fix `unsafe` `reduce_vars` on arrays & objects (#2397)

1 files changed, 7 insertions, 3 deletions

diff --git a/lib/compress.js b/lib/compress.js
index 25718a5e..670a3b0d 100644
--- a/lib/compress.js
+++ b/lib/compress.js
@@ -567,18 +567,18 @@ merge(Compressor.prototype, {
         function read_property(obj, key) {
             if (key instanceof AST_Constant) key = key.getValue();
             if (key instanceof AST_Node) return null;
+            var value;
             if (obj instanceof AST_Array) {
-                return obj.elements[key];
+                value = obj.elements[key];
             } else if (obj instanceof AST_Object) {
                 var props = obj.properties;
-                var value;
                 for (var i = props.length; --i >= 0;) {
                     var prop = props[i];
                     if (!(prop instanceof AST_ObjectKeyVal)) return;
                     if (!value && props[i].key === key) value = props[i].value;
                 }
-                return value;
             }
+            return value instanceof AST_SymbolRef ? value.fixed_value() : value;
         }
 
         function is_modified(node, value, level, immutable) {
@@ -589,6 +589,8 @@ merge(Compressor.prototype, {
                     && parent.expression === node
                     && (!(value instanceof AST_Function) || value.contains_this())) {
                 return true;
+            } else if (parent instanceof AST_Array || parent instanceof AST_Object) {
+                return is_modified(parent, parent, level + 1);
             } else if (parent instanceof AST_PropAccess && parent.expression === node) {
                 return !immutable && is_modified(parent, read_property(value, parent.property), level + 1);
             }
@@ -602,6 +604,8 @@ merge(Compressor.prototype, {
                 || parent instanceof AST_Return && node === parent.value && node.scope !== d.scope
                 || parent instanceof AST_VarDef && node === parent.value) {
                 d.escaped = true;
+            } else if (parent instanceof AST_Array || parent instanceof AST_Object) {
+                mark_escaped(d, parent, parent, level + 1);
             } else if (parent instanceof AST_PropAccess && node === parent.expression) {
                 mark_escaped(d, parent, read_property(value, parent.property), level + 1);
             }