Simplify the `G` in `Diag<'a, G>` by nnethercote · Pull Request #162630 · rust-lang/rust

nnethercote · 2026-09-11T10:24:46Z

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The EmissionGuarantee trait isn't necessary, and just complicates things. Details in individual commits.

r? @oli-obk

rustbot · 2026-09-11T10:24:50Z

HIR ty lowering was modified

cc @fmease

The parser was modified, potentially altering the grammar of (stable) Rust
which would be a breaking change.

cc @fmease

Some changes occurred in compiler/rustc_attr_parsing

cc @jdonszelmann, @JonathanBrouwer

The rustc-dev-guide subtree was changed. If your future PRs only touch the subtree, consider submitting them directly to rust-lang/rustc-dev-guide, which is where the document is primarily maintained (and has faster CI).

cc @BoxyUwU, @tshepang

Some changes occurred in match checking

cc @Nadrieril

Some changes occurred to MIR optimizations

cc @rust-lang/wg-mir-opt

rustc_macros::diagnostics was changed

cc @TaKO8Ki, @JonathanBrouwer

clippy is developed in its own repository. If possible, consider making this change to rust-lang/rust-clippy instead.

cc @rust-lang/clippy

miri is developed in its own repository. If the Miri part of this change can be broken out, consider making this change to rust-lang/miri instead. However, if Miri needs adjusting for rustc changes, just ignore this message.

cc @rust-lang/miri

Some changes occurred to constck

cc @fee1-dead

Some changes occurred to the CTFE machinery

cc @RalfJung, @oli-obk, @lcnr

Some changes occurred in const_evaluatable.rs

cc @BoxyUwU

nnethercote · 2026-09-11T10:25:36Z

The first two commits here are definite wins. I'm more ambivalent about the third commit: it makes some things better and some things worse and I'm not sure if it's a good idea overall.

oli-obk

I was initially a bit sceptical about the third commit, but overall I think it's an improvement. The idea of carrying the emission guarantee as a generic param is nice, but ended up not that useful in practice

@bors r+

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rust-bors · 2026-09-11T12:47:11Z

📌 Commit 4377560 has been approved by oli-obk

It is now in the queue for this repository.

oli-obk · 2026-09-11T12:47:42Z

@bors r- I raced my review with other reviews by not checking that something changed oops

rust-bors · 2026-09-11T12:47:47Z

This pull request was unapproved.

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Kobzol · 2026-09-11T13:37:18Z

@bors try @rust-timer queue

Simplify the `G` in `Diag<'a, G>`

rust-bors · 2026-09-11T14:43:42Z

☀️ Try build successful (CI)
Build commit: ecf783e (ecf783ea825f14de5262e03ad65fd0a2d0bfab8b)
Base parent: ca0a647 (ca0a6473ffde01deb7fce24cc04864cf723e14a0)

@oli-obk

…-obk Simplify the `G` in `Diag<'a, G>` The `EmissionGuarantee` trait isn't necessary, and just complicates things. Details in individual commits. r? @oli-obk

…uwer Rollup of 11 pull requests Successful merges: - #162752 (`rust-analyzer` subtree update) - #161868 (libtest: never iterate over all tests in `--exact` mode) - #161903 (Fix initialization cycle in `target_config`) - #162240 (Garbage-collect old incremental compilation sessions) - #161675 (document that t-lang does not need involvement for unobservable intrisics) - #162630 (Simplify the `G` in `Diag<'a, G>`) - #162647 (Add regression test for previous overflow evaluating the requirement) - #162703 (regression test for valtree leaf const) - #162723 (Add regression test for unexpected type for constructor) - #162735 (Remove pointless `A: Allocator` bounds in boxed.rs) - #162736 (clean up trivial region constraint filtering)

@oli-obk

…-obk Simplify the `G` in `Diag<'a, G>` The `EmissionGuarantee` trait isn't necessary, and just complicates things. Details in individual commits. r? @oli-obk

