Use `rustc_type_ir` directly less in the codebase #138464

compiler-errors · 2025-03-13T18:37:09Z

This is a somewhat opinionated bundle of changes that will make working on #138449 more easy, since it cuts out the bulk of the changes that would be necessitated by the lint. Namely:

Fold rustc_middle::ty::fold and rustc_middle::ty::visit into rustc_middle::ty. This is because we already reexport some parts of these modules into rustc_middle::ty, and there's really no benefit from namespacing away the rest of these modules's functionality given how important folding and visiting is to the type layer.
Rename {Decodable,Encodable}_Generic to {Decodable,Encodable}_NoContext¹, change it to be "perfect derive" (synstructure::AddBounds::Fields), use it throughout rustc_type_ir instead of TyEncodable/TyDecodable.
Make TyEncodable and TyDecodable derives use ::rustc_middle::ty::codec::TyEncoder (etc) for its generated paths, and move the rustc_type_ir::codec module back to rustc_middle::ty::codec 🎉.
Stop using rustc_type_ir in crates that aren't "fundamental" to the type system, namely middle/infer/trait-selection. This amounted mostly to changing imports from use rustc_type_ir::... to use rustc_middle::ty::..., but also this means that we can't glob import TyKind::* since the reexport into rustc_middle::ty::TyKind is a type alias. Instead, use the prefixed variants like ty::Str everywhere -- IMO this is a good change, since it makes it more regularized with most of the rest of the compiler.

I'm happy to cut out some of these changes into separate PRs to make landing it a bit easier, though I don't expect to have much trouble with bitrot.

r? lcnr

_NoContext is the name for derive macros with no additional generic bounds and which do "perfect derive" by generating bounds based on field types. See HashStable_NoContext. ↩

rustbot · 2025-03-13T18:37:20Z

changes to the core type system

cc @compiler-errors, @lcnr

Some changes occurred to the core trait solver

cc @rust-lang/initiative-trait-system-refactor

Some changes occurred in compiler/rustc_sanitizers

cc @rust-lang/project-exploit-mitigations, @rcvalle

changes to inspect_obligations.rs

cc @compiler-errors, @lcnr

These commits modify the Cargo.lock file. Unintentional changes to Cargo.lock can be introduced when switching branches and rebasing PRs.

If this was unintentional then you should revert the changes before this PR is merged.
Otherwise, you can ignore this comment.

Some changes occurred to the CTFE machinery

cc @RalfJung, @oli-obk, @lcnr

Some changes occurred to MIR optimizations

cc @rust-lang/wg-mir-opt

Some changes occurred to the CTFE / Miri interpreter

cc @rust-lang/miri, @RalfJung, @oli-obk, @lcnr

Some changes occurred in compiler/rustc_codegen_ssa

cc @WaffleLapkin

HIR ty lowering was modified

cc @fmease

Some changes occurred in src/tools/clippy

cc @rust-lang/clippy

Some changes occurred to the CTFE / Miri interpreter

cc @rust-lang/miri

Some changes occurred in need_type_info.rs

cc @lcnr

lcnr · 2025-03-14T07:46:12Z

@bors r+ rollup=iffy

bors · 2025-03-14T07:46:14Z

📌 Commit e4a6593 has been approved by lcnr

It is now in the queue for this repository.

Use `rustc_type_ir` directly less in the codebase cc rust-lang#138449 This is a somewhat opinionated bundle of changes that will make working on rust-lang#138449 more easy, since it cuts out the bulk of the changes that would be necessitated by the lint. Namely: 1. Fold `rustc_middle::ty::fold` and `rustc_middle::ty::visit` into `rustc_middle::ty`. This is because we already reexport some parts of these modules into `rustc_middle::ty`, and there's really no benefit from namespacing away the rest of these modules's functionality given how important folding and visiting is to the type layer. 2. Rename `{Decodable,Encodable}_Generic` to `{Decodable,Encodable}_NoContext`[^why], change it to be "perfect derive" (`synstructure::AddBounds::Fields`), use it throughout `rustc_type_ir` instead of `TyEncodable`/`TyDecodable`. 3. Make `TyEncodable` and `TyDecodable` derives use `::rustc_middle::ty::codec::TyEncoder` (etc) for its generated paths, and move the `rustc_type_ir::codec` module back to `rustc_middle::ty::codec` :tada:. 4. Stop using `rustc_type_ir` in crates that aren't "fundamental" to the type system, namely middle/infer/trait-selection. This amounted mostly to changing imports from `use rustc_type_ir::...` to `use rustc_middle::ty::...`, but also this means that we can't glob import `TyKind::*` since the reexport into `rustc_middle::ty::TyKind` is a type alias. Instead, use the prefixed variants like `ty::Str` everywhere -- IMO this is a good change, since it makes it more regularized with most of the rest of the compiler. [^why]: `_NoContext` is the name for derive macros with no additional generic bounds and which do "perfect derive" by generating bounds based on field types. See `HashStable_NoContext`. I'm happy to cut out some of these changes into separate PRs to make landing it a bit easier, though I don't expect to have much trouble with bitrot. r? lcnr

bors · 2025-03-14T10:09:21Z

⌛ Testing commit e4a6593 with merge 6fbc082...

