Rollup of 9 pull requests

compiler/rustc_codegen_cranelift/example/alloc_example.rs

@@ -1,10 +1,10 @@
-#![feature(start, core_intrinsics, alloc_prelude, alloc_error_handler, box_syntax)]
+#![feature(start, core_intrinsics, alloc_error_handler, box_syntax)]
 #![no_std]
 
 extern crate alloc;
 extern crate alloc_system;
 
-use alloc::prelude::v1::*;
+use alloc::boxed::Box;
 
 use alloc_system::System;
 

compiler/rustc_codegen_gcc/example/alloc_example.rs

@@ -1,10 +1,10 @@
-#![feature(start, box_syntax, core_intrinsics, alloc_prelude, alloc_error_handler)]
+#![feature(start, box_syntax, core_intrinsics, alloc_error_handler)]
 #![no_std]
 
 extern crate alloc;
 extern crate alloc_system;
 
-use alloc::prelude::v1::*;
+use alloc::boxed::Box;
 
 use alloc_system::System;
 

compiler/rustc_errors/src/lib.rs

@@ -341,7 +341,7 @@ impl CodeSuggestion {
                     });
                     buf.push_str(&part.snippet);
                     let cur_hi = sm.lookup_char_pos(part.span.hi());
-                    if prev_hi.line == cur_lo.line {
+                    if prev_hi.line == cur_lo.line && cur_hi.line == cur_lo.line {
                         // Account for the difference between the width of the current code and the
                         // snippet being suggested, so that the *later* suggestions are correctly
                         // aligned on the screen.

compiler/rustc_infer/src/infer/error_reporting/nice_region_error/trait_impl_difference.rs

@@ -46,7 +46,9 @@ impl<'a, 'tcx> NiceRegionError<'a, 'tcx> {
                 }
             }
         }
-        if let RegionResolutionError::ConcreteFailure(origin, _, _) = error.clone() {
+        if let RegionResolutionError::ConcreteFailure(origin, _, _)
+        | RegionResolutionError::GenericBoundFailure(origin, _, _) = error.clone()
+        {
             if let SubregionOrigin::CompareImplTypeObligation {
                 span,
                 item_name,

compiler/rustc_middle/src/ty/outlives.rs → compiler/rustc_infer/src/infer/outlives/components.rs

@@ -2,10 +2,10 @@
 // refers to rules defined in RFC 1214 (`OutlivesFooBar`), so see that
 // RFC for reference.
 
-use crate::ty::subst::{GenericArg, GenericArgKind};
-use crate::ty::{self, Ty, TyCtxt, TypeFoldable};
 use rustc_data_structures::sso::SsoHashSet;
-use smallvec::SmallVec;
+use rustc_middle::ty::subst::{GenericArg, GenericArgKind};
+use rustc_middle::ty::{self, Ty, TyCtxt, TypeFoldable};
+use smallvec::{smallvec, SmallVec};
 
 #[derive(Debug)]
 pub enum Component<'tcx> {
@@ -47,14 +47,16 @@ pub enum Component<'tcx> {
     EscapingProjection(Vec<Component<'tcx>>),
 }
 
-impl<'tcx> TyCtxt<'tcx> {
-    /// Push onto `out` all the things that must outlive `'a` for the condition
-    /// `ty0: 'a` to hold. Note that `ty0` must be a **fully resolved type**.
-    pub fn push_outlives_components(self, ty0: Ty<'tcx>, out: &mut SmallVec<[Component<'tcx>; 4]>) {
-        let mut visited = SsoHashSet::new();
-        compute_components(self, ty0, out, &mut visited);
-        debug!("components({:?}) = {:?}", ty0, out);
-    }
+/// Push onto `out` all the things that must outlive `'a` for the condition
+/// `ty0: 'a` to hold. Note that `ty0` must be a **fully resolved type**.
+pub fn push_outlives_components(
+    tcx: TyCtxt<'tcx>,
+    ty0: Ty<'tcx>,
+    out: &mut SmallVec<[Component<'tcx>; 4]>,
+) {
+    let mut visited = SsoHashSet::new();
+    compute_components(tcx, ty0, out, &mut visited);
+    debug!("components({:?}) = {:?}", ty0, out);
 }
 
 fn compute_components(

compiler/rustc_infer/src/infer/outlives/mod.rs

@@ -1,5 +1,6 @@
 //! Various code related to computing outlives relations.
 
