Fix access to type variables in initializer expressions

runtime/vm/scopes.cc

Index: runtime/vm/scopes.cc
===================================================================
--- runtime/vm/scopes.cc	(revision 25809)
+++ runtime/vm/scopes.cc	(working copy)
@@ -309,7 +309,7 @@
   for (intptr_t i = 0; i < variables_.length(); i++) {
     LocalVariable* var = variables_[i];
     ASSERT(var->name().IsSymbol());
-    if ((var->name().raw() == name.raw()) && !var->is_invisible_) {
+    if (var->name().raw() == name.raw()) {
       return var;
     }
   }
@@ -321,7 +321,7 @@
   LocalScope* current_scope = this;
   while (current_scope != NULL) {
     LocalVariable* var = current_scope->LocalLookupVariable(name);
-    if (var != NULL) {
+    if ((var != NULL) && !var->is_invisible_) {

[regis, 2013/08/07 18:28:26]

As far as I understand, if a variable is marked invisible, you are not going to
find it in the parent scope. I guess that most of the time, there is no parent
scope anyway, but still, it would be a bit more efficient to return immediately:
if (var != NULL) {
  if (var->is_invisible_) return NULL;
  ...

[hausner, 2013/08/08 09:26:06]

That may be a shortcut that works now, since we use the invisible flag only on
variables in the outermost scopes, as you say. But I think the optimization is
not worth the compromise in correctness (should we ever use "invisible" on other
variables).

       if (!test_only) {
         if (var->owner()->function_level() != function_level()) {
           var->set_is_captured();
@@ -342,6 +342,29 @@
 }
 
 
+void LocalScope::CaptureVariable(const String& name) {

[regis, 2013/08/07 18:28:26]

I would still return the captured variable or a bool, so that the caller can
assert that the variable was found.

[hausner, 2013/08/08 09:26:06]

Ok, good point. will do in a follow-on CL.

+  ASSERT(name.IsSymbol());
+  LocalScope* current_scope = this;
+  while (current_scope != NULL) {
+    LocalVariable* var = current_scope->LocalLookupVariable(name);
+    if (var != NULL) {
+      if (var->owner()->function_level() != function_level()) {
+        var->set_is_captured();
+      }
+      // Insert aliases of the variable in intermediate scopes.
+      LocalScope* intermediate_scope = this;
+      while (intermediate_scope != current_scope) {
+        intermediate_scope->variables_.Add(var);
+        ASSERT(var->owner() != intermediate_scope);  // Item is an alias.
+        intermediate_scope = intermediate_scope->parent();
+      }
+      return;
+    }
+    current_scope = current_scope->parent();
+  }
+}
+
+
 SourceLabel* LocalScope::LookupLabel(const String& name) {
   LocalScope* current_scope = this;
   while (current_scope != NULL) {