Port diagnosttic::on_unimplemented by mejrs · Pull Request #151558 · rust-lang/rust

mejrs · 2026-01-23T23:46:13Z

I mostly just want a perf run to see if this is the right way to go (thoughts welcome btw)

won't pass ci (needs #151516), also it's a huge mess of duplication rn

r? ghost

JonathanBrouwer · 2026-01-23T23:54:41Z

Port diagnosttic::unimplemented

rust-bors · 2026-01-24T02:12:50Z

☀️ Try build successful (CI)
Build commit: e5e5a65 (e5e5a6588240040eb81cfb52d8b9c3281547ef47, parent: d222ddc4d90743dfc1e53b610be8fc9d95893d2c)

rust-timer · 2026-01-24T02:54:28Z

Finished benchmarking commit (e5e5a65): comparison URL.

Overall result: ❌ regressions - no action needed

Benchmarking this pull request means it may be perf-sensitive – we'll automatically label it not fit for rolling up. You can override this, but we strongly advise not to, due to possible changes in compiler perf.

@bors rollup=never
@rustbot label: -S-waiting-on-perf -perf-regression

Instruction count

Our most reliable metric. Used to determine the overall result above. However, even this metric can be noisy.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	0.3%	[0.3%, 0.3%]	1
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-	-	0

Max RSS (memory usage)

Results (primary -1.7%, secondary -0.1%)

A less reliable metric. May be of interest, but not used to determine the overall result above.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	3.9%	[3.9%, 3.9%]	1
Improvements ✅ (primary)	-1.7%	[-1.7%, -1.7%]	1
Improvements ✅ (secondary)	-4.2%	[-4.2%, -4.2%]	1
All ❌✅ (primary)	-1.7%	[-1.7%, -1.7%]	1

Cycles

Results (secondary -4.3%)

A less reliable metric. May be of interest, but not used to determine the overall result above.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-4.3%	[-4.9%, -3.0%]	3
All ❌✅ (primary)	-	-	0

Binary size

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

Bootstrap: 470.684s -> 471.14s (0.10%)
Artifact size: 383.48 MiB -> 383.64 MiB (0.04%)

rust-log-analyzer · 2026-02-08T20:07:10Z

The job aarch64-gnu-llvm-20-1 failed! Check out the build log: (web) (plain enhanced) (plain)

Click to see the possible cause of the failure (guessed by this bot)

