---

yaml
---
r: 219391
b: refs/heads/snap-stage3
c: 5726026
h: refs/heads/master
i:
  219389: 7112926
  219387: eb5c059
  219383: f548767
  219375: ead05ef
  219359: 9eb34fe
  219327: fe4b198
  219263: a123f1a
  219135: 196ee9c
v: v3

Author: alexcrichton

[refs]

@@ -1,6 +1,6 @@
 ---
 refs/heads/master: c044791d80ea0dc5c4b57b6030a67b69f8510239
-refs/heads/snap-stage3: da55e244a6829e94ef94c4e43243a3436b6a2dd4
+refs/heads/snap-stage3: 57260262e76ec35f05d4a9fad4d13cda212f2c62
 refs/heads/try: b53c0f93eedcdedd4fd89bccc5a3a09d1c5cd23e
 refs/tags/release-0.1: 1f5c5126e96c79d22cb7862f75304136e204f105
 refs/tags/release-0.2: c870d2dffb391e14efb05aa27898f1f6333a9596

branches/snap-stage3/src/librustc/middle/traits/mod.rs

@@ -245,7 +245,7 @@ pub enum Vtable<'tcx, N> {
     /// Vtable automatically generated for a closure. The def ID is the ID
     /// of the closure expression. This is a `VtableImpl` in spirit, but the
     /// impl is generated by the compiler and does not appear in the source.
-    VtableClosure(VtableClosureData<'tcx, N>),
+    VtableClosure(ast::DefId, subst::Substs<'tcx>),
 
     /// Same as above, but for a fn pointer type with the given signature.
     VtableFnPointer(ty::Ty<'tcx>),
@@ -268,16 +268,7 @@ pub struct VtableImplData<'tcx, N> {
     pub nested: Vec<N>
 }
 
-#[derive(Clone, PartialEq, Eq)]
-pub struct VtableClosureData<'tcx, N> {
-    pub closure_def_id: ast::DefId,
-    pub substs: subst::Substs<'tcx>,
-    /// Nested obligations. This can be non-empty if the closure
-    /// signature contains associated types.
-    pub nested: Vec<N>
-}
-
-#[derive(Debug, Clone)]
+#[derive(Debug,Clone)]
 pub struct VtableDefaultImplData<N> {
     pub trait_def_id: ast::DefId,
     pub nested: Vec<N>
@@ -313,12 +304,12 @@ pub fn predicates_for_generics<'tcx>(tcx: &ty::ctxt<'tcx>,
 /// `bound` or is not known to meet bound (note that this is
 /// conservative towards *no impl*, which is the opposite of the
 /// `evaluate` methods).
-pub fn type_known_to_meet_builtin_bound<'a,'tcx>(infcx: &InferCtxt<'a,'tcx>,
-                                                 typer: &ty::ClosureTyper<'tcx>,
-                                                 ty: Ty<'tcx>,
-                                                 bound: ty::BuiltinBound,
-                                                 span: Span)
-                                                 -> bool
+pub fn evaluate_builtin_bound<'a,'tcx>(infcx: &InferCtxt<'a,'tcx>,
+                                       typer: &ty::ClosureTyper<'tcx>,
+                                       ty: Ty<'tcx>,
+                                       bound: ty::BuiltinBound,
+                                       span: Span)
+                                       -> SelectionResult<'tcx, ()>
 {
     debug!("type_known_to_meet_builtin_bound(ty={}, bound={:?})",
            ty.repr(infcx.tcx),
@@ -336,18 +327,61 @@ pub fn type_known_to_meet_builtin_bound<'a,'tcx>(infcx: &InferCtxt<'a,'tcx>,
     // Note: we only assume something is `Copy` if we can
     // *definitively* show that it implements `Copy`. Otherwise,
     // assume it is move; linear is always ok.
-    match fulfill_cx.select_all_or_error(infcx, typer) {
-        Ok(()) => {
-            debug!("type_known_to_meet_builtin_bound: ty={} bound={:?} success",
-                   ty.repr(infcx.tcx),
-                   bound);
+    let result = match fulfill_cx.select_all_or_error(infcx, typer) {
+        Ok(()) => Ok(Some(())), // Success, we know it implements Copy.
+        Err(errors) => {
+            // If there were any hard errors, propagate an arbitrary
+            // one of those. If no hard errors at all, report
+            // ambiguity.
+            let sel_error =
+                errors.iter()
+                      .filter_map(|err| {
+                          match err.code {
+                              CodeAmbiguity => None,
+                              CodeSelectionError(ref e) => Some(e.clone()),
+                              CodeProjectionError(_) => {
+                                  infcx.tcx.sess.span_bug(
+                                      span,
+                                      "projection error while selecting?")
+                              }
+                          }
+                      })
+                      .next();
+            match sel_error {
+                None => { Ok(None) }
+                Some(e) => { Err(e) }
+            }
+        }
+    };
+
+    debug!("type_known_to_meet_builtin_bound: ty={} bound={:?} result={:?}",
+           ty.repr(infcx.tcx),
+           bound,
+           result);
+
+    result
+}
+
+pub fn type_known_to_meet_builtin_bound<'a,'tcx>(infcx: &InferCtxt<'a,'tcx>,
+                                                 typer: &ty::ClosureTyper<'tcx>,
+                                                 ty: Ty<'tcx>,
+                                                 bound: ty::BuiltinBound,
+                                                 span: Span)
+                                                 -> bool
+{
+    match evaluate_builtin_bound(infcx, typer, ty, bound, span) {
+        Ok(Some(())) => {
+            // definitely impl'd
             true
         }
-        Err(e) => {
-            debug!("type_known_to_meet_builtin_bound: ty={} bound={:?} errors={}",
-                   ty.repr(infcx.tcx),
-                   bound,
-                   e.repr(infcx.tcx));
+        Ok(None) => {
+            // ambiguous: if coherence check was successful, shouldn't
+            // happen, but we might have reported an error and been
+            // soldering on, so just treat this like not implemented
+            false
+        }
+        Err(_) => {
+            // errors: not implemented.
             false
         }
     }
@@ -511,8 +545,8 @@ impl<'tcx, N> Vtable<'tcx, N> {
             VtableParam(n) => n,
             VtableBuiltin(i) => i.nested,
             VtableDefaultImpl(d) => d.nested,
-            VtableClosure(c) => c.nested,
-            VtableObject(_) | VtableFnPointer(..) => vec![]
+            VtableObject(_) | VtableFnPointer(..) |
+            VtableClosure(..) => vec![]
         }
     }
 