…uwer Rollup of 15 pull requests Successful merges: - #162752 (`rust-analyzer` subtree update) - #161903 (Fix initialization cycle in `target_config`) - #162240 (Garbage-collect old incremental compilation sessions) - #162610 (fix tailcall indirect return) - #162634 (Implement semantic analysis for named `Fn` trait params) - #161675 (document that t-lang does not need involvement for unobservable intrisics) - #162160 (turn aligned-in-packed error into lint) - #162504 (Stabilize `unsafe_cell_access`) - #162516 (tidy: Sort multi-line types by treating `>` as a closing bracket) - #162630 (Simplify the `G` in `Diag<'a, G>`) - #162647 (Add regression test for previous overflow evaluating the requirement) - #162703 (regression test for valtree leaf const) - #162723 (Add regression test for unexpected type for constructor) - #162735 (Remove pointless `A: Allocator` bounds in boxed.rs) - #162736 (clean up trivial region constraint filtering)

…uwer Rollup of 16 pull requests Successful merges: - #162762 (Subtree sync for rustc_codegen_cranelift) - #162752 (`rust-analyzer` subtree update) - #161903 (Fix initialization cycle in `target_config`) - #162240 (Garbage-collect old incremental compilation sessions) - #162610 (fix tailcall indirect return) - #162634 (Implement semantic analysis for named `Fn` trait params) - #161675 (document that t-lang does not need involvement for unobservable intrisics) - #162160 (turn aligned-in-packed error into lint) - #162504 (Stabilize `unsafe_cell_access`) - #162516 (tidy: Sort multi-line types by treating `>` as a closing bracket) - #162630 (Simplify the `G` in `Diag<'a, G>`) - #162647 (Add regression test for previous overflow evaluating the requirement) - #162703 (regression test for valtree leaf const) - #162723 (Add regression test for unexpected type for constructor) - #162735 (Remove pointless `A: Allocator` bounds in boxed.rs) - #162736 (clean up trivial region constraint filtering)

@oli-obk

Rollup merge of #162630 - nnethercote:simplify-Diag-G, r=oli-obk Simplify the `G` in `Diag<'a, G>` The `EmissionGuarantee` trait isn't necessary, and just complicates things. Details in individual commits. r? @oli-obk

@oli-obk

…-obk Simplify the `G` in `Diag<'a, G>` The `EmissionGuarantee` trait isn't necessary, and just complicates things. Details in individual commits. r? @oli-obk

…uwer Rollup of 16 pull requests Successful merges: - rust-lang/rust#162762 (Subtree sync for rustc_codegen_cranelift) - rust-lang/rust#162752 (`rust-analyzer` subtree update) - rust-lang/rust#161903 (Fix initialization cycle in `target_config`) - rust-lang/rust#162240 (Garbage-collect old incremental compilation sessions) - rust-lang/rust#162610 (fix tailcall indirect return) - rust-lang/rust#162634 (Implement semantic analysis for named `Fn` trait params) - rust-lang/rust#161675 (document that t-lang does not need involvement for unobservable intrisics) - rust-lang/rust#162160 (turn aligned-in-packed error into lint) - rust-lang/rust#162504 (Stabilize `unsafe_cell_access`) - rust-lang/rust#162516 (tidy: Sort multi-line types by treating `>` as a closing bracket) - rust-lang/rust#162630 (Simplify the `G` in `Diag<'a, G>`) - rust-lang/rust#162647 (Add regression test for previous overflow evaluating the requirement) - rust-lang/rust#162703 (regression test for valtree leaf const) - rust-lang/rust#162723 (Add regression test for unexpected type for constructor) - rust-lang/rust#162735 (Remove pointless `A: Allocator` bounds in boxed.rs) - rust-lang/rust#162736 (clean up trivial region constraint filtering)

Remove `G` generic param from `Diag<'_, G>` The benefits are outweighed by the costs. Details in invidual commits. some minor earlier discussion about this change in rust-lang#162630 (comment)

Remove `G` generic param from `Diag<'_, G>` The benefits are outweighed by the costs. Details in invidual commits. some minor earlier discussion about this change in #162630 (comment)

