handle multiline comments surrounding @ if condition

src/atrule/if_rule.rs

@@ -8,7 +8,7 @@ use crate::error::SassResult;
 use crate::scope::Scope;
 use crate::selector::Selector;
 use crate::utils::{
-    devour_whitespace, eat_ident, read_until_closing_curly_brace, read_until_open_curly_brace,
+    devour_whitespace, eat_ident, read_until_closing_curly_brace, read_until_open_curly_brace, devour_whitespace_or_comment
 };
 use crate::value::Value;
 use crate::{Stmt, Token};
@@ -35,10 +35,11 @@ impl If {
     pub fn from_tokens<I: Iterator<Item = Token>>(
         toks: &mut PeekMoreIterator<I>,
     ) -> SassResult<If> {
+        devour_whitespace_or_comment(toks)?;
         let mut branches = Vec::new();
         let init_cond = read_until_open_curly_brace(toks);
         toks.next();
-        devour_whitespace(toks);
+        devour_whitespace_or_comment(toks)?;
         let mut init_toks = read_until_closing_curly_brace(toks);
         init_toks.push(toks.next().unwrap());
         devour_whitespace(toks);

src/lib.rs

@@ -357,8 +357,7 @@ impl<'a> StyleSheetParser<'a> {
                             });
                         }
                         v => {
-                            let pos = self.lexer.next().unwrap().pos();
+                            let rule = AtRule::from_tokens(&v, span, &mut self.lexer, &mut Scope::new(), &Selector::new())?;
-                            let rule = AtRule::from_tokens(&v, pos, &mut self.lexer, &mut Scope::new(), &Selector::new())?;
                             match rule.node {
                                 AtRule::Mixin(name, mixin) => {
                                     insert_global_mixin(&name, *mixin);

src/utils/comment_whitespace.rs

@@ -40,13 +40,20 @@ pub(crate) fn devour_whitespace_or_comment<I: Iterator<Item = Token>>(
     let mut found_whitespace = false;
     while let Some(tok) = toks.peek() {
         if tok.kind == '/' {
-            let pos = toks.next().unwrap().pos();
+            let next = match toks.peek_forward(1) {
-            match toks.peek().unwrap().kind {
+                Some(v) => v,
+                None => return Ok(found_whitespace),
+            };
+            match next.kind {
                 '*' => {
+                    toks.next();
                     eat_comment(toks, &Scope::new(), &Selector::new())?;
                 }
                 '/' => read_until_newline(toks),
-                _ => return Err(("Expected expression.", pos).into()),
+                _ => {
+                    toks.reset_view();
+                    return Ok(found_whitespace)
+                },
             };
             found_whitespace = true;
             continue;

tests/if.rs

@@ -78,3 +78,13 @@ test!(
     a { color: foo(bar); }",
     "a {\n  color: bar;\n}\n"
 );
+test!(
+    multiline_comments_surrounding_condition_empty,
+    "@if/**/true/**/{ a { color: red; } }",
+    "a {\n  color: red;\n}\n"
+);
+test!(
+    multiline_comments_surrounding_condition,
+    "@if/* pre 1 */true/* post 1 */{ a { color: red; } }",
+    "a {\n  color: red;\n}\n"
+);