Fixing closures-generated-within-comprehensions to preserve block local scope for range comprehensions

lib/nodes.js

@@ -1529,7 +1529,7 @@
       scope = o.scope;
       name = (this.name && this.name.compile(o)) || scope.freeVariable();
       index = this.index && this.index.compile(o);
-      if (name && !this.pattern && !codeInBody) {
+      if (name && !this.pattern && (range || !codeInBody)) {
         scope.find(name);
       }
       if (index) {
@@ -1539,10 +1539,10 @@
         rvar = scope.freeVariable();
       }
       ivar = (function() {
-        if (range) {
+        if (codeInBody) {
-          return name;
-        } else if (codeInBody) {
           return scope.freeVariable();
+        } else if (range) {
+          return name;
         } else {
           return index || scope.freeVariable();
         }
@@ -1583,6 +1583,9 @@
       }
       this.guard ? (body = Expressions.wrap([new IfNode(this.guard, body)])) : null;
       if (codeInBody) {
+        if (range) {
+          body.unshift(literal(("var " + (name) + " = " + (ivar))));
+        }
         if (namePart) {
           body.unshift(literal(("var " + (namePart))));
         }

src/nodes.coffee

@@ -1305,10 +1305,10 @@ exports.ForNode = class ForNode extends BaseNode
     scope         = o.scope
     name          = (@name and @name.compile(o)) or scope.freeVariable()
     index         = @index and @index.compile o
-    scope.find name  if name and not @pattern and not codeInBody
+    scope.find name  if name and not @pattern and (range or not codeInBody)
     scope.find index if index
     rvar          = scope.freeVariable() unless topLevel
-    ivar          = if range then name else if codeInBody then scope.freeVariable() else index or scope.freeVariable()
+    ivar          = if codeInBody then scope.freeVariable() else if range then name else index or scope.freeVariable()
     varPart       = ''
     guardPart     = ''
     body          = Expressions.wrap([@body])
@@ -1334,6 +1334,7 @@ exports.ForNode = class ForNode extends BaseNode
     if @guard
       body        = Expressions.wrap([new IfNode(@guard, body)])
     if codeInBody
+      body.unshift  literal "var #{name} = #{ivar}" if range
       body.unshift  literal "var #{namePart}" if namePart
       body.unshift  literal "var #{index} = #{ivar}" if index
       body        = ClosureNode.wrap(body, true)

test/test_comprehensions.coffee

@@ -71,6 +71,13 @@ ok obj.two()   is "I'm two"
 ok obj.three() is "I'm three"
 
 
+# Ensure that local variables are closed over for range comprehensions.
+funcs = for i in [1..3]
+  -> -i
+
+ok (func() for func in funcs).join(' ') is '-1 -2 -3'
+
+
 # Even when referenced in the filter.
 list = ['one', 'two', 'three']