Avoid ICE when param-env normalization leaves unresolved inference variables by TaKO8Ki · Pull Request #153574 · rust-lang/rust

TaKO8Ki · 2026-03-08T16:48:39Z

Because the impl is already ill-formed, those variables are not fully constrained, so zfully_resolvefails. We previously treated that as an immediate compiler bug withspan_bug!`, which caused an ICE on invalid input.

rustbot · 2026-03-08T16:48:43Z

r? @JonathanBrouwer

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JonathanBrouwer · 2026-03-08T18:20:26Z

r? lcnr

lcnr · 2026-03-30T11:35:12Z

compiler/rustc_trait_selection/src/traits/mod.rs

@@ -308,11 +308,10 @@ fn do_normalize_predicates<'tcx>(
            //
            // @lcnr: Let's still ICE here for now. I want a test case
            // for that.


sorry for the late review

please update this comment, r=me otherwise

lcnr · 2026-03-30T11:35:40Z

tests/ui/traits/non_lifetime_binders/normalized-param-env-unconstrained-type-120033.rs

+#![allow(sized_hierarchy_migration)] //~ WARN unknown lint: `sized_hierarchy_migration`
+#![feature(sized_hierarchy)] // added to keep parameters unconstrained
+
+pub trait Foo<T: std::marker::PointeeSized> {


please use #[rustc_no_implicit_bounds] instead of PointeeSized

rustbot · 2026-03-30T12:57:29Z

This PR changes a file inside tests/crashes. If a crash was fixed, please move into the corresponding ui subdir and add 'Fixes #' to the PR description to autoclose the issue upon merge.

TaKO8Ki · 2026-03-30T13:01:12Z

@bors r=lcnr

rust-bors · 2026-03-30T13:01:16Z

📌 Commit 1df1c8a has been approved by lcnr

It is now in the queue for this repository.

…-normalization-ice, r=lcnr Avoid ICE when param-env normalization leaves unresolved inference variables Fixes rust-lang#153354 Because the impl is already ill-formed, those variables are not fully constrained, so zfully_resolve` fails. We previously treated that as an immediate compiler bug with `span_bug!`, which caused an ICE on invalid input.

JonathanBrouwer · 2026-03-30T13:38:51Z

@bors r-
#154584 (comment)

rust-bors · 2026-03-30T13:39:11Z

This pull request was unapproved.

This PR was contained in a rollup (#154584), which was unapproved.

avoid ICE on invalid param-env normalization remove 120033 crash test fix comments use rustc_no_implicit_bounds set #![allow(incomplete_features)]

TaKO8Ki · 2026-03-30T14:59:59Z

@bors r=lcnr

rust-bors · 2026-03-30T15:00:02Z

📌 Commit d29c489 has been approved by lcnr

It is now in the queue for this repository.

…-normalization-ice, r=lcnr Avoid ICE when param-env normalization leaves unresolved inference variables Fixes rust-lang#153354 Because the impl is already ill-formed, those variables are not fully constrained, so zfully_resolve` fails. We previously treated that as an immediate compiler bug with `span_bug!`, which caused an ICE on invalid input.

Rollup of 7 pull requests Successful merges: - #142659 (compiler-builtins: Clean up features) - #153574 (Avoid ICE when param-env normalization leaves unresolved inference variables) - #153648 (Fix EII function aliases eliminated by LTO) - #153790 (Fix regression when dealing with generics/values with unresolved inference) - #153893 (Lex lifetimes as identifiers, recover from emoji and emit appropriate error) - #153980 (refactor: move doc(rust_logo) check to parser) - #154551 (Skip suggestions pointing to macro def for assert_eq)

…-normalization-ice, r=lcnr Avoid ICE when param-env normalization leaves unresolved inference variables Fixes rust-lang#153354 Because the impl is already ill-formed, those variables are not fully constrained, so zfully_resolve` fails. We previously treated that as an immediate compiler bug with `span_bug!`, which caused an ICE on invalid input.

Rollup of 9 pull requests Successful merges: - #154582 (miri subtree update) - #142659 (compiler-builtins: Clean up features) - #153574 (Avoid ICE when param-env normalization leaves unresolved inference variables) - #153648 (Fix EII function aliases eliminated by LTO) - #153790 (Fix regression when dealing with generics/values with unresolved inference) - #154551 (Skip suggestions pointing to macro def for assert_eq) - #154574 (delete several `ui/consts` tests) - #154577 (Update `mir-opt` 64-bit panic-abort tests for `Alignment` rename) - #154579 (remove debug requirement from hooks)

Rollup merge of #153574 - TaKO8Ki:self-referential-param-env-normalization-ice, r=lcnr Avoid ICE when param-env normalization leaves unresolved inference variables Fixes #153354 Because the impl is already ill-formed, those variables are not fully constrained, so zfully_resolve` fails. We previously treated that as an immediate compiler bug with `span_bug!`, which caused an ICE on invalid input.

rustbot assigned JonathanBrouwer Mar 8, 2026

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. labels Mar 8, 2026

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TaKO8Ki force-pushed the self-referential-param-env-normalization-ice branch from aeeca98 to c652d9d Compare March 8, 2026 18:14

rustbot assigned lcnr and unassigned JonathanBrouwer Mar 8, 2026

lcnr reviewed Mar 30, 2026

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TaKO8Ki force-pushed the self-referential-param-env-normalization-ice branch from a8f3a2a to 1df1c8a Compare March 30, 2026 12:58

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JonathanBrouwer mentioned this pull request Mar 30, 2026

Rollup of 6 pull requests #154584

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rust-bors bot added S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. and removed S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. labels Mar 30, 2026

add self-referential param-env normalization regression

d29c489

avoid ICE on invalid param-env normalization remove 120033 crash test fix comments use rustc_no_implicit_bounds set #![allow(incomplete_features)]

TaKO8Ki force-pushed the self-referential-param-env-normalization-ice branch from 1df1c8a to d29c489 Compare March 30, 2026 13:50

rust-bors bot added the S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. label Mar 30, 2026

rust-bors bot removed the S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. label Mar 30, 2026

tgross35 mentioned this pull request Mar 30, 2026

Rollup of 7 pull requests #154611

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tgross35 mentioned this pull request Mar 31, 2026

Rollup of 8 pull requests #154625

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tgross35 mentioned this pull request Mar 31, 2026

Rollup of 8 pull requests #154628

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JonathanBrouwer mentioned this pull request Mar 31, 2026

Rollup of 21 pull requests #154629

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tgross35 mentioned this pull request Mar 31, 2026

Rollup of 9 pull requests #154633

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rust-bors bot merged commit 3479a1d into rust-lang:main Mar 31, 2026
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rustbot added this to the 1.96.0 milestone Mar 31, 2026

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TaKO8Ki commented Mar 8, 2026 •

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