From f0cbb35e2d1f81e73dec339dcdbabdb352009ebb Mon Sep 17 00:00:00 2001
From: Marijn Haverbeke <marijn@haverbeke.nl>
Date: Mon, 5 Nov 2018 09:59:21 +0100
Subject: [PATCH] Force-retokenize regexps when a slash is found in expression
 position

Issue #751
Issue #589
---
 acorn/src/expression.js | 4 ++++
 test/tests.js           | 1 +
 2 files changed, 5 insertions(+)

diff --git a/acorn/src/expression.js b/acorn/src/expression.js
index 310b3931f..04ecd6238 100644
--- a/acorn/src/expression.js
+++ b/acorn/src/expression.js
@@ -304,6 +304,10 @@ pp.parseSubscripts = function(base, startPos, startLoc, noCalls) {
 // or `{}`.
 
 pp.parseExprAtom = function(refDestructuringErrors) {
+  // If a division operator appears in an expression position, the
+  // tokenizer got confused, and we force it to read a regexp instead.
+  if (this.type === tt.slash) this.readRegexp()
+
   let node, canBeArrow = this.potentialArrowAt === this.start
   switch (this.type) {
   case tt._super:
diff --git a/test/tests.js b/test/tests.js
index b958026e1..8ea25aae9 100644
--- a/test/tests.js
+++ b/test/tests.js
@@ -26840,6 +26840,7 @@ test("x = {foo: function x() {} / divide}", {});
 test("foo; function f() {} /regexp/", {});
 test("{function f() {} /regexp/}", {});
 test("function fn() {return\nfunction foo() {}\n/42/}", {});
+test("var x\n/foo/", {});
 
 test("{}/=/", {
   type: "Program",