Issue #897 ... fixed leaking direct-call-plucked comprehension variables, due to shared scope.

lib/command.js

@@ -56,7 +56,7 @@
     return compileScripts();
   };
   compileScripts = function() {
-    var base, compile, _fn, _i, _len, _results;
+    var base, compile, source, _fn, _i, _len, _results;
     _fn = function(source) {
       base = path.join(source);
       compile = function(source, topLevel) {

lib/nodes.js

@@ -1204,9 +1204,12 @@
       return !!this.ctor;
     };
     Code.prototype.compileNode = function(o) {
-      var code, exprs, i, idt, lit, p, param, ref, scope, sharedScope, splats, v, val, vars, wasEmpty, _i, _j, _k, _len, _len2, _len3, _len4, _ref, _ref2, _ref3, _ref4, _results;
+      var code, exprs, i, idt, lit, p, param, ref, sharedScope, splats, v, val, vars, wasEmpty, _i, _j, _k, _len, _len2, _len3, _len4, _ref, _ref2, _ref3, _ref4, _results;
       sharedScope = del(o, 'sharedScope');
-      o.scope = scope = sharedScope || new Scope(o.scope, this.body, this);
+      o.scope = sharedScope || new Scope(o.scope, this.body, this);
+      if (sharedScope) {
+        o.scope.shared = true;
+      }
       o.indent += TAB;
       delete o.bare;
       delete o.globals;
@@ -1259,7 +1262,7 @@
       if (!splats) {
         for (i = 0, _len4 = vars.length; i < _len4; i++) {
           v = vars[i];
-          scope.parameter(vars[i] = v.compile(o));
+          o.scope.parameter(vars[i] = v.compile(o));
         }
       }
       if (!(wasEmpty || this.noReturn)) {
@@ -1769,7 +1772,6 @@
       scope = o.scope;
       name = this.name && this.name.compile(o, LEVEL_LIST);
       index = this.index && this.index.compile(o, LEVEL_LIST);
-      if (!hasCode) {
       if (name && !this.pattern) {
         scope.find(name, {
           immediate: true
@@ -1780,7 +1782,6 @@
           immediate: true
         });
       }
-      }
       if (this.returns && !hasPure) {
         rvar = scope.freeVariable('results');
       }

lib/scope.js

@@ -48,6 +48,9 @@
       return false;
     };
     Scope.prototype.parameter = function(name) {
+      if (this.shared && this.check(name, true)) {
+        return;
+      }
       return this.add(name, 'param');
     };
     Scope.prototype.check = function(name, immediate) {

src/nodes.coffee

@@ -983,7 +983,8 @@ exports.Code = class Code extends Base
   # a closure.
   compileNode: (o) ->
     sharedScope     = del o, 'sharedScope'
-    o.scope     = scope = sharedScope or new Scope o.scope, @body, this
+    o.scope         = sharedScope or new Scope o.scope, @body, this
+    o.scope.shared  = yes if sharedScope
     o.indent        += TAB
     delete o.bare
     delete o.globals
@@ -1008,7 +1009,7 @@ exports.Code = class Code extends Base
     wasEmpty = @body.isEmpty()
     exprs.unshift splats if splats
     @body.expressions.unshift exprs... if exprs.length
-    scope.parameter vars[i] = v.compile o for v, i in vars unless splats
+    o.scope.parameter vars[i] = v.compile o for v, i in vars unless splats
     @body.makeReturn() unless wasEmpty or @noReturn
     idt   = o.indent
     code  = 'function'
@@ -1425,7 +1426,6 @@ exports.For = class For extends Base
     scope         = o.scope
     name          = @name  and @name.compile o, LEVEL_LIST
     index         = @index and @index.compile o, LEVEL_LIST
-    unless hasCode
     scope.find(name,  immediate: yes) if name and not @pattern
     scope.find(index, immediate: yes) if index
     rvar          = scope.freeVariable 'results' if @returns and not hasPure

src/scope.coffee

@@ -44,6 +44,7 @@ exports.Scope = class Scope
   # Reserve a variable name as originating from a function parameter for this
   # scope. No `var` required for internal references.
   parameter: (name) ->
+    return if @shared and @check name, yes
     @add name, 'param'
 
   # Just check to see if a variable has already been declared, without reserving,

test/test_comprehensions.coffee

@@ -228,3 +228,16 @@ foo = ->
       -> i + j
 
 eq foo()[3][4](), 7
+
+
+# Issue #897: Ensure that plucked function variables aren't leaked.
+facets = {}
+list = ['one', 'two']
+
+(->
+  for entity in list
+	  facets[entity] = -> entity
+)()
+
+eq typeof entity, 'undefined'
+eq facets['two'](), 'two'