Normalize non-rigid aliases in ty_known_to_outlive by amirHdev · Pull Request #161246 · rust-lang/rust

amirHdev · 2026-08-17T15:32:49Z

ty_known_to_outlive directly registers a TypeOutlives region obligation without normalization. With the next solver, we do not expect non-rigid aliases in lexical region solving.

Normalize non-rigid aliases before registering the obligation while avoiding trait solving for inputs that do not contain them.

fmease · 2026-08-23T13:50:17Z

r? lcnr

lcnr · 2026-09-07T15:11:05Z

r? adwinwhite I think

adwinwhite · 2026-09-15T07:24:35Z

                    parent_param_env,
                    &wf_tys,
-                    t,
+                    ty::Unnormalized::new_wip(t),


We probably don't want to have trait solving inside liveness analysis.
The types here are actually Params so they don't need normalization.
A quick solution is to have a private ty_known_to_outlive in this module, duplicated from the original impl.
A minimal param outlives evaluator would be good but we need to handle region graph. Then it's no longer minimal :<

As a micro-optimization, we can use resolve_regions_with_outlives_env rather than resolve_regions in this private helper since the wf_tys are the same. This might not matter.

View changes since the review

adwinwhite · 2026-09-15T07:30:25Z

-    })
+    let infcx = tcx.infer_ctxt().build(TypingMode::non_body_analysis());
+
+    let ty = ty.skip_norm_wip();


We only need to skip in the old solver branch.

View changes since the review

adwinwhite · 2026-09-15T07:37:28Z

+    ty: Unnormalized<'tcx, Ty<'tcx>>,
    region: ty::Region<'tcx>,
 ) -> bool {
-    test_region_obligations(tcx, id, param_env, wf_tys, |infcx| {


we can still use test_region_obligations and just normalize the ty?

View changes since the review

yeah that's the part I overlooked 😬 I reused test_region_obligations here

adwinwhite · 2026-09-15T07:42:21Z

Thanks for working on this!

@rustbot author

rustbot · 2026-09-15T07:42:25Z

Reminder, once the PR becomes ready for a review, use @rustbot ready.

rustbot · 2026-09-15T10:56:02Z

⚠️ Warning ⚠️

The following commits have merge commits (commits with multiple parents) in your changes. We have a no merge policy so these commits will need to be removed for this pull request to be merged.
- b7361f8
You can start a rebase with the following commands:
```
$ # rebase
$ git pull --rebase https://github.com/rust-lang/rust.git main
$ git push --force-with-lease
```

adwinwhite · 2026-09-17T01:20:34Z

@bors try @rust-timer queue

Normalize non-rigid aliases in ty_known_to_outlive

rust-bors · 2026-09-17T02:24:51Z

☀️ Try build successful (CI)
Build commit: 8fb5e25 (8fb5e252455e58022a18ace472331d58600f2600)
Base parent: 923c95c (923c95cdf5ba65cea505aa2ea829f578e1506ed8)

rust-timer · 2026-09-17T03:09:10Z

Finished benchmarking commit (8fb5e25): comparison URL.

Overall result: no relevant changes - no action needed

Benchmarking means the PR may be perf-sensitive. Consider adding rollup=never if this change is not fit for rolling up.

@rustbot label: -S-waiting-on-perf -perf-regression

Instruction count

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Max RSS (memory usage)

Results (secondary -2.1%)

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	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	3.4%	[2.3%, 4.5%]	2
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-4.0%	[-4.7%, -1.6%]	6
All ❌✅ (primary)	-	-	0

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Results (secondary 2.5%)

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	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	8.2%	[8.2%, 8.2%]	1
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-3.3%	[-3.3%, -3.3%]	1
All ❌✅ (primary)	-	-	0

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This perf run didn't have relevant results for this metric.

Bootstrap: 497.899s -> 498.337s (0.09%)
Artifact size: 406.75 MiB -> 408.85 MiB (0.51%)

adwinwhite · 2026-09-17T03:19:07Z

@bors r+ rollup

rust-bors · 2026-09-17T03:19:09Z

📌 Commit 7f7e359 has been approved by adwinwhite

It is now in the queue for this repository.

…s, r=adwinwhite Normalize non-rigid aliases in ty_known_to_outlive Fixes rust-lang#161067 `ty_known_to_outlive` directly registers a TypeOutlives region obligation without normalization. With the next solver, we do not expect non-rigid aliases in lexical region solving. Normalize non-rigid aliases before registering the obligation while avoiding trait solving for inputs that do not contain them.

