retrofit `try-catch-finally` as block-scoped (#4178)

- support optional catch binding

1 files changed, 9 insertions, 1 deletions

diff --git a/lib/scope.js b/lib/scope.js
index 359bd883..86fd3957 100644
--- a/lib/scope.js
+++ b/lib/scope.js
@@ -114,6 +114,14 @@ AST_Toplevel.DEFMETHOD("figure_out_scope", function(options) {
             });
             return true;
         }
+        if (node instanceof AST_Try) {
+            walk_scope(function() {
+                walk_body(node, tw);
+            });
+            if (node.bcatch) node.bcatch.walk(tw);
+            if (node.bfinally) node.bfinally.walk(tw);
+            return true;
+        }
         if (node instanceof AST_BlockScope) {
             walk_scope(descend);
             return true;
@@ -468,7 +476,7 @@ AST_Toplevel.DEFMETHOD("mangle_names", function(options) {
             node.mangled_name = name;
             return true;
         }
-        if (!options.ie8 && node instanceof AST_Catch) {
+        if (!options.ie8 && node instanceof AST_Catch && node.argname) {
             var def = node.argname.definition();
             var redef = defer_redef(def, node.argname);
             descend();