fix `dead_code` on `return`/`throw` within `try` (#2588)

1 files changed, 13 insertions, 0 deletions

diff --git a/lib/compress.js b/lib/compress.js
index 559fb51a..e394e8b2 100644
--- a/lib/compress.js
+++ b/lib/compress.js
@@ -4674,6 +4674,11 @@ merge(Compressor.prototype, {
                 node = parent;
                 parent = compressor.parent(level++);
                 if (parent instanceof AST_Exit) {
+                    var try_node = find_try(level);
+                    if (try_node) {
+                        if (try_node.bfinally) break;
+                        if (parent instanceof AST_Throw && try_node.bcatch) break;
+                    }
                     if (self.operator == "=") return self.right;
                     return make_node(AST_Binary, self, {
                         operator: self.operator.slice(0, -1),
@@ -4704,6 +4709,14 @@ merge(Compressor.prototype, {
             }
         }
         return self;
+
+        function find_try(level) {
+            var scope = self.left.definition().scope;
+            var parent;
+            while ((parent = compressor.parent(level++)) !== scope) {
+                if (parent instanceof AST_Try) return parent;
+            }
+        }
     });
 
     OPT(AST_Conditional, function(self, compressor){