fix `has_side_effects()` (#1675)

`AST_Try` is an `AST_Block`, so besides try block we also need to inspect catch and finally blocks for possible side effects.

Also extend this functionality to handle `AST_If` and `AST_LabeledStatement` while we are at it.

fixes #1673

1 files changed, 22 insertions, 13 deletions

diff --git a/lib/compress.js b/lib/compress.js
index bea9c9a4..805a84a7 100644
--- a/lib/compress.js
+++ b/lib/compress.js
@@ -1600,14 +1600,29 @@ merge(Compressor.prototype, {
             return false;
         });
 
-        def(AST_Block, function(compressor){
-            for (var i = this.body.length; --i >= 0;) {
-                if (this.body[i].has_side_effects(compressor))
+        function any(list, compressor) {
+            for (var i = list.length; --i >= 0;)
+                if (list[i].has_side_effects(compressor))
                     return true;
-            }
             return false;
-        });
+        }
 
+        def(AST_Block, function(compressor){
+            return any(this.body, compressor);
+        });
+        def(AST_Try, function(compressor){
+            return any(this.body, compressor)
+                || this.bcatch && this.bcatch.has_side_effects(compressor)
+                || this.bfinally && this.bfinally.has_side_effects(compressor);
+        });
+        def(AST_If, function(compressor){
+            return this.condition.has_side_effects(compressor)
+                || this.body && this.body.has_side_effects(compressor)
+                || this.alternative && this.alternative.has_side_effects(compressor);
+        });
+        def(AST_LabeledStatement, function(compressor){
+            return this.body.has_side_effects(compressor);
+        });
         def(AST_SimpleStatement, function(compressor){
             return this.body.has_side_effects(compressor);
         });
@@ -1633,19 +1648,13 @@ merge(Compressor.prototype, {
             return this.global() && this.undeclared();
         });
         def(AST_Object, function(compressor){
-            for (var i = this.properties.length; --i >= 0;)
-                if (this.properties[i].has_side_effects(compressor))
-                    return true;
-            return false;
+            return any(this.properties, compressor);
         });
         def(AST_ObjectProperty, function(compressor){
             return this.value.has_side_effects(compressor);
         });
         def(AST_Array, function(compressor){
-            for (var i = this.elements.length; --i >= 0;)
-                if (this.elements[i].has_side_effects(compressor))
-                    return true;
-            return false;
+            return any(this.elements, compressor);
         });
         def(AST_Dot, function(compressor){
             if (!compressor.option("pure_getters")) return true;