@@ -533,11 +567,7 @@ impl<'tcx, N> Vtable<'tcx, N> {
                 nested: d.nested.into_iter().map(f).collect()
             }),
             VtableFnPointer(f) => VtableFnPointer(f),
-            VtableClosure(c) => VtableClosure(VtableClosureData {
-                closure_def_id: c.closure_def_id,
-                substs: c.substs,
-                nested: c.nested.into_iter().map(f).collect()
-            })
+            VtableClosure(d, s) => VtableClosure(d, s),
         }
     }
 }

branches/snap-stage3/src/librustc/middle/traits/project.rs

@@ -17,15 +17,15 @@ use super::ObligationCause;
 use super::PredicateObligation;
 use super::SelectionContext;
 use super::SelectionError;
-use super::VtableClosureData;
 use super::VtableImplData;
 use super::util;
 
 use middle::infer;
-use middle::subst::Subst;
+use middle::subst::{Subst, Substs};
 use middle::ty::{self, AsPredicate, ReferencesError, RegionEscape,
                  HasProjectionTypes, ToPolyTraitRef, Ty};
 use middle::ty_fold::{self, TypeFoldable, TypeFolder};
+use syntax::ast;
 use syntax::parse::token;
 use util::common::FN_OUTPUT_NAME;
 use util::ppaux::Repr;
@@ -57,7 +57,7 @@ pub struct MismatchedProjectionTypes<'tcx> {
 enum ProjectionTyCandidate<'tcx> {
     ParamEnv(ty::PolyProjectionPredicate<'tcx>),
     Impl(VtableImplData<'tcx, PredicateObligation<'tcx>>),
-    Closure(VtableClosureData<'tcx, PredicateObligation<'tcx>>),
+    Closure(ast::DefId, Substs<'tcx>),
     FnPointer(Ty<'tcx>),
 }
 
@@ -162,16 +162,11 @@ fn consider_unification_despite_ambiguity<'cx,'tcx>(selcx: &mut SelectionContext
                                                         self_ty,
                                                         &closure_type.sig,
                                                         util::TupleArgumentsFlag::No);
-            // We don't have to normalize the return type here - this is only
-            // reached for TyClosure: Fn inputs where the closure kind is
-            // still unknown, which should only occur in typeck where the
-            // closure type is already normalized.
             let (ret_type, _) =
                 infcx.replace_late_bound_regions_with_fresh_var(
                     obligation.cause.span,
                     infer::AssocTypeProjection(obligation.predicate.projection_ty.item_name),
                     &ty::Binder(ret_type));
-
             debug!("consider_unification_despite_ambiguity: ret_type={:?}",
                    ret_type.repr(selcx.tcx()));
             let origin = infer::RelateOutputImplTypes(obligation.cause.span);
@@ -691,9 +686,9 @@ fn assemble_candidates_from_impls<'cx,'tcx>(
                 selcx, obligation, obligation_trait_ref, candidate_set,
                 data.object_ty);
         }
-        super::VtableClosure(data) => {
+        super::VtableClosure(closure_def_id, substs) => {
             candidate_set.vec.push(
-                ProjectionTyCandidate::Closure(data));
+                ProjectionTyCandidate::Closure(closure_def_id, substs));
         }
         super::VtableFnPointer(fn_type) => {
             candidate_set.vec.push(
@@ -760,8 +755,8 @@ fn confirm_candidate<'cx,'tcx>(
             confirm_impl_candidate(selcx, obligation, impl_vtable)
         }
 
