I encountered the issue with Dart compiler errors related to the following statement.

@extend .button-secondary:hover;

The Sass compiler error suggested the following change:

@extend .button-secondary, :hover;

What is happening in the compiled CSS when you specify

@extends :hover;

? I can not find any documentation about this when you extend a pseudo-class.

I just don't extend pseudo classes.

&:hover {
		color: $sc-button-secondary-hover-text-color;
		background: $sc-button-secondary-hover-background-color;
		border-color: $sc-button-secondary-hover-border-color;
		text-decoration: none;
	}

hi @Chris, I dug deeper into this today and talked with another developer. I also downloaded the compiled CSS file and fetched the latest SuiteCommerce Base Theme to find out what the NetSuite developers implemented to fix this issue. I compared the 2022.2 version and 2023.2 versions of the base theme, and the developers implemented the Sass compiler suggestion. SuiteCommerce Base Theme 2023.2.3

.open .split-button-toggle {
	@extend .button-secondary, :hover;

	i.split-button-toggle-icon {
		color: $sc-neutral-shade-0;
	}
}

I don’t think is the correct. I don’t think the original implementation intended to extend the .button-secondary styles, just the hover styles. I think what you did is correct and is what the original developers intended. The developer and I came up with a different approach which I think is the same thing, but I haven’t tested it:

%placeholder:hover {
	color: $sc-button-secondary-hover-text-color;
	background: $sc-button-secondary-hover-background-color;
	border-color: $sc-button-secondary-hover-border-color;
	text-decoration: none;
}

.open .split-button-toggle {
@extends %placeholder;
}

When I looked at the compiled CSS file, the

@extend .button-secondary, :hover;

added a large chunk of css that was associated with

.open .split-button-toggle

that I think was created due to the

@extends :hover;

When code reuse makes original intent undecipherable, it makes copy/paste the sane option. There are too many tasks in the day to make everything super-elegant.

I agree. Figuring this out was a huge suck of time and there was very little discussion on Google about extending pseudo-classes.