auto merge of #20412 : nikomatsakis/rust/assoc-types, r=aturon

These changes fix various problems encountered getting japaric's `at-iter` branch to work. This branch converts the `Iterator` trait to use an associated type.

Author: bors

src/librustc/middle/expr_use_visitor.rs

@@ -1229,7 +1229,7 @@ impl<'d,'t,'tcx,TYPER:mc::Typer<'tcx>> ExprUseVisitor<'d,'t,'tcx,TYPER> {
             // inferred by regionbk
             let upvar_id = ty::UpvarId { var_id: id_var,
                                          closure_expr_id: closure_expr.id };
-            let upvar_borrow = self.typer.upvar_borrow(upvar_id);
+            let upvar_borrow = self.typer.upvar_borrow(upvar_id).unwrap();
 
             self.delegate.borrow(closure_expr.id,
                                  closure_expr.span,

src/librustc/middle/liveness.rs

@@ -111,7 +111,9 @@ use self::VarKind::*;
 
 use middle::def::*;
 use middle::mem_categorization::Typer;
-use middle::{pat_util, ty};
+use middle::pat_util;
+use middle::ty;
+use middle::ty::UnboxedClosureTyper;
 use lint;
 use util::nodemap::NodeMap;
 
@@ -1515,16 +1517,10 @@ impl<'a, 'tcx> Liveness<'a, 'tcx> {
     fn fn_ret(&self, id: NodeId) -> ty::FnOutput<'tcx> {
         let fn_ty = ty::node_id_to_type(self.ir.tcx, id);
         match fn_ty.sty {
-            ty::ty_unboxed_closure(closure_def_id, _, _) =>
-                self.ir.tcx.unboxed_closures()
-                    .borrow()
-                    .get(&closure_def_id)
-                    .unwrap()
-                    .closure_type
-                    .sig
-                    .0
-                    .output,
-            _ => ty::ty_fn_ret(fn_ty)
+            ty::ty_unboxed_closure(closure_def_id, _, substs) =>
+                self.ir.tcx.unboxed_closure_type(closure_def_id, substs).sig.0.output,
+            _ =>
+                ty::ty_fn_ret(fn_ty),
         }
     }
 

src/librustc/middle/mem_categorization.rs

@@ -74,7 +74,7 @@ pub use self::categorization::*;
 use middle::def;
 use middle::region;
 use middle::ty::{mod, Ty};
-use util::nodemap::{DefIdMap, NodeMap};
+use util::nodemap::{NodeMap};
 use util::ppaux::{ty_to_string, Repr};
 
 use syntax::ast::{MutImmutable, MutMutable};
@@ -280,7 +280,7 @@ impl<'t,TYPER:'t> Copy for MemCategorizationContext<'t,TYPER> {}
 /// In the borrow checker, in contrast, type checking is complete and we
 /// know that no errors have occurred, so we simply consult the tcx and we
 /// can be sure that only `Ok` results will occur.
-pub trait Typer<'tcx> {
+pub trait Typer<'tcx> : ty::UnboxedClosureTyper<'tcx> {
     fn tcx<'a>(&'a self) -> &'a ty::ctxt<'tcx>;
     fn node_ty(&self, id: ast::NodeId) -> Ty<'tcx>;
     fn expr_ty_adjusted(&self, expr: &ast::Expr) -> Ty<'tcx>;
@@ -290,11 +290,9 @@ pub trait Typer<'tcx> {
     fn adjustments<'a>(&'a self) -> &'a RefCell<NodeMap<ty::AutoAdjustment<'tcx>>>;
     fn is_method_call(&self, id: ast::NodeId) -> bool;
     fn temporary_scope(&self, rvalue_id: ast::NodeId) -> Option<region::CodeExtent>;
-    fn upvar_borrow(&self, upvar_id: ty::UpvarId) -> ty::UpvarBorrow;
+    fn upvar_borrow(&self, upvar_id: ty::UpvarId) -> Option<ty::UpvarBorrow>;
     fn capture_mode(&self, closure_expr_id: ast::NodeId)
                     -> ast::CaptureClause;
-    fn unboxed_closures<'a>(&'a self)
-                        -> &'a RefCell<DefIdMap<ty::UnboxedClosure<'tcx>>>;
 }
 
 impl MutabilityCategory {
@@ -622,8 +620,7 @@ impl<'t,'tcx,TYPER:Typer<'tcx>> MemCategorizationContext<'t,TYPER> {
                       self.cat_upvar(id, span, var_id, fn_node_id, kind, mode, false)
                   }
                   ty::ty_unboxed_closure(closure_id, _, _) => {
-                      let unboxed_closures = self.typer.unboxed_closures().borrow();
-                      let kind = (*unboxed_closures)[closure_id].kind;
+                      let kind = self.typer.unboxed_closure_kind(closure_id);
                       let mode = self.typer.capture_mode(fn_node_id);
                       self.cat_upvar(id, span, var_id, fn_node_id, kind, mode, true)
                   }
@@ -800,7 +797,7 @@ impl<'t,'tcx,TYPER:Typer<'tcx>> MemCategorizationContext<'t,TYPER> {
                 }
 