Rollup of 16 pull requests Successful merges: - #161596 (coretests: Add more pattern tests.) - #162796 (libtest: do not early exit from test runners) - #162844 (Add loan reachability traces to polonius MIR dumps) - #162876 (Move operations out of `rustc_middle::query::job`) - #160108 (Stabilize `windows_process_extensions_main_thread_handle`) - #160212 (traits: Fix rigid alias liveness matching) - #160544 (Stabilize `feature(trim_prefix_suffix)` (`{str, [T], Path}::trim_prefix` and `{str, [T]}::trim_suffix`)) - #161246 (Normalize non-rigid aliases in ty_known_to_outlive) - #161305 (Use the entire type of a dropped local to compute variance (edge direction) for Polonius alpha) - #161838 (tests: accept LLVM 24 optimization in this test) - #162805 (Add `must_use` lint to `ExitCode`) - #162825 (core: Add examples for `debug_closure_helpers`) - #162841 (enable asm tests for xtensa targets) - #162842 (reintroduce check RibKind::ConstParamTy did in direct consts) - #162845 (mgca: fix issue with mismatched array valtree/valtree tys) - #162856 (Stabilize CommandExt::show_window)

lcnr · 2026-09-17T10:28:33Z

@@ -0,0 +1,17 @@
+//@ compile-flags: -Zassumptions-on-binders
+//@ needs-rustc-debug-assertions
+//@ normalize-stderr: "(\n)\n$" -> "$1"


why this?

View changes since the review

this was only normalizing an extra trailing newline in stderr

pls remove, that doesn't feel worth it

lcnr · 2026-09-17T10:29:10Z

    param_env: ty::ParamEnv<'tcx>,
    wf_tys: &FxIndexSet<Ty<'tcx>>,
-    add_constraints: impl FnOnce(&InferCtxt<'tcx>),
+    add_constraints: impl FnOnce(&InferCtxt<'tcx>) -> bool,


maybe Result<(), ()> instead of bool?

View changes since the review

the bool is only being used to signal normalization failure. I think Result is clearer here

do you want me to update this and cleanup now ?

either now, or in a separate PR. I guess if u fix the ui test, doing it in this PR would be easier

Signed-off-by: Amirhossein Akhlaghpour <m9.akhlaghpoor@gmail.com>

rust-bors · 2026-09-17T11:39:48Z

⚠️ A new commit c6c7dfd27c2dfcfba28372a3612e5169d61834ee was pushed.

This pull request was unapproved.

This PR was contained in a rollup (#162887), which was closed.

lcnr · 2026-09-17T12:30:50Z

    wf_tys: &FxIndexSet<Ty<'tcx>>,
-    add_constraints: impl FnOnce(&InferCtxt<'tcx>),
+    add_constraints: impl FnOnce(&InferCtxt<'tcx>) -> Result<(), ()>,
 ) -> bool {


don't have to do it in this PR, but you can also return Result here and imo should do so then you can do ?

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amirHdev force-pushed the fix-161067-non-rigid-alias branch 2 times, most recently from 1103014 to b881312 Compare August 18, 2026 07:53

rustbot added the T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. label Aug 18, 2026

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amirHdev force-pushed the fix-161067-non-rigid-alias branch 3 times, most recently from d0aeadc to 8806add Compare August 20, 2026 10:51

amirHdev changed the title ~~fix: normalize non-rigid aliases in ty_known_to_outlive~~ Normalize non-rigid aliases in ty_known_to_outlive Aug 20, 2026

amirHdev force-pushed the fix-161067-non-rigid-alias branch from 8806add to 52cc388 Compare August 21, 2026 13:55

amirHdev marked this pull request as ready for review August 21, 2026 13:58

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amirHdev force-pushed the fix-161067-non-rigid-alias branch from b7361f8 to ed266c7 Compare September 15, 2026 11:05

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rust-bors Bot pushed a commit that referenced this pull request Sep 17, 2026

Auto merge of #161246 - amirHdev:fix-161067-non-rigid-alias, r=<try>

8fb5e25

Normalize non-rigid aliases in ty_known_to_outlive

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Zalathar mentioned this pull request Sep 17, 2026

Rollup of 16 pull requests #162887

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lcnr reviewed Sep 17, 2026

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fix: normalize non-rigid aliases in ty_known_to_outlive

c6c7dfd

Signed-off-by: Amirhossein Akhlaghpour <m9.akhlaghpoor@gmail.com>

amirHdev force-pushed the fix-161067-non-rigid-alias branch from 7f7e359 to c6c7dfd Compare September 17, 2026 11:39

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amirHdev requested a review from lcnr September 17, 2026 11:40

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