fix a couple of bugs in global_defs (#1802)

- `optimize()` substituted expression
- compute nested property string correctly

fixes #1801

Miscellaneous
- reset optimisation flags on all node types

lib/compress.js

@@ -260,10 +260,8 @@ merge(Compressor.prototype, {
             }
         });
         var tw = new TreeWalker(function(node, descend){
-            if (!(node instanceof AST_Directive || node instanceof AST_Constant)) {
-                node._squeezed = false;
-                node._optimized = false;
-            }
+            node._squeezed = false;
+            node._optimized = false;
             if (reduce_vars) {
                 if (node instanceof AST_Toplevel) node.globals.each(reset_def);
                 if (node instanceof AST_Scope) node.variables.each(reset_def);
@@ -1346,7 +1344,7 @@ merge(Compressor.prototype, {
         }
         def(AST_Node, noop);
         def(AST_Dot, function(compressor, suffix){
-            return this.expression._find_defs(compressor, suffix + "." + this.property);
+            return this.expression._find_defs(compressor, "." + this.property + suffix);
         });
         def(AST_SymbolRef, function(compressor, suffix){
             if (!this.global()) return;
@@ -3582,7 +3580,7 @@ merge(Compressor.prototype, {
     OPT(AST_SymbolRef, function(self, compressor){
         var def = self.resolve_defines(compressor);
         if (def) {
-            return def;
+            return def.optimize(compressor);
         }
         // testing against !self.scope.uses_with first is an optimization
         if (compressor.option("screw_ie8")
@@ -3932,7 +3930,7 @@ merge(Compressor.prototype, {
     OPT(AST_Dot, function(self, compressor){
         var def = self.resolve_defines(compressor);
         if (def) {
-            return def;
+            return def.optimize(compressor);
         }
         var prop = self.property;
         if (RESERVED_WORDS(prop) && !compressor.option("screw_ie8")) {