From 52872ac36eee15ec5227ad52fa780b4013de6f7f Mon Sep 17 00:00:00 2001
From: Prashanth Govindarajan <prgovi@microsoft.com>
Date: Tue, 17 Dec 2019 13:15:27 -0800
Subject: [PATCH] Parse [^] when ecmascript is set

---
 .../src/System/Text/RegularExpressions/RegexParser.cs       |  4 ++++
 .../tests/Regex.MultipleMatches.Tests.cs                    | 13 +++++++++++++
 .../tests/RegexParserTests.cs                               |  8 --------
 3 files changed, 17 insertions(+), 8 deletions(-)

diff --git a/src/libraries/System.Text.RegularExpressions/src/System/Text/RegularExpressions/RegexParser.cs b/src/libraries/System.Text.RegularExpressions/src/System/Text/RegularExpressions/RegexParser.cs
index 4f3ae32..edfe8bc 100644
--- a/src/libraries/System.Text.RegularExpressions/src/System/Text/RegularExpressions/RegexParser.cs
+++ b/src/libraries/System.Text.RegularExpressions/src/System/Text/RegularExpressions/RegexParser.cs
@@ -562,6 +562,10 @@ namespace System.Text.RegularExpressions
                 {
                     charClass!.Negate = true;
                 }
+                if ((_options & RegexOptions.ECMAScript) != 0 && CharAt(_currentPos) == ']')
+                {
+                    firstChar = false;
+                }
             }
 
             for (; CharsRight() > 0; firstChar = false)
diff --git a/src/libraries/System.Text.RegularExpressions/tests/Regex.MultipleMatches.Tests.cs b/src/libraries/System.Text.RegularExpressions/tests/Regex.MultipleMatches.Tests.cs
index da03141..321ffe5 100644
--- a/src/libraries/System.Text.RegularExpressions/tests/Regex.MultipleMatches.Tests.cs
+++ b/src/libraries/System.Text.RegularExpressions/tests/Regex.MultipleMatches.Tests.cs
@@ -140,6 +140,19 @@ namespace System.Text.RegularExpressions.Tests
                     new CaptureData("C789", 10, 4),
                 }
             };
+
+            yield return new object[]
+            {
+                "[^]", "every", RegexOptions.ECMAScript,
+                new CaptureData[]
+                {
+                    new CaptureData("e", 0, 1),
+                    new CaptureData("v", 1, 1),
+                    new CaptureData("e", 2, 1),
+                    new CaptureData("r", 3, 1),
+                    new CaptureData("y", 4, 1),
+                }
+            };
         }
 
         [Theory]
diff --git a/src/libraries/System.Text.RegularExpressions/tests/RegexParserTests.cs b/src/libraries/System.Text.RegularExpressions/tests/RegexParserTests.cs
index a0d4e0d..aa108fd 100644
--- a/src/libraries/System.Text.RegularExpressions/tests/RegexParserTests.cs
+++ b/src/libraries/System.Text.RegularExpressions/tests/RegexParserTests.cs
@@ -882,13 +882,5 @@ namespace System.Text.RegularExpressions.Tests
 
             throw new XunitException($"Expected RegexParseException with error: ({error}) -> Actual: No exception thrown");
         }
-
-        [Fact]
-        public void TestPattern()
-        {
-            Debugger.Launch();
-            string pattern = @"[b-\-a]";
-            var regex = new Regex(pattern);
-        }
     }
 }
-- 
2.7.4