Rollup of 7 pull requests

src/libcore/time.rs

@@ -152,7 +152,6 @@ impl Duration {
     /// ```
     #[stable(feature = "duration", since = "1.3.0")]
     #[inline]
-    #[rustc_promotable]
     #[rustc_const_stable(feature = "duration_consts", since = "1.32.0")]
     pub const fn from_secs(secs: u64) -> Duration {
         Duration { secs, nanos: 0 }

src/librustc_expand/expand.rs

@@ -1789,6 +1789,7 @@ pub struct ExpansionConfig<'feat> {
     pub trace_mac: bool,
     pub should_test: bool, // If false, strip `#[test]` nodes
     pub keep_macs: bool,
+    pub span_debug: bool, // If true, use verbose debugging for `proc_macro::Span`
 }
 
 impl<'feat> ExpansionConfig<'feat> {
@@ -1800,6 +1801,7 @@ impl<'feat> ExpansionConfig<'feat> {
             trace_mac: false,
             should_test: false,
             keep_macs: false,
+            span_debug: false,
         }
     }
 

src/librustc_expand/proc_macro_server.rs

@@ -352,6 +352,7 @@ pub(crate) struct Rustc<'a> {
     def_site: Span,
     call_site: Span,
     mixed_site: Span,
+    span_debug: bool,
 }
 
 impl<'a> Rustc<'a> {
@@ -362,6 +363,7 @@ impl<'a> Rustc<'a> {
             def_site: cx.with_def_site_ctxt(expn_data.def_site),
             call_site: cx.with_call_site_ctxt(expn_data.call_site),
             mixed_site: cx.with_mixed_site_ctxt(expn_data.call_site),
+            span_debug: cx.ecfg.span_debug,
         }
     }
 
@@ -646,7 +648,11 @@ impl server::Diagnostic for Rustc<'_> {
 
 impl server::Span for Rustc<'_> {
     fn debug(&mut self, span: Self::Span) -> String {
-        format!("{:?} bytes({}..{})", span.ctxt(), span.lo().0, span.hi().0)
+        if self.span_debug {
+            format!("{:?}", span)
+        } else {
+            format!("{:?} bytes({}..{})", span.ctxt(), span.lo().0, span.hi().0)
+        }
     }
     fn def_site(&mut self) -> Self::Span {
         self.def_site

src/librustc_interface/passes.rs

@@ -291,6 +291,7 @@ fn configure_and_expand_inner<'a>(
             recursion_limit: sess.recursion_limit(),
             trace_mac: sess.opts.debugging_opts.trace_macros,
             should_test: sess.opts.test,
+            span_debug: sess.opts.debugging_opts.span_debug,
             ..rustc_expand::expand::ExpansionConfig::default(crate_name.to_string())
         };
 

src/librustc_interface/tests.rs

@@ -506,6 +506,7 @@ fn test_debugging_options_tracking_hash() {
     untracked!(save_analysis, true);
     untracked!(self_profile, SwitchWithOptPath::Enabled(None));
     untracked!(self_profile_events, Some(vec![String::new()]));
+    untracked!(span_debug, true);
     untracked!(span_free_formats, true);
     untracked!(strip, Strip::None);
     untracked!(terminal_width, Some(80));

src/librustc_middle/ty/sty.rs

@@ -724,10 +724,6 @@ impl<'tcx> Binder<&'tcx List<ExistentialPredicate<'tcx>>> {
 ///
 /// Trait references also appear in object types like `Foo<U>`, but in
 /// that case the `Self` parameter is absent from the substitutions.
-///
-/// Note that a `TraitRef` introduces a level of region binding, to
-/// account for higher-ranked trait bounds like `T: for<'a> Foo<&'a U>`
-/// or higher-ranked object types.
 #[derive(Copy, Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
 #[derive(HashStable, TypeFoldable)]
 pub struct TraitRef<'tcx> {
@@ -765,8 +761,8 @@ impl<'tcx> TraitRef<'tcx> {
 pub type PolyTraitRef<'tcx> = Binder<TraitRef<'tcx>>;
 
 impl<'tcx> PolyTraitRef<'tcx> {
-    pub fn self_ty(&self) -> Ty<'tcx> {
-        self.skip_binder().self_ty()
+    pub fn self_ty(&self) -> Binder<Ty<'tcx>> {
+        self.map_bound_ref(|tr| tr.self_ty())
     }
 
