auto merge of #16318 : nikomatsakis/rust/issue-5723-bootstrap-2, r=pnkfelix

Introduce syntax for lifetime bounds like `'b:'a`, meaning `'b outlives 'a`. Syntax currently does nothing but is needed for full fix to #5763. To use this syntax, the issue_5763_bootstrap feature guard is required.

Author: bors

src/librustc/lint/context.rs

@@ -576,7 +576,7 @@ impl<'a> Visitor<()> for Context<'a> {
         run_lints!(self, check_lifetime_ref, lt);
     }
 
-    fn visit_lifetime_decl(&mut self, lt: &ast::Lifetime, _: ()) {
+    fn visit_lifetime_decl(&mut self, lt: &ast::LifetimeDef, _: ()) {
         run_lints!(self, check_lifetime_decl, lt);
     }
 

src/librustc/lint/mod.rs

@@ -150,7 +150,7 @@ pub trait LintPass {
     fn check_variant(&mut self, _: &Context, _: &ast::Variant, _: &ast::Generics) { }
     fn check_opt_lifetime_ref(&mut self, _: &Context, _: Span, _: &Option<ast::Lifetime>) { }
     fn check_lifetime_ref(&mut self, _: &Context, _: &ast::Lifetime) { }
-    fn check_lifetime_decl(&mut self, _: &Context, _: &ast::Lifetime) { }
+    fn check_lifetime_decl(&mut self, _: &Context, _: &ast::LifetimeDef) { }
     fn check_explicit_self(&mut self, _: &Context, _: &ast::ExplicitSelf) { }
     fn check_mac(&mut self, _: &Context, _: &ast::Mac) { }
     fn check_path(&mut self, _: &Context, _: &ast::Path, _: ast::NodeId) { }

src/librustc/middle/resolve_lifetime.rs

@@ -59,10 +59,10 @@ struct LifetimeContext<'a> {
 enum ScopeChain<'a> {
     /// EarlyScope(i, ['a, 'b, ...], s) extends s with early-bound
     /// lifetimes, assigning indexes 'a => i, 'b => i+1, ... etc.
-    EarlyScope(subst::ParamSpace, &'a Vec<ast::Lifetime>, Scope<'a>),
+    EarlyScope(subst::ParamSpace, &'a Vec<ast::LifetimeDef>, Scope<'a>),
     /// LateScope(binder_id, ['a, 'b, ...], s) extends s with late-bound
     /// lifetimes introduced by the declaration binder_id.
-    LateScope(ast::NodeId, &'a Vec<ast::Lifetime>, Scope<'a>),
+    LateScope(ast::NodeId, &'a Vec<ast::LifetimeDef>, Scope<'a>),
     /// lifetimes introduced by items within a code block are scoped
     /// to that block.
     BlockScope(ast::NodeId, Scope<'a>),
@@ -136,7 +136,7 @@ impl<'a, 'b> Visitor<Scope<'a>> for LifetimeContext<'b> {
         fn push_fn_scope(this: &mut LifetimeContext,
                          ty: &ast::Ty,
                          scope: Scope,
-                         lifetimes: &Vec<ast::Lifetime>) {
+                         lifetimes: &Vec<ast::LifetimeDef>) {
             let scope1 = LateScope(ty.id, lifetimes, scope);
             this.check_lifetime_names(lifetimes);
             debug!("pushing fn scope id={} due to type", ty.id);
@@ -216,7 +216,7 @@ impl<'a> LifetimeContext<'a> {
             walk(self, &scope1)
         } else {
             let (early, late) = generics.lifetimes.clone().partition(
-                |l| referenced_idents.iter().any(|&i| i == l.name));
+                |l| referenced_idents.iter().any(|&i| i == l.lifetime.name));
 
             let scope1 = EarlyScope(subst::FnSpace, &early, scope);
             let scope2 = LateScope(n, &late, &scope1);
@@ -334,29 +334,39 @@ impl<'a> LifetimeContext<'a> {
                     token::get_name(lifetime_ref.name)).as_slice());
     }
 
