Fixes #3259 -- Use placeholders when adding params to scope

Don't register nested variables of complex parameters as parameters of the compiled function. Use the computed placeholder name instead.

lib/coffee-script/nodes.js

@@ -1813,7 +1813,7 @@
     };
 
     Code.prototype.compileNode = function(o) {
-      var answer, boundfunc, code, exprs, i, lit, p, param, params, ref, splats, uniqs, val, wasEmpty, wrapper, _i, _j, _k, _l, _len, _len1, _len2, _len3, _len4, _m, _ref2, _ref3, _ref4, _ref5, _ref6;
+      var answer, boundfunc, code, exprs, i, lit, p, param, params, ref, splats, uniqs, val, wasEmpty, wrapper, _i, _j, _k, _l, _len, _len1, _len2, _len3, _len4, _len5, _m, _n, _ref2, _ref3, _ref4, _ref5, _ref6, _ref7;
       if (this.bound && ((_ref2 = o.scope.method) != null ? _ref2.bound : void 0)) {
         this.context = o.scope.method.context;
       }
@@ -1831,20 +1831,20 @@
       delete o.isExistentialEquals;
       params = [];
       exprs = [];
-      this.eachParamName(function(name) {
-        if (!o.scope.check(name)) {
-          return o.scope.parameter(name);
-        }
-      });
       _ref3 = this.params;
       for (_i = 0, _len = _ref3.length; _i < _len; _i++) {
         param = _ref3[_i];
+        o.scope.parameter(param.asReference(o));
+      }
+      _ref4 = this.params;
+      for (_j = 0, _len1 = _ref4.length; _j < _len1; _j++) {
+        param = _ref4[_j];
         if (!param.splat) {
           continue;
         }
-        _ref4 = this.params;
+        _ref5 = this.params;
-        for (_j = 0, _len1 = _ref4.length; _j < _len1; _j++) {
+        for (_k = 0, _len2 = _ref5.length; _k < _len2; _k++) {
-          p = _ref4[_j].name;
+          p = _ref5[_k].name;
           if (p["this"]) {
             p = p.properties[0].name;
           }
@@ -1853,20 +1853,20 @@
           }
         }
         splats = new Assign(new Value(new Arr((function() {
-          var _k, _len2, _ref5, _results;
+          var _l, _len3, _ref6, _results;
-          _ref5 = this.params;
+          _ref6 = this.params;
           _results = [];
-          for (_k = 0, _len2 = _ref5.length; _k < _len2; _k++) {
+          for (_l = 0, _len3 = _ref6.length; _l < _len3; _l++) {
-            p = _ref5[_k];
+            p = _ref6[_l];
             _results.push(p.asReference(o));
           }
           return _results;
         }).call(this))), new Value(new Literal('arguments')));
         break;
       }
-      _ref5 = this.params;
+      _ref6 = this.params;
-      for (_k = 0, _len2 = _ref5.length; _k < _len2; _k++) {
+      for (_l = 0, _len3 = _ref6.length; _l < _len3; _l++) {
-        param = _ref5[_k];
+        param = _ref6[_l];
         if (param.isComplex()) {
           val = ref = param.asReference(o);
           if (param.value) {
@@ -1892,9 +1892,9 @@
         exprs.unshift(splats);
       }
       if (exprs.length) {
-        (_ref6 = this.body.expressions).unshift.apply(_ref6, exprs);
+        (_ref7 = this.body.expressions).unshift.apply(_ref7, exprs);
       }
-      for (i = _l = 0, _len3 = params.length; _l < _len3; i = ++_l) {
+      for (i = _m = 0, _len4 = params.length; _m < _len4; i = ++_m) {
         p = params[i];
         params[i] = p.compileToFragments(o);
         o.scope.parameter(fragmentsToText(params[i]));
@@ -1915,7 +1915,7 @@
       }
       code += '(';
       answer = [this.makeCode(code)];
-      for (i = _m = 0, _len4 = params.length; _m < _len4; i = ++_m) {
+      for (i = _n = 0, _len5 = params.length; _n < _len5; i = ++_n) {
         p = params[i];
         if (i) {
           answer.push(this.makeCode(", "));

src/nodes.coffee

@@ -1336,8 +1336,8 @@ exports.Code = class Code extends Base
     delete o.isExistentialEquals
     params = []
     exprs  = []
-    @eachParamName (name) -> # this step must be performed before the others
+    for param in @params
-      unless o.scope.check name then o.scope.parameter name
+      o.scope.parameter param.asReference o
     for param in @params when param.splat
       for {name: p} in @params
         if p.this then p = p.properties[0].name

test/scope.coffee

@@ -103,4 +103,14 @@ test "#2331: bound super regression", ->
   class B extends A
     method: => super
   
-  eq (new B).method(), 'A'
+  eq (new B).method(), 'A'
+
+test "#3259: leak with @-params within destructured parameters", ->
+  fn = ({@foo}, [@bar], [{@baz}]) ->
+    foo = bar = baz = false
+
+  fn.call {}, {foo: 'foo'}, ['bar'], [{baz: 'baz'}]
+
+  eq 'undefined', typeof foo
+  eq 'undefined', typeof bar
+  eq 'undefined', typeof baz