Changed lists of lifetimes in ast and ty to use Vec instead of OptVec.

There is a broader revision (that does this across the board) pending
in rust-lang#12675, but that is awaiting the arrival of more data (to decide
whether to keep OptVec alive by using a non-Vec internally).

For this code, the representation of lifetime lists needs to be the
same in both ScopeChain and in the ast and ty structures.  So it
seemed cleanest to just use `vec_ng::Vec`, now that it has a cheaper
empty representation than the current `vec` code.

Author: pnkfelix

src/librustc/front/std_inject.rs

@@ -164,12 +164,12 @@ impl fold::Folder for PreludeInjector {
             segments: vec!(
                 ast::PathSegment {
                     identifier: token::str_to_ident("std"),
-                    lifetimes: opt_vec::Empty,
+                    lifetimes: Vec::new(),
                     types: opt_vec::Empty,
                 },
                 ast::PathSegment {
                     identifier: token::str_to_ident("prelude"),
-                    lifetimes: opt_vec::Empty,
+                    lifetimes: Vec::new(),
                     types: opt_vec::Empty,
                 }),
         };

src/librustc/front/test.rs

@@ -369,7 +369,7 @@ fn path_node(ids: Vec<ast::Ident> ) -> ast::Path {
         global: false,
         segments: ids.move_iter().map(|identifier| ast::PathSegment {
             identifier: identifier,
-            lifetimes: opt_vec::Empty,
+            lifetimes: Vec::new(),
             types: opt_vec::Empty,
         }).collect()
     }
@@ -381,7 +381,7 @@ fn path_node_global(ids: Vec<ast::Ident> ) -> ast::Path {
         global: true,
         segments: ids.move_iter().map(|identifier| ast::PathSegment {
             identifier: identifier,
-            lifetimes: opt_vec::Empty,
+            lifetimes: Vec::new(),
             types: opt_vec::Empty,
         }).collect()
     }

src/librustc/middle/privacy.rs

@@ -13,6 +13,7 @@
 //! which are available for use externally when compiled as a library.
 
 use std::mem::replace;
+use std::vec_ng::Vec;
 
 use metadata::csearch;
 use middle::lint;
@@ -855,7 +856,7 @@ impl<'a> Visitor<()> for PrivacyVisitor<'a> {
                                 debug!("privacy - list {}", pid.node.id);
                                 let seg = ast::PathSegment {
                                     identifier: pid.node.name,
-                                    lifetimes: opt_vec::Empty,
+                                    lifetimes: Vec::new(),
                                     types: opt_vec::Empty,
                                 };
                                 let segs = vec!(seg);

src/librustc/middle/resolve_lifetime.rs

@@ -19,10 +19,10 @@
 
 use driver::session;
 use std::cell::RefCell;
+use std::vec_ng::Vec;
 use util::nodemap::NodeMap;
 use syntax::ast;
 use syntax::codemap::Span;
-use syntax::opt_vec::OptVec;
 use syntax::parse::token::special_idents;
 use syntax::parse::token;
 use syntax::print::pprust::{lifetime_to_str};
@@ -39,8 +39,8 @@ struct LifetimeContext {
 }
 
 enum ScopeChain<'a> {
-    ItemScope(&'a OptVec<ast::Lifetime>),
-    FnScope(ast::NodeId, &'a OptVec<ast::Lifetime>, Scope<'a>),
+    ItemScope(&'a Vec<ast::Lifetime>),
+    FnScope(ast::NodeId, &'a Vec<ast::Lifetime>, Scope<'a>),
     BlockScope(ast::NodeId, Scope<'a>),
     RootScope
 }
@@ -267,7 +267,7 @@ impl LifetimeContext {
                     token::get_name(lifetime_ref.name)));
     }
 
-    fn check_lifetime_names(&self, lifetimes: &OptVec<ast::Lifetime>) {
+    fn check_lifetime_names(&self, lifetimes: &Vec<ast::Lifetime>) {
         for i in range(0, lifetimes.len()) {
             let lifetime_i = lifetimes.get(i);
 
@@ -313,7 +313,7 @@ impl LifetimeContext {
     }
 }
 
-fn search_lifetimes(lifetimes: &OptVec<ast::Lifetime>,
+fn search_lifetimes(lifetimes: &Vec<ast::Lifetime>,
                     lifetime_ref: &ast::Lifetime)
                     -> Option<(uint, ast::NodeId)> {
     for (i, lifetime_decl) in lifetimes.iter().enumerate() {

src/librustc/middle/trans/debuginfo.rs

@@ -540,7 +540,7 @@ pub fn create_function_debug_context(cx: &CrateContext,
         return FunctionWithoutDebugInfo;
     }
 
-    let empty_generics = ast::Generics { lifetimes: opt_vec::Empty, ty_params: opt_vec::Empty };
+    let empty_generics = ast::Generics { lifetimes: Vec::new(), ty_params: opt_vec::Empty };
 
     let fnitem = cx.tcx.map.get(fn_ast_id);
 

src/librustc/middle/typeck/astconv.rs

@@ -186,9 +186,9 @@ fn ast_path_substs<AC:AstConv,RS:RegionScope>(
         }
 
         match anon_regions {
-            Ok(v) => opt_vec::from(v.move_iter().collect()),
-            Err(()) => opt_vec::from(Vec::from_fn(expected_num_region_params,
-                                                  |_| ty::ReStatic)) // hokey
+            Ok(v) => v.move_iter().collect(),
+            Err(()) => Vec::from_fn(expected_num_region_params,
+                                    |_| ty::ReStatic) // hokey
         }
     };
 