-    fn check_lifetime_names(&self, lifetimes: &Vec<ast::Lifetime>) {
+    fn check_lifetime_names(&self, lifetimes: &Vec<ast::LifetimeDef>) {
         for i in range(0, lifetimes.len()) {
             let lifetime_i = lifetimes.get(i);
 
             let special_idents = [special_idents::static_lifetime];
             for lifetime in lifetimes.iter() {
-                if special_idents.iter().any(|&i| i.name == lifetime.name) {
+                if special_idents.iter().any(|&i| i.name == lifetime.lifetime.name) {
                     self.sess.span_err(
-                        lifetime.span,
+                        lifetime.lifetime.span,
                         format!("illegal lifetime parameter name: `{}`",
-                                token::get_name(lifetime.name)).as_slice());
+                                token::get_name(lifetime.lifetime.name))
+                            .as_slice());
                 }
             }
 
             for j in range(i + 1, lifetimes.len()) {
                 let lifetime_j = lifetimes.get(j);
 
-                if lifetime_i.name == lifetime_j.name {
+                if lifetime_i.lifetime.name == lifetime_j.lifetime.name {
                     self.sess.span_err(
-                        lifetime_j.span,
+                        lifetime_j.lifetime.span,
                         format!("lifetime name `{}` declared twice in \
                                 the same scope",
-                                token::get_name(lifetime_j.name)).as_slice());
+                                token::get_name(lifetime_j.lifetime.name))
+                            .as_slice());
+                }
+            }
+
+            for bound in lifetime_i.bounds.iter() {
+                if !self.sess.features.issue_5723_bootstrap.get() {
+                    self.sess.span_err(
+                        bound.span,
+                        "region bounds require `issue_5723_bootstrap`");
                 }
             }
         }
@@ -379,28 +389,28 @@ impl<'a> LifetimeContext<'a> {
     }
 }
 
-fn search_lifetimes(lifetimes: &Vec<ast::Lifetime>,
+fn search_lifetimes(lifetimes: &Vec<ast::LifetimeDef>,
                     lifetime_ref: &ast::Lifetime)
                     -> Option<(uint, ast::NodeId)> {
     for (i, lifetime_decl) in lifetimes.iter().enumerate() {
-        if lifetime_decl.name == lifetime_ref.name {
-            return Some((i, lifetime_decl.id));
+        if lifetime_decl.lifetime.name == lifetime_ref.name {
+            return Some((i, lifetime_decl.lifetime.id));
         }
     }
     return None;
 }
 
 ///////////////////////////////////////////////////////////////////////////
 
-pub fn early_bound_lifetimes<'a>(generics: &'a ast::Generics) -> Vec<ast::Lifetime> {
+pub fn early_bound_lifetimes<'a>(generics: &'a ast::Generics) -> Vec<ast::LifetimeDef> {
     let referenced_idents = free_lifetimes(&generics.ty_params);
     if referenced_idents.is_empty() {
         return Vec::new();
     }
 
     generics.lifetimes.iter()
-        .filter(|l| referenced_idents.iter().any(|&i| i == l.name))
-        .map(|l| *l)
+        .filter(|l| referenced_idents.iter().any(|&i| i == l.lifetime.name))
+        .map(|l| (*l).clone())
         .collect()
 }
 

src/librustc/middle/typeck/collect.rs

@@ -804,9 +804,10 @@ pub fn trait_def_of_item(ccx: &CrateCtxt, it: &ast::Item) -> Rc<ty::TraitDef> {
             generics.lifetimes
                     .iter()
                     .enumerate()
-                    .map(|(i, def)| ty::ReEarlyBound(def.id,
+                    .map(|(i, def)| ty::ReEarlyBound(def.lifetime.id,
                                                      subst::TypeSpace,
-                                                     i, def.name))
+                                                     i,
+                                                     def.lifetime.name))
                     .collect();
 
