Add lint against invalid runtime symbol definitions by Urgau · Pull Request #155521 · rust-lang/rust

Urgau · 2026-04-19T16:12:22Z

This PR adds a deny-by-default lint againts invalid runtime symbol definitions, those runtime symbols are assumed and used by core¹ and rustc with a specific definition.

We have had multiple reports of users tripping over std symbols (addressed in a future PR):

This PR is a second attempt after #146505, where T-lang had some reservations about a blanket lint that does not check the signature, which is now done with this PR, and about linting of std runtime symbols when std is not linked, which this PR omits by not including any std runtime symbols (for now).

`invalid_runtime_symbol_definitions`

(deny-by-default)

The invalid_runtime_symbol_definitions lint checks the signature of items whose symbol name is a runtime symbols expected by core differs significantly from the expected signature (like mismatch ABI, mismatch C variadics, mismatch argument count, missing return type, ...).

Example

#[unsafe(no_mangle)]
pub fn memcmp() {} // invalid definition of the `memcmp` runtime symbol

error: invalid definition of the runtime `memcmp` symbol used by the standard library
 --> a.rs:2:1
  |
4 | fn memcmp() {}
  | ^^^^^^^^^^^
  |
  = note: expected `unsafe extern "C" fn(*const c_void, *const c_void, usize) -> i32`
          found    `fn()`
  = help: either fix the signature or remove any attributes like `#[unsafe(no_mangle)]`, `#[unsafe(export_name = "memcmp")]`, or `#[link_name = "memcmp"]`
  = note: `#[deny(invalid_runtime_symbol_definitions)]` on by default

Explanation

Up-most care is required when defining runtime symbols assumed and used by the standard library. They must follow the C specification, not use any standard-library facility or undefined behavior may occur.

The symbols currently checked are memcpy, memmove, memset, memcmp, bcmp and strlen.

`suspicious_runtime_symbol_definitions`

(warn-by-default, asked in this comment)

The suspicious_runtime_symbol_definitions lint checks the signature of items whose symbol name is a runtime symbol expected by core.

Example

#[unsafe(no_mangle)]
pub extern "C" fn strlen(ptr: *mut f32) -> usize { 0 }
// suspicious definition of the `strlen` function
// `ptr` should be `*const std::ffi::c_char`

Explanation

Up-most care is required when defining runtime symbols assumed and used by the standard library. They must follow the C specification, not use any standard-library facility or undefined behavior may occur.

@rustbot labels +I-lang-nominated +T-lang +needs-fcp +A-lints
cc @rust-lang/lang-ops
r? compiler

https://doc.rust-lang.org/core/index.html#how-to-use-the-core-library ↩

rustbot · 2026-04-19T16:12:26Z

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.

PatchMixolydic · 2026-04-19T21:04:36Z

+    ///
+    /// ### Explanation
+    ///
+    /// Up-most care is required when defining runtime symbols assumed and


Nit:

Suggested change

/// Up-most care is required when defining runtime symbols assumed and

/// Utmost care is required when defining runtime symbols assumed and

View changes since the review

traviscross · 2026-04-22T15:51:31Z

Thanks @Urgau for adjusting based on the feedback and moving this forward.

@rfcbot fcp merge lang

jackh726 · 2026-04-22T15:55:32Z

Should this also include rust_eh_personality?

steffahn · 2026-04-22T15:58:40Z

As far as I understood the lang meeting discussion, there was no concern with this PR.

But some opinion that it doesn’t fully replace the previous PR, since some warn-by-default lint more generally applicable (and to actually address the user reports, which were about open and read) might also be desirable. All of this can of course be follow-up work so it shouldn’t block us from getting the lint as in this PR; but it’s be useful to clarify that the user reports (currently mentioned in the OP of this PR) aren’t addressed yet with this PR merged, and in this regard this isn’t a full replacement of #146505.

scottmcm · 2026-04-22T16:51:18Z

My interpretation here: this lint is valuable because the wrong signature for something on the well-known list is clearly and always wrong, so deny makes sense. We should have this lint. (And I'm find expanding to more functions so long as they meet that "definitely incontrovertibly wrong signature for that name that rustc or one of your linked libraries uses" bar. I don't know if we include extern function declarations in rlibs, but if this expanded to a general check that you're not conflicting with other rust libraries that'd also be cool -- not this PR I assume, though.)