     pub fn def_id(&self) -> DefId {

src/librustc_mir/transform/generator.rs

@@ -669,40 +669,33 @@ fn compute_storage_conflicts(
     storage_conflicts
 }
 
-fn compute_layout<'tcx>(
+/// Validates the typeck view of the generator against the actual set of types retained between
+/// yield points.
+fn sanitize_witness<'tcx>(
     tcx: TyCtxt<'tcx>,
-    source: MirSource<'tcx>,
+    body: &Body<'tcx>,
+    did: DefId,
+    witness: Ty<'tcx>,
     upvars: &Vec<Ty<'tcx>>,
-    interior: Ty<'tcx>,
-    always_live_locals: &storage::AlwaysLiveLocals,
-    movable: bool,
-    body: &mut Body<'tcx>,
-) -> (
-    FxHashMap<Local, (Ty<'tcx>, VariantIdx, usize)>,
-    GeneratorLayout<'tcx>,
-    IndexVec<BasicBlock, Option<BitSet<Local>>>,
+    retained: &BitSet<Local>,
 ) {
-    // Use a liveness analysis to compute locals which are live across a suspension point
-    let LivenessInfo {
-        live_locals,
-        live_locals_at_suspension_points,
-        storage_conflicts,
-        storage_liveness,
-    } = locals_live_across_suspend_points(tcx, body, source, always_live_locals, movable);
-
-    // Erase regions from the types passed in from typeck so we can compare them with
-    // MIR types
     let allowed_upvars = tcx.erase_regions(upvars);
-    let allowed = match interior.kind {
+    let allowed = match witness.kind {
         ty::GeneratorWitness(s) => tcx.erase_late_bound_regions(&s),
-        _ => bug!(),
+        _ => {
+            tcx.sess.delay_span_bug(
+                body.span,
+                &format!("unexpected generator witness type {:?}", witness.kind),
+            );
+            return;
+        }
     };
 
-    let param_env = tcx.param_env(source.def_id());
+    let param_env = tcx.param_env(did);
 
     for (local, decl) in body.local_decls.iter_enumerated() {
-        // Ignore locals which are internal or not live
-        if !live_locals.contains(local) || decl.internal {
+        // Ignore locals which are internal or not retained between yields.
+        if !retained.contains(local) || decl.internal {
             continue;
         }
         let decl_ty = tcx.normalize_erasing_regions(param_env, decl.ty);
@@ -715,10 +708,34 @@ fn compute_layout<'tcx>(
                 "Broken MIR: generator contains type {} in MIR, \
                        but typeck only knows about {}",
                 decl.ty,
-                interior
+                witness,
             );
         }
     }
+}
+
+fn compute_layout<'tcx>(
+    tcx: TyCtxt<'tcx>,
+    source: MirSource<'tcx>,
+    upvars: &Vec<Ty<'tcx>>,
+    interior: Ty<'tcx>,
+    always_live_locals: &storage::AlwaysLiveLocals,
+    movable: bool,
+    body: &mut Body<'tcx>,
+) -> (
+    FxHashMap<Local, (Ty<'tcx>, VariantIdx, usize)>,
+    GeneratorLayout<'tcx>,
+    IndexVec<BasicBlock, Option<BitSet<Local>>>,
+) {
+    // Use a liveness analysis to compute locals which are live across a suspension point
+    let LivenessInfo {
+        live_locals,
+        live_locals_at_suspension_points,
+        storage_conflicts,
+        storage_liveness,
+    } = locals_live_across_suspend_points(tcx, body, source, always_live_locals, movable);
+
+    sanitize_witness(tcx, body, source.def_id(), interior, upvars, &live_locals);
 
     // Gather live local types and their indices.
     let mut locals = IndexVec::<GeneratorSavedLocal, _>::new();

src/librustc_save_analysis/dump_visitor.rs

@@ -210,9 +210,11 @@ impl<'l, 'tcx> DumpVisitor<'l, 'tcx> {
     // As write_sub_paths, but does not process the last ident in the path (assuming it
     // will be processed elsewhere). See note on write_sub_paths about global.
     fn write_sub_paths_truncated(&mut self, path: &'tcx hir::Path<'tcx>) {
-        for seg in &path.segments[..path.segments.len() - 1] {
-            if let Some(data) = self.save_ctxt.get_path_segment_data(seg) {
-                self.dumper.dump_ref(data);
+        if path.segments.len() > 0 {
+            for seg in &path.segments[..path.segments.len() - 1] {
+                if let Some(data) = self.save_ctxt.get_path_segment_data(seg) {
+                    self.dumper.dump_ref(data);
+                }
             }
         }
     }