         let types =
@@ -1073,18 +1074,18 @@ fn add_unsized_bound(ccx: &CrateCtxt,
 
 fn ty_generics(ccx: &CrateCtxt,
                space: subst::ParamSpace,
-               lifetimes: &Vec<ast::Lifetime>,
+               lifetimes: &Vec<ast::LifetimeDef>,
                types: &OwnedSlice<ast::TyParam>,
                base_generics: ty::Generics)
                -> ty::Generics
 {
     let mut result = base_generics;
 
     for (i, l) in lifetimes.iter().enumerate() {
-        let def = ty::RegionParameterDef { name: l.name,
+        let def = ty::RegionParameterDef { name: l.lifetime.name,
                                            space: space,
                                            index: i,
-                                           def_id: local_def(l.id) };
+                                           def_id: local_def(l.lifetime.id) };
         debug!("ty_generics: def for region param: {}", def);
         result.regions.push(space, def);
     }

src/librustc/middle/typeck/infer/error_reporting.rs

@@ -976,10 +976,13 @@ impl<'a> Rebuilder<'a> {
                         -> ast::Generics {
         let mut lifetimes = Vec::new();
         for lt in add.iter() {
-            lifetimes.push(*lt);
+            lifetimes.push(ast::LifetimeDef { lifetime: *lt,
+                                              bounds: Vec::new() });
         }
         for lt in generics.lifetimes.iter() {
-            if keep.contains(&lt.name) || !remove.contains(&lt.name) {
+            if keep.contains(&lt.lifetime.name) ||
+                !remove.contains(&lt.lifetime.name)
+            {
                 lifetimes.push((*lt).clone());
             }
         }
@@ -1439,7 +1442,7 @@ impl Resolvable for Rc<ty::TraitRef> {
 
 fn lifetimes_in_scope(tcx: &ty::ctxt,
                       scope_id: ast::NodeId)
-                      -> Vec<ast::Lifetime> {
+                      -> Vec<ast::LifetimeDef> {
     let mut taken = Vec::new();
     let parent = tcx.map.get_parent(scope_id);
     let method_id_opt = match tcx.map.find(parent) {
@@ -1486,10 +1489,10 @@ struct LifeGiver {
 }
 
 impl LifeGiver {
-    fn with_taken(taken: &[ast::Lifetime]) -> LifeGiver {
+    fn with_taken(taken: &[ast::LifetimeDef]) -> LifeGiver {
         let mut taken_ = HashSet::new();
         for lt in taken.iter() {
-            let lt_name = token::get_name(lt.name).get().to_string();
+            let lt_name = token::get_name(lt.lifetime.name).get().to_string();
             taken_.insert(lt_name);
         }
         LifeGiver {

src/librustc/middle/typeck/variance.rs

@@ -358,7 +358,8 @@ impl<'a> Visitor<()> for TermsContext<'a> {
             ast::ItemStruct(_, ref generics) |
             ast::ItemTrait(ref generics, _, _, _) => {
                 for (i, p) in generics.lifetimes.iter().enumerate() {
-                    self.add_inferred(item.id, RegionParam, TypeSpace, i, p.id);
+                    let id = p.lifetime.id;
+                    self.add_inferred(item.id, RegionParam, TypeSpace, i, id);
                 }
                 for (i, p) in generics.ty_params.iter().enumerate() {
                     self.add_inferred(item.id, TypeParam, TypeSpace, i, p.id);

src/librustc_back/svh.rs

@@ -410,8 +410,8 @@ mod svh_visitor {
             SawLifetimeRef(content(l.name)).hash(self.st);
         }
 
-        fn visit_lifetime_decl(&mut self, l: &Lifetime, _: E) {
-            SawLifetimeDecl(content(l.name)).hash(self.st);
+        fn visit_lifetime_decl(&mut self, l: &LifetimeDef, _: E) {
+            SawLifetimeDecl(content(l.lifetime.name)).hash(self.st);
         }
 