Another lint, for "it's very suspicious that you're defining an unmangled open" kinds of things probably also makes sense. That might not be deny though, since it's not as unquestionably wrong. It's a rare case of a rustc lint where I'm plausibly fine with the only mitigation being to allow it, since you could just crate-level-allow it for those very few crates where doing this is intentional because it's trying to implement such things. (Notably if you're trying to define a memcpy you'll need to do extra steps already anyway, IIRC.) But that wouldn't be this PR.

JonathanBrouwer · 2026-06-26T06:17:31Z

@bors p=1 to get around tree closure

rust-bors · 2026-06-26T06:50:55Z

💔 Test for 60c3805 failed: CI. Failed job:

auto - x86_64-gnu-stable (web logs, enhanced plaintext logs)

jhpratt · 2026-06-26T07:04:54Z

@bors retry

rust-log-analyzer · 2026-06-26T07:24:36Z

A job failed! Check out the build log: (web) (plain enhanced) (plain)

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

  TOOLSTATE_PUBLISH: 1
##[endgroup]
    Updating crates.io index
error: failed to get `simd-adler32` as a dependency of package `miniz_oxide v0.8.8`
    ... which satisfies dependency `miniz_oxide = "^0.8.5"` of package `flate2 v1.1.9`
    ... which satisfies dependency `flate2 = "^1.1.9"` of package `citool v0.1.0 (/home/runner/work/rust/rust/src/ci/citool)`

Caused by:
  failed to load source for dependency `simd-adler32`

Caused by:

rust-bors · 2026-06-26T07:34:57Z

💔 Test for 8e191f3 failed: CI. Failed job:

auto - x86_64-gnu-distcheck (web logs, enhanced plaintext logs)

JonathanBrouwer · 2026-06-26T07:43:46Z

@bors retry

rust-bors · 2026-06-26T08:12:19Z

💔 Test for d7af889 failed: CI. Failed job:

auto - x86_64-gnu-llvm-22-3 (web logs, enhanced plaintext logs)

rust-log-analyzer · 2026-06-26T08:49:32Z

The job x86_64-gnu-llvm-22-3 failed! Check out the build log: (web) (plain enhanced) (plain)

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


---- [codegen] tests/codegen-llvm/issues/issue-107681-unwrap_unchecked.rs stdout ----
------FileCheck stdout------------------------------

------FileCheck stderr------------------------------
/checkout/tests/codegen-llvm/issues/issue-107681-unwrap_unchecked.rs:17:12: error: CHECK: expected string not found in input
 // CHECK: [[RET:%.*]] = load i32, ptr [[INNER]]
           ^
/checkout/obj/build/x86_64-unknown-linux-gnu/test/codegen-llvm/issues/issue-107681-unwrap_unchecked/issue-107681-unwrap_unchecked.ll:11:24: note: scanning from here
 %_7 = load ptr, ptr %x, align 8, !nonnull !4, !noundef !4
                       ^
/checkout/obj/build/x86_64-unknown-linux-gnu/test/codegen-llvm/issues/issue-107681-unwrap_unchecked/issue-107681-unwrap_unchecked.ll:11:24: note: with "INNER" equal to "%_7"
 %_7 = load ptr, ptr %x, align 8, !nonnull !4, !noundef !4
                       ^
/checkout/obj/build/x86_64-unknown-linux-gnu/test/codegen-llvm/issues/issue-107681-unwrap_unchecked/issue-107681-unwrap_unchecked.ll:15:2: note: possible intended match here
 %_4 = load i32, ptr %_6, align 4, !noundef !4
 ^

Input file: /checkout/obj/build/x86_64-unknown-linux-gnu/test/codegen-llvm/issues/issue-107681-unwrap_unchecked/issue-107681-unwrap_unchecked.ll
Check file: /checkout/tests/codegen-llvm/issues/issue-107681-unwrap_unchecked.rs

-dump-input=help explains the following input dump.

