ParameterInitializerRewriter must maintain temporary variable order

src/ast/scopes.cc

Index: src/ast/scopes.cc
diff --git a/src/ast/scopes.cc b/src/ast/scopes.cc
index 5b91bb6b7edee3be392a05077e73537a448a2a2c..b019276bee8b56acb7b117d9f5836ed6ff5e8aca 100644
--- a/src/ast/scopes.cc
+++ b/src/ast/scopes.cc
@@ -558,17 +558,19 @@ Variable* Scope::NewTemporary(const AstRawString* name) {
   return var;
 }
 
-
-bool Scope::RemoveTemporary(Variable* var) {
+int Scope::RemoveTemporary(Variable* var) {
+  DCHECK_NOT_NULL(var);
   // Most likely (always?) any temporary variable we want to remove
   // was just added before, so we search backwards.
   for (int i = temps_.length(); i-- > 0;) {
     if (temps_[i] == var) {
-      temps_.Remove(i);
-      return true;
+      // Don't shrink temps_, as callers of this method expect
+      // the returned indices to be unique per-scope.
+      temps_[i] = nullptr;
+      return i;
     }
   }
-  return false;
+  return -1;
 }
 
 
@@ -635,6 +637,7 @@ void Scope::CollectStackAndContextLocals(ZoneList<Variable*>* stack_locals,
   // context as a whole has forced context allocation.
   for (int i = 0; i < temps_.length(); i++) {
     Variable* var = temps_[i];
+    if (var == nullptr) continue;
     if (var->is_used()) {
       if (var->IsContextSlot()) {
         DCHECK(has_forced_context_allocation());
@@ -986,7 +989,9 @@ void Scope::Print(int n) {
   if (temps_.length() > 0) {

[nickie, 2016/05/10 13:47:08]

If you have length() > 0 but only null elements, you'll still print the header.

[adamk, 2016/05/10 17:36:11]

This is probably the ugliest part of this approach :)

Fixed.

     Indent(n1, "// temporary vars:\n");
     for (int i = 0; i < temps_.length(); i++) {
-      PrintVar(n1, temps_[i]);
+      if (temps_[i] != NULL) {

[nickie, 2016/05/10 13:47:08]

Not nullptr?  :-)

[adamk, 2016/05/10 17:36:11]

Was going for consistent, but looks like this function is already inconsistent.
Switched :)

+        PrintVar(n1, temps_[i]);
+      }
     }
   }
 
@@ -1416,6 +1421,7 @@ void Scope::AllocateDeclaredGlobal(Isolate* isolate, Variable* var) {
 void Scope::AllocateNonParameterLocalsAndDeclaredGlobals(Isolate* isolate) {
   // All variables that have no rewrite yet are non-parameter locals.
   for (int i = 0; i < temps_.length(); i++) {
+    if (temps_[i] == nullptr) continue;
     AllocateNonParameterLocal(isolate, temps_[i]);
   }