Rollup merge of #127386 - compiler-errors:uplift-outlives-components, r=lcnr

Uplift outlives components to `rustc_type_ir`

We need this to uplift `push_outlives_components`, since the elaborator uses `push_outlives_components` to elaborate type outlives obligations and I want to uplift elaboration.

This ends up reworking and inlining a fair portion of the `GenericArg::walk_shallow` function, whose only callsite was this one. I believe I got the logic correct, but may be worthwhile to look at it closely just in case. Unfortunately github was too dumb to understand that this is a rename + change -- I could also rework the git history to split the "copy the file over" part from the actual logical changes if that makes this easier to review.

r? lcnr

Author: compiler-errors

compiler/rustc_hir_analysis/src/outlives/utils.rs

@@ -1,9 +1,9 @@
 use rustc_data_structures::fx::FxIndexMap;
-use rustc_infer::infer::outlives::components::{push_outlives_components, Component};
 use rustc_middle::ty::{self, Region, Ty, TyCtxt};
 use rustc_middle::ty::{GenericArg, GenericArgKind};
 use rustc_middle::{bug, span_bug};
 use rustc_span::Span;
+use rustc_type_ir::outlives::{push_outlives_components, Component};
 use smallvec::smallvec;
 
 /// Tracks the `T: 'a` or `'a: 'a` predicates that we have inferred

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

@@ -8,7 +8,6 @@ use crate::infer::lexical_region_resolve;
 use rustc_middle::traits::query::{NoSolution, OutlivesBound};
 use rustc_middle::ty;
 
-pub mod components;
 pub mod env;
 pub mod for_liveness;
 pub mod obligations;

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

@@ -59,7 +59,6 @@
 //! 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::resolve::OpportunisticRegionResolver;
@@ -75,6 +74,7 @@ use rustc_middle::ty::{
 };
 use rustc_middle::ty::{GenericArgKind, PolyTypeOutlivesPredicate};
 use rustc_span::DUMMY_SP;
+use rustc_type_ir::outlives::{push_outlives_components, Component};
 use smallvec::smallvec;
 
 use super::env::OutlivesEnvironment;
@@ -291,7 +291,7 @@ where
     fn components_must_outlive(
         &mut self,
         origin: infer::SubregionOrigin<'tcx>,
-        components: &[Component<'tcx>],
+        components: &[Component<TyCtxt<'tcx>>],
         region: ty::Region<'tcx>,
         category: ConstraintCategory<'tcx>,
     ) {

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

@@ -1,10 +1,10 @@
-use crate::infer::outlives::components::{compute_alias_components_recursive, Component};
 use crate::infer::outlives::env::RegionBoundPairs;
 use crate::infer::region_constraints::VerifyIfEq;
 use crate::infer::{GenericKind, VerifyBound};
 use rustc_data_structures::sso::SsoHashSet;
 use rustc_middle::ty::GenericArg;
 use rustc_middle::ty::{self, OutlivesPredicate, Ty, TyCtxt};
+use rustc_type_ir::outlives::{compute_alias_components_recursive, Component};
 
 use smallvec::smallvec;
 
@@ -139,7 +139,7 @@ impl<'cx, 'tcx> VerifyBoundCx<'cx, 'tcx> {
 
     fn bound_from_components(
         &self,
-        components: &[Component<'tcx>],
+        components: &[Component<TyCtxt<'tcx>>],
         visited: &mut SsoHashSet<GenericArg<'tcx>>,
     ) -> VerifyBound<'tcx> {
         let mut bounds = components
@@ -158,7 +158,7 @@ impl<'cx, 'tcx> VerifyBoundCx<'cx, 'tcx> {
 
     fn bound_from_single_component(
         &self,
-        component: &Component<'tcx>,
+        component: &Component<TyCtxt<'tcx>>,
         visited: &mut SsoHashSet<GenericArg<'tcx>>,
     ) -> VerifyBound<'tcx> {
         match *component {

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

@@ -1,12 +1,12 @@
 use smallvec::smallvec;
 
-use crate::infer::outlives::components::{push_outlives_components, Component};
 use crate::traits::{self, Obligation, ObligationCauseCode, PredicateObligation};
 use rustc_data_structures::fx::FxHashSet;
 use rustc_middle::ty::ToPolyTraitRef;
 use rustc_middle::ty::{self, Ty, TyCtxt, Upcast};
 use rustc_span::symbol::Ident;
 use rustc_span::Span;
+use rustc_type_ir::outlives::{push_outlives_components, Component};
 
 pub fn anonymize_predicate<'tcx>(
     tcx: TyCtxt<'tcx>,

compiler/rustc_infer/src/traits/util.rs

@@ -54,6 +54,13 @@ pub struct Expr<'tcx> {
     pub kind: ExprKind,
     args: ty::GenericArgsRef<'tcx>,
 }
+
+impl<'tcx> rustc_type_ir::inherent::ExprConst<TyCtxt<'tcx>> for Expr<'tcx> {
+    fn args(self) -> ty::GenericArgsRef<'tcx> {
+        self.args
+    }
+}
+
 impl<'tcx> Expr<'tcx> {
     pub fn new_binop(
         tcx: TyCtxt<'tcx>,

compiler/rustc_middle/src/ty/consts/kind.rs

@@ -78,23 +78,6 @@ impl<'tcx> GenericArg<'tcx> {
     pub fn walk(self) -> TypeWalker<'tcx> {
         TypeWalker::new(self)
     }
-
-    /// Iterator that walks the immediate children of `self`. Hence
-    /// `Foo<Bar<i32>, u32>` yields the sequence `[Bar<i32>, u32]`
-    /// (but not `i32`, like `walk`).
-    ///
-    /// Iterator only walks items once.
-    /// It accepts visited set, updates it with all visited types
-    /// and skips any types that are already there.
-    pub fn walk_shallow(
-        self,
-        visited: &mut SsoHashSet<GenericArg<'tcx>>,
-    ) -> impl Iterator<Item = GenericArg<'tcx>> {
-        let mut stack = SmallVec::new();
-        push_inner(&mut stack, self);
-        stack.retain(|a| visited.insert(*a));
-        stack.into_iter()
-    }
 }
 
 impl<'tcx> Ty<'tcx> {