fix corner cases with arrow functions (#4688)

fixes #4687

1 files changed, 18 insertions, 10 deletions

diff --git a/lib/compress.js b/lib/compress.js
index ae96b764..2b28c754 100644
--- a/lib/compress.js
+++ b/lib/compress.js
@@ -2106,12 +2106,17 @@ merge(Compressor.prototype, {
                     } : function(node) {
                         return node instanceof AST_Await && !tw.find_parent(AST_Scope);
                     };
-                    var tw = new TreeWalker(function(node) {
+                    var arg_scope = null;
+                    var tw = new TreeWalker(function(node, descend) {
                         if (!arg) return true;
                         if (has_await(node) || node instanceof AST_Yield) {
                             arg = null;
                             return true;
                         }
+                        if (node instanceof AST_ObjectIdentity && (fn_strict || !arg_scope)) {
+                            arg = null;
+                            return true;
+                        }
                         if (node instanceof AST_SymbolRef && fn.variables.has(node.name)) {
                             var s = node.definition().scope;
                             if (s !== scope) while (s = s.parent_scope) {
@@ -2119,10 +2124,11 @@ merge(Compressor.prototype, {
                             }
                             arg = null;
                         }
-                        if (node instanceof AST_ObjectIdentity && (fn_strict
-                            || !tw.find_parent(AST_Scope)
-                            || is_arrow(arg) && iife instanceof AST_New)) {
-                            arg = null;
+                        if (node instanceof AST_Scope && !is_arrow(node)) {
+                            var save_scope = arg_scope;
+                            arg_scope = node;
+                            descend();
+                            arg_scope = save_scope;
                             return true;
                         }
                     });
@@ -4977,7 +4983,7 @@ merge(Compressor.prototype, {
 
     // determine if expression is constant
     (function(def) {
-        function all(list) {
+        function all_constant(list) {
             for (var i = list.length; --i >= 0;)
                 if (!list[i].is_constant_expression())
                     return false;
@@ -4985,7 +4991,7 @@ merge(Compressor.prototype, {
         }
         def(AST_Node, return_false);
         def(AST_Array, function() {
-            return all(this.elements);
+            return all_constant(this.elements);
         });
         def(AST_Binary, function() {
             return this.left.is_constant_expression()
@@ -4993,7 +4999,7 @@ merge(Compressor.prototype, {
                 && (this.operator != "in" || is_object(this.right));
         });
         def(AST_Class, function() {
-            return !this.extends && all(this.properties);
+            return !this.extends && all_constant(this.properties);
         });
         def(AST_ClassProperty, function() {
             return typeof this.key == "string" && (!this.value || this.value.is_constant_expression());
@@ -5031,14 +5037,16 @@ merge(Compressor.prototype, {
                     return true;
                 }
                 if (node instanceof AST_ObjectIdentity) {
-                    if (scopes.length == 0 && is_arrow(self)) result = false;
+                    if (is_arrow(self) && all(scopes, function(s) {
+                        return !(s instanceof AST_Scope) || is_arrow(s);
+                    })) result = false;
                     return true;
                 }
             }));
             return result;
         });
         def(AST_Object, function() {
-            return all(this.properties);
+            return all_constant(this.properties);
         });
         def(AST_ObjectProperty, function() {
             return typeof this.key == "string" && this.value.is_constant_expression();