                 // Look up upvar borrow so we can get its region
-                let upvar_borrow = self.typer.upvar_borrow(upvar_id);
+                let upvar_borrow = self.typer.upvar_borrow(upvar_id).unwrap();
                 let ptr = BorrowedPtr(upvar_borrow.kind, upvar_borrow.region);
 
                 Rc::new(cmt_ {

src/librustc/middle/traits/fulfill.rs

@@ -110,7 +110,7 @@ impl<'tcx> FulfillmentContext<'tcx> {
     pub fn normalize_projection_type<'a>(&mut self,
                                          infcx: &InferCtxt<'a,'tcx>,
                                          param_env: &ty::ParameterEnvironment<'tcx>,
-                                         typer: &Typer<'tcx>,
+                                         typer: &ty::UnboxedClosureTyper<'tcx>,
                                          projection_ty: ty::ProjectionTy<'tcx>,
                                          cause: ObligationCause<'tcx>)
                                          -> Ty<'tcx>
@@ -187,7 +187,7 @@ impl<'tcx> FulfillmentContext<'tcx> {
     pub fn select_all_or_error<'a>(&mut self,
                                    infcx: &InferCtxt<'a,'tcx>,
                                    param_env: &ty::ParameterEnvironment<'tcx>,
-                                   typer: &Typer<'tcx>)
+                                   typer: &ty::UnboxedClosureTyper<'tcx>)
                                    -> Result<(),Vec<FulfillmentError<'tcx>>>
     {
         try!(self.select_where_possible(infcx, param_env, typer));
@@ -213,7 +213,7 @@ impl<'tcx> FulfillmentContext<'tcx> {
     pub fn select_new_obligations<'a>(&mut self,
                                       infcx: &InferCtxt<'a,'tcx>,
                                       param_env: &ty::ParameterEnvironment<'tcx>,
-                                      typer: &Typer<'tcx>)
+                                      typer: &ty::UnboxedClosureTyper<'tcx>)
                                       -> Result<(),Vec<FulfillmentError<'tcx>>>
     {
         let mut selcx = SelectionContext::new(infcx, param_env, typer);
@@ -223,7 +223,7 @@ impl<'tcx> FulfillmentContext<'tcx> {
     pub fn select_where_possible<'a>(&mut self,
                                      infcx: &InferCtxt<'a,'tcx>,
                                      param_env: &ty::ParameterEnvironment<'tcx>,
-                                     typer: &Typer<'tcx>)
+                                     typer: &ty::UnboxedClosureTyper<'tcx>)
                                      -> Result<(),Vec<FulfillmentError<'tcx>>>
     {
         let mut selcx = SelectionContext::new(infcx, param_env, typer);

src/librustc/middle/traits/project.rs

@@ -102,7 +102,7 @@ pub fn poly_project_and_unify_type<'cx,'tcx>(
 
 /// Compute result of projecting an associated type and unify it with
 /// `obligation.predicate.ty` (if we can).
-pub fn project_and_unify_type<'cx,'tcx>(
+fn project_and_unify_type<'cx,'tcx>(
     selcx: &mut SelectionContext<'cx,'tcx>,
     obligation: &ProjectionObligation<'tcx>)
     -> Result<Option<Vec<PredicateObligation<'tcx>>>, MismatchedProjectionTypes<'tcx>>
@@ -135,9 +135,19 @@ pub fn normalize<'a,'b,'tcx,T>(selcx: &'a mut SelectionContext<'b,'tcx>,
                                cause: ObligationCause<'tcx>,
                                value: &T)
                                -> Normalized<'tcx, T>
-    where T : TypeFoldable<'tcx> + HasProjectionTypes + Clone
+    where T : TypeFoldable<'tcx> + HasProjectionTypes + Clone + Repr<'tcx>
 {
-    let mut normalizer = AssociatedTypeNormalizer::new(selcx, cause, 0);
+    normalize_with_depth(selcx, cause, 0, value)
+}
+
+pub fn normalize_with_depth<'a,'b,'tcx,T>(selcx: &'a mut SelectionContext<'b,'tcx>,
+                                          cause: ObligationCause<'tcx>,
+                                          depth: uint,
+                                          value: &T)
+                                          -> Normalized<'tcx, T>
+    where T : TypeFoldable<'tcx> + HasProjectionTypes + Clone + Repr<'tcx>
+{
+    let mut normalizer = AssociatedTypeNormalizer::new(selcx, cause, depth);
     let result = normalizer.fold(value);
     Normalized {
         value: result,
@@ -278,9 +288,10 @@ fn opt_normalize_projection_type<'a,'b,'tcx>(
             // an impl, where-clause etc) and hence we must
             // re-normalize it
 