Input was:
<<<<<<
            1: ; ModuleID = 'issue_107681_unwrap_unchecked.67fd71670d665894-cgu.0' 
            2: source_filename = "issue_107681_unwrap_unchecked.67fd71670d665894-cgu.0" 
            3: target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128" 
            4: target triple = "x86_64-unknown-linux-gnu" 
            5:  
            6: ; Function Attrs: mustprogress nofree norecurse nosync nounwind nonlazybind willreturn memory(read, argmem: readwrite, inaccessiblemem: write, target_mem0: none, target_mem1: none) uwtable 
            7: define noundef i32 @foo(ptr noalias nofree noundef align 8 captures(none) dereferenceable(16) %x) unnamed_addr #0 { 
            8: start: 
            9:  %0 = getelementptr inbounds nuw i8, ptr %x, i64 8 
           10:  %_6 = load ptr, ptr %0, align 8, !nonnull !4, !noundef !4 
           11:  %_7 = load ptr, ptr %x, align 8, !nonnull !4, !noundef !4 
check:17'0                            X~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ error: no match found
check:17'1                                                                 with "INNER" equal to "%_7"
           12:  %_8 = icmp ne ptr %_6, %_7 
check:17'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
           13:  %_14 = getelementptr inbounds nuw i8, ptr %_6, i64 4 
check:17'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
           14:  store ptr %_14, ptr %0, align 8 
check:17'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
           15:  %_4 = load i32, ptr %_6, align 4, !noundef !4 
check:17'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
check:17'2      ?                                              possible intended match
           16:  tail call void @llvm.assume(i1 %_8) 
check:17'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
           17:  ret i32 %_4 
check:17'0     ~~~~~~~~~~~~~
           18: } 
check:17'0     ~~
           19:  
check:17'0     ~
           20: ; Function Attrs: mustprogress nocallback nofree nosync nounwind willreturn memory(inaccessiblemem: write) 
check:17'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
           21: declare void @llvm.assume(i1 noundef) #1 
check:17'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
           22:  
check:17'0     ~
           23: attributes #0 = { mustprogress nofree norecurse nosync nounwind nonlazybind willreturn memory(read, argmem: readwrite, inaccessiblemem: write, target_mem0: none, target_mem1: none) uwtable "probe-stack"="inline-asm" "target-cpu"="x86-64" } 
check:17'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
           24: attributes #1 = { mustprogress nocallback nofree nosync nounwind willreturn memory(inaccessiblemem: write) } 
check:17'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
           25:  
check:17'0     ~
           26: !llvm.module.flags = !{!0, !1, !2} 
check:17'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
           27: !llvm.ident = !{!3} 
check:17'0     ~~~~~~~~~~~~~~~~~~~~
           28:  
check:17'0     ~
           29: !0 = !{i32 8, !"PIC Level", i32 2} 
check:17'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
           30: !1 = !{i32 2, !"RtLibUseGOT", i32 1} 
check:17'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
           31: !2 = !{i32 7, !"uwtable", i32 2} 
check:17'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
           32: !3 = !{!"rustc version 1.98.0-nightly (d7af88977 2026-06-26)"} 
check:17'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
           33: !4 = !{} 
check:17'0     ~~~~~~~~~
>>>>>>

------------------------------------------

error: verification with 'FileCheck' failed
status: exit status: 1
command: "/usr/lib/llvm-22/bin/FileCheck" "--input-file" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/codegen-llvm/issues/issue-107681-unwrap_unchecked/issue-107681-unwrap_unchecked.ll" "/checkout/tests/codegen-llvm/issues/issue-107681-unwrap_unchecked.rs" "--check-prefix=CHECK" "--allow-unused-prefixes" "--dump-input-context" "100" "--implicit-check-not" "br {{.*}}" "--implicit-check-not" "select"
stdout: none
--- stderr -------------------------------
/checkout/tests/codegen-llvm/issues/issue-107681-unwrap_unchecked.rs:17:12: error: CHECK: expected string not found in input
 // CHECK: [[RET:%.*]] = load i32, ptr [[INNER]]
           ^
/checkout/obj/build/x86_64-unknown-linux-gnu/test/codegen-llvm/issues/issue-107681-unwrap_unchecked/issue-107681-unwrap_unchecked.ll:11:24: note: scanning from here
 %_7 = load ptr, ptr %x, align 8, !nonnull !4, !noundef !4
                       ^
/checkout/obj/build/x86_64-unknown-linux-gnu/test/codegen-llvm/issues/issue-107681-unwrap_unchecked/issue-107681-unwrap_unchecked.ll:11:24: note: with "INNER" equal to "%_7"
 %_7 = load ptr, ptr %x, align 8, !nonnull !4, !noundef !4
                       ^
/checkout/obj/build/x86_64-unknown-linux-gnu/test/codegen-llvm/issues/issue-107681-unwrap_unchecked/issue-107681-unwrap_unchecked.ll:15:2: note: possible intended match here
 %_4 = load i32, ptr %_6, align 4, !noundef !4
 ^

Input file: /checkout/obj/build/x86_64-unknown-linux-gnu/test/codegen-llvm/issues/issue-107681-unwrap_unchecked/issue-107681-unwrap_unchecked.ll
Check file: /checkout/tests/codegen-llvm/issues/issue-107681-unwrap_unchecked.rs

-dump-input=help explains the following input dump.

