LibRegex: Use the correct capture group index in ERE bytecode generation

Otherwise the left and right capture instructions wouldn't point to the
same capture group if there was another nested group there.

1 files changed, 12 insertions, 0 deletions

diff --git a/Tests/LibRegex/Regex.cpp b/Tests/LibRegex/Regex.cpp
index be2b026fd0..5203a277a0 100644
--- a/Tests/LibRegex/Regex.cpp
+++ b/Tests/LibRegex/Regex.cpp
@@ -485,6 +485,18 @@ TEST_CASE(simple_period_end_benchmark)
     EXPECT_EQ(re.search("hello?", m), true);
 }
 
+TEST_CASE(posix_extended_nested_capture_group)
+{
+    Regex<PosixExtended> re("(h(e(?<llo>llo)))"); // group 0 -> "hello", group 1 -> "ello", group 2/"llo" -> "llo"
+    auto result = re.match("hello");
+    EXPECT(result.success);
+    EXPECT_EQ(result.capture_group_matches.size(), 1u);
+    EXPECT_EQ(result.capture_group_matches[0].size(), 3u);
+    EXPECT_EQ(result.capture_group_matches[0][0].view, "hello"sv);
+    EXPECT_EQ(result.capture_group_matches[0][1].view, "ello"sv);
+    EXPECT_EQ(result.capture_group_matches[0][2].view, "llo"sv);
+}
+
 TEST_CASE(ECMA262_parse)
 {
     struct _test {