Case-insensitive regex with repetitions does not match uppercase characters correctly

[fwcd]

Description

In case-insensitive regular expressions containing repetitions (+ or *), the repeated part is not matched correctly against differently cased characters in the string to be searched.

Reproduction

func test(_ pattern: Regex<Substring>, on s: String) throws {
    print("\(s) contains \(try pattern.firstMatch(in: s)?.output ?? "no match")")
}

for s in ["ab", "Ab"] {
    try test(#/ab/#.ignoresCase(), on: s)
    try test(#/a*b/#.ignoresCase(), on: s)
    try test(#/a+b/#.ignoresCase(), on: s)
}

This snippet outputs

ab contains ab
ab contains ab
ab contains ab
Ab contains Ab
Ab contains b
Ab contains no match

Expected behavior

I would expect it to output

ab contains ab
ab contains ab
ab contains ab
Ab contains Ab
Ab contains Ab
Ab contains Ab

Environment

swift-driver version: 1.115 Apple Swift version 6.0.2 (swiftlang-6.0.2.1.2 clang-1600.0.26.4)
Target: arm64-apple-macosx15.0

Additional information

No response

[jdberry]

Per swiftlang/swift#78155, optional characters indicated by ? also fail to match correctly.