add #![rustc_no_implicit_bounds] #142671

davidtwco · 2025-06-18T13:00:40Z

Follow-up from #137944.

Adds a new rustc_attrs attribute that stops rustc from adding any default bounds. Useful for tests where default bounds just add noise and make debugging harder.

After reviewing all tests with ?Sized, these tests seem like they could probably benefit from #![rustc_no_implicit_bounds].

Skipping most of tests/ui/unsized as these seem to want to test ?Sized
Skipping tests that used Box<T> because it's still bound by T: MetaSized
Skipping parsing or other tests that cared about ?Sized syntactically
Skipping tests for derive(CoercePointee) because this appears to check that the pointee type is relaxed with ?Sized explicitly

r? @lcnr

rustbot · 2025-06-18T13:00:48Z

HIR ty lowering was modified

cc @fmease

compiler/rustc_hir_analysis/src/hir_ty_lowering/bounds.rs

tests/ui/cast/cast-rfc0401-vtable-kinds.rs

tests/ui/traits/next-solver/cycles/coinduction/incompleteness-unstable-result.rs

lcnr

r=me on the rustc impl. I personally feel like applying this attribute in some of the tests makes them worse 🤔 if u want I can check out your PR locally, reset the last commit and manually only readd the tests where I consider the attribute to be useful

davidtwco · 2025-06-18T13:27:28Z

r=me on the rustc impl. I personally feel like applying this attribute in some of the tests makes them worse 🤔 if u want I can check out your PR locally, reset the last commit and manually only readd the tests where I consider the attribute to be useful

Sure, go ahead :)

compiler/rustc_hir_analysis/src/hir_ty_lowering/bounds.rs

Adds a new `rustc_attrs` attribute that stops rustc from adding any default bounds. Useful for tests where default bounds just add noise and make debugging harder.

After reviewing all tests with `?Sized` and discussing with lcnr, these tests seem like they could probably benefit from `#![rustc_no_implicit_bounds]`.

davidtwco · 2025-06-27T11:32:16Z

Had a chat with @lcnr and using the attribute now in just the tests that we think are improvements.

davidtwco · 2025-06-27T12:54:40Z

@bors r=lcnr rollup

bors · 2025-06-27T12:54:43Z

📌 Commit 1fd13fd has been approved by lcnr

It is now in the queue for this repository.

Rollup of 10 pull requests Successful merges: - #142270 (Rustdoc js: even more typechecking improvements) - #142420 (Report infer ty errors during hir ty lowering) - #142671 (add #![rustc_no_implicit_bounds]) - #142721 (Add tracing to `InterpCx::layout_of()` ) - #142818 (Port `#[used]` to new attribute parsing infrastructure) - #143020 (codegen_fn_attrs: make comment more precise) - #143051 (Add tracing to `validate_operand`) - #143060 (Only args in main diag are saved and restored without removing the newly added ones) - #143065 (Improve recovery when users write `where:`) - #143084 (const-eval: error when initializing a static writes to that static) r? `@ghost` `@rustbot` modify labels: rollup

Rollup merge of #142671 - davidtwco:no-default-bounds-attr, r=lcnr add #![rustc_no_implicit_bounds] Follow-up from #137944. Adds a new `rustc_attrs` attribute that stops rustc from adding any default bounds. Useful for tests where default bounds just add noise and make debugging harder. After reviewing all tests with `?Sized`, these tests seem like they could probably benefit from `#![rustc_no_implicit_bounds]`. - Skipping most of `tests/ui/unsized` as these seem to want to test `?Sized` - Skipping tests that used `Box<T>` because it's still bound by `T: MetaSized` - Skipping parsing or other tests that cared about `?Sized` syntactically - Skipping tests for `derive(CoercePointee)` because this appears to check that the pointee type is relaxed with `?Sized` explicitly r? `@lcnr`

Rollup of 10 pull requests Successful merges: - rust-lang/rust#142270 (Rustdoc js: even more typechecking improvements) - rust-lang/rust#142420 (Report infer ty errors during hir ty lowering) - rust-lang/rust#142671 (add #![rustc_no_implicit_bounds]) - rust-lang/rust#142721 (Add tracing to `InterpCx::layout_of()` ) - rust-lang/rust#142818 (Port `#[used]` to new attribute parsing infrastructure) - rust-lang/rust#143020 (codegen_fn_attrs: make comment more precise) - rust-lang/rust#143051 (Add tracing to `validate_operand`) - rust-lang/rust#143060 (Only args in main diag are saved and restored without removing the newly added ones) - rust-lang/rust#143065 (Improve recovery when users write `where:`) - rust-lang/rust#143084 (const-eval: error when initializing a static writes to that static) r? `@ghost` `@rustbot` modify labels: rollup

rustbot assigned lcnr Jun 18, 2025

rustbot added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. WG-trait-system-refactor The Rustc Trait System Refactor Initiative (-Znext-solver) labels Jun 18, 2025