@davidbjames could you please share the overloads you've added as well as the code snippets?

Hi theindigamer (JIRA User) thanks for the response. I was able to narrow down the compiler slowdown to a prefix operator ➕ that had several implementations.

public prefix func +(tag:ExtendedStyleTag) -> ExtendedStyleTag {
    return tag
}
internal prefix func +(tag:InternalTag) -> InternalTag {
    return tag
}
// etc

.. where the "tag" (in this example) was an enum of some kind. It is shorthand for spelling out the entire enum type name, so

+.implicitCorners vs. ExtendedStyleTag.implicitCorners

This was causing a compiler slowdown (in recent Xcode, not before):

((Typographicals & +.subTitle) | (UIButton.self - +.title)) => [
    .font(fonts.subTitle),
    .textAlignment(.center),
],

.. but changing it to this (spelling out the enum type), fixed the slowdown

((Typographicals & ExtendedStyleTag.subTitle) | (UIButton.self - ExtendedStyleTag.title)) => [
    .font(fonts.subTitle),
    .textAlignment(.center),
],

@swift-ci create

@davidbjames Is there any chance you could come up with a self-contained test case demonstrating the problem? In particular, having the definitions of ExtendedStyleTag and InternalTag (I'm guessing they're enums?) with the relevant members would be helpful.