From 37ed7a4438a24bcbe13986c82f193fd8e8d88221 Mon Sep 17 00:00:00 2001 From: Noah Lev Date: Tue, 16 Jul 2024 19:07:36 -0700 Subject: Add `ConstArgKind::Path` and make `ConstArg` its own HIR node This is a very large commit since a lot needs to be changed in order to make the tests pass. The salient changes are: - `ConstArgKind` gets a new `Path` variant, and all const params are now represented using it. Non-param paths still use `ConstArgKind::Anon` to prevent this change from getting too large, but they will soon use the `Path` variant too. - `ConstArg` gets a distinct `hir_id` field and its own variant in `hir::Node`. This affected many parts of the compiler that expected the parent of an `AnonConst` to be the containing context (e.g., an array repeat expression). They have been changed to check the "grandparent" where necessary. - Some `ast::AnonConst`s now have their `DefId`s created in rustc_ast_lowering rather than `DefCollector`. This is because in some cases they will end up becoming a `ConstArgKind::Path` instead, which has no `DefId`. We have to solve this in a hacky way where we guess whether the `AnonConst` could end up as a path const since we can't know for sure until after name resolution (`N` could refer to a free const or a nullary struct). If it has no chance as being a const param, then we create a `DefId` in `DefCollector` -- otherwise we decide during ast_lowering. This will have to be updated once all path consts use `ConstArgKind::Path`. - We explicitly use `ConstArgHasType` for array lengths, rather than implicitly relying on anon const type feeding -- this is due to the addition of `ConstArgKind::Path`. - Some tests have their outputs changed, but the changes are for the most part minor (including removing duplicate or almost-duplicate errors). One test now ICEs, but it is for an incomplete, unstable feature and is now tracked at #127009. --- compiler/rustc_trait_selection/src/traits/wf.rs | 16 ++++++++++++++-- 1 file changed, 14 insertions(+), 2 deletions(-) (limited to 'compiler/rustc_trait_selection') diff --git a/compiler/rustc_trait_selection/src/traits/wf.rs b/compiler/rustc_trait_selection/src/traits/wf.rs index f071dc6c784..e77a05dd8e6 100644 --- a/compiler/rustc_trait_selection/src/traits/wf.rs +++ b/compiler/rustc_trait_selection/src/traits/wf.rs @@ -672,9 +672,21 @@ impl<'a, 'tcx> TypeVisitor> for WfPredicates<'a, 'tcx> { self.require_sized(subty, ObligationCauseCode::SliceOrArrayElem); } - ty::Array(subty, _) => { + ty::Array(subty, len) => { self.require_sized(subty, ObligationCauseCode::SliceOrArrayElem); - // Note that we handle the len is implicitly checked while walking `arg`. + // Note that the len being WF is implicitly checked while visiting. + // Here we just check that it's of type usize. + let cause = self.cause(ObligationCauseCode::Misc); + self.out.push(traits::Obligation::with_depth( + tcx, + cause, + self.recursion_depth, + self.param_env, + ty::Binder::dummy(ty::PredicateKind::Clause(ty::ClauseKind::ConstArgHasType( + len, + tcx.types.usize, + ))), + )); } ty::Pat(subty, _) => { -- cgit 1.4.1-3-g733a5