-            debug!("normalize_projection_type: projected_ty={} depth={}",
+            debug!("normalize_projection_type: projected_ty={} depth={} obligations={}",
                    projected_ty.repr(selcx.tcx()),
-                   depth);
+                   depth,
+                   obligations.repr(selcx.tcx()));
 
             if ty::type_has_projection(projected_ty) {
                 let tcx = selcx.tcx();
@@ -644,3 +655,20 @@ impl<'tcx> Repr<'tcx> for ProjectionTyCandidate<'tcx> {
         }
     }
 }
+
+impl<'tcx, T: TypeFoldable<'tcx>> TypeFoldable<'tcx> for Normalized<'tcx, T> {
+    fn fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Normalized<'tcx, T> {
+        Normalized {
+            value: self.value.fold_with(folder),
+            obligations: self.obligations.fold_with(folder),
+        }
+    }
+}
+
+impl<'tcx, T:Repr<'tcx>> Repr<'tcx> for Normalized<'tcx, T> {
+    fn repr(&self, tcx: &ty::ctxt<'tcx>) -> String {
+        format!("Normalized({},{})",
+                self.value.repr(tcx),
+                self.obligations.repr(tcx))
+    }
+}

src/librustc/middle/traits/select.rs

@@ -18,6 +18,7 @@ use self::BuiltinBoundConditions::*;
 use self::EvaluationResult::*;
 
 use super::{DerivedObligationCause};
+use super::{project};
 use super::{PredicateObligation, Obligation, TraitObligation, ObligationCause};
 use super::{ObligationCauseCode, BuiltinDerivedObligation};
 use super::{SelectionError, Unimplemented, Overflow, OutputTypeParameterMismatch};
@@ -29,7 +30,7 @@ use super::{util};
 
 use middle::fast_reject;
 use middle::mem_categorization::Typer;
-use middle::subst::{Subst, Substs, VecPerParamSpace};
+use middle::subst::{Subst, Substs, TypeSpace, VecPerParamSpace};
 use middle::ty::{mod, AsPredicate, RegionEscape, ToPolyTraitRef, Ty};
 use middle::infer;
 use middle::infer::{InferCtxt, TypeFreshener};
@@ -44,7 +45,7 @@ use util::ppaux::Repr;
 pub struct SelectionContext<'cx, 'tcx:'cx> {
     infcx: &'cx InferCtxt<'cx, 'tcx>,
     param_env: &'cx ty::ParameterEnvironment<'tcx>,
-    typer: &'cx (Typer<'tcx>+'cx),
+    closure_typer: &'cx (ty::UnboxedClosureTyper<'tcx>+'cx),
 
     /// Freshener used specifically for skolemizing entries on the
     /// obligation stack. This ensures that all entries on the stack
@@ -177,25 +178,25 @@ enum EvaluationResult<'tcx> {
 impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
     pub fn new(infcx: &'cx InferCtxt<'cx, 'tcx>,
                param_env: &'cx ty::ParameterEnvironment<'tcx>,
-               typer: &'cx Typer<'tcx>)
+               closure_typer: &'cx ty::UnboxedClosureTyper<'tcx>)
                -> SelectionContext<'cx, 'tcx> {
         SelectionContext {
             infcx: infcx,
             param_env: param_env,
-            typer: typer,
+            closure_typer: closure_typer,
             freshener: infcx.freshener(),
             intercrate: false,
         }
     }
 
     pub fn intercrate(infcx: &'cx InferCtxt<'cx, 'tcx>,
                       param_env: &'cx ty::ParameterEnvironment<'tcx>,
-                      typer: &'cx Typer<'tcx>)
+                      closure_typer: &'cx ty::UnboxedClosureTyper<'tcx>)
                       -> SelectionContext<'cx, 'tcx> {
         SelectionContext {
             infcx: infcx,
             param_env: param_env,
-            typer: typer,
+            closure_typer: closure_typer,
             freshener: infcx.freshener(),
             intercrate: true,
         }
@@ -918,15 +919,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                kind,
                obligation.repr(self.tcx()));
 
