auto merge of #8623 : pnkfelix/rust/fsk-visitor-vpar-defaults-step4, r=nmatsakis

Follow up to #8619 (step 3 of 5).

(See #8527, which was step 1 of 5, for the full outline.)

Part of #7081.

diff --combined src/librustc/middle/lang_items.rs
index ae9d3d5ec0e0b390186d768b5a5d7dbeebca7562,18af303f239a3fce42f6b65d1a0c51e27a9255cf..9b11301a9c494256c644730a9d4f049783d77b6e
--- 1/src/librustc/middle/lang_items.rs
--- 2/src/librustc/middle/lang_items.rs
+++ b/src/librustc/middle/lang_items.rs
@@@ -26,8 -26,9 +26,9 @@@ use metadata::cstore::iter_crate_data
  use syntax::ast::{Crate, def_id, MetaItem};
  use syntax::ast_util::local_def;
  use syntax::attr::AttrMetaMethods;
- use syntax::oldvisit::{default_simple_visitor, mk_simple_visitor};
- use syntax::oldvisit::{SimpleVisitor, visit_crate};
+ use syntax::ast::{item};
+ use syntax::visit;
+ use syntax::visit::Visitor;
  
  use std::hashmap::HashMap;
  
@@@ -57,27 -58,28 +58,27 @@@ pub enum LangItem 
  
      StrEqFnLangItem,                   // 19
      UniqStrEqFnLangItem,               // 20
 -    AnnihilateFnLangItem,              // 21
 -    LogTypeFnLangItem,                 // 22
 -    FailFnLangItem,                    // 23
 -    FailBoundsCheckFnLangItem,         // 24
 -    ExchangeMallocFnLangItem,          // 25
 -    ClosureExchangeMallocFnLangItem,   // 26
 -    ExchangeFreeFnLangItem,            // 27
 -    MallocFnLangItem,                  // 28
 -    FreeFnLangItem,                    // 29
 -    BorrowAsImmFnLangItem,             // 30
 -    BorrowAsMutFnLangItem,             // 31
 -    ReturnToMutFnLangItem,             // 32
 -    CheckNotBorrowedFnLangItem,        // 33
 -    StrDupUniqFnLangItem,              // 34
 -    RecordBorrowFnLangItem,            // 35
 -    UnrecordBorrowFnLangItem,          // 36
 -
 -    StartFnLangItem,                   // 37
 -
 -    TyDescStructLangItem,              // 38
 -    TyVisitorTraitLangItem,            // 39
 -    OpaqueStructLangItem,              // 40
 +    LogTypeFnLangItem,                 // 21
 +    FailFnLangItem,                    // 22
 +    FailBoundsCheckFnLangItem,         // 23
 +    ExchangeMallocFnLangItem,          // 24
 +    ClosureExchangeMallocFnLangItem,   // 25
 +    ExchangeFreeFnLangItem,            // 26
 +    MallocFnLangItem,                  // 27
 +    FreeFnLangItem,                    // 28
 +    BorrowAsImmFnLangItem,             // 29
 +    BorrowAsMutFnLangItem,             // 30
 +    ReturnToMutFnLangItem,             // 31
 +    CheckNotBorrowedFnLangItem,        // 32
 +    StrDupUniqFnLangItem,              // 33
 +    RecordBorrowFnLangItem,            // 34
 +    UnrecordBorrowFnLangItem,          // 35
 +
 +    StartFnLangItem,                   // 36
 +
 +    TyDescStructLangItem,              // 37
 +    TyVisitorTraitLangItem,            // 38
 +    OpaqueStructLangItem,              // 39
  }
  
