From bc1d7875c4722967c75274c543a2855c990984b1 Mon Sep 17 00:00:00 2001
From: Oguz Ulgen <oulgen@fb.com>
Date: Thu, 1 Mar 2018 15:58:08 -0800
Subject: [PATCH] Fix emitting of empty($this)

Summary: as per title

Reviewed By: vladima

Differential Revision: D7106478

fbshipit-source-id: 177039d96a09b1985eac42a30753d9b17a414797
---
 hphp/hack/src/hhbc/decl_vars.ml       |  2 +-
 hphp/hack/src/hhbc/emit_expression.ml | 12 ++++++++++--
 2 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/hphp/hack/src/hhbc/decl_vars.ml b/hphp/hack/src/hhbc/decl_vars.ml
index fd45d361ff1..ec25b1975a0 100644
--- a/hphp/hack/src/hhbc/decl_vars.ml
+++ b/hphp/hack/src/hhbc/decl_vars.ml
@@ -154,7 +154,7 @@ class declvar_visitor explicit_use_set_opt is_in_static_method = object(this)
       | _ -> acc in
     let call_w_bareparam =
       match e with
-      | (_, Ast.Id(_, ("isset" | "echo"))) -> false
+      | (_, Ast.Id(_, ("isset" | "echo" | "empty"))) -> false
       | _ -> true in
     let on_arg acc e =
       match e with
diff --git a/hphp/hack/src/hhbc/emit_expression.ml b/hphp/hack/src/hhbc/emit_expression.ml
index 3602e0944c8..c00f2028747 100644
--- a/hphp/hack/src/hhbc/emit_expression.ml
+++ b/hphp/hack/src/hhbc/emit_expression.ml
@@ -1482,8 +1482,16 @@ and emit_call_empty_expr env outer_pos (pos, expr_ as expr) =
       Emit_pos.emit_pos outer_pos;
       instr_emptyg
     ]
-  | A.Lvar id when not (is_local_this env (snd id)) ->
-    instr_emptyl (get_local env id)
+  | A.Lvar id ->
+    if not (is_local_this env (snd id)) ||
+      Emit_env.get_needs_local_this env then
+      instr_emptyl (get_local env id)
+    else
+      gather [
+        instr (IMisc (BareThis NoNotice));
+        Emit_pos.emit_pos outer_pos;
+        instr_not
+      ]
   | A.Dollar e ->
     gather [
       emit_expr ~need_ref:false env e;
-- 
2.11.4.GIT