$bg: background;
$color: color;
div {
	$bg: none;
	background-#{$color}: blue;
	#{$bg}-repeat: no-repeat;
}

----------------------------------------------------

[
	["property", [["variable", "$bg"]]], ["punctuation", ":"], " background", ["punctuation", ";"],
	["property", [["variable", "$color"]]], ["punctuation", ":"], " color", ["punctuation", ";"],
	["selector", ["div "]], ["punctuation", "{"],
	["property", [["variable", "$bg"]]], ["punctuation", ":"], " none", ["punctuation", ";"],
	["property", ["background-", ["variable", "#{$color}"]]], ["punctuation", ":"], " blue", ["punctuation", ";"],
	["property", [["variable", "#{$bg}"], "-repeat"]], ["punctuation", ":"], " no-repeat", ["punctuation", ";"],
	["punctuation", "}"]
]

----------------------------------------------------

Checks for properties.