auto merge of #13898 : nikomatsakis/rust/type-bounds-b, r=acrichto

This is needed to bootstrap fix for #5723.

Author: bors

src/librustc/front/feature_gate.rs

@@ -59,6 +59,10 @@ static KNOWN_FEATURES: &'static [(&'static str, Status)] = &[
 
     ("quad_precision_float", Active),
 
+    // A temporary feature gate used to enable parser extensions needed
+    // to bootstrap fix for #5723.
+    ("issue_5723_bootstrap", Active),
+
     // These are used to test this portion of the compiler, they don't actually
     // mean anything
     ("test_accepted_feature", Accepted),
@@ -80,14 +84,16 @@ enum Status {
 /// A set of features to be used by later passes.
 pub struct Features {
     pub default_type_params: Cell<bool>,
-    pub quad_precision_float: Cell<bool>
+    pub quad_precision_float: Cell<bool>,
+    pub issue_5723_bootstrap: Cell<bool>,
 }
 
 impl Features {
     pub fn new() -> Features {
         Features {
             default_type_params: Cell::new(false),
-            quad_precision_float: Cell::new(false)
+            quad_precision_float: Cell::new(false),
+            issue_5723_bootstrap: Cell::new(false),
         }
     }
 }
@@ -367,4 +373,5 @@ pub fn check_crate(sess: &Session, krate: &ast::Crate) {
 
     sess.features.default_type_params.set(cx.has_feature("default_type_params"));
     sess.features.quad_precision_float.set(cx.has_feature("quad_precision_float"));
+    sess.features.issue_5723_bootstrap.set(cx.has_feature("issue_5723_bootstrap"));
 }

src/librustc/middle/resolve.rs

@@ -3824,7 +3824,8 @@ impl<'a> Resolver<'a> {
             TraitTyParamBound(ref tref) => {
                 self.resolve_trait_reference(id, tref, TraitBoundingTypeParameter)
             }
-            RegionTyParamBound => {}
+            StaticRegionTyParamBound => {}
+            OtherRegionTyParamBound(_) => {}
         }
     }
 

src/librustc/middle/typeck/astconv.rs

@@ -898,9 +898,17 @@ fn conv_builtin_bounds(tcx: &ty::ctxt, ast_bounds: &Option<OwnedSlice<ast::TyPar
                             format!("only the builtin traits can be used \
                                   as closure or object bounds"));
                     }
-                    ast::RegionTyParamBound => {
+                    ast::StaticRegionTyParamBound => {
                         builtin_bounds.add(ty::BoundStatic);
                     }
+                    ast::OtherRegionTyParamBound(span) => {
+                        if !tcx.sess.features.issue_5723_bootstrap.get() {
+                            tcx.sess.span_err(
+                                span,
+                                format!("only the 'static lifetime is \
+                                         accepted here."));
+                        }
+                    }
                 }
             }
             builtin_bounds

src/librustc/middle/typeck/collect.rs

@@ -50,7 +50,8 @@ use std::rc::Rc;
 use collections::{HashMap, HashSet};
 
 use syntax::abi;
-use syntax::ast::{RegionTyParamBound, TraitTyParamBound};
+use syntax::ast::{StaticRegionTyParamBound, OtherRegionTyParamBound,
+                  TraitTyParamBound};
 use syntax::ast;
 use syntax::ast_map;
 use syntax::ast_util::{local_def, split_trait_methods};
@@ -1102,9 +1103,18 @@ fn ty_generics(ccx: &CrateCtxt,
                     }
                 }
 
-                RegionTyParamBound => {
+                StaticRegionTyParamBound => {
                     param_bounds.builtin_bounds.add(ty::BoundStatic);
                 }
+
+                OtherRegionTyParamBound(span) => {
+                    if !ccx.tcx.sess.features.issue_5723_bootstrap.get() {
+                        ccx.tcx.sess.span_err(
+                            span,
+                            format!("only the 'static lifetime is \
+                                     accepted here."));
+                    }
+                }
             }
         }
 