bors · 2025-03-14T10:18:32Z

💔 Test failed - checks-actions

compiler-errors · 2025-03-15T06:43:21Z

@bors r=lcnr

bors · 2025-03-15T06:43:24Z

📌 Commit b88f85a has been approved by lcnr

It is now in the queue for this repository.

bors · 2025-03-15T08:36:42Z

⌛ Testing commit b88f85a with merge aa95b96...

bors · 2025-03-15T11:39:10Z

☀️ Test successful - checks-actions
Approved by: lcnr
Pushing aa95b96 to master...

github-actions · 2025-03-15T11:40:47Z

This is an experimental post-merge analysis report. You can ignore it.

Post-merge report

Comparing adea7cb (base) -> aa95b96 (this PR)

Test differences

Additionally, 136 doctest diffs were found. These are ignored, as they are noisy.

Job group index

rust-timer · 2025-03-15T12:57:04Z

Finished benchmarking commit (aa95b96): comparison URL.

Overall result: ❌ regressions - no action needed

@rustbot label: -perf-regression

Instruction count

This is the most reliable metric that we have; it was used to determine the overall result at the top of this comment. However, even this metric can sometimes exhibit noise.

	mean	range	count
Regressions ❌ (primary)	2.1%	[2.1%, 2.1%]	1
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	2.1%	[2.1%, 2.1%]	1

Max RSS (memory usage)

This benchmark run did not return any relevant results for this metric.

Cycles

This benchmark run did not return any relevant results for this metric.

Binary size

This benchmark run did not return any relevant results for this metric.

Bootstrap: 773.052s -> 771.649s (-0.18%)
Artifact size: 365.08 MiB -> 365.07 MiB (-0.00%)

Use `rustc_type_ir` directly less in the codebase cc rust-lang#138449 This is a somewhat opinionated bundle of changes that will make working on rust-lang#138449 more easy, since it cuts out the bulk of the changes that would be necessitated by the lint. Namely: 1. Fold `rustc_middle::ty::fold` and `rustc_middle::ty::visit` into `rustc_middle::ty`. This is because we already reexport some parts of these modules into `rustc_middle::ty`, and there's really no benefit from namespacing away the rest of these modules's functionality given how important folding and visiting is to the type layer. 2. Rename `{Decodable,Encodable}_Generic` to `{Decodable,Encodable}_NoContext`[^why], change it to be "perfect derive" (`synstructure::AddBounds::Fields`), use it throughout `rustc_type_ir` instead of `TyEncodable`/`TyDecodable`. 3. Make `TyEncodable` and `TyDecodable` derives use `::rustc_middle::ty::codec::TyEncoder` (etc) for its generated paths, and move the `rustc_type_ir::codec` module back to `rustc_middle::ty::codec` :tada:. 4. Stop using `rustc_type_ir` in crates that aren't "fundamental" to the type system, namely middle/infer/trait-selection. This amounted mostly to changing imports from `use rustc_type_ir::...` to `use rustc_middle::ty::...`, but also this means that we can't glob import `TyKind::*` since the reexport into `rustc_middle::ty::TyKind` is a type alias. Instead, use the prefixed variants like `ty::Str` everywhere -- IMO this is a good change, since it makes it more regularized with most of the rest of the compiler. [^why]: `_NoContext` is the name for derive macros with no additional generic bounds and which do "perfect derive" by generating bounds based on field types. See `HashStable_NoContext`. I'm happy to cut out some of these changes into separate PRs to make landing it a bit easier, though I don't expect to have much trouble with bitrot. r? lcnr

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workingjubilee mentioned this pull request Mar 14, 2025

shared-generics: Do not share instantiations that contain local-only types #138522

Open

compiler-errors added 5 commits March 15, 2025 06:34

Squash fold into ty

dc0cdfd

Fold visit into ty

e5a2220

Use {Decodable,Encodable}_NoContext in type_ir

6438b9e

Move codec module back into middle

19c84c8

Stop relying on rustc_type_ir in non-type-system crates

b88f85a

compiler-errors force-pushed the less-type-ir branch from e4a6593 to b88f85a Compare March 15, 2025 06:43

bors 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-review Status: Awaiting review from the assignee but also interested parties. labels Mar 15, 2025

bors added the merged-by-bors This PR was explicitly merged by bors. label Mar 15, 2025

bors merged commit aa95b96 into rust-lang:master Mar 15, 2025
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Use `rustc_type_ir` directly less in the codebase #138464

Use `rustc_type_ir` directly less in the codebase #138464

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Test differences

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Use rustc_type_ir directly less in the codebase #138464

Use rustc_type_ir directly less in the codebase #138464

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Test differences

rust-timer commented Mar 15, 2025

Overall result: ❌ regressions - no action needed

Instruction count

Max RSS (memory usage)

Cycles

Binary size

Use `rustc_type_ir` directly less in the codebase #138464

Use `rustc_type_ir` directly less in the codebase #138464