Remove `G` generic param from `Diag<'_, G>` The benefits are outweighed by the costs. Details in invidual commits. some minor earlier discussion about this change in rust-lang#162630 (comment)

Remove `G` generic param from `Diag<'_, G>` The benefits are outweighed by the costs. Details in invidual commits. some minor earlier discussion about this change in #162630 (comment)

Rollup merge of #163083 - nnethercote:rm-Diag-G, r=oli-obk Remove `G` generic param from `Diag<'_, G>` The benefits are outweighed by the costs. Details in invidual commits. some minor earlier discussion about this change in #162630 (comment)

Remove `G` generic param from `Diag<'_, G>` The benefits are outweighed by the costs. Details in invidual commits. some minor earlier discussion about this change in rust-lang/rust#162630 (comment)

…e list (#10) nightly-2026-09-27 does not compile this library. Two upstream changes: 1. rust-lang/rust#162630 (merged 2026-09-14) deleted `rustc_errors::EmissionGuarantee`; `Diagnostic<'a>` and `Diag<'a>` lost the `G` parameter. `RustLintsPolicyDiag` now implements the plain trait. 2. HIR no longer splits `use a::{b, c::*}` into one item per element. It is one `ItemKind::Use(UseTree)` with `UseKind::Nested { items }`. The old `matches!(item.kind, ItemKind::Use(_, UseKind::Glob))` stopped compiling, and a plain port to the new shape would only catch top-level globs. `check_wildcard_import` now recurses and reports each glob at its own path span. Also: `nix flake update rust-overlay nixpkgs` so the rolling default resolves the new nightly, and `supplied-toolchain-identity` moves from 2026-08-26 (no longer compiles) to 2026-09-26: new enough for the new API, and still different from the rolling default, which is what that check is asserting. Needed by techzenlabs/benefits-platform's move to nightly-2026-09-27. ## How verified | Command | Result | |---|---| | `nix flake check` | all 24 checks passed | | `nix develop -c cargo test --release` | 23 passed | | `nix develop -c scripts/check-blocking-in-async-fixture.sh` | OK: 11 expected sites, no others | | fixture `cargo dylint --all -- --workspace` (README command) | 2 wildcard warnings: `product-core/src/lib.rs:7:1` (`use sqlx::*`) and the new `lib.rs:24:21` (`deep::*` inside `use nested::{Named, deep::*}`) | | `cargo fmt --check` | clean | GATE_AT_COMMIT=2ec820e5e23465de0216b1e9561ed561f5c07686

Remove `G` generic param from `Diag<'_, G>` The benefits are outweighed by the costs. Details in invidual commits. some minor earlier discussion about this change in rust-lang#162630 (comment)

rustbot assigned oli-obk Sep 11, 2026

ada4a reviewed Sep 11, 2026

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Comment thread compiler/rustc_ast_lowering/src/lib.rs Outdated

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Auto merge of #162630 - nnethercote:simplify-Diag-G, r=<try>

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Simplify the `G` in `Diag<'a, G>`

rust-bors Bot added S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. and removed S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. labels Sep 14, 2026

JonathanBrouwer mentioned this pull request Sep 14, 2026

Rollup of 11 pull requests #162755

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JonathanBrouwer mentioned this pull request Sep 14, 2026

Rollup of 15 pull requests #162764

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JonathanBrouwer mentioned this pull request Sep 14, 2026

Rollup of 16 pull requests #162767

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rust-bors Bot merged commit 305d36b into rust-lang:main Sep 14, 2026
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nnethercote deleted the simplify-Diag-G branch September 14, 2026 21:53

oli-obk mentioned this pull request Sep 21, 2026

Remove G generic param from Diag<'_, G> #163083

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mikeslade mentioned this pull request Sep 27, 2026

fix(lib): build on nightly-2026-09-27, and find a glob nested in a use list mikeslade/rust-lints#10

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github-actions Bot mentioned this pull request Oct 2, 2026

Toolchain upgrade to nightly-2026-09-25 flux-rs/flux#1803

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Simplify the `G` in `Diag<'a, G>` - #162630

Simplify the `G` in `Diag<'a, G>`#162630
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