REPOSITORY                                   TAG       IMAGE ID       CREATED       SIZE
ghcr.io/dependabot/dependabot-updater-core   latest    afc745c7535d   13 days ago   783MB
=> Removing docker images...
Deleted Images:
untagged: ghcr.io/dependabot/dependabot-updater-core:latest
untagged: ghcr.io/dependabot/dependabot-updater-core@sha256:faae3d3a1dedd24cde388bb506bbacc0f7ed1eae99ebac129af66acd8540c84a
deleted: sha256:afc745c7535da1bb12f92c273b9a7e9c52c3f12c5873714b2542da259c6d9769
deleted: sha256:64e147d5e54d9be8b8aa322e511cda02296eda4b8b8d063c6a314833aca50e29
deleted: sha256:5cba409bb463f4e7fa1a19f695450170422582c1bc7c0e934d893b4e5f558bc6
deleted: sha256:cddc6ebd344b0111eaab170ead1dfda24acdfe865ed8a12599a34d338fa8e28b
deleted: sha256:2412c3f334d79134573cd45e657fb6cc0abd75bef3881458b0d498d936545c8d
---
test [ui] tests/ui/abi/abi-sysv64-register-usage.rs ... ignored, ignored when the architecture is aarch64
test [ui] tests/ui/abi/abi-typo-unstable.rs#feature_disabled ... ok
test [ui] tests/ui/abi/abi-typo-unstable.rs#feature_enabled ... ok
test [ui] tests/ui/abi/anon-extern-mod.rs ... ok
test [ui] tests/ui/abi/avr-sram.rs#disable_sram ... ok
test [ui] tests/ui/abi/avr-sram.rs#has_sram ... ok
test [ui] tests/ui/abi/arm-unadjusted-intrinsic.rs#aarch64 ... ok
test [ui] tests/ui/abi/avr-sram.rs#no_sram ... ok
test [ui] tests/ui/abi/arm-unadjusted-intrinsic.rs#arm ... ok
test [ui] tests/ui/abi/bad-custom.rs ... ok
test [ui] tests/ui/abi/c-stack-as-value.rs ... ok
test [ui] tests/ui/abi/c-zst.rs#aarch64-darwin ... ok
test [ui] tests/ui/abi/c-zst.rs#s390x-linux ... ok
---
test [ui] tests/ui/asm/aarch64/type-check-3.rs ... ok
test [ui] tests/ui/asm/aarch64/type-check-2.rs ... ok
test [ui] tests/ui/asm/aarch64/type-f16.rs ... ok
test [ui] tests/ui/asm/aarch64/sym.rs ... ok
test [ui] tests/ui/asm/aarch64v8r.rs#r82 ... ok
test [ui] tests/ui/asm/aarch64v8r.rs#hf ... ok
test [ui] tests/ui/asm/aarch64v8r.rs#sf ... ok
test [ui] tests/ui/asm/bad-template.rs#x86_64 ... ok
test [ui] tests/ui/asm/binary_asm_labels.rs ... ignored, only executed when the architecture is x86_64
test [ui] tests/ui/asm/arm-low-dreg.rs ... ok
test [ui] tests/ui/asm/asm-with-nested-closure.rs ... ok
test [ui] tests/ui/asm/cfg.rs#reva ... ignored, only executed when the architecture is x86_64
---
test [ui] tests/ui/extern/issue-64655-extern-rust-must-allow-unwind.rs#fat3 ... ok
test [ui] tests/ui/extern/issue-80074.rs ... ok
test [ui] tests/ui/extern/issue-95829.rs ... ok
test [ui] tests/ui/extern/issue-64655-extern-rust-must-allow-unwind.rs#thin1 ... ok
test [ui] tests/ui/extern/lgamma-linkage.rs ... ok
test [ui] tests/ui/extern/not-in-block.rs ... ok
test [ui] tests/ui/extern/no-mangle-associated-fn.rs ... ok
test [ui] tests/ui/extern/unsized-extern-derefmove.rs ... ok
test [ui] tests/ui/feature-gates/allow-features-empty.rs ... ok
test [ui] tests/ui/extern/windows-tcb-trash-13259.rs ... ok
---
test [ui] tests/ui/imports/ambiguous-9.rs ... ok
test [ui] tests/ui/imports/ambiguous-import-visibility-module.rs ... ok
test [ui] tests/ui/imports/ambiguous-glob-vs-expanded-extern.rs ... ok
test [ui] tests/ui/imports/ambiguous-8.rs ... ok
test [ui] tests/ui/imports/ambiguous-panic-glob-vs-multiouter.rs ... ok
test [ui] tests/ui/imports/ambiguous-panic-globvsglob.rs ... ok
test [ui] tests/ui/imports/ambiguous-panic-no-implicit-prelude.rs ... ok
test [ui] tests/ui/imports/ambiguous-panic-non-prelude-core-glob.rs ... ok
test [ui] tests/ui/imports/ambiguous-panic-non-prelude-std-glob.rs ... ok
test [ui] tests/ui/imports/ambiguous-panic-pick-core.rs ... ok
test [ui] tests/ui/imports/ambiguous-panic-pick-std.rs ... ok
---