-        let closure_kind = match self.typer.unboxed_closures().borrow().get(&closure_def_id) {
-            Some(closure) => closure.kind,
-            None => {
-                self.tcx().sess.span_bug(
-                    obligation.cause.span,
-                    format!("No entry for unboxed closure: {}",
-                            closure_def_id.repr(self.tcx()))[]);
-            }
-        };
+        let closure_kind = self.closure_typer.unboxed_closure_kind(closure_def_id);
 
         debug!("closure_kind = {}", closure_kind);
 
@@ -1398,32 +1391,21 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                     return Ok(ParameterBuiltin);
                 }
 
-                match self.tcx().freevars.borrow().get(&def_id.node) {
-                    None => {
-                        // No upvars.
-                        Ok(If(Vec::new()))
+                match self.closure_typer.unboxed_closure_upvars(def_id, substs) {
+                    Some(upvars) => {
+                        Ok(If(upvars.iter().map(|c| c.ty).collect()))
                     }
-
-                    Some(freevars) => {
-                        let tys: Vec<Ty> =
-                            freevars
-                            .iter()
-                            .map(|freevar| {
-                                let freevar_def_id = freevar.def.def_id();
-                                self.typer.node_ty(freevar_def_id.node).subst(self.tcx(), substs)
-                            })
-                            .collect();
-                        Ok(If(tys))
+                    None => {
+                        Ok(AmbiguousBuiltin)
                     }
                 }
             }
 
             ty::ty_struct(def_id, substs) => {
                 let types: Vec<Ty> =
-                    ty::struct_fields(self.tcx(), def_id, substs)
-                    .iter()
-                    .map(|f| f.mt.ty)
-                    .collect();
+                    ty::struct_fields(self.tcx(), def_id, substs).iter()
+                                                                 .map(|f| f.mt.ty)
+                                                                 .collect();
                 nominal(self, bound, def_id, types)
             }
 
@@ -1798,27 +1780,22 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                closure_def_id.repr(self.tcx()),
                substs.repr(self.tcx()));
 
-        let closure_type = match self.typer.unboxed_closures().borrow().get(&closure_def_id) {
-            Some(closure) => closure.closure_type.clone(),
-            None => {
-                self.tcx().sess.span_bug(
-                    obligation.cause.span,
-                    format!("No entry for unboxed closure: {}",
-                            closure_def_id.repr(self.tcx()))[]);
-            }
-        };
+        let closure_type = self.closure_typer.unboxed_closure_type(closure_def_id, substs);
+
+        debug!("confirm_unboxed_closure_candidate: closure_def_id={} closure_type={}",
+               closure_def_id.repr(self.tcx()),
+               closure_type.repr(self.tcx()));
 
         let closure_sig = &closure_type.sig;
         let arguments_tuple = closure_sig.0.inputs[0];
-        let substs =
+        let trait_substs =
             Substs::new_trait(
-                vec![arguments_tuple.subst(self.tcx(), substs),
-                     closure_sig.0.output.unwrap().subst(self.tcx(), substs)],
+                vec![arguments_tuple, closure_sig.0.output.unwrap()],
                 vec![],
                 obligation.self_ty());
         let trait_ref = ty::Binder(Rc::new(ty::TraitRef {
             def_id: obligation.predicate.def_id(),
-            substs: self.tcx().mk_substs(substs),
+            substs: self.tcx().mk_substs(trait_substs),
         }));
 
         debug!("confirm_unboxed_closure_candidate(closure_def_id={}, trait_ref={})",
@@ -2100,7 +2077,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
         }
     }
 
-    fn impl_predicates(&self,
+    fn impl_predicates(&mut self,
                        cause: ObligationCause<'tcx>,
                        recursion_depth: uint,
                        impl_def_id: ast::DefId,
@@ -2111,8 +2088,19 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
     {
         let impl_generics = ty::lookup_item_type(self.tcx(), impl_def_id).generics;
         let bounds = impl_generics.to_bounds(self.tcx(), impl_substs);
-        let bounds = self.infcx().plug_leaks(skol_map, snapshot, &bounds);
-        util::predicates_for_generics(self.tcx(), cause, recursion_depth, &bounds)
+        let normalized_bounds =
+            project::normalize_with_depth(self, cause.clone(), recursion_depth, &bounds);
+        let normalized_bounds =
+            self.infcx().plug_leaks(skol_map, snapshot, &normalized_bounds);
+        let mut impl_obligations =
+            util::predicates_for_generics(self.tcx(),
+                                          cause,
+                                          recursion_depth,
+                                          &normalized_bounds.value);
+        for obligation in normalized_bounds.obligations.into_iter() {
+            impl_obligations.push(TypeSpace, obligation);
+        }
+        impl_obligations
     }
 
     fn fn_family_trait_kind(&self,