fix bugs with getter/setter (#1926)

- `reduce_vars`
- `side_effects`
- property access for object
- `AST_SymbolAccessor` as key names

enhance `test/ufuzz.js`
- add object getter & setter
  - property assignment to setter
  - avoid infinite recursion in setter
- fix & adjust assignment operators
  - 50% `=`
  - 25% `+=`
  - 2.5% each for the rest
- avoid "Invalid array length"
- fix `console.log()`
  - bypass getter
  - curb recursive reference
- deprecate `-E`, always report runtime errors

4 files changed, 40 insertions, 27 deletions

diff --git a/lib/ast.js b/lib/ast.js
index 57956233..2972b7aa 100644
--- a/lib/ast.js
+++ b/lib/ast.js
@@ -685,8 +685,8 @@ var AST_Object = DEFNODE("Object", "properties", {
 var AST_ObjectProperty = DEFNODE("ObjectProperty", "key value", {
     $documentation: "Base class for literal object properties",
     $propdoc: {
-        key: "[string] the property name converted to a string for ObjectKeyVal.  For setters and getters this is an arbitrary AST_Node.",
-        value: "[AST_Node] property value.  For setters and getters this is an AST_Function."
+        key: "[string] the property name converted to a string for ObjectKeyVal.  For setters and getters this is an AST_SymbolAccessor.",
+        value: "[AST_Node] property value.  For setters and getters this is an AST_Accessor."
     },
     _walk: function(visitor) {
         return visitor._visit(this, function(){
diff --git a/lib/compress.js b/lib/compress.js
index 892bceef..f168b942 100644
--- a/lib/compress.js
+++ b/lib/compress.js
@@ -368,6 +368,13 @@ merge(Compressor.prototype, {
                     pop();
                     return true;
                 }
+                if (node instanceof AST_Accessor) {
+                    var save_ids = safe_ids;
+                    safe_ids = Object.create(null);
+                    descend();
+                    safe_ids = save_ids;
+                    return true;
+                }
                 if (node instanceof AST_Binary
                     && (node.operator == "&&" || node.operator == "||")) {
                     node.left.walk(tw);
@@ -1220,12 +1227,12 @@ merge(Compressor.prototype, {
                 && !node.expression.has_side_effects(compressor);
     }
 
-    // may_eq_null()
-    // returns true if this node may evaluate to null or undefined
+    // may_throw_on_access()
+    // returns true if this node may be null, undefined or contain `AST_Accessor`
     (function(def) {
-        AST_Node.DEFMETHOD("may_eq_null", function(compressor) {
+        AST_Node.DEFMETHOD("may_throw_on_access", function(compressor) {
             var pure_getters = compressor.option("pure_getters");
-            return !pure_getters || this._eq_null(pure_getters);
+            return !pure_getters || this._throw_on_access(pure_getters);
         });
 
         function is_strict(pure_getters) {
@@ -1237,7 +1244,12 @@ merge(Compressor.prototype, {
         def(AST_Undefined, return_true);
         def(AST_Constant, return_false);
         def(AST_Array, return_false);
-        def(AST_Object, return_false);
+        def(AST_Object, function(pure_getters) {
+            if (!is_strict(pure_getters)) return false;
+            for (var i = this.properties.length; --i >=0;)
+                if (this.properties[i].value instanceof AST_Accessor) return true;
+            return false;
+        });
         def(AST_Function, return_false);
         def(AST_UnaryPostfix, return_false);
         def(AST_UnaryPrefix, function() {
@@ -1246,33 +1258,33 @@ merge(Compressor.prototype, {
         def(AST_Binary, function(pure_getters) {
             switch (this.operator) {
               case "&&":
-                return this.left._eq_null(pure_getters);
+                return this.left._throw_on_access(pure_getters);
               case "||":
-                return this.left._eq_null(pure_getters)
-                    && this.right._eq_null(pure_getters);
+                return this.left._throw_on_access(pure_getters)
+                    && this.right._throw_on_access(pure_getters);
               default:
                 return false;
             }
         })
         def(AST_Assign, function(pure_getters) {
             return this.operator == "="
-                && this.right._eq_null(pure_getters);
+                && this.right._throw_on_access(pure_getters);
         })
         def(AST_Conditional, function(pure_getters) {
-            return this.consequent._eq_null(pure_getters)
-                || this.alternative._eq_null(pure_getters);
+            return this.consequent._throw_on_access(pure_getters)
+                || this.alternative._throw_on_access(pure_getters);
         })
         def(AST_Sequence, function(pure_getters) {
-            return this.expressions[this.expressions.length - 1]._eq_null(pure_getters);
+            return this.expressions[this.expressions.length - 1]._throw_on_access(pure_getters);
         });
         def(AST_SymbolRef, function(pure_getters) {
             if (this.is_undefined) return true;
             if (!is_strict(pure_getters)) return false;
             var fixed = this.fixed_value();
-            return !fixed || fixed._eq_null(pure_getters);
+            return !fixed || fixed._throw_on_access(pure_getters);
         });
     })(function(node, func) {
-        node.DEFMETHOD("_eq_null", func);
+        node.DEFMETHOD("_throw_on_access", func);
     });
 