Input was:
<<<<<<
            1: ; ModuleID = 'issue_107681_unwrap_unchecked.67fd71670d665894-cgu.0' 
            2: source_filename = "issue_107681_unwrap_unchecked.67fd71670d665894-cgu.0" 
            3: target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128" 
            4: target triple = "x86_64-unknown-linux-gnu" 
            5:  
            6: ; Function Attrs: mustprogress nofree norecurse nosync nounwind nonlazybind willreturn memory(read, argmem: readwrite, inaccessiblemem: write, target_mem0: none, target_mem1: none) uwtable 
            7: define noundef i32 @foo(ptr noalias nofree noundef align 8 captures(none) dereferenceable(16) %x) unnamed_addr #0 { 
            8: start: 
            9:  %0 = getelementptr inbounds nuw i8, ptr %x, i64 8 
           10:  %_6 = load ptr, ptr %0, align 8, !nonnull !4, !noundef !4 
           11:  %_7 = load ptr, ptr %x, align 8, !nonnull !4, !noundef !4 
check:17'0                            X~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ error: no match found
check:17'1                                                                 with "INNER" equal to "%_7"
           12:  %_8 = icmp ne ptr %_6, %_7 
check:17'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
           13:  %_14 = getelementptr inbounds nuw i8, ptr %_6, i64 4 
check:17'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
           14:  store ptr %_14, ptr %0, align 8 
check:17'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
           15:  %_4 = load i32, ptr %_6, align 4, !noundef !4 
check:17'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
check:17'2      ?                                              possible intended match
           16:  tail call void @llvm.assume(i1 %_8) 
check:17'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
           17:  ret i32 %_4 
check:17'0     ~~~~~~~~~~~~~
           18: } 
check:17'0     ~~
           19:  
check:17'0     ~
           20: ; Function Attrs: mustprogress nocallback nofree nosync nounwind willreturn memory(inaccessiblemem: write) 
check:17'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
           21: declare void @llvm.assume(i1 noundef) #1 
check:17'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
           22:  
check:17'0     ~
           23: attributes #0 = { mustprogress nofree norecurse nosync nounwind nonlazybind willreturn memory(read, argmem: readwrite, inaccessiblemem: write, target_mem0: none, target_mem1: none) uwtable "probe-stack"="inline-asm" "target-cpu"="x86-64" } 
check:17'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
           24: attributes #1 = { mustprogress nocallback nofree nosync nounwind willreturn memory(inaccessiblemem: write) } 
check:17'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
           25:  
check:17'0     ~
           26: !llvm.module.flags = !{!0, !1, !2} 
check:17'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
           27: !llvm.ident = !{!3} 
check:17'0     ~~~~~~~~~~~~~~~~~~~~
           28:  
check:17'0     ~
           29: !0 = !{i32 8, !"PIC Level", i32 2} 
check:17'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
           30: !1 = !{i32 2, !"RtLibUseGOT", i32 1} 
check:17'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
           31: !2 = !{i32 7, !"uwtable", i32 2} 
check:17'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
           32: !3 = !{!"rustc version 1.98.0-nightly (d7af88977 2026-06-26)"} 
check:17'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
           33: !4 = !{} 
check:17'0     ~~~~~~~~~
>>>>>>
------------------------------------------

---- [codegen] tests/codegen-llvm/issues/issue-107681-unwrap_unchecked.rs stdout end ----

JonathanBrouwer · 2026-06-26T09:16:25Z

This is possibly real? Haven't seen this spurious failure before
@bors r-
@bors try jobs=x86_64-gnu-llvm-22-3

rust-bors · 2026-06-26T09:16:30Z

View changes since this unapproval

rust-bors · 2026-06-26T09:43:08Z

💔 Test for 0f09409 failed: CI. Failed job:

try - x86_64-gnu-llvm-22-3 (web logs, enhanced plaintext logs)

rust-log-analyzer · 2026-06-26T11:08:44Z

The job x86_64-gnu-llvm-22-3 failed! Check out the build log: (web) (plain enhanced) (plain)

