enhance `collapse_vars` (#3697)

1 files changed, 28 insertions, 1 deletions

diff --git a/lib/compress.js b/lib/compress.js
index 9b054ca3..85ad449e 100644
--- a/lib/compress.js
+++ b/lib/compress.js
@@ -1382,7 +1382,34 @@ merge(Compressor.prototype, {
             }
 
             function is_last_node(node, parent) {
-                if (node instanceof AST_Call) return true;
+                if (node instanceof AST_Call) {
+                    var fn = node.expression;
+                    if (fn instanceof AST_SymbolRef) fn = fn.fixed_value();
+                    if (!(fn instanceof AST_Lambda)) return true;
+                    if (fn.collapse_scanning) return false;
+                    fn.collapse_scanning = true;
+                    var replace = can_replace;
+                    can_replace = false;
+                    var after = stop_after;
+                    var if_hit = stop_if_hit;
+                    var rhs_fn = scan_rhs;
+                    for (var i = 0; !abort && i < fn.body.length; i++) {
+                        var stat = fn.body[i];
+                        if (stat instanceof AST_Exit) {
+                            if (stat.value) stat.value.transform(scanner);
+                            break;
+                        }
+                        stat.transform(scanner);
+                    }
+                    scan_rhs = rhs_fn;
+                    stop_if_hit = if_hit;
+                    stop_after = after;
+                    can_replace = replace;
+                    delete fn.collapse_scanning;
+                    if (!abort) return false;
+                    abort = false;
+                    return true;
+                }
                 if (node instanceof AST_Exit) {
                     if (in_try) {
                         if (in_try.bfinally) return true;