fix corner case in `hoist_props` (#4024)

fixes #4023

1 files changed, 9 insertions, 3 deletions

diff --git a/lib/compress.js b/lib/compress.js
index 1da49955..3405253d 100644
--- a/lib/compress.js
+++ b/lib/compress.js
@@ -5071,6 +5071,7 @@ merge(Compressor.prototype, {
             }
         }));
         self.transform(new TreeTransformer(function(node, descend) {
+            if (node instanceof AST_Binary) return replace("right");
             if (node instanceof AST_PropAccess) {
                 if (!(node.expression instanceof AST_SymbolRef)) return;
                 var defs = defs_by_id[node.expression.definition().id];
@@ -5086,10 +5087,15 @@ merge(Compressor.prototype, {
             }
             if (node instanceof AST_Unary) {
                 if (unary_side_effects[node.operator]) return;
-                if (!(node.expression instanceof AST_SymbolRef)) return;
-                if (!(node.expression.definition().id in defs_by_id)) return;
+                return replace("expression");
+            }
+
+            function replace(prop) {
+                var sym = node[prop];
+                if (!(sym instanceof AST_SymbolRef)) return;
+                if (!(sym.definition().id in defs_by_id)) return;
                 var opt = node.clone();
-                opt.expression = make_node(AST_Object, node, {
+                opt[prop] = make_node(AST_Object, sym, {
                     properties: []
                 });
                 return opt;