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

@@ -893,7 +893,8 @@ impl<'a> Rebuilder<'a> {
                                -> OwnedSlice<ast::TyParamBound> {
         ty_param_bounds.map(|tpb| {
             match tpb {
-                &ast::RegionTyParamBound => ast::RegionTyParamBound,
+                &ast::StaticRegionTyParamBound => ast::StaticRegionTyParamBound,
+                &ast::OtherRegionTyParamBound(s) => ast::OtherRegionTyParamBound(s),
                 &ast::TraitTyParamBound(ref tr) => {
                     let last_seg = tr.path.segments.last().unwrap();
                     let mut insert = Vec::new();

src/librustdoc/clean.rs

@@ -349,7 +349,8 @@ pub enum TyParamBound {
 impl Clean<TyParamBound> for ast::TyParamBound {
     fn clean(&self) -> TyParamBound {
         match *self {
-            ast::RegionTyParamBound => RegionBound,
+            ast::StaticRegionTyParamBound => RegionBound,
+            ast::OtherRegionTyParamBound(_) => RegionBound,
             ast::TraitTyParamBound(ref t) => TraitBound(t.clean()),
         }
     }

src/libsyntax/ast.rs

@@ -173,7 +173,8 @@ pub static DUMMY_NODE_ID: NodeId = -1;
 #[deriving(Clone, Eq, TotalEq, Encodable, Decodable, Hash)]
 pub enum TyParamBound {
     TraitTyParamBound(TraitRef),
-    RegionTyParamBound
+    StaticRegionTyParamBound,
+    OtherRegionTyParamBound(Span) // FIXME -- just here until work for #5723 lands
 }
 
 #[deriving(Clone, Eq, TotalEq, Encodable, Decodable, Hash)]

src/libsyntax/fold.rs

@@ -437,7 +437,8 @@ fn fold_ty_param_bound<T: Folder>(tpb: &TyParamBound, fld: &mut T)
                                     -> TyParamBound {
     match *tpb {
         TraitTyParamBound(ref ty) => TraitTyParamBound(fold_trait_ref(ty, fld)),
-        RegionTyParamBound => RegionTyParamBound
+        StaticRegionTyParamBound => StaticRegionTyParamBound,
+        OtherRegionTyParamBound(s) => OtherRegionTyParamBound(s)
     }
 }
 

src/libsyntax/parse/parser.rs

@@ -12,7 +12,7 @@
 
 use abi;
 use ast::{BareFnTy, ClosureTy};
-use ast::{RegionTyParamBound, TraitTyParamBound};
+use ast::{StaticRegionTyParamBound, OtherRegionTyParamBound, TraitTyParamBound};
 use ast::{Provided, Public, FnStyle};
 use ast::{Mod, BiAdd, Arg, Arm, Attribute, BindByRef, BindByValue};
 use ast::{BiBitAnd, BiBitOr, BiBitXor, Block};
@@ -3351,7 +3351,7 @@ impl<'a> Parser<'a> {
                 token::LIFETIME(lifetime) => {
                     let lifetime_interned_string = token::get_ident(lifetime);
                     if lifetime_interned_string.equiv(&("static")) {
-                        result.push(RegionTyParamBound);
+                        result.push(StaticRegionTyParamBound);
                         if allow_any_lifetime && ret_lifetime.is_none() {
                             ret_lifetime = Some(ast::Lifetime {
                                 id: ast::DUMMY_NODE_ID,
@@ -3366,8 +3366,7 @@ impl<'a> Parser<'a> {
                             name: lifetime.name
                         });
                     } else {
-                        self.span_err(self.span,
-                                      "`'static` is the only permissible region bound here");
+                        result.push(OtherRegionTyParamBound(self.span));
                     }
                     self.bump();
                 }

src/libsyntax/print/pprust.rs

@@ -9,7 +9,8 @@
 // except according to those terms.
 
 use abi;
-use ast::{P, RegionTyParamBound, TraitTyParamBound, Required, Provided};
+use ast::{P, StaticRegionTyParamBound, OtherRegionTyParamBound,
+          TraitTyParamBound, Required, Provided};
 use ast;
 use ast_util;
 use owned_slice::OwnedSlice;
@@ -1881,7 +1882,8 @@ impl<'a> State<'a> {
 
                 try!(match *bound {
                     TraitTyParamBound(ref tref) => self.print_trait_ref(tref),
-                    RegionTyParamBound => word(&mut self.s, "'static"),
+                    StaticRegionTyParamBound => word(&mut self.s, "'static"),
+                    OtherRegionTyParamBound(_) => Ok(())
                 })
             }
             Ok(())