avoid cloning selector to determine visibility

src/common.rs

@@ -115,33 +115,31 @@ impl ListSeparator {
 #[derive(Debug, Clone, Eq, PartialEq, Hash, PartialOrd, Ord, Copy)]
 pub(crate) struct Identifier(InternedString);
 
+impl Identifier {
+    fn from_str(s: &str) -> Self {
+        if s.contains('_') {
+            Identifier(InternedString::get_or_intern(s.replace('_', "-")))
+        } else {
+            Identifier(InternedString::get_or_intern(s))
+        }
+    }
+}
+
 impl From<String> for Identifier {
     fn from(s: String) -> Identifier {
-        Identifier(InternedString::get_or_intern(if s.contains('_') {
+        Self::from_str(&s)
-            s.replace('_', "-")
-        } else {
-            s
-        }))
     }
 }
 
 impl From<&String> for Identifier {
     fn from(s: &String) -> Identifier {
-        if s.contains('_') {
+        Self::from_str(s)
-            Identifier(InternedString::get_or_intern(s.replace('_', "-")))
-        } else {
-            Identifier(InternedString::get_or_intern(s))
-        }
     }
 }
 
 impl From<&str> for Identifier {
     fn from(s: &str) -> Identifier {
-        if s.contains('_') {
+        Self::from_str(s)
-            Identifier(InternedString::get_or_intern(s.replace('_', "-")))
-        } else {
-            Identifier(InternedString::get_or_intern(s))
-        }
     }
 }
 

src/parse/mod.rs

@@ -672,13 +672,7 @@ impl<'a, 'b> Parser<'a, 'b> {
             }
         }
 
-        if !self
+        if !self.super_selectors.last().as_selector_list().is_empty() {
-            .super_selectors
-            .last()
-            .clone()
-            .into_selector()
-            .is_empty()
-        {
             body = vec![Stmt::RuleSet {
                 selector: self.super_selectors.last().clone(),
                 body,
@@ -719,13 +713,7 @@ impl<'a, 'b> Parser<'a, 'b> {
             }
         }
 
-        if !self
+        if !self.super_selectors.last().as_selector_list().is_empty() {
-            .super_selectors
-            .last()
-            .clone()
-            .into_selector()
-            .is_empty()
-        {
             body = vec![Stmt::RuleSet {
                 selector: self.super_selectors.last().clone(),
                 body,
@@ -860,14 +848,14 @@ impl<'a, 'b> Parser<'a, 'b> {
             }
 
             let compound = match complex.components.first() {
-                Some(ComplexSelectorComponent::Compound(c)) => c.clone(),
+                Some(ComplexSelectorComponent::Compound(c)) => c,
                 Some(..) | None => todo!(),
             };
             if compound.components.len() != 1 {
                 return Err((
                     format!(
                         "compound selectors may no longer be extended.\nConsider `@extend {}` instead.\nSee http://bit.ly/ExtendCompound for details.\n",
-                        compound.components.into_iter().map(|x| x.to_string()).collect::<Vec<String>>().join(", ")
+                        compound.components.iter().map(|x| x.to_string()).collect::<Vec<String>>().join(", ")
                     )
                 , self.span_before).into());
             }
@@ -907,13 +895,7 @@ impl<'a, 'b> Parser<'a, 'b> {
             }
         }
 
-        if !self
+        if !self.super_selectors.last().as_selector_list().is_empty() {
-            .super_selectors
-            .last()
-            .clone()
-            .into_selector()
-            .is_empty()
-        {
             body = vec![Stmt::RuleSet {
                 selector: self.super_selectors.last().clone(),
                 body,

src/selector/extend/extended_selector.rs

@@ -2,6 +2,7 @@ use std::{
     cell::RefCell,
     collections::{hash_set::IntoIter, HashSet},
     hash::{Hash, Hasher},
+    ops::Deref,
     ptr,
     rc::Rc,
 };
@@ -43,6 +44,10 @@ impl ExtendedSelector {
         })
     }
 
+    pub fn as_selector_list(&self) -> impl Deref<Target = SelectorList> + '_ {
+        self.0.borrow()
+    }
+
     pub fn set_inner(&mut self, selector: SelectorList) {
         self.0.replace(selector);
     }