-        ProjectionTyCandidate::Closure(closure_vtable) => {
-            confirm_closure_candidate(selcx, obligation, closure_vtable)
+        ProjectionTyCandidate::Closure(def_id, substs) => {
+            confirm_closure_candidate(selcx, obligation, def_id, &substs)
         }
 
         ProjectionTyCandidate::FnPointer(fn_type) => {
@@ -784,24 +779,13 @@ fn confirm_fn_pointer_candidate<'cx,'tcx>(
 fn confirm_closure_candidate<'cx,'tcx>(
     selcx: &mut SelectionContext<'cx,'tcx>,
     obligation: &ProjectionTyObligation<'tcx>,
-    vtable: VtableClosureData<'tcx, PredicateObligation<'tcx>>)
+    closure_def_id: ast::DefId,
+    substs: &Substs<'tcx>)
     -> (Ty<'tcx>, Vec<PredicateObligation<'tcx>>)
 {
     let closure_typer = selcx.closure_typer();
-    let closure_type = closure_typer.closure_type(vtable.closure_def_id, &vtable.substs);
-    let Normalized {
-        value: closure_type,
-        mut obligations
-    } = normalize_with_depth(selcx,
-                             obligation.cause.clone(),
-                             obligation.recursion_depth+1,
-                             &closure_type);
-    let (ty, mut cc_obligations) = confirm_callable_candidate(selcx,
-                                                              obligation,
-                                                              &closure_type.sig,
-                                                              util::TupleArgumentsFlag::No);
-    obligations.append(&mut cc_obligations);
-    (ty, obligations)
+    let closure_type = closure_typer.closure_type(closure_def_id, substs);
+    confirm_callable_candidate(selcx, obligation, &closure_type.sig, util::TupleArgumentsFlag::No)
 }
 
 fn confirm_callable_candidate<'cx,'tcx>(
@@ -813,7 +797,7 @@ fn confirm_callable_candidate<'cx,'tcx>(
 {
     let tcx = selcx.tcx();
 
-    debug!("confirm_callable_candidate({},{})",
+    debug!("confirm_closure_candidate({},{})",
            obligation.repr(tcx),
            fn_sig.repr(tcx));
 
@@ -937,8 +921,8 @@ impl<'tcx> Repr<'tcx> for ProjectionTyCandidate<'tcx> {
                 format!("ParamEnv({})", data.repr(tcx)),
             ProjectionTyCandidate::Impl(ref data) =>
                 format!("Impl({})", data.repr(tcx)),
-            ProjectionTyCandidate::Closure(ref data) =>
-                format!("Closure({})", data.repr(tcx)),
+            ProjectionTyCandidate::Closure(ref a, ref b) =>
+                format!("Closure(({},{}))", a.repr(tcx), b.repr(tcx)),
             ProjectionTyCandidate::FnPointer(a) =>
                 format!("FnPointer(({}))", a.repr(tcx)),
         }

branches/snap-stage3/src/librustc/middle/traits/select.rs

@@ -31,8 +31,7 @@ use super::Selection;
 use super::SelectionResult;
 use super::{VtableBuiltin, VtableImpl, VtableParam, VtableClosure,
             VtableFnPointer, VtableObject, VtableDefaultImpl};
-use super::{VtableImplData, VtableObjectData, VtableBuiltinData,
-            VtableClosureData, VtableDefaultImplData};
+use super::{VtableImplData, VtableObjectData, VtableBuiltinData, VtableDefaultImplData};
 use super::object_safety;
 use super::util;
 
@@ -356,14 +355,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
         };
         assert!(!substs.has_escaping_regions());
 
