMatch}};
+    _ ->
+      {{'<-', Meta, [ELeft, ERight]}, {SL, EL, true}}
+  end;
 expand_with(Expr, {S, E, HasMatch}) ->
   {EExpr, SE, EE} = elixir_expand:expand(Expr, S, E),
   {EExpr, {SE, EE, HasMatch}}.

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

@@ -1009,7 +1009,7 @@ defmodule Kernel.ExpansionTest do
       after_expansion =
         quote do
           with(
-            b <-
+            b =
               (
                 a = 1
                 2
@@ -1042,12 +1042,12 @@ defmodule Kernel.ExpansionTest do
       after_expansion =
         quote do
           with(
-            b <-
+            b =
               (
                 a = 1
                 2
               ),
-            d <-
+            d =
               (
                 c = 3
                 4