Stall computing instance for drop shim until it has no unsubstituted const params
Do not inline the drop shim for types that still have unsubstituted const params.
## Why?
#127030 ICEs because it tries to inline the drop shim for a type with an unsubstituted const param. In order to generate this shim, this requires calling the drop shim builder, which invokes the trait solver to compute whether constituent types need drop (since we compute if a type is copy to disqualify any `Drop` behavior):
9c3bc805dd/compiler/rustc_mir_dataflow/src/elaborate_drops.rs (L378)
However, since we don't keep the param-env of the instance we resolved the item for, we use the wrong param-env:
9c3bc805dd/compiler/rustc_mir_transform/src/shim.rs (L278)
(which is the param-env of `std::ptr::drop_in_place`)
This param-env is notably missing `ConstParamHasTy` predicates, and since we removed the type from consts in https://github.com/rust-lang/rust/pull/125958, we literally cannot prove these predicates in this (relatively) empty param-env. This currently happens in places like the MIR inliner, but may happen elsewhere such as in lints that resolve terminators.
## What?
We force the inliner to not consider calls for `drop_in_place` for types that have unsubstituted const params.
## So what?
This may negatively affect MIR inlining, but I doubt this matters in practice, and fixes a beta regression, so let's fix it. I will look into approaches for fixing this in a more maintainable way, perhaps delaying the creation of drop shim bodies until codegen (like how intrinsics work).
Enable const casting for `f16` and `f128`
I have an open PR to the Miri repo adding tests for this behavior https://github.com/rust-lang/miri/pull/3688, but that unfortunately hits the ICE path here. The changes seem reasonably low risk that it might be okay to merge separately from the tests, and I tested the result locally against an older version of https://github.com/rust-lang/miri/pull/3688.
Cc ``````@RalfJung``````
Switch back `non_local_definitions` lint to allow-by-default
This PR switch back (again) the `non_local_definitions` lint to allow-by-default as T-lang is requesting some (major) changes in the lint inner workings in https://github.com/rust-lang/rust/issues/126768#issuecomment-2192634762.
This PR will need to be beta-backported, as the lint is currently warn-by-default in beta.
Update AST validation module docs
Drive-by doc update for AST validation pass:
- Syntax extensions are replaced by proc macros.
- Add rationale for why AST validation pass need to be run
post-expansion and why the pass is needed in the first place.
This was discussed during this week's [rustc-dev-guide reading club](https://rust-lang.zulipchat.com/#narrow/stream/196385-t-compiler.2Fwg-rustc-dev-guide), and the rationale was explained by cc ``````@bjorn3.``````
Instead of keeping a list of architectures which have native support
for 64-bit atomics, just use #[cfg(target_has_atomic = "64")] and its
inverted counterpart to determine whether we need to use portable
AtomicU64 on the target architecture.
Tighten `fn_decl_span` for async blocks
Tightens the span of `async {}` blocks in diagnostics, and subsequently async closures and async fns, by actually setting the `fn_decl_span` correctly. This is kinda a follow-up on #125078, but it fixes the problem in a more general way.
I think the diagnostics are significantly improved, since we no longer have a bunch of overlapping spans. I'll point out one caveat where I think the diagnostic may get a bit more confusing, but where I don't think it matters.
r? ````@estebank```` or ````@oli-obk```` or someone else on wg-diag or compiler i dont really care lol
Support fetching `Attribute` of items.
Fixes [https://github.com/rust-lang/project-stable-mir/issues/83](https://github.com/rust-lang/project-stable-mir/issues/83)
`rustc_ast::ast::Attribute` doesn't impl `Hash` and `Eq`. Thus it cannot be directly used as key of `IndexMap` in `rustc_smir::rustc_smir::Tables` and we cannot define stable `Attribute` as index to `rustc_ast::ast::Attribute` like `Span` and many other stable definitions.
Since an string (or tokens) and its span contain all info about an attribute, I defined a simple `Attribute` struct on stable side.
I choose to fetch attributes via `tcx::get_attrs_by_path()` due to `get_attrs()` is marked as deprecated and `get_attrs_by_name()` cannot handle name of multiple segments like `rustfmt::skip`.
r? `@celinval`
patchable-function-entry: Add unstable compiler flag and attribute
Tracking issue: #123115
Add the -Z patchable-function-entry compiler flag and the #[patchable_function_entry(prefix_nops = m, entry_nops = n)] attribute.
Rebased and adjusted the canditate implementation to match changes in the RFC.
ast: Standardize visiting order
Order: ID, attributes, inner nodes in source order if possible, tokens, span.
Also always use exhaustive matching in visiting infra, and visit some discovered missing nodes.
Unlike https://github.com/rust-lang/rust/pull/125741 this shouldn't affect anything serious like `macro_rules` scopes.
coverage: Make `#[coverage(..)]` apply recursively to nested functions
This PR makes the (currently-unstable) `#[coverage(off)]` and `#[coverage(on)]` attributes apply recursively to all nested functions/closures, instead of just the function they are directly attached to.
Those attributes can now also be applied to modules and to impl/impl-trait blocks, where they have no direct effect, but will be inherited by all enclosed functions/closures/methods that don't override the inherited value.
---
Fixes#126625.
Fixes for 32-bit SPARC on Linux
This PR fixes a number of issues which previously prevented `rustc` from being built
successfully for 32-bit SPARC using the `sparc-unknown-linux-gnu` triplet.
In particular, it adds linking against `libatomic` where necessary, uses portable `AtomicU64`
for `rustc_data_structures` and rewrites the spec for `sparc_unknown_linux_gnu` to use
`TargetOptions` and replaces the previously used `-mv8plus` with the more portable
`-mcpu=v9 -m32`.
To make `rustc` build successfully, support for 32-bit SPARC needs to be added to the `object`
crate as well as the `nix` crate which I will be sending out later as well.
r? nagisa
Under gate `ref_pat_eat_one_layer_2024_structural`.
Enabling `ref_pat_eat_one_layer_2024` at the same time allows the union
of what the individual gates allow.
