Merge pull request jashkenas#4071 from lydell/lone-expansion

Fix jashkenas#4070: Improve error message for lone expansion
cclauss · Aug 27, 2015 · 66716cd · 66716cd
2 parents dc3e177 + f588ecb
commit 66716cd
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Showing 3 changed files with 25 additions and 2 deletions.
diff --git a/lib/coffee-script/nodes.js b/lib/coffee-script/nodes.js
diff --git a/src/nodes.coffee b/src/nodes.coffee
@@ -1234,8 +1234,11 @@ exports.Assign = class Assign extends Base
     unless olen = objects.length
       code = value.compileToFragments o
       return if o.level >= LEVEL_OP then @wrapInBraces code else code
+    [obj] = objects
+    if olen is 1 and obj instanceof Expansion
+      obj.error 'Destructuring assignment has no target'
     isObject = @variable.isObject()
-    if top and olen is 1 and (obj = objects[0]) not instanceof Splat
+    if top and olen is 1 and obj not instanceof Splat
       # Unroll simplest cases: `{v} = x` -> `v = x.v`
       if obj instanceof Assign
         {variable: {base: idx}, value: obj} = obj

diff --git a/test/error_messages.coffee b/test/error_messages.coffee
@@ -776,3 +776,19 @@ test "invalid object keys", ->
       @a: 1
       ^^
   '''
+
+test "#4070: lone expansion", ->
+  assertErrorFormat '''
+    [...] = a
+  ''', '''
+    [stdin]:1:2: error: Destructuring assignment has no target
+    [...] = a
+     ^^^
+  '''
+  assertErrorFormat '''
+    [ ..., ] = a
+  ''', '''
+    [stdin]:1:3: error: Destructuring assignment has no target
+    [ ..., ] = a
+      ^^^
+  '''