  pub struct LanguageItems {
@@@ -121,27 -123,28 +122,27 @@@ impl LanguageItems 
  
              19 => "str_eq",
              20 => "uniq_str_eq",
 -            21 => "annihilate",
 -            22 => "log_type",
 -            23 => "fail_",
 -            24 => "fail_bounds_check",
 -            25 => "exchange_malloc",
 -            26 => "closure_exchange_malloc",
 -            27 => "exchange_free",
 -            28 => "malloc",
 -            29 => "free",
 -            30 => "borrow_as_imm",
 -            31 => "borrow_as_mut",
 -            32 => "return_to_mut",
 -            33 => "check_not_borrowed",
 -            34 => "strdup_uniq",
 -            35 => "record_borrow",
 -            36 => "unrecord_borrow",
 -
 -            37 => "start",
 -
 -            38 => "ty_desc",
 -            39 => "ty_visitor",
 -            40 => "opaque",
 +            21 => "log_type",
 +            22 => "fail_",
 +            23 => "fail_bounds_check",
 +            24 => "exchange_malloc",
 +            25 => "closure_exchange_malloc",
 +            26 => "exchange_free",
 +            27 => "malloc",
 +            28 => "free",
 +            29 => "borrow_as_imm",
 +            30 => "borrow_as_mut",
 +            31 => "return_to_mut",
 +            32 => "check_not_borrowed",
 +            33 => "strdup_uniq",
 +            34 => "record_borrow",
 +            35 => "unrecord_borrow",
 +
 +            36 => "start",
 +
 +            37 => "ty_desc",
 +            38 => "ty_visitor",
 +            39 => "opaque",
  
              _ => "???"
          }
@@@ -224,6 -227,9 +225,6 @@@
      pub fn uniq_str_eq_fn(&self) -> Option<def_id> {
          self.items[UniqStrEqFnLangItem as uint]
      }
 -    pub fn annihilate_fn(&self) -> Option<def_id> {
 -        self.items[AnnihilateFnLangItem as uint]
 -    }
      pub fn log_type_fn(&self) -> Option<def_id> {
          self.items[LogTypeFnLangItem as uint]
      }
@@@ -292,6 -298,27 +293,27 @@@ struct LanguageItemCollector<'self> 
      item_refs: HashMap<@str, uint>,
  }
  
+ struct LanguageItemVisitor<'self> {
+     this: *mut LanguageItemCollector<'self>,
+ }
+ 
+ impl<'self> Visitor<()> for LanguageItemVisitor<'self> {
+ 
+     fn visit_item(&mut self, item:@item, _:()) {
+ 
+                 for attribute in item.attrs.iter() {
+                     unsafe {
+                         (*self.this).match_and_collect_meta_item(
+                             local_def(item.id),
+                             attribute.node.value
+                         );
+                     }
+                 }
+ 
+         visit::walk_item(self, item, ());
+     }
+ }
+ 
  impl<'self> LanguageItemCollector<'self> {
      pub fn new<'a>(crate: &'a Crate, session: Session)
                     -> LanguageItemCollector<'a> {
@@@ -322,6 -349,7 +344,6 @@@
  
          item_refs.insert(@"str_eq", StrEqFnLangItem as uint);
          item_refs.insert(@"uniq_str_eq", UniqStrEqFnLangItem as uint);
 -        item_refs.insert(@"annihilate", AnnihilateFnLangItem as uint);
          item_refs.insert(@"log_type", LogTypeFnLangItem as uint);
          item_refs.insert(@"fail_", FailFnLangItem as uint);
          item_refs.insert(@"fail_bounds_check",
@@@ -404,19 -432,8 +426,8 @@@
  
      pub fn collect_local_language_items(&mut self) {
          let this: *mut LanguageItemCollector = &mut *self;
-         visit_crate(self.crate, ((), mk_simple_visitor(@SimpleVisitor {
-             visit_item: |item| {
-                 for attribute in item.attrs.iter() {
-                     unsafe {
-                         (*this).match_and_collect_meta_item(
-                             local_def(item.id),
-                             attribute.node.value
-                         );
-                     }
-                 }
-             },
-             .. *default_simple_visitor()
-         })));
+         let mut v = LanguageItemVisitor { this: this };
+         visit::walk_crate(&mut v, self.crate, ());
      }
  
      pub fn collect_external_language_items(&mut self) {