         // We do recursively walk the bodies of functions/methods

src/librustdoc/clean/mod.rs

@@ -614,6 +614,12 @@ impl Clean<Lifetime> for ast::Lifetime {
     }
 }
 
+impl Clean<Lifetime> for ast::LifetimeDef {
+    fn clean(&self) -> Lifetime {
+        Lifetime(token::get_name(self.lifetime.name).get().to_string())
+    }
+}
+
 impl Clean<Lifetime> for ty::RegionParameterDef {
     fn clean(&self) -> Lifetime {
         Lifetime(token::get_name(self.name).get().to_string())

src/libsyntax/ast.rs

@@ -160,6 +160,12 @@ pub struct Lifetime {
     pub name: Name
 }
 
+#[deriving(Clone, PartialEq, Eq, Encodable, Decodable, Hash, Show)]
+pub struct LifetimeDef {
+    pub lifetime: Lifetime,
+    pub bounds: Vec<Lifetime>
+}
+
 /// A "Path" is essentially Rust's notion of a name; for instance:
 /// std::cmp::PartialEq  .  It's represented as a sequence of identifiers,
 /// along with a bunch of supporting information.
@@ -231,7 +237,7 @@ pub struct TyParam {
 /// of a function, enum, trait, etc.
 #[deriving(Clone, PartialEq, Eq, Encodable, Decodable, Hash, Show)]
 pub struct Generics {
-    pub lifetimes: Vec<Lifetime>,
+    pub lifetimes: Vec<LifetimeDef>,
     pub ty_params: OwnedSlice<TyParam>,
 }
 
@@ -861,7 +867,7 @@ impl fmt::Show for Onceness {
 /// Represents the type of a closure
 #[deriving(PartialEq, Eq, Encodable, Decodable, Hash, Show)]
 pub struct ClosureTy {
-    pub lifetimes: Vec<Lifetime>,
+    pub lifetimes: Vec<LifetimeDef>,
     pub fn_style: FnStyle,
     pub onceness: Onceness,
     pub decl: P<FnDecl>,
@@ -876,7 +882,7 @@ pub struct ClosureTy {
 pub struct BareFnTy {
     pub fn_style: FnStyle,
     pub abi: Abi,
-    pub lifetimes: Vec<Lifetime>,
+    pub lifetimes: Vec<LifetimeDef>,
     pub decl: P<FnDecl>
 }
 

src/libsyntax/ast_util.rs

@@ -369,7 +369,7 @@ impl<'a, O: IdVisitingOperation> IdVisitor<'a, O> {
             self.operation.visit_id(type_parameter.id)
         }
         for lifetime in generics.lifetimes.iter() {
-            self.operation.visit_id(lifetime.id)
+            self.operation.visit_id(lifetime.lifetime.id)
         }
     }
 }

src/libsyntax/ext/build.rs

@@ -73,6 +73,11 @@ pub trait AstBuilder {
     fn trait_ref(&self, path: ast::Path) -> ast::TraitRef;
     fn typarambound(&self, path: ast::Path) -> ast::TyParamBound;
     fn lifetime(&self, span: Span, ident: ast::Name) -> ast::Lifetime;
+    fn lifetime_def(&self,
+                    span: Span,
+                    name: ast::Name,
+                    bounds: Vec<ast::Lifetime>)
+                    -> ast::LifetimeDef;
 
     // statements
     fn stmt_expr(&self, expr: Gc<ast::Expr>) -> Gc<ast::Stmt>;
@@ -456,6 +461,17 @@ impl<'a> AstBuilder for ExtCtxt<'a> {
         ast::Lifetime { id: ast::DUMMY_NODE_ID, span: span, name: name }
     }
 