src/librustc_save_analysis/lib.rs

@@ -534,10 +534,14 @@ impl<'l, 'tcx> SaveContext<'l, 'tcx> {
                     }
                 }
             }
-            hir::ExprKind::Struct(hir::QPath::Resolved(_, path), ..) => {
+            hir::ExprKind::Struct(qpath, ..) => {
+                let segment = match qpath {
+                    hir::QPath::Resolved(_, path) => path.segments.last().unwrap(),
+                    hir::QPath::TypeRelative(_, segment) => segment,
+                };
                 match self.tables.expr_ty_adjusted(&hir_node).kind {
                     ty::Adt(def, _) if !def.is_enum() => {
-                        let sub_span = path.segments.last().unwrap().ident.span;
+                        let sub_span = segment.ident.span;
                         filter!(self.span_utils, sub_span);
                         let span = self.span_from_span(sub_span);
                         Some(Data::RefData(Ref {
@@ -580,7 +584,7 @@ impl<'l, 'tcx> SaveContext<'l, 'tcx> {
             }
             _ => {
                 // FIXME
-                bug!();
+                bug!("invalid expression: {:?}", expr);
             }
         }
     }

src/librustc_session/options.rs

@@ -996,6 +996,8 @@ options! {DebuggingOptions, DebuggingSetter, basic_debugging_options,
         "make the current crate share its generic instantiations"),
     show_span: Option<String> = (None, parse_opt_string, [TRACKED],
         "show spans for compiler debugging (expr|pat|ty)"),
+    span_debug: bool = (false, parse_bool, [UNTRACKED],
+        "forward proc_macro::Span's `Debug` impl to `Span`"),
     // o/w tests have closure@path
     span_free_formats: bool = (false, parse_bool, [UNTRACKED],
         "exclude spans when debug-printing compiler state (default: no)"),

src/librustc_trait_selection/traits/error_reporting/mod.rs

@@ -290,7 +290,7 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
                             (
                                 Some(format!(
                                     "`?` couldn't convert the error to `{}`",
-                                    trait_ref.self_ty(),
+                                    trait_ref.skip_binder().self_ty(),
                                 )),
                                 Some(
                                     "the question mark operation (`?`) implicitly performs a \
@@ -340,7 +340,10 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
                             if let Some(ret_span) = self.return_type_span(obligation) {
                                 err.span_label(
                                     ret_span,
-                                    &format!("expected `{}` because of this", trait_ref.self_ty()),
+                                    &format!(
+                                        "expected `{}` because of this",
+                                        trait_ref.skip_binder().self_ty()
+                                    ),
                                 );
                             }
                         }
@@ -353,7 +356,7 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
                                     "{}the trait `{}` is not implemented for `{}`",
                                     pre_message,
                                     trait_ref.print_only_trait_path(),
-                                    trait_ref.self_ty(),
+                                    trait_ref.skip_binder().self_ty(),
                                 )
                             };
 
@@ -643,7 +646,10 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
                     return;
                 }
 
-                let found_trait_ty = found_trait_ref.self_ty();
+                let found_trait_ty = match found_trait_ref.self_ty().no_bound_vars() {
+                    Some(ty) => ty,
+                    None => return,
+                };
 
                 let found_did = match found_trait_ty.kind {
                     ty::Closure(did, _) | ty::Foreign(did) | ty::FnDef(did, _) => Some(did),
@@ -1360,11 +1366,15 @@ impl<'a, 'tcx> InferCtxtPrivExt<'tcx> for InferCtxt<'a, 'tcx> {
     ) {
         let get_trait_impl = |trait_def_id| {
             let mut trait_impl = None;
-            self.tcx.for_each_relevant_impl(trait_def_id, trait_ref.self_ty(), |impl_def_id| {
-                if trait_impl.is_none() {
-                    trait_impl = Some(impl_def_id);
-                }
-            });
+            self.tcx.for_each_relevant_impl(
+                trait_def_id,
+                trait_ref.skip_binder().self_ty(),
+                |impl_def_id| {
+                    if trait_impl.is_none() {
+                        trait_impl = Some(impl_def_id);
+                    }
+                },
+            );
             trait_impl
         };
         let required_trait_path = self.tcx.def_path_str(trait_ref.def_id());
@@ -1435,7 +1445,7 @@ impl<'a, 'tcx> InferCtxtPrivExt<'tcx> for InferCtxt<'a, 'tcx> {
         let mut err = match predicate.kind() {
             ty::PredicateKind::Trait(ref data, _) => {
                 let trait_ref = data.to_poly_trait_ref();
-                let self_ty = trait_ref.self_ty();
+                let self_ty = trait_ref.skip_binder().self_ty();
                 debug!("self_ty {:?} {:?} trait_ref {:?}", self_ty, self_ty.kind, trait_ref);
 
