Strings containing interpolation are double quoted

src/selector.rs

@@ -375,7 +375,7 @@ impl Attribute {
                 }
                 q @ TokenKind::Symbol(Symbol::DoubleQuote)
                 | q @ TokenKind::Symbol(Symbol::SingleQuote) => {
-                    parse_quoted_string(toks, scope, q)?
+                    parse_quoted_string(toks, scope, q)?.to_string()
                 }
                 _ => return Err("Expected identifier.".into()),
             }
@@ -437,7 +437,7 @@ impl Attribute {
                 }
                 q @ TokenKind::Symbol(Symbol::DoubleQuote)
                 | q @ TokenKind::Symbol(Symbol::SingleQuote) => {
-                    parse_quoted_string(toks, scope, q)?
+                    parse_quoted_string(toks, scope, q)?.to_string()
                 }
                 _ => return Err("Expected identifier.".into()),
             }

src/utils.rs

@@ -152,9 +152,10 @@ pub(crate) fn parse_quoted_string<I: Iterator<Item = Token>>(
     toks: &mut Peekable<I>,
     scope: &Scope,
     q: TokenKind,
-) -> SassResult<String> {
+) -> SassResult<Value> {
     let mut s = String::new();
     let mut is_escaped = false;
+    let mut found_interpolation = false;
     while let Some(tok) = toks.next() {
         match tok.kind {
             TokenKind::Symbol(Symbol::DoubleQuote)
@@ -170,6 +171,7 @@ pub(crate) fn parse_quoted_string<I: Iterator<Item = Token>>(
             TokenKind::Symbol(Symbol::BackSlash) if !is_escaped => is_escaped = true,
             TokenKind::Symbol(Symbol::BackSlash) => s.push('\\'),
             TokenKind::Interpolation => {
+                found_interpolation = true;
                 s.push_str(
                     &parse_interpolation(toks, scope)?
                         .iter()
@@ -185,10 +187,14 @@ pub(crate) fn parse_quoted_string<I: Iterator<Item = Token>>(
         }
         s.push_str(&tok.kind.to_string());
     }
-    let quotes = match q {
+    let quotes = if found_interpolation {
+        QuoteKind::Double
+    } else {
+        match q {
             TokenKind::Symbol(Symbol::DoubleQuote) => QuoteKind::Double,
             TokenKind::Symbol(Symbol::SingleQuote) => QuoteKind::Single,
             _ => unreachable!(),
-    };
+        }
-    Ok(format!("{}{}{}", quotes, s, quotes))
+    };
+    Ok(Value::Ident(s, quotes))
 }

src/value/parse.rs

@@ -11,7 +11,7 @@ use crate::color::Color;
 use crate::common::{Keyword, ListSeparator, Op, QuoteKind, Scope, Symbol};
 use crate::error::SassResult;
 use crate::units::Unit;
-use crate::utils::{devour_whitespace_or_comment, parse_interpolation};
+use crate::utils::{devour_whitespace_or_comment, parse_interpolation, parse_quoted_string};
 use crate::value::Value;
 use crate::{Token, TokenKind};
 
@@ -287,46 +287,7 @@ impl Value {
                 }
             }
             q @ TokenKind::Symbol(Symbol::DoubleQuote)
-            | q @ TokenKind::Symbol(Symbol::SingleQuote) => {
+            | q @ TokenKind::Symbol(Symbol::SingleQuote) => parse_quoted_string(toks, scope, q),
-                let mut s = String::new();
-                let mut is_escaped = false;
-                while let Some(tok) = toks.next() {
-                    match tok.kind {
-                        TokenKind::Symbol(Symbol::DoubleQuote)
-                            if !is_escaped && q == TokenKind::Symbol(Symbol::DoubleQuote) =>
-                        {
-                            break
-                        }
-                        TokenKind::Symbol(Symbol::SingleQuote)
-                            if !is_escaped && q == TokenKind::Symbol(Symbol::SingleQuote) =>
-                        {
-                            break
-                        }
-                        TokenKind::Symbol(Symbol::BackSlash) if !is_escaped => is_escaped = true,
-                        TokenKind::Symbol(Symbol::BackSlash) => s.push('\\'),
-                        TokenKind::Interpolation => {
-                            s.push_str(
-                                &parse_interpolation(toks, scope)?
-                                    .iter()
-                                    .map(|x| x.kind.to_string())
-                                    .collect::<String>(),
-                            );
-                            continue;
-                        }
-                        _ => {}
-                    }
-                    if is_escaped && tok.kind != TokenKind::Symbol(Symbol::BackSlash) {
-                        is_escaped = false;
-                    }
-                    s.push_str(&tok.kind.to_string());
-                }
-                let quotes = match q {
-                    TokenKind::Symbol(Symbol::DoubleQuote) => QuoteKind::Double,
-                    TokenKind::Symbol(Symbol::SingleQuote) => QuoteKind::Single,
-                    _ => unreachable!(),
-                };
-                Ok(Value::Ident(s, quotes))
-            }
             TokenKind::Variable(ref v) => Ok(scope.get_var(v)?.clone()),
             TokenKind::Interpolation => {
                 let mut s = parse_interpolation(toks, scope)?