Fix comment typos

src/ast/scopes.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/ast/scopes.h"
 
 #include <set>
 
 #include "src/accessors.h"
 #include "src/ast/ast.h"
@@ skipping 1433 matching lines @@
          scope = scope->sibling_) {
       PrintF("\n");
       scope->Print(n1);
     }
   }
 
   Indent(n0, "}\n");
 }
 
 void Scope::CheckScopePositions() {
-  // A scope is allowed to have invalid positions if it is hidden and has no
-  // inner scopes

[jwolfe, 2016/10/06 19:17:44]

The typo here is a bit subtle. A minimal change to correct it would be s/hidden
and has/hidden or has/, but i thought that was still too confusing. I changed
the logic in the comment to what I think is much easier to understand, as
opposed to simply translating the code in the if condition into English.

+  // Visible leaf scopes must have real positions.
   if (!is_hidden() && inner_scope_ == nullptr) {
     CHECK_NE(kNoSourcePosition, start_position());
     CHECK_NE(kNoSourcePosition, end_position());
   }
   for (Scope* scope = inner_scope_; scope != nullptr; scope = scope->sibling_) {
     scope->CheckScopePositions();
   }
 }
 
 void Scope::CheckZones() {
@@ skipping 446 matching lines @@
   Variable* function =
       is_function_scope() ? AsDeclarationScope()->function_var() : nullptr;
   bool is_function_var_in_context =
       function != nullptr && function->IsContextSlot();
   return num_heap_slots() - Context::MIN_CONTEXT_SLOTS -
          (is_function_var_in_context ? 1 : 0);
 }
 
 }  // namespace internal
 }  // namespace v8