interpolated strings are literal

src/utils.rs

@@ -707,7 +707,10 @@ pub(crate) fn parse_quoted_string<I: Iterator<Item = Token>>(
                 if toks.peek().unwrap().kind == '{' {
                     toks.next();
                     let interpolation = parse_interpolation(toks, scope, super_selector)?;
-                    s.push_str(&interpolation.node.to_css_string(interpolation.span)?);
+                    s.push_str(&match interpolation.node {
+                        Value::Ident(s, ..) => s,
+                        v => v.to_css_string(interpolation.span)?,
+                    });
                     continue;
                 } else {
                     s.push('#');

tests/interpolation.rs

@@ -43,3 +43,8 @@ test!(
     "a {\n  color: #{\"a\" 'b'};\n}\n",
     "a {\n  color: a b;\n}\n"
 );
+test!(
+    interpolated_string_literally_inserted,
+    "a {\n  color: \"#{\"\\a\"}\";\n}\n",
+    "a {\n  color: \"\\a\";\n}\n"
+);

tests/str-escape.rs

@@ -150,3 +150,7 @@ test!(
     allows_escaped_quote_at_start_of_ident,
     "a {\n  color: \\\"c\\\";\n}\n"
 );
+test!(
+    quoted_escaped_newline_unchanged,
+    "a {\n  color: \"\\a\";\n}\n"
+);