fix corner case in unused (#3517)

fixes #3515
2019-10-23 01:58:40 +08:00
parent a53ab99378
commit 267bc70d33
2 changed files with 28 additions and 1 deletions
--- a/lib/compress.js
+++ b/lib/compress.js
@@ -3737,7 +3737,9 @@ merge(Compressor.prototype, {
                        def.value = null;
                        head.push(def);
                    } else {
-                        var value = def.value && def.value.drop_side_effect_free(compressor);
+                        var value = def.value
+                            && (sym.references.length != 1 || !sym.replaced)
+                            && def.value.drop_side_effect_free(compressor);
                        if (value) {
                            AST_Node.warn("Side effects in initialization of unused variable {name} [{file}:{line},{col}]", template(def.name));
                            side_effects.push(value);