@@ -231,7 +231,7 @@ fn ast_path_substs<AC:AstConv,RS:RegionScope>(
                             .collect();
 
     let mut substs = substs {
-        regions: ty::NonerasedRegions(regions),
+        regions: ty::NonerasedRegions(opt_vec::from(regions)),
         self_ty: self_ty,
         tps: tps
     };

src/librustc/middle/typeck/check/mod.rs

@@ -1453,8 +1453,7 @@ pub fn impl_self_ty(vcx: &VtableContext,
     let tps = vcx.infcx.next_ty_vars(n_tps);
 
     let substs = substs {
-        regions: ty::NonerasedRegions(opt_vec::from(rps.move_iter()
-                                                       .collect())),
+        regions: ty::NonerasedRegions(opt_vec::from(rps.move_iter().collect())),
         self_ty: None,
         tps: tps,
     };
@@ -3741,11 +3740,11 @@ pub fn instantiate_path(fcx: @FnCtxt,
                         nsupplied = num_supplied_regions));
         }
 
-        opt_vec::from(fcx.infcx().next_region_vars(
+        fcx.infcx().next_region_vars(
                 infer::BoundRegionInTypeOrImpl(span),
-                num_expected_regions).move_iter().collect())
+                num_expected_regions).move_iter().collect()
     };
-    let regions = ty::NonerasedRegions(regions);
+    let regions = ty::NonerasedRegions(opt_vec::from(regions));
 
     // Special case: If there is a self parameter, omit it from the list of
     // type parameters.

src/libsyntax/ast.rs

@@ -142,7 +142,7 @@ pub struct PathSegment {
     /// The identifier portion of this path segment.
     identifier: Ident,
     /// The lifetime parameters for this path segment.
-    lifetimes: OptVec<Lifetime>,
+    lifetimes: Vec<Lifetime>,
     /// The type parameters for this path segment, if present.
     types: OptVec<P<Ty>>,
 }
@@ -187,7 +187,7 @@ pub struct TyParam {
 
 #[deriving(Clone, Eq, Encodable, Decodable, Hash)]
 pub struct Generics {
-    lifetimes: OptVec<Lifetime>,
+    lifetimes: Vec<Lifetime>,
     ty_params: OptVec<TyParam>,
 }
 
@@ -795,7 +795,7 @@ impl fmt::Show for Onceness {
 pub struct ClosureTy {
     sigil: Sigil,
     region: Option<Lifetime>,
-    lifetimes: OptVec<Lifetime>,
+    lifetimes: Vec<Lifetime>,
     purity: Purity,
     onceness: Onceness,
     decl: P<FnDecl>,
@@ -810,7 +810,7 @@ pub struct ClosureTy {
 pub struct BareFnTy {
     purity: Purity,
     abis: AbiSet,
-    lifetimes: OptVec<Lifetime>,
+    lifetimes: Vec<Lifetime>,
     decl: P<FnDecl>
 }
 

src/libsyntax/ast_util.rs

@@ -195,7 +195,7 @@ pub fn ident_to_path(s: Span, identifier: Ident) -> Path {
         segments: vec!(
             ast::PathSegment {
                 identifier: identifier,
-                lifetimes: opt_vec::Empty,
+                lifetimes: Vec::new(),
                 types: opt_vec::Empty,
             }
         ),
@@ -311,7 +311,7 @@ pub fn operator_prec(op: ast::BinOp) -> uint {
 pub static as_prec: uint = 12u;
 
 pub fn empty_generics() -> Generics {
-    Generics {lifetimes: opt_vec::Empty,
+    Generics {lifetimes: Vec::new(),
               ty_params: opt_vec::Empty}
 }
 

src/libsyntax/ext/build.rs

@@ -42,7 +42,7 @@ pub trait AstBuilder {
     fn path_all(&self, sp: Span,
                 global: bool,
                 idents: Vec<ast::Ident> ,
-                lifetimes: OptVec<ast::Lifetime>,
+                lifetimes: Vec<ast::Lifetime>,
                 types: Vec<P<ast::Ty>> )
         -> ast::Path;
 
@@ -255,27 +255,27 @@ pub trait AstBuilder {
 
 impl<'a> AstBuilder for ExtCtxt<'a> {
     fn path(&self, span: Span, strs: Vec<ast::Ident> ) -> ast::Path {
-        self.path_all(span, false, strs, opt_vec::Empty, Vec::new())
+        self.path_all(span, false, strs, Vec::new(), Vec::new())
     }
     fn path_ident(&self, span: Span, id: ast::Ident) -> ast::Path {
         self.path(span, vec!(id))
     }
     fn path_global(&self, span: Span, strs: Vec<ast::Ident> ) -> ast::Path {
-        self.path_all(span, true, strs, opt_vec::Empty, Vec::new())
+        self.path_all(span, true, strs, Vec::new(), Vec::new())
     }
     fn path_all(&self,
                 sp: Span,
                 global: bool,
                 mut idents: Vec<ast::Ident> ,
-                lifetimes: OptVec<ast::Lifetime>,
+                lifetimes: Vec<ast::Lifetime>,
                 types: Vec<P<ast::Ty>> )
                 -> ast::Path {
         let last_identifier = idents.pop().unwrap();
         let mut segments: Vec<ast::PathSegment> = idents.move_iter()
                                                       .map(|ident| {
             ast::PathSegment {
                 identifier: ident,
-                lifetimes: opt_vec::Empty,
+                lifetimes: Vec::new(),
                 types: opt_vec::Empty,
             }
         }).collect();
@@ -342,7 +342,7 @@ impl<'a> AstBuilder for ExtCtxt<'a> {
                               self.ident_of("option"),
                               self.ident_of("Option")
                           ),
-                          opt_vec::Empty,
+                          Vec::new(),
                           vec!( ty )), None)
     }