+pub mod components;
 pub mod env;
 pub mod obligations;
 pub mod verify;

compiler/rustc_infer/src/infer/outlives/obligations.rs

@@ -1,5 +1,5 @@
 //! Code that handles "type-outlives" constraints like `T: 'a`. This
-//! is based on the `push_outlives_components` function defined on the tcx,
+//! is based on the `push_outlives_components` function defined in rustc_infer,
 //! but it adds a bit of heuristics on top, in particular to deal with
 //! associated types and projections.
 //!
@@ -59,13 +59,13 @@
 //! might later infer `?U` to something like `&'b u32`, which would
 //! imply that `'b: 'a`.
 
+use crate::infer::outlives::components::{push_outlives_components, Component};
 use crate::infer::outlives::env::RegionBoundPairs;
 use crate::infer::outlives::verify::VerifyBoundCx;
 use crate::infer::{
     self, GenericKind, InferCtxt, RegionObligation, SubregionOrigin, UndoLog, VerifyBound,
 };
 use crate::traits::{ObligationCause, ObligationCauseCode};
-use rustc_middle::ty::outlives::Component;
 use rustc_middle::ty::subst::GenericArgKind;
 use rustc_middle::ty::{self, Region, Ty, TyCtxt, TypeFoldable};
 
@@ -271,7 +271,7 @@ where
         assert!(!ty.has_escaping_bound_vars());
 
         let mut components = smallvec![];
-        self.tcx.push_outlives_components(ty, &mut components);
+        push_outlives_components(self.tcx, ty, &mut components);
         self.components_must_outlive(origin, &components, region);
     }
 

compiler/rustc_infer/src/traits/util.rs

@@ -1,8 +1,8 @@
 use smallvec::smallvec;
 
+use crate::infer::outlives::components::{push_outlives_components, Component};
 use crate::traits::{Obligation, ObligationCause, PredicateObligation};
 use rustc_data_structures::fx::{FxHashSet, FxIndexSet};
-use rustc_middle::ty::outlives::Component;
 use rustc_middle::ty::{self, ToPredicate, TyCtxt, WithConstness};
 use rustc_span::symbol::Ident;
 
@@ -200,7 +200,7 @@ impl Elaborator<'tcx> {
 
                 let visited = &mut self.visited;
                 let mut components = smallvec![];
-                tcx.push_outlives_components(ty_max, &mut components);
+                push_outlives_components(tcx, ty_max, &mut components);
                 self.stack.extend(
                     components
                         .into_iter()

compiler/rustc_middle/src/ty/mod.rs

@@ -92,7 +92,6 @@ pub mod fold;
 pub mod inhabitedness;
 pub mod layout;
 pub mod normalize_erasing_regions;
-pub mod outlives;
 pub mod print;
 pub mod query;
 pub mod relate;

compiler/rustc_trait_selection/src/infer.rs

@@ -1,12 +1,8 @@
 use crate::traits::query::evaluate_obligation::InferCtxtExt as _;
-use crate::traits::query::outlives_bounds::InferCtxtExt as _;
 use crate::traits::{self, TraitEngine, TraitEngineExt};
 
