enhance `join_vars` (#4089)

1 files changed, 8 insertions, 0 deletions

diff --git a/lib/compress.js b/lib/compress.js
index 6761c246..9aa70ef9 100644
--- a/lib/compress.js
+++ b/lib/compress.js
@@ -2644,6 +2644,14 @@ merge(Compressor.prototype, {
                         defs = stat.init;
                     }
                 } else if (stat instanceof AST_ForIn) {
+                    if (defs && defs.TYPE == stat.init.TYPE) {
+                        defs.definitions = defs.definitions.concat(stat.init.definitions);
+                        var name = stat.init.definitions[0].name;
+                        var ref = make_node(AST_SymbolRef, name, name);
+                        name.definition().references.push(ref);
+                        stat.init = ref;
+                        CHANGED = true;
+                    }
                     stat.object = join_assigns_expr(stat.object);
                 } else if (stat instanceof AST_If) {
                     stat.condition = join_assigns_expr(stat.condition);