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


---- [codegen] tests/codegen-llvm/issues/issue-107681-unwrap_unchecked.rs stdout ----
------FileCheck stdout------------------------------

------FileCheck stderr------------------------------
/checkout/tests/codegen-llvm/issues/issue-107681-unwrap_unchecked.rs:17:12: error: CHECK: expected string not found in input
 // CHECK: [[RET:%.*]] = load i32, ptr [[INNER]]
           ^
/checkout/obj/build/x86_64-unknown-linux-gnu/test/codegen-llvm/issues/issue-107681-unwrap_unchecked/issue-107681-unwrap_unchecked.ll:11:24: note: scanning from here
 %_7 = load ptr, ptr %x, align 8, !nonnull !4, !noundef !4
                       ^
/checkout/obj/build/x86_64-unknown-linux-gnu/test/codegen-llvm/issues/issue-107681-unwrap_unchecked/issue-107681-unwrap_unchecked.ll:11:24: note: with "INNER" equal to "%_7"
 %_7 = load ptr, ptr %x, align 8, !nonnull !4, !noundef !4
                       ^
/checkout/obj/build/x86_64-unknown-linux-gnu/test/codegen-llvm/issues/issue-107681-unwrap_unchecked/issue-107681-unwrap_unchecked.ll:15:2: note: possible intended match here
 %_4 = load i32, ptr %_6, align 4, !noundef !4
 ^

Input file: /checkout/obj/build/x86_64-unknown-linux-gnu/test/codegen-llvm/issues/issue-107681-unwrap_unchecked/issue-107681-unwrap_unchecked.ll
Check file: /checkout/tests/codegen-llvm/issues/issue-107681-unwrap_unchecked.rs

-dump-input=help explains the following input dump.

Input was:
<<<<<<
            1: ; ModuleID = 'issue_107681_unwrap_unchecked.67fd71670d665894-cgu.0' 
            2: source_filename = "issue_107681_unwrap_unchecked.67fd71670d665894-cgu.0" 
            3: target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128" 
            4: target triple = "x86_64-unknown-linux-gnu" 
            5:  
            6: ; Function Attrs: mustprogress nofree norecurse nosync nounwind nonlazybind willreturn memory(read, argmem: readwrite, inaccessiblemem: write, target_mem0: none, target_mem1: none) uwtable 
            7: define noundef i32 @foo(ptr noalias nofree noundef align 8 captures(none) dereferenceable(16) %x) unnamed_addr #0 { 
            8: start: 
            9:  %0 = getelementptr inbounds nuw i8, ptr %x, i64 8 
           10:  %_6 = load ptr, ptr %0, align 8, !nonnull !4, !noundef !4 
           11:  %_7 = load ptr, ptr %x, align 8, !nonnull !4, !noundef !4 
check:17'0                            X~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ error: no match found
check:17'1                                                                 with "INNER" equal to "%_7"
           12:  %_8 = icmp ne ptr %_6, %_7 
check:17'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
           13:  %_14 = getelementptr inbounds nuw i8, ptr %_6, i64 4 
check:17'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
           14:  store ptr %_14, ptr %0, align 8 
check:17'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
           15:  %_4 = load i32, ptr %_6, align 4, !noundef !4 
check:17'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
check:17'2      ?                                              possible intended match
           16:  tail call void @llvm.assume(i1 %_8) 
check:17'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
           17:  ret i32 %_4 
check:17'0     ~~~~~~~~~~~~~
           18: } 
check:17'0     ~~
           19:  
check:17'0     ~
           20: ; Function Attrs: mustprogress nocallback nofree nosync nounwind willreturn memory(inaccessiblemem: write) 
check:17'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
           21: declare void @llvm.assume(i1 noundef) #1 
check:17'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
           22:  
check:17'0     ~
           23: attributes #0 = { mustprogress nofree norecurse nosync nounwind nonlazybind willreturn memory(read, argmem: readwrite, inaccessiblemem: write, target_mem0: none, target_mem1: none) uwtable "probe-stack"="inline-asm" "target-cpu"="x86-64" } 
check:17'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
           24: attributes #1 = { mustprogress nocallback nofree nosync nounwind willreturn memory(inaccessiblemem: write) } 
check:17'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
           25:  
check:17'0     ~
           26: !llvm.module.flags = !{!0, !1, !2} 
check:17'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
           27: !llvm.ident = !{!3} 
check:17'0     ~~~~~~~~~~~~~~~~~~~~
           28:  
check:17'0     ~
           29: !0 = !{i32 8, !"PIC Level", i32 2} 
check:17'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
           30: !1 = !{i32 2, !"RtLibUseGOT", i32 1} 
check:17'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
           31: !2 = !{i32 7, !"uwtable", i32 2} 
check:17'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
           32: !3 = !{!"rustc version 1.98.0-nightly (0f09409de 2026-06-26)"} 
check:17'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
           33: !4 = !{} 
check:17'0     ~~~~~~~~~
>>>>>>