- error: expected identifier, found keyword `if`
-   --> $DIR/ignore_unsupported_options_and_continue_to_use_fallback.rs:4:5
-    |
- LL |     if(Self = "()"),
-    |     ^^ expected identifier, found keyword
-    |
- help: escape `if` to use it as an identifier
-    |
- LL |     r#if(Self = "()"),
-    |     ++
- 
- warning: malformed `on_unimplemented` attribute
-   --> $DIR/ignore_unsupported_options_and_continue_to_use_fallback.rs:4:5
-    |
- LL |     if(Self = "()"),
-    |     ^^^^^^^^^^^^^^^ invalid option found here
-    |
-    = help: only `message`, `note` and `label` are allowed as options
-    = note: `#[warn(malformed_diagnostic_attributes)]` (part of `#[warn(unknown_or_malformed_diagnostic_attributes)]`) on by default
- 
- warning: `message` is ignored due to previous definition of `message`
-   --> $DIR/ignore_unsupported_options_and_continue_to_use_fallback.rs:9:32
-    |
- LL |     message = "custom message",
-    |     -------------------------- `message` is first declared here
- ...
- LL | #[diagnostic::on_unimplemented(message = "fallback!!")]
-    |                                ^^^^^^^^^^^^^^^^^^^^^^ `message` is later redundantly declared here
- 
- error[E0277]: custom message
+ error[E0277]: fallback!!
31   --> $DIR/ignore_unsupported_options_and_continue_to_use_fallback.rs:18:15
32    |
33 LL |     takes_foo(());

36    |     required by a bound introduced by this call
37    |
38    = help: the trait `Foo` is not implemented for `()`
-    = note: custom note
40    = note: fallback note
41 help: this trait has no implementations, consider adding one
42   --> $DIR/ignore_unsupported_options_and_continue_to_use_fallback.rs:13:1

49 LL | fn takes_foo(_: impl Foo) {}
50    |                      ^^^ required by this bound in `takes_foo`
51 
- error: aborting due to 2 previous errors; 2 warnings emitted
+ error: aborting due to 1 previous error
53 
54 For more information about this error, try `rustc --explain E0277`.
---
To only update this specific test, also pass `--test-args diagnostic_namespace/on_unimplemented/ignore_unsupported_options_and_continue_to_use_fallback.rs`

error: 1 errors occurred comparing output.
status: exit status: 1
command: env -u RUSTC_LOG_COLOR RUSTC_ICE="0" RUST_BACKTRACE="short" "/checkout/obj/build/aarch64-unknown-linux-gnu/stage2/bin/rustc" "/checkout/tests/ui/diagnostic_namespace/on_unimplemented/ignore_unsupported_options_and_continue_to_use_fallback.rs" "-Zthreads=1" "-Zsimulate-remapped-rust-src-base=/rustc/FAKE_PREFIX" "-Ztranslate-remapped-path-to-local-path=no" "-Z" "ignore-directory-in-diagnostics-source-blocks=/cargo" "-Z" "ignore-directory-in-diagnostics-source-blocks=/checkout/vendor" "--sysroot" "/checkout/obj/build/aarch64-unknown-linux-gnu/stage2" "--target=aarch64-unknown-linux-gnu" "--check-cfg" "cfg(test,FALSE)" "--error-format" "json" "--json" "future-incompat" "-Ccodegen-units=1" "-Zui-testing" "-Zdeduplicate-diagnostics=no" "-Zwrite-long-types-to-disk=no" "-Cstrip=debuginfo" "--emit" "metadata" "-C" "prefer-dynamic" "--out-dir" "/checkout/obj/build/aarch64-unknown-linux-gnu/test/ui/diagnostic_namespace/on_unimplemented/ignore_unsupported_options_and_continue_to_use_fallback" "-A" "unused" "-W" "unused_attributes" "-A" "internal_features" "-A" "unused_parens" "-A" "unused_braces" "-Crpath" "-Cdebuginfo=0" "-Lnative=/checkout/obj/build/aarch64-unknown-linux-gnu/native/rust-test-helpers"
stdout: none
--- stderr -------------------------------
error[E0277]: fallback!!
##[error]  --> /checkout/tests/ui/diagnostic_namespace/on_unimplemented/ignore_unsupported_options_and_continue_to_use_fallback.rs:18:15
   |
LL |     takes_foo(());
   |     --------- ^^ fallback label
   |     |
   |     required by a bound introduced by this call
   |
   = help: the trait `Foo` is not implemented for `()`
   = note: fallback note
---
   | ^^^^^^^^^
note: required by a bound in `takes_foo`
  --> /checkout/tests/ui/diagnostic_namespace/on_unimplemented/ignore_unsupported_options_and_continue_to_use_fallback.rs:15:22
   |
LL | fn takes_foo(_: impl Foo) {}
   |                      ^^^ required by this bound in `takes_foo`

