Fixes #2580 -- Try/Catch is allowed to destructure the error object.

lib/coffee-script/grammar.js

@@ -336,6 +336,8 @@
     Catch: [
       o('CATCH Identifier Block', function() {
         return [$2, $3];
+      }), o('CATCH Object Block', function() {
+        return [new Value($2), $3];
       })
     ],
     Throw: [

lib/coffee-script/nodes.js

@@ -2398,20 +2398,24 @@
     };
 
     Try.prototype.compileNode = function(o) {
-      var catchPart, ensurePart, errorPart, tryPart;
+      var catchPart, ensurePart, placeholder, tryPart;
       o.indent += TAB;
-      errorPart = this.error ? " (" + (this.error.compile(o)) + ") " : ' ';
       tryPart = this.attempt.compile(o, LEVEL_TOP);
       catchPart = (function() {
-        var _ref2;
+        var _base, _ref2;
         if (this.recovery) {
+          if (typeof (_base = this.error).isObject === "function" ? _base.isObject() : void 0) {
+            placeholder = new Literal('_error');
+            this.recovery.unshift(new Assign(this.error, placeholder));
+            this.error = placeholder;
+          }
           if (_ref2 = this.error.value, __indexOf.call(STRICT_PROSCRIBED, _ref2) >= 0) {
             throw SyntaxError("catch variable may not be \"" + this.error.value + "\"");
           }
           if (!o.scope.check(this.error.value)) {
             o.scope.add(this.error.value, 'param');
           }
-          return " catch" + errorPart + "{\n" + (this.recovery.compile(o, LEVEL_TOP)) + "\n" + this.tab + "}";
+          return " catch (" + (this.error.compile(o)) + ") {\n" + (this.recovery.compile(o, LEVEL_TOP)) + "\n" + this.tab + "}";
         } else if (!(this.ensure || this.recovery)) {
           return ' catch (_error) {}';
         }

src/grammar.coffee

@@ -383,6 +383,7 @@ grammar =
   # A catch clause names its error and runs a block of code.
   Catch: [
     o 'CATCH Identifier Block',                 -> [$2, $3]
+    o 'CATCH Object Block',                     -> [new Value($2), $3]
   ]
 
   # Throw an exception object.

src/nodes.coffee

@@ -1604,14 +1604,17 @@ exports.Try = class Try extends Base
   # is optional, the *catch* is not.
   compileNode: (o) ->
     o.indent  += TAB
-    errorPart = if @error then " (#{ @error.compile o }) " else ' '
     tryPart   = @attempt.compile o, LEVEL_TOP
 
     catchPart = if @recovery
+      if @error.isObject?()
+        placeholder = new Literal '_error'
+        @recovery.unshift new Assign @error, placeholder
+        @error = placeholder
       if @error.value in STRICT_PROSCRIBED
         throw SyntaxError "catch variable may not be \"#{@error.value}\""
       o.scope.add @error.value, 'param' unless o.scope.check @error.value
-      " catch#{errorPart}{\n#{ @recovery.compile o, LEVEL_TOP }\n#{@tab}}"
+      " catch (#{ @error.compile o }) {\n#{ @recovery.compile o, LEVEL_TOP }\n#{@tab}}"
     else unless @ensure or @recovery
       ' catch (_error) {}'
 

test/exception_handling.coffee

@@ -99,4 +99,17 @@ test "try/catch with a reused variable name.", ->
     catch inner
       # nothing
   eq typeof inner, 'undefined'
+  
+  
+# Allowed to destructure exceptions: #2580
+
+test "try/catch with destructuring the exception object", ->
+  
+  result = try
+    missing.object
+  catch {message}
+    message
+    
+  eq message, 'missing is not defined'
+