From 9d197959f065e178f88440a5f048085db8c78374 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jochen=20K=C3=BChner?= <jochen.kuehner@gmx.de>
Date: Mon, 1 Nov 2021 13:19:59 +0100
Subject: [PATCH] Fix parsing error in exponent expressions with unary
 left-hand sides.

Esprima (correctly) rejects expressions like -1**2. - https://github.com/jquery/esprima/pull/2070
However, expressions like (-1)**2 are valid but still rejected.
This commit fixes this issue by identifying when the left operand
is parenthesized.

Fixes https://github.com/jquery/esprima/issues/1981
---
 src/Esprima/JavascriptParser.cs | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/src/Esprima/JavascriptParser.cs b/src/Esprima/JavascriptParser.cs
index fd2b8869..107cb7a2 100644
--- a/src/Esprima/JavascriptParser.cs
+++ b/src/Esprima/JavascriptParser.cs
@@ -1860,10 +1860,14 @@ private Expression ParseUnaryExpression()
 
         private Expression ParseExponentiationExpression()
         {
-            var startToken = _lookahead;
-
-            var expr = InheritCoverGrammar(parseUnaryExpression);
-            if (expr.Type != Nodes.UnaryExpression && Match("**"))
+            var startToken = _lookahead;
+
+            var isLeftParenthesized = this.Match("(");
+            var expr = InheritCoverGrammar(parseUnaryExpression);
+
+            var exponentAllowed = expr.Type != Nodes.UnaryExpression || isLeftParenthesized;
+
+            if (exponentAllowed && Match("**"))
             {
                 NextToken();
                 _context.IsAssignmentTarget = false;