error: aborting due to 1 previous error

For more information about this error, try `rustc --explain E0277`.
------------------------------------------
---

thread '[ui] tests/ui/on-unimplemented/bad-annotation.rs' panicked at src/tools/compiletest/src/runtest.rs:932:13:
errors differ from expected
status: exit status: 1
command: env -u RUSTC_LOG_COLOR RUSTC_ICE="0" RUST_BACKTRACE="short" "/checkout/obj/build/aarch64-unknown-linux-gnu/stage2/bin/rustc" "/checkout/tests/ui/on-unimplemented/bad-annotation.rs" "-Zthreads=1" "-Zsimulate-remapped-rust-src-base=/rustc/FAKE_PREFIX" "-Ztranslate-remapped-path-to-local-path=no" "-Z" "ignore-directory-in-diagnostics-source-blocks=/cargo" "-Z" "ignore-directory-in-diagnostics-source-blocks=/checkout/vendor" "--sysroot" "/checkout/obj/build/aarch64-unknown-linux-gnu/stage2" "--target=aarch64-unknown-linux-gnu" "--check-cfg" "cfg(test,FALSE)" "--error-format" "json" "--json" "future-incompat" "-Ccodegen-units=1" "-Zui-testing" "-Zdeduplicate-diagnostics=no" "-Zwrite-long-types-to-disk=no" "-Cstrip=debuginfo" "--emit" "metadata" "-C" "prefer-dynamic" "--out-dir" "/checkout/obj/build/aarch64-unknown-linux-gnu/test/ui/on-unimplemented/bad-annotation" "-A" "unused" "-W" "unused_attributes" "-A" "internal_features" "-A" "unused_parens" "-A" "unused_braces" "-Crpath" "-Cdebuginfo=0" "-Lnative=/checkout/obj/build/aarch64-unknown-linux-gnu/native/rust-test-helpers"

stack backtrace:
   8: __rustc::rust_begin_unwind
             at /rustc/9b1f8ff42d110b0ca138116745be921df5dc97e7/library/std/src/panicking.rs:689:5
   9: core::panicking::panic_fmt

rust-bors · 2026-02-10T16:42:33Z

☔ The latest upstream changes (presumably #152437) made this pull request unmergeable. Please resolve the merge conflicts.

rustbot added A-attributes Area: Attributes (`#[…]`, `#![…]`) S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. labels Jan 23, 2026

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rust-bors bot pushed a commit that referenced this pull request Jan 23, 2026

Auto merge of #151558 - mejrs:port_on_unimplemented, r=<try>

e5e5a65

Port diagnosttic::unimplemented

rustbot added the S-waiting-on-perf Status: Waiting on a perf run to be completed. label Jan 23, 2026

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rustbot removed the S-waiting-on-perf Status: Waiting on a perf run to be completed. label Jan 24, 2026

fmease changed the title ~~Port diagnosttic::unimplemented~~ Port diagnosttic::on_unimplemented Jan 24, 2026

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mejrs force-pushed the port_on_unimplemented branch from 314a3ab to a1841a0 Compare February 2, 2026 12:03

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rperier mentioned this pull request Feb 4, 2026

Allow #[diagnostic::on_unimplemented] on impls, specially inherent impls #151796

Open

mejrs added 2 commits February 8, 2026 19:19

on_unimplemented: split structs and implementations

c24fb3b

port over diagnostic::on_unimplemented

f85b181

mejrs force-pushed the port_on_unimplemented branch from a1841a0 to f85b181 Compare February 8, 2026 19:25

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rust-timer commented Jan 24, 2026

Overall result: ❌ regressions - no action needed

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