fix unused on var of the same name within catch (#1716)

fixes #1715
2017-03-28 21:25:49 +08:00
parent f71f4905b0
commit c909ffb715
2 changed files with 94 additions and 1 deletions
--- a/lib/compress.js
+++ b/lib/compress.js
@@ -1894,7 +1894,13 @@ merge(Compressor.prototype, {
                    if (drop_vars && node instanceof AST_Definitions && !(tt.parent() instanceof AST_ForIn)) {
                        var def = node.definitions.filter(function(def){
                            if (def.value) def.value = def.value.transform(tt);
-                            if (def.name.definition().id in in_use_ids) return true;
+                            var sym = def.name.definition();
+                            if (sym.id in in_use_ids) return true;
+                            if (sym.orig[0] instanceof AST_SymbolCatch
+                                && sym.scope.parent_scope.find_variable(def.name).orig[0] === def.name) {
+                                def.value = def.value && def.value.drop_side_effect_free(compressor);
+                                return true;
+                            }
                            var w = {
                                name : def.name.name,
                                file : def.name.start.file,