------------------------------------------

error: verification with 'FileCheck' failed
status: exit status: 1
command: "/usr/lib/llvm-22/bin/FileCheck" "--input-file" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/codegen-llvm/issues/issue-107681-unwrap_unchecked/issue-107681-unwrap_unchecked.ll" "/checkout/tests/codegen-llvm/issues/issue-107681-unwrap_unchecked.rs" "--check-prefix=CHECK" "--allow-unused-prefixes" "--dump-input-context" "100" "--implicit-check-not" "br {{.*}}" "--implicit-check-not" "select"
stdout: none
--- stderr -------------------------------
/checkout/tests/codegen-llvm/issues/issue-107681-unwrap_unchecked.rs:17:12: error: CHECK: expected string not found in input
 // CHECK: [[RET:%.*]] = load i32, ptr [[INNER]]
           ^
/checkout/obj/build/x86_64-unknown-linux-gnu/test/codegen-llvm/issues/issue-107681-unwrap_unchecked/issue-107681-unwrap_unchecked.ll:11:24: note: scanning from here
 %_7 = load ptr, ptr %x, align 8, !nonnull !4, !noundef !4
                       ^
/checkout/obj/build/x86_64-unknown-linux-gnu/test/codegen-llvm/issues/issue-107681-unwrap_unchecked/issue-107681-unwrap_unchecked.ll:11:24: note: with "INNER" equal to "%_7"
 %_7 = load ptr, ptr %x, align 8, !nonnull !4, !noundef !4
                       ^
/checkout/obj/build/x86_64-unknown-linux-gnu/test/codegen-llvm/issues/issue-107681-unwrap_unchecked/issue-107681-unwrap_unchecked.ll:15:2: note: possible intended match here
 %_4 = load i32, ptr %_6, align 4, !noundef !4
 ^

Input file: /checkout/obj/build/x86_64-unknown-linux-gnu/test/codegen-llvm/issues/issue-107681-unwrap_unchecked/issue-107681-unwrap_unchecked.ll
Check file: /checkout/tests/codegen-llvm/issues/issue-107681-unwrap_unchecked.rs

-dump-input=help explains the following input dump.

Input was:
<<<<<<
            1: ; ModuleID = 'issue_107681_unwrap_unchecked.67fd71670d665894-cgu.0' 
            2: source_filename = "issue_107681_unwrap_unchecked.67fd71670d665894-cgu.0" 
            3: target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128" 
            4: target triple = "x86_64-unknown-linux-gnu" 
            5:  
            6: ; Function Attrs: mustprogress nofree norecurse nosync nounwind nonlazybind willreturn memory(read, argmem: readwrite, inaccessiblemem: write, target_mem0: none, target_mem1: none) uwtable 
            7: define noundef i32 @foo(ptr noalias nofree noundef align 8 captures(none) dereferenceable(16) %x) unnamed_addr #0 { 
            8: start: 
            9:  %0 = getelementptr inbounds nuw i8, ptr %x, i64 8 
           10:  %_6 = load ptr, ptr %0, align 8, !nonnull !4, !noundef !4 
           11:  %_7 = load ptr, ptr %x, align 8, !nonnull !4, !noundef !4 
check:17'0                            X~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ error: no match found
check:17'1                                                                 with "INNER" equal to "%_7"
           12:  %_8 = icmp ne ptr %_6, %_7 
check:17'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
           13:  %_14 = getelementptr inbounds nuw i8, ptr %_6, i64 4 
check:17'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
           14:  store ptr %_14, ptr %0, align 8 
check:17'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
           15:  %_4 = load i32, ptr %_6, align 4, !noundef !4 
check:17'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
check:17'2      ?                                              possible intended match
           16:  tail call void @llvm.assume(i1 %_8) 
check:17'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
           17:  ret i32 %_4 
check:17'0     ~~~~~~~~~~~~~
           18: } 
check:17'0     ~~
           19:  
check:17'0     ~
           20: ; Function Attrs: mustprogress nocallback nofree nosync nounwind willreturn memory(inaccessiblemem: write) 
check:17'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
           21: declare void @llvm.assume(i1 noundef) #1 
check:17'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
           22:  
check:17'0     ~
           23: attributes #0 = { mustprogress nofree norecurse nosync nounwind nonlazybind willreturn memory(read, argmem: readwrite, inaccessiblemem: write, target_mem0: none, target_mem1: none) uwtable "probe-stack"="inline-asm" "target-cpu"="x86-64" } 
check:17'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
           24: attributes #1 = { mustprogress nocallback nofree nosync nounwind willreturn memory(inaccessiblemem: write) } 
check:17'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
           25:  
check:17'0     ~
           26: !llvm.module.flags = !{!0, !1, !2} 
check:17'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
           27: !llvm.ident = !{!3} 
check:17'0     ~~~~~~~~~~~~~~~~~~~~
           28:  
check:17'0     ~
           29: !0 = !{i32 8, !"PIC Level", i32 2} 
check:17'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
           30: !1 = !{i32 2, !"RtLibUseGOT", i32 1} 
check:17'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
           31: !2 = !{i32 7, !"uwtable", i32 2} 
check:17'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
           32: !3 = !{!"rustc version 1.98.0-nightly (0f09409de 2026-06-26)"} 
check:17'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
           33: !4 = !{} 
check:17'0     ~~~~~~~~~
>>>>>>
------------------------------------------