+    fn lifetime_def(&self,
+                    span: Span,
+                    name: ast::Name,
+                    bounds: Vec<ast::Lifetime>)
+                    -> ast::LifetimeDef {
+        ast::LifetimeDef {
+            lifetime: self.lifetime(span, name),
+            bounds: bounds
+        }
+    }
+
     fn stmt_expr(&self, expr: Gc<ast::Expr>) -> Gc<ast::Stmt> {
         box(GC) respan(expr.span, ast::StmtSemi(expr, ast::DUMMY_NODE_ID))
     }

src/libsyntax/ext/deriving/generic/mod.rs

@@ -395,7 +395,7 @@ impl<'a> TraitDef<'a> {
         let mut ty_params = ty_params.into_vec();
 
         // Copy the lifetimes
-        lifetimes.extend(generics.lifetimes.iter().map(|l| *l));
+        lifetimes.extend(generics.lifetimes.iter().map(|l| (*l).clone()));
 
         // Create the type parameters.
         ty_params.extend(generics.ty_params.iter().map(|ty_param| {
@@ -429,7 +429,11 @@ impl<'a> TraitDef<'a> {
             cx.ty_ident(self.span, ty_param.ident)
         });
 
-        let self_lifetimes = generics.lifetimes.clone();
+        let self_lifetimes: Vec<ast::Lifetime> =
+            generics.lifetimes
+            .iter()
+            .map(|ld| ld.lifetime)
+            .collect();
 
         // Create the type of `self`.
         let self_type = cx.ty_path(

src/libsyntax/ext/deriving/generic/ty.rs

@@ -174,7 +174,9 @@ impl<'a> Ty<'a> {
                 let self_params = self_generics.ty_params.map(|ty_param| {
                     cx.ty_ident(span, ty_param.ident)
                 });
-                let lifetimes = self_generics.lifetimes.clone();
+                let lifetimes = self_generics.lifetimes.iter()
+                                                       .map(|d| d.lifetime)
+                                                       .collect();
 
                 cx.path_all(span, false, vec!(self_ty), lifetimes,
                             self_params.into_vec())
@@ -200,7 +202,7 @@ fn mk_ty_param(cx: &ExtCtxt, span: Span, name: &str,
     cx.typaram(span, cx.ident_of(name), bounds, unbound, None)
 }
 
-fn mk_generics(lifetimes: Vec<ast::Lifetime>, ty_params: Vec<ast::TyParam> ) -> Generics {
+fn mk_generics(lifetimes: Vec<ast::LifetimeDef>, ty_params: Vec<ast::TyParam> ) -> Generics {
     Generics {
         lifetimes: lifetimes,
         ty_params: OwnedSlice::from_vec(ty_params)
@@ -210,7 +212,7 @@ fn mk_generics(lifetimes: Vec<ast::Lifetime>, ty_params: Vec<ast::TyParam> ) ->
 /// Lifetimes and bounds on type parameters
 #[deriving(Clone)]
 pub struct LifetimeBounds<'a> {
-    pub lifetimes: Vec<&'a str>,
+    pub lifetimes: Vec<(&'a str, Vec<&'a str>)>,
     pub bounds: Vec<(&'a str, Option<ast::TyParamBound>, Vec<Path<'a>>)>,
 }
 
@@ -226,8 +228,11 @@ impl<'a> LifetimeBounds<'a> {
                        self_ty: Ident,
                        self_generics: &Generics)
                        -> Generics {
-        let lifetimes = self.lifetimes.iter().map(|lt| {
-            cx.lifetime(span, cx.ident_of(*lt).name)
+        let lifetimes = self.lifetimes.iter().map(|&(ref lt, ref bounds)| {
+            let bounds =
+                bounds.iter().map(
+                    |b| cx.lifetime(span, cx.ident_of(*b).name)).collect();
+            cx.lifetime_def(span, cx.ident_of(*lt).name, bounds)
         }).collect();
         let ty_params = self.bounds.iter().map(|t| {
             match t {