-use rustc_data_structures::stable_set::FxHashSet;
-use rustc_hir as hir;
 use rustc_hir::def_id::DefId;
 use rustc_hir::lang_items::LangItem;
-use rustc_infer::infer::outlives::env::OutlivesEnvironment;
 use rustc_infer::traits::ObligationCause;
 use rustc_middle::arena::ArenaAllocatable;
 use rustc_middle::infer::canonical::{Canonical, CanonicalizedQueryResponse, QueryResponse};
@@ -180,48 +176,3 @@ impl<'tcx> InferCtxtBuilderExt<'tcx> for InferCtxtBuilder<'tcx> {
         )
     }
 }
-
-pub trait OutlivesEnvironmentExt<'tcx> {
-    fn add_implied_bounds(
-        &mut self,
-        infcx: &InferCtxt<'a, 'tcx>,
-        fn_sig_tys: FxHashSet<Ty<'tcx>>,
-        body_id: hir::HirId,
-        span: Span,
-    );
-}
-
-impl<'tcx> OutlivesEnvironmentExt<'tcx> for OutlivesEnvironment<'tcx> {
-    /// This method adds "implied bounds" into the outlives environment.
-    /// Implied bounds are outlives relationships that we can deduce
-    /// on the basis that certain types must be well-formed -- these are
-    /// either the types that appear in the function signature or else
-    /// the input types to an impl. For example, if you have a function
-    /// like
-    ///
-    /// ```
-    /// fn foo<'a, 'b, T>(x: &'a &'b [T]) { }
-    /// ```
-    ///
-    /// we can assume in the caller's body that `'b: 'a` and that `T:
-    /// 'b` (and hence, transitively, that `T: 'a`). This method would
-    /// add those assumptions into the outlives-environment.
-    ///
-    /// Tests: `src/test/ui/regions/regions-free-region-ordering-*.rs`
-    fn add_implied_bounds(
-        &mut self,
-        infcx: &InferCtxt<'a, 'tcx>,
-        fn_sig_tys: FxHashSet<Ty<'tcx>>,
-        body_id: hir::HirId,
-        span: Span,
-    ) {
-        debug!("add_implied_bounds()");
-
-        for ty in fn_sig_tys {
-            let ty = infcx.resolve_vars_if_possible(ty);
-            debug!("add_implied_bounds: ty = {}", ty);
-            let implied_bounds = infcx.implied_outlives_bounds(self.param_env, body_id, ty, span);
-            self.add_outlives_bounds(Some(infcx), implied_bounds)
-        }
-    }
-}

compiler/rustc_trait_selection/src/traits/query/mod.rs

@@ -9,7 +9,6 @@ pub mod dropck_outlives;
 pub mod evaluate_obligation;
 pub mod method_autoderef;
 pub mod normalize;
-pub mod outlives_bounds;
 pub mod type_op;
 
 pub use rustc_middle::traits::query::*;

compiler/rustc_trait_selection/src/traits/query/type_op/implied_outlives_bounds.rs

@@ -1,6 +1,6 @@
 use crate::infer::canonical::{Canonicalized, CanonicalizedQueryResponse};
-use crate::traits::query::outlives_bounds::OutlivesBound;
 use crate::traits::query::Fallible;
+use rustc_infer::traits::query::OutlivesBound;
 use rustc_middle::ty::{ParamEnvAnd, Ty, TyCtxt};
 
 #[derive(Copy, Clone, Debug, HashStable, TypeFoldable, Lift)]

compiler/rustc_traits/src/implied_outlives_bounds.rs

@@ -4,14 +4,14 @@
 
 use rustc_hir as hir;
 use rustc_infer::infer::canonical::{self, Canonical};
+use rustc_infer::infer::outlives::components::{push_outlives_components, Component};
 use rustc_infer::infer::{InferCtxt, TyCtxtInferExt};
+use rustc_infer::traits::query::OutlivesBound;
 use rustc_infer::traits::TraitEngineExt as _;
-use rustc_middle::ty::outlives::Component;
 use rustc_middle::ty::query::Providers;
 use rustc_middle::ty::{self, Ty, TyCtxt, TypeFoldable};
 use rustc_span::source_map::DUMMY_SP;
 use rustc_trait_selection::infer::InferCtxtBuilderExt;
-use rustc_trait_selection::traits::query::outlives_bounds::OutlivesBound;
 use rustc_trait_selection::traits::query::{CanonicalTyGoal, Fallible, NoSolution};
 use rustc_trait_selection::traits::wf;
 use rustc_trait_selection::traits::FulfillmentContext;
@@ -118,7 +118,7 @@ fn compute_implied_outlives_bounds<'tcx>(
                     ty::PredicateKind::TypeOutlives(ty::OutlivesPredicate(ty_a, r_b)) => {
                         let ty_a = infcx.resolve_vars_if_possible(ty_a);
                         let mut components = smallvec![];
-                        tcx.push_outlives_components(ty_a, &mut components);
+                        push_outlives_components(tcx, ty_a, &mut components);
                         implied_bounds_from_components(r_b, components)
                     }
                 },

