From dac9e69f9efb491c274670f36301fd38b0ef4dd6 Mon Sep 17 00:00:00 2001
From: "Alex Lam S.L" <alexlamsl@gmail.com>
Date: Sat, 18 Apr 2020 03:06:20 +0100
Subject: enhance `collapse_vars` (#3793)

---
 lib/compress.js | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

(limited to 'lib')

diff --git a/lib/compress.js b/lib/compress.js
index 70ac9b8f..d07c2412 100644
--- a/lib/compress.js
+++ b/lib/compress.js
@@ -1307,12 +1307,10 @@ merge(Compressor.prototype, {
                         if (candidate instanceof AST_Assign) referenced--;
                         if (replaced && referenced == replaced) {
                             abort = false;
-                        } else if (candidate instanceof AST_Assign) {
+                        } else {
                             candidates.push(hit_stack);
                             force_single = true;
                             continue;
-                        } else {
-                            replaced = false;
                         }
                         if (replaced) {
                             hit_index = 0;
@@ -1320,6 +1318,9 @@ merge(Compressor.prototype, {
                             for (var i = stat_index; !abort && i < statements.length; i++) {
                                 if (!statements[i].transform(multi_replacer)) statements.splice(i--, 1);
                             }
+                            if (candidate instanceof AST_VarDef) {
+                                replaced = !compressor.exposed(def) && def.references.length == def.replaced;
+                            }
                             value_def.single_use = false;
                         }
                     }
@@ -1738,8 +1739,11 @@ merge(Compressor.prototype, {
                     if (!member(expr.name, def.orig)) return;
                     var referenced = def.references.length - def.replaced;
                     var declared = def.orig.length - def.eliminated;
-                    if (declared > 1 && !(expr.name instanceof AST_SymbolFunarg)
-                        || (referenced > 1 ? mangleable_var(expr.value) : !compressor.exposed(def))) {
+                    if (declared > 1 && !(expr.name instanceof AST_SymbolFunarg)) {
+                        mangleable_var(expr.value);
+                        return make_node(AST_SymbolRef, expr.name, expr.name);
+                    }
+                    if (referenced > 1 ? mangleable_var(expr.value) : !compressor.exposed(def)) {
                         return make_node(AST_SymbolRef, expr.name, expr.name);
                     }
                 } else if (expr instanceof AST_Assign) {
@@ -1863,6 +1867,7 @@ merge(Compressor.prototype, {
                     found = true;
                     if (node instanceof AST_VarDef) {
                         node.value = null;
+                        if (value_def) value_def.replaced++;
                         return node;
                     }
                     return in_list ? List.skip : null;
-- 
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