From a6873a38590a9176c607bcdbff726daa93e1fec7 Mon Sep 17 00:00:00 2001
From: "Alex Lam S.L" <alexlamsl@gmail.com>
Date: Thu, 4 Jan 2018 18:45:51 +0800
Subject: forbid block-scoped `AST_Defun` in strict mode (#2718)

---
 lib/parse.js | 15 +++++++++------
 1 file changed, 9 insertions(+), 6 deletions(-)

(limited to 'lib/parse.js')

diff --git a/lib/parse.js b/lib/parse.js
index 03455348..001587bc 100644
--- a/lib/parse.js
+++ b/lib/parse.js
@@ -800,7 +800,7 @@ function parse($TEXT, options) {
     function embed_tokens(parser) {
         return function() {
             var start = S.token;
-            var expr = parser();
+            var expr = parser.apply(null, arguments);
             var end = prev();
             expr.start = start;
             expr.end = end;
@@ -815,7 +815,7 @@ function parse($TEXT, options) {
         }
     };
 
-    var statement = embed_tokens(function() {
+    var statement = embed_tokens(function(strict_defun) {
         handle_regexp();
         switch (S.token.type) {
           case "string":
@@ -901,6 +901,9 @@ function parse($TEXT, options) {
                 return for_();
 
               case "function":
+                if (!strict_defun && S.input.has_directive("use strict")) {
+                    croak("In strict mode code, functions can only be declared at top level or immediately within another function.");
+                }
                 next();
                 return function_(AST_Defun);
 
@@ -1083,7 +1086,7 @@ function parse($TEXT, options) {
         S.input.push_directives_stack();
         S.in_loop = 0;
         S.labels = [];
-        var body = block_();
+        var body = block_(true);
         if (S.input.has_directive("use strict")) {
             if (name) strict_verify_symbol(name);
             argnames.forEach(strict_verify_symbol);
@@ -1112,12 +1115,12 @@ function parse($TEXT, options) {
         });
     };
 
-    function block_() {
+    function block_(strict_defun) {
         expect("{");
         var a = [];
         while (!is("punc", "}")) {
             if (is("eof")) unexpected();
-            a.push(statement());
+            a.push(statement(strict_defun));
         }
         next();
         return a;
@@ -1630,7 +1633,7 @@ function parse($TEXT, options) {
         var body = [];
         S.input.push_directives_stack();
         while (!is("eof"))
-            body.push(statement());
+            body.push(statement(true));
         S.input.pop_directives_stack();
         var end = prev();
         var toplevel = options.toplevel;
-- 
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