compiler/rustc_typeck/src/check/regionck.rs

@@ -76,19 +76,19 @@ use crate::check::dropck;
 use crate::check::FnCtxt;
 use crate::mem_categorization as mc;
 use crate::middle::region;
+use crate::outlives::outlives_bounds::InferCtxtExt as _;
 use rustc_data_structures::stable_set::FxHashSet;
 use rustc_hir as hir;
 use rustc_hir::def_id::LocalDefId;
 use rustc_hir::intravisit::{self, NestedVisitorMap, Visitor};
 use rustc_hir::PatKind;
 use rustc_infer::infer::outlives::env::OutlivesEnvironment;
-use rustc_infer::infer::{self, RegionObligation, RegionckMode};
+use rustc_infer::infer::{self, InferCtxt, RegionObligation, RegionckMode};
 use rustc_middle::hir::place::{PlaceBase, PlaceWithHirId};
 use rustc_middle::ty::adjustment;
 use rustc_middle::ty::{self, Ty};
 use rustc_span::Span;
-use rustc_trait_selection::infer::OutlivesEnvironmentExt;
-use rustc_trait_selection::opaque_types::InferCtxtExt;
+use rustc_trait_selection::opaque_types::InferCtxtExt as _;
 use std::ops::Deref;
 
 // a variation on try that just returns unit
@@ -104,6 +104,51 @@ macro_rules! ignore_err {
     };
 }
 
+trait OutlivesEnvironmentExt<'tcx> {
+    fn add_implied_bounds(
+        &mut self,
+        infcx: &InferCtxt<'a, 'tcx>,
+        fn_sig_tys: FxHashSet<Ty<'tcx>>,
+        body_id: hir::HirId,
+        span: Span,
+    );
+}
+
+impl<'tcx> OutlivesEnvironmentExt<'tcx> for OutlivesEnvironment<'tcx> {
+    /// This method adds "implied bounds" into the outlives environment.
+    /// Implied bounds are outlives relationships that we can deduce
+    /// on the basis that certain types must be well-formed -- these are
+    /// either the types that appear in the function signature or else
+    /// the input types to an impl. For example, if you have a function
+    /// like
+    ///
+    /// ```
+    /// fn foo<'a, 'b, T>(x: &'a &'b [T]) { }
+    /// ```
+    ///
+    /// we can assume in the caller's body that `'b: 'a` and that `T:
+    /// 'b` (and hence, transitively, that `T: 'a`). This method would
+    /// add those assumptions into the outlives-environment.
+    ///
+    /// Tests: `src/test/ui/regions/regions-free-region-ordering-*.rs`
+    fn add_implied_bounds(
+        &mut self,
+        infcx: &InferCtxt<'a, 'tcx>,
+        fn_sig_tys: FxHashSet<Ty<'tcx>>,
+        body_id: hir::HirId,
+        span: Span,
+    ) {
+        debug!("add_implied_bounds()");
+
+        for ty in fn_sig_tys {
+            let ty = infcx.resolve_vars_if_possible(ty);
+            debug!("add_implied_bounds: ty = {}", ty);
+            let implied_bounds = infcx.implied_outlives_bounds(self.param_env, body_id, ty, span);
+            self.add_outlives_bounds(Some(infcx), implied_bounds)
+        }
+    }
+}
+
 ///////////////////////////////////////////////////////////////////////////
 // PUBLIC ENTRY POINTS