-        // It is OK to call the unnormalized variant here - this is only
-        // reached for TyClosure: Fn inputs where the closure kind is
-        // still unknown, which should only occur in typeck where the
-        // closure type is already normalized.
-        let closure_trait_ref = self.closure_trait_ref_unnormalized(obligation,
-                                                                    closure_def_id,
-                                                                    substs);
-
+        let closure_trait_ref = self.closure_trait_ref(obligation, closure_def_id, substs);
         match self.confirm_poly_trait_refs(obligation.cause.clone(),
                                            obligation.predicate.to_poly_trait_ref(),
                                            closure_trait_ref) {
@@ -2009,9 +2001,8 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
             }
 
             ClosureCandidate(closure_def_id, substs) => {
-                let vtable_closure =
-                    try!(self.confirm_closure_candidate(obligation, closure_def_id, &substs));
-                Ok(VtableClosure(vtable_closure))
+                try!(self.confirm_closure_candidate(obligation, closure_def_id, &substs));
+                Ok(VtableClosure(closure_def_id, substs))
             }
 
             BuiltinObjectCandidate => {
@@ -2352,33 +2343,24 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                                  obligation: &TraitObligation<'tcx>,
                                  closure_def_id: ast::DefId,
                                  substs: &Substs<'tcx>)
-                                 -> Result<VtableClosureData<'tcx, PredicateObligation<'tcx>>,
-                                           SelectionError<'tcx>>
+                                 -> Result<(),SelectionError<'tcx>>
     {
         debug!("confirm_closure_candidate({},{},{})",
                obligation.repr(self.tcx()),
                closure_def_id.repr(self.tcx()),
                substs.repr(self.tcx()));
 
-        let Normalized {
-            value: trait_ref,
-            obligations
-        } = self.closure_trait_ref(obligation, closure_def_id, substs);
+        let trait_ref = self.closure_trait_ref(obligation,
+                                               closure_def_id,
+                                               substs);
 
-        debug!("confirm_closure_candidate(closure_def_id={}, trait_ref={}, obligations={})",
+        debug!("confirm_closure_candidate(closure_def_id={}, trait_ref={})",
                closure_def_id.repr(self.tcx()),
-               trait_ref.repr(self.tcx()),
-               obligations.repr(self.tcx()));
-
-        try!(self.confirm_poly_trait_refs(obligation.cause.clone(),
-                                          obligation.predicate.to_poly_trait_ref(),
-                                          trait_ref));
+               trait_ref.repr(self.tcx()));
 
-        Ok(VtableClosureData {
-            closure_def_id: closure_def_id,
-            substs: substs.clone(),
-            nested: obligations
-        })
+        self.confirm_poly_trait_refs(obligation.cause.clone(),
+                                     obligation.predicate.to_poly_trait_ref(),
+                                     trait_ref)
     }
 
     /// In the case of closure types and fn pointers,
@@ -2837,11 +2819,11 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
         }
     }
 
-    fn closure_trait_ref_unnormalized(&mut self,
-                                      obligation: &TraitObligation<'tcx>,
-                                      closure_def_id: ast::DefId,
-                                      substs: &Substs<'tcx>)
-                                      -> ty::PolyTraitRef<'tcx>
+    fn closure_trait_ref(&self,
+                         obligation: &TraitObligation<'tcx>,
+                         closure_def_id: ast::DefId,
+                         substs: &Substs<'tcx>)
+                         -> ty::PolyTraitRef<'tcx>
     {
         let closure_type = self.closure_typer.closure_type(closure_def_id, substs);
         let ty::Binder((trait_ref, _)) =
@@ -2850,6 +2832,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                                                     obligation.predicate.0.self_ty(), // (1)
                                                     &closure_type.sig,
                                                     util::TupleArgumentsFlag::No);
+
         // (1) Feels icky to skip the binder here, but OTOH we know
         // that the self-type is an unboxed closure type and hence is
         // in fact unparameterized (or at least does not reference any
@@ -2859,23 +2842,6 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
         ty::Binder(trait_ref)
     }
 
-    fn closure_trait_ref(&mut self,
-                         obligation: &TraitObligation<'tcx>,
-                         closure_def_id: ast::DefId,
-                         substs: &Substs<'tcx>)
-                         -> Normalized<'tcx, ty::PolyTraitRef<'tcx>>
-    {
-        let trait_ref = self.closure_trait_ref_unnormalized(
-            obligation, closure_def_id, substs);
-
-        // A closure signature can contain associated types which
-        // must be normalized.
-        normalize_with_depth(self,
-                             obligation.cause.clone(),
-                             obligation.recursion_depth+1,
-                             &trait_ref)
-    }
-
     /// Returns the obligations that are implied by instantiating an
     /// impl or trait. The obligations are substituted and fully
     /// normalized. This is used when confirming an impl or default