     /* -----[ boolean/negation helpers ]----- */
@@ -1813,11 +1825,11 @@ merge(Compressor.prototype, {
             return any(this.elements, compressor);
         });
         def(AST_Dot, function(compressor){
-            return this.expression.may_eq_null(compressor)
+            return this.expression.may_throw_on_access(compressor)
                 || this.expression.has_side_effects(compressor);
         });
         def(AST_Sub, function(compressor){
-            return this.expression.may_eq_null(compressor)
+            return this.expression.may_throw_on_access(compressor)
                 || this.expression.has_side_effects(compressor)
                 || this.property.has_side_effects(compressor);
         });
@@ -2370,6 +2382,7 @@ merge(Compressor.prototype, {
             var args = trim(this.args, compressor, first_in_statement);
             return args && make_sequence(this, args);
         });
+        def(AST_Accessor, return_null);
         def(AST_Function, return_null);
         def(AST_Binary, function(compressor, first_in_statement){
             var right = this.right.drop_side_effect_free(compressor);
@@ -2437,11 +2450,11 @@ merge(Compressor.prototype, {
             return values && make_sequence(this, values);
         });
         def(AST_Dot, function(compressor, first_in_statement){
-            if (this.expression.may_eq_null(compressor)) return this;
+            if (this.expression.may_throw_on_access(compressor)) return this;
             return this.expression.drop_side_effect_free(compressor, first_in_statement);
         });
         def(AST_Sub, function(compressor, first_in_statement){
-            if (this.expression.may_eq_null(compressor)) return this;
+            if (this.expression.may_throw_on_access(compressor)) return this;
             var expression = this.expression.drop_side_effect_free(compressor, first_in_statement);
             if (!expression) return this.property.drop_side_effect_free(compressor, first_in_statement);
             var property = this.property.drop_side_effect_free(compressor);
diff --git a/lib/parse.js b/lib/parse.js
index c432ad7a..f1089501 100644
--- a/lib/parse.js
+++ b/lib/parse.js
@@ -1310,10 +1310,15 @@ function parse($TEXT, options) {
             var type = start.type;
             var name = as_property_name();
             if (type == "name" && !is("punc", ":")) {
+                var key = new AST_SymbolAccessor({
+                    start: S.token,
+                    name: as_property_name(),
+                    end: prev()
+                });
                 if (name == "get") {
                     a.push(new AST_ObjectGetter({
                         start : start,
-                        key   : as_atom_node(),
+                        key   : key,
                         value : create_accessor(),
                         end   : prev()
                     }));
@@ -1322,7 +1327,7 @@ function parse($TEXT, options) {
                 if (name == "set") {
                     a.push(new AST_ObjectSetter({
                         start : start,
-                        key   : as_atom_node(),
+                        key   : key,
                         value : create_accessor(),
                         end   : prev()
                     }));
diff --git a/lib/scope.js b/lib/scope.js
index ea08d775..14ffb46f 100644
--- a/lib/scope.js
+++ b/lib/scope.js
@@ -360,11 +360,6 @@ AST_Symbol.DEFMETHOD("unmangleable", function(options){
     return this.definition().unmangleable(options);
 });
 
-// property accessors are not mangleable
-AST_SymbolAccessor.DEFMETHOD("unmangleable", function(){
-    return true;
-});
-
 // labels are always mangleable
 AST_Label.DEFMETHOD("unmangleable", function(){
     return false;