do not match args with a variadic mixin that does not have enough arguments. Fixes #1527

lib/less/tree/mixin.js

@@ -225,7 +225,8 @@ tree.mixin.Definition.prototype = {
         if (! this.variadic) {
             if (argsLength < this.required)                               { return false; }
             if (argsLength > this.params.length)                          { return false; }
-            if ((this.required > 0) && (argsLength > this.params.length)) { return false; }
+        } else {
+            if (argsLength < (this.required - 1))                         { return false; }
         }
 
         len = Math.min(argsLength, this.arity);

test/less/mixins-args.less

@@ -203,3 +203,13 @@ body {
 .selector3 {
   .mixin-comma-default3(4,2,2,2);
 }
+
+.test-calling-one-arg-mixin(@a) {
+}
+
+.test-calling-one-arg-mixin(@a, @b, @rest...) {
+}
+
+div {
+  .test-calling-one-arg-mixin(1);
+}