loop indexing vars do not affect outer scopes

src/parse/control_flow.rs

@@ -294,7 +294,7 @@ impl<'a> Parser<'a> {
         self.scopes.enter_new_scope();
 
         for i in iter {
-            self.scopes.insert_var(
+            self.scopes.insert_var_last(
                 var.node,
                 Spanned {
                     node: Value::Dimension(Number::from(i), Unit::None),
@@ -464,9 +464,11 @@ impl<'a> Parser<'a> {
 
         let mut stmts = Vec::new();
 
+        self.scopes.enter_new_scope();
+
         for row in iter {
             if vars.len() == 1 {
-                self.scopes.insert_var(
+                self.scopes.insert_var_last(
                     vars[0].node,
                     Spanned {
                         node: row,
@@ -479,7 +481,7 @@ impl<'a> Parser<'a> {
                         .into_iter()
                         .chain(std::iter::once(Value::Null).cycle()),
                 ) {
-                    self.scopes.insert_var(
+                    self.scopes.insert_var_last(
                         var.node,
                         Spanned {
                             node: val,
@@ -531,6 +533,8 @@ impl<'a> Parser<'a> {
             }
         }
 
+        self.scopes.exit_scope();
+
         Ok(stmts)
     }
 }

src/scope.rs

@@ -128,6 +128,20 @@ impl Scopes {
         }
     }
 
+    /// Always insert this variable into the innermost scope
+    ///
+    /// Used, for example, for variables from `@each` and `@for`
+    pub fn insert_var_last(&mut self, s: Identifier, v: Spanned<Value>) -> Option<Spanned<Value>> {
+        if let Some(scope) = self.0.last_mut() {
+            scope.insert_var(s, v)
+        } else {
+            let mut scope = Scope::new();
+            scope.insert_var(s, v);
+            self.0.push(scope);
+            None
+        }
+    }
+
     pub fn insert_default_var(
         &mut self,
         s: Identifier,

tests/each.rs

@@ -61,6 +61,22 @@ test!(
     }",
     "a {\n  color: (a: b, c: d);\n}\n"
 );
+test!(
+    indexing_variable_does_not_affect_outer_scopes,
+    "a {
+        $a: 1;
+        $b: 1;
+
+        @each $a in a b {
+            color: $a;
+            $b: $a;
+        }
+
+        color: $a;
+        color: $b;
+    }",
+    "a {\n  color: a;\n  color: b;\n  color: 1;\n  color: b;\n}\n"
+);
 error!(
     list_of_single_map,
     "a {

tests/for.rs

@@ -97,3 +97,19 @@ test!(
     }",
     "a {\n  color: \\}}}{{{#;\n}\n"
 );
+test!(
+    indexing_variable_does_not_affect_outer_scopes,
+    "a {
+        $a: 1;
+        $b: 1;
+
+        @for $a from 1 through 2 {
+            color: $a;
+            $b: $a;
+        }
+
+        color: $a;
+        color: $b;
+    }",
+    "a {\n  color: 1;\n  color: 2;\n  color: 1;\n  color: 2;\n}\n"
+);