fix corner cases in `unused` (#3519)

1 files changed, 2 insertions, 1 deletions

diff --git a/lib/compress.js b/lib/compress.js
index f7fedeb2..7202219a 100644
--- a/lib/compress.js
+++ b/lib/compress.js
@@ -3738,7 +3738,7 @@ merge(Compressor.prototype, {
                         head.push(def);
                     } else {
                         var value = def.value
-                            && (sym.references.length != 1 || !sym.replaced)
+                            && !def.value.single_use
                             && 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));
@@ -6158,6 +6158,7 @@ merge(Compressor.prototype, {
             if (single_use && fixed) {
                 def.single_use = false;
                 fixed._squeezed = true;
+                fixed.single_use = true;
                 if (fixed instanceof AST_Defun) {
                     fixed = make_node(AST_Function, fixed, fixed);
                     fixed.name = make_node(AST_SymbolLambda, fixed.name, fixed.name);