Merge pull request #4652 from GeoffreyBooth/bug-fix-4651

[CS2] Fix #4651: object spread destructuring bug

Author: connec

lib/coffeescript/nodes.js

@@ -2120,8 +2120,9 @@ exports.Assign = class Assign extends Base
         @variable.base.lhs = yes
         return @compileDestructuring o unless @variable.isAssignable()
         # Object destructuring. Can be removed once ES proposal hits Stage 4.
-        return @compileObjectDestruct(o) if @variable.isObject() and @variable.contains (node) ->
+        objDestructAnswer = @compileObjectDestruct(o) if @variable.isObject() and @variable.contains (node) ->
           node instanceof Obj and node.hasSplat()
+        return objDestructAnswer if objDestructAnswer
 
       return @compileSplice       o if @variable.isSplice()
       return @compileConditional  o if @context in ['||=', '&&=', '?=']
@@ -2214,12 +2215,16 @@ exports.Assign = class Assign extends Base
     traverseRest = (properties, source) =>
       restElements = []
       restIndex = undefined
+      source = new Value source unless source.properties?
 
       for prop, index in properties
+        nestedSourceDefault = nestedSource = nestedProperties = null
         setScopeVar prop.unwrap()
         if prop instanceof Assign
           # prop is `k: expr`, we need to check `expr` for nested splats
           if prop.value.isObject?()
+            # prop is `k = {...} `
+            continue unless prop.context is 'object'
             # prop is `k: {...}`
             nestedProperties = prop.value.base.properties
           else if prop.value instanceof Assign and prop.value.variable.isObject()
@@ -2245,13 +2250,19 @@ exports.Assign = class Assign extends Base
 
       restElements
 
-    # Cache the value for reuse with rest elements
-    [@value, valueRef] = @value.cache o
+    # Cache the value for reuse with rest elements.
+    if @value.shouldCache()
+      valueRefTemp = new IdentifierLiteral o.scope.freeVariable 'ref', reserve: false
+    else
+      valueRefTemp = @value.base
 
     # Find all rest elements.
-    restElements = traverseRest @variable.base.properties, valueRef
+    restElements = traverseRest @variable.base.properties, valueRefTemp
+    return no unless restElements and restElements.length > 0
 
+    [@value, valueRef] = @value.cache o
     result = new Block [@]
+
     for restElement in restElements
       value = new Call new Value(new Literal utility 'objectWithoutKeys', o), [restElement.source, restElement.excludeProps]
       result.push new Assign restElement.name, value

src/nodes.coffee

@@ -296,6 +296,29 @@ test "destructuring assignment with multiple splats in different objects", ->
   deepEqual a, val: 1
   deepEqual b, val: 2
 
+  o = {
+    props: {
+      p: {
+        n: 1
+        m: 5
+      }
+      s: 6
+    }
+  }
+  {p: {m, q..., t = {obj...}}, r...} = o.props
+  eq m, o.props.p.m
+  deepEqual r, s: 6
+  deepEqual q, n: 1
+  deepEqual t, obj
+
+  @props = o.props
+  {p: {m}, r...} = @props
+  eq m, @props.p.m
+  deepEqual r, s: 6
+
+  {p: {m}, r...} = {o.props..., p:{m:9}}
+  eq m, 9
+
   # Should not trigger implicit call, e.g. rest ... => rest(...)
   {
     a: {