The Sass, you can write .class1 .class2 {} , and .class1 .class3 {} as,
.class1 .class2 {}
.class1 .class3 {}
.class1 { &.class2, &.class3 {} }
How do you cut
div.class1, h2.class1, p.class1 {}
This doesn't work as expected,
.class1 { & div, & h2, & p {} }
You have the right idea, you just made a small mistake in your shortcut. Remove the space between the & and element and nest the class .class1 instead of the individual elements.
&
.class1
div, h2, p { &.class1 {} }