fix corner case in functions (#3365)

fixes #3364

lib/compress.js

@@ -3602,7 +3602,7 @@ merge(Compressor.prototype, {
                             compressor.warn("Declaring {name} as function [{file}:{line},{col}]", template(def.name));
                             var defun = make_node(AST_Defun, def, def.value);
                             defun.name = make_node(AST_SymbolDefun, def.name, def.name);
-                            self.def_function(defun.name);
+                            defun.parent_scope.resolve().def_function(defun.name);
                             body.push(defun);
                         } else {
                             if (side_effects.length > 0) {

lib/scope.js

@@ -61,8 +61,6 @@ SymbolDef.next_id = 1;
 
 SymbolDef.prototype = {
     unmangleable: function(options) {
-        if (!options) options = {};
-
         return this.global && !options.toplevel
             || this.undeclared
             || !options.eval && this.scope.pinned()
@@ -296,7 +294,7 @@ AST_Scope.DEFMETHOD("def_variable", function(symbol, init) {
 
 AST_Lambda.DEFMETHOD("resolve", return_this);
 AST_Scope.DEFMETHOD("resolve", function() {
-    return this.parent_scope;
+    return this.parent_scope.resolve();
 });
 AST_Toplevel.DEFMETHOD("resolve", return_this);