Merge pull request #3791 from lydell/issue-3502

Fix #3502: Define param variables when expansion

Author: michaelficarra

lib/coffee-script/nodes.js

@@ -1360,8 +1360,8 @@ exports.Code = class Code extends Base
     for param in @params when param not instanceof Expansion
       o.scope.parameter param.asReference o
     for param in @params when param.splat or param instanceof Expansion
-      for {name: p} in @params when param not instanceof Expansion
-        if p.value then o.scope.add p.value, 'var', yes
+      for p in @params when p not instanceof Expansion and p.name.value
+        o.scope.add p.name.value, 'var', yes
       splats = new Assign new Value(new Arr(p.asReference o for p in @params)),
                           new Value new Literal 'arguments'
       break

src/nodes.coffee

@@ -198,6 +198,20 @@ test "#156: parameter lists with expansion in array destructuring", ->
     last
   eq 3, expandArray 1, 2, 3, [1, 2, 3]
 
+test "#3502: variable definitions and expansion", ->
+  a = b = 0
+  f = (a, ..., b) -> [a, b]
+  arrayEq [1, 5], f 1, 2, 3, 4, 5
+  eq 0, a
+  eq 0, b
+
+test "variable definitions and splat", ->
+  a = b = 0
+  f = (a, middle..., b) -> [a, middle, b]
+  arrayEq [1, [2, 3, 4], 5], f 1, 2, 3, 4, 5
+  eq 0, a
+  eq 0, b
+
 test "default values with function calls", ->
   doesNotThrow -> CoffeeScript.compile "(x = f()) ->"