                 if predicate.references_error() {
@@ -1564,7 +1574,7 @@ impl<'a, 'tcx> InferCtxtPrivExt<'tcx> for InferCtxt<'a, 'tcx> {
             }
             ty::PredicateKind::Projection(ref data) => {
                 let trait_ref = data.to_poly_trait_ref(self.tcx);
-                let self_ty = trait_ref.self_ty();
+                let self_ty = trait_ref.skip_binder().self_ty();
                 let ty = data.skip_binder().ty;
                 if predicate.references_error() {
                     return;

src/librustc_trait_selection/traits/error_reporting/suggestions.rs

@@ -318,7 +318,7 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
         trait_ref: ty::PolyTraitRef<'tcx>,
         body_id: hir::HirId,
     ) {
-        let self_ty = trait_ref.self_ty();
+        let self_ty = trait_ref.skip_binder().self_ty();
         let (param_ty, projection) = match &self_ty.kind {
             ty::Param(_) => (true, None),
             ty::Projection(projection) => (false, Some(projection)),
@@ -524,7 +524,11 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
         trait_ref: &ty::Binder<ty::TraitRef<'tcx>>,
         points_at_arg: bool,
     ) {
-        let self_ty = trait_ref.self_ty();
+        let self_ty = match trait_ref.self_ty().no_bound_vars() {
+            None => return,
+            Some(ty) => ty,
+        };
+
         let (def_id, output_ty, callable) = match self_ty.kind {
             ty::Closure(def_id, substs) => (def_id, substs.as_closure().sig().output(), "closure"),
             ty::FnDef(def_id, _) => (def_id, self_ty.fn_sig(self.tcx).output(), "function"),
@@ -707,7 +711,10 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
                 return;
             }
 
-            let mut suggested_ty = trait_ref.self_ty();
+            let mut suggested_ty = match trait_ref.self_ty().no_bound_vars() {
+                Some(ty) => ty,
+                None => return,
+            };
 
             for refs_remaining in 0..refs_number {
                 if let ty::Ref(_, inner_ty, _) = suggested_ty.kind {
@@ -829,6 +836,9 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
         span: Span,
         trait_ref: &ty::Binder<ty::TraitRef<'tcx>>,
     ) {
+        let is_empty_tuple =
+            |ty: ty::Binder<Ty<'_>>| ty.skip_binder().kind == ty::Tuple(ty::List::empty());
+
         let hir = self.tcx.hir();
         let parent_node = hir.get_parent_node(obligation.cause.body_id);
         let node = hir.find(parent_node);
@@ -840,7 +850,7 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
             if let hir::ExprKind::Block(blk, _) = &body.value.kind {
                 if sig.decl.output.span().overlaps(span)
                     && blk.expr.is_none()
-                    && "()" == &trait_ref.self_ty().to_string()
+                    && is_empty_tuple(trait_ref.self_ty())
                 {
                     // FIXME(estebank): When encountering a method with a trait
                     // bound not satisfied in the return type with a body that has
@@ -1271,7 +1281,7 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
                 ObligationCauseCode::DerivedObligation(derived_obligation)
                 | ObligationCauseCode::BuiltinDerivedObligation(derived_obligation)
                 | ObligationCauseCode::ImplDerivedObligation(derived_obligation) => {
-                    let ty = derived_obligation.parent_trait_ref.self_ty();
+                    let ty = derived_obligation.parent_trait_ref.skip_binder().self_ty();
                     debug!(
                         "maybe_note_obligation_cause_for_async_await: \
                             parent_trait_ref={:?} self_ty.kind={:?}",
@@ -1917,7 +1927,7 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
 
                 let impls_future = self.tcx.type_implements_trait((
                     future_trait,
-                    self_ty,
+                    self_ty.skip_binder(),
                     ty::List::empty(),
                     obligation.param_env,
                 ));
@@ -1933,7 +1943,7 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
                 let projection_ty = ty::ProjectionTy {
                     // `T`
                     substs: self.tcx.mk_substs_trait(
-                        trait_ref.self_ty(),
+                        trait_ref.self_ty().skip_binder(),
                         self.fresh_substs_for_item(span, item_def_id),
                     ),
                     // `Future::Output`