Merge pull request jashkenas#1851 from michaelficarra/issue1844

fixes jashkenas#1844: bound functions in nested comprehensions causing empty var statements

src/nodes.coffee

@@ -269,12 +269,15 @@ exports.Block = class Block extends Base
     if scope.expressions is this
       declars = o.scope.hasDeclarations()
       assigns = scope.hasAssignments
-      if (declars or assigns) and i
-        code += '\n'
-      if declars
-        code += "#{@tab}var #{ scope.declaredVariables().join(', ') };\n"
-      if assigns
-        code += "#{@tab}var #{ multident scope.assignedVariables().join(', '), @tab };\n"
+      if declars or assigns
+        code += '\n' if i
+        code += "#{@tab}var "
+        if declars
+          code += scope.declaredVariables().join ', '
+        if assigns
+          code += ",\n#{@tab + TAB}" if declars
+          code += scope.assignedVariables().join ",\n#{@tab + TAB}"
+        code += ';\n'
     code + post
 
   # Wrap up the given nodes as a **Block**, unless it already happens

src/scope.coffee

@@ -25,8 +25,8 @@ exports.Scope = class Scope
   # Adds a new variable or overrides an existing one.
   add: (name, type, immediate) ->
     return @parent.add name, type, immediate if @shared and not immediate
-    if typeof (pos = @positions[name]) is 'number'
-      @variables[pos].type = type
+    if @positions.hasOwnProperty name
+      @variables[@positions[name]].type = type
     else
       @positions[name] = @variables.push({name, type}) - 1
 
@@ -73,7 +73,7 @@ exports.Scope = class Scope
   # Ensure that an assignment is made at the top of this scope
   # (or at the top-level scope, if requested).
   assign: (name, value) ->
-    @add name, value: value, assigned: true
+    @add name, {value, assigned: yes}, yes
     @hasAssignments = yes
 
   # Does this scope have any declared variables?

test/functions.coffee

@@ -178,3 +178,7 @@ test "arguments vs parameters", ->
   doesNotThrow -> CoffeeScript.compile "f(x) ->"
   f = (g) -> g()
   eq 5, f (x) -> 5
+
+test "#1844: bound functions in nested comprehensions causing empty var statements", ->
+  a = ((=>) for a in [0] for b in [0])
+  eq 1, a.length