Regression in interpolating lists function return value

[xzyfer]

@function foo() {
  @return "foo" + "," + bar;
}
foo {
  with-semicolon: #{foo()};
  without-semicolon: #{foo()}
}

Ruby Sass

foo {
  with-semicolon: foo,bar;
  without-semicolon: foo,bar; }

LibSass 3.3.0-beta.3

foo {
  with-semicolon: foo,bar;
  without-semicolon: "foo,bar" ; }

This can complete changes the semantics of declaration i.e. font-family: "foo,bar"

Specs added sass/sass-spec#547