Fix negate_iife transform to return a correct tree for nested IIFEs

Fix for #1256, partially reverts d854523783b4

2 files changed, 8 insertions, 3 deletions

diff --git a/lib/compress.js b/lib/compress.js
index fd839fa1..f8d9d329 100644
--- a/lib/compress.js
+++ b/lib/compress.js
@@ -831,6 +831,13 @@ merge(Compressor.prototype, {
         };
 
         function negate_iifes(statements, compressor) {
+            function is_iife_call(node) {
+                if (node instanceof AST_Call) {
+                    return node.expression instanceof AST_Function || is_iife_call(node.expression);
+                }
+                return false;
+            }
+
             statements.forEach(function(stat){
                 if (stat instanceof AST_SimpleStatement) {
                     stat.body = (function transform(thing) {
@@ -838,7 +845,7 @@ merge(Compressor.prototype, {
                             if (node instanceof AST_New) {
                                 return node;
                             }
-                            if (node instanceof AST_Call && node.expression instanceof AST_Function) {
+                            if (is_iife_call(node)) {
                                 return make_node(AST_UnaryPrefix, node, {
                                     operator: "!",
                                     expression: node
diff --git a/lib/output.js b/lib/output.js
index f1e0c2f1..801f7516 100644
--- a/lib/output.js
+++ b/lib/output.js
@@ -531,8 +531,6 @@ function OutputStream(options) {
     });
 
     PARENS([ AST_Unary, AST_Undefined ], function(output){
-        if (this.expression instanceof AST_Call)
-            return false;
         var p = output.parent();
         return p instanceof AST_PropAccess && p.expression === this
             || p instanceof AST_Call && p.expression === this;