More test cases for mixin scope and rebinding of variables.

mixins.scss

@@ -82,4 +82,33 @@ $da: some other default;
 
 div {
   @include default_args(boogoo);
+}
+
+@mixin original() {
+  value: original;
+}
+
+div {
+  @include original();
+}
+
+@mixin original() {
+  value: no longer original;
+}
+
+div {
+  @include original();
+}
+
+@mixin set-x($x) {
+  $x: changed local x;
+  arg: $x;
+  $y: changed global y;
+  blarg: $y;
+}
+
+div {
+  @include set-x(blah);
+  a: $x;
+  b: $y;
 }
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