---- [codegen] tests/codegen-llvm/issues/issue-107681-unwrap_unchecked.rs stdout end ----

Urgau · 2026-06-26T16:33:37Z

This is possibly real? Haven't seen this spurious failure before

Looks like it's new spurious failure. I'm seeing in on other PRs (#158115 (comment)), and of course it doesn't reproduce locally for me.

Re-adding to the queue, hopefully it will pass next time 🤞

@bors r=davidtwco

rust-bors · 2026-06-26T16:33:41Z

📌 Commit 56d17c4 has been approved by davidtwco

It is now in the queue for this repository.

rust-bors · 2026-06-26T18:09:47Z

💔 Test for 390231d failed: CI. Failed job:

auto - aarch64-msvc-1 (web logs, enhanced plaintext logs)

JonathanBrouwer · 2026-06-26T18:16:14Z

@bors retry

rust-bors · 2026-06-26T18:19:14Z

💔 Test for d12bbc8 failed: CI. Failed job:

auto - x86_64-gnu-llvm-21-2 (web logs, enhanced plaintext logs)

JonathanBrouwer · 2026-06-26T18:22:06Z

@bors retry

rust-bors · 2026-06-26T21:37:03Z

☀️ Test successful - CI
Approved by: davidtwco
Duration: 3h 8m 7s
Pushing ce9954c to main...

github-actions · 2026-06-26T21:40:10Z

What is this?

This is an experimental post-merge analysis report that shows differences in test outcomes between the merged PR and its parent PR.

Comparing eb6346c (parent) -> ce9954c (this PR)

Test differences

Show 9 test diffs

Stage 1

[ui] tests/ui/lint/runtime-symbols.rs: [missing] -> pass (J0)
[ui (polonius)] tests/ui/lint/runtime-symbols.rs: [missing] -> pass (J1)

Stage 2

[ui] tests/ui/lint/runtime-symbols.rs: [missing] -> pass (J2)

Additionally, 6 doctest diffs were found. These are ignored, as they are noisy.

Job group index

Test dashboard

Run

cargo run --manifest-path src/ci/citool/Cargo.toml -- \
    test-dashboard ce9954c0cfc4bf26b82aef16e6fd8b020c237992 --output-dir test-dashboard

And then open test-dashboard/index.html in your browser to see an overview of all executed tests.

Job duration changes

x86_64-rust-for-linux: 28m 8s -> 46m 48s (+66.3%)
dist-i586-gnu-i586-i686-musl: 1h 5m -> 1h 33m (+42.5%)
dist-various-2: 46m -> 28m 10s (-38.8%)
x86_64-gnu-distcheck: 2h 19m -> 1h 26m (-38.3%)
dist-riscv64-linux: 1h 29m -> 58m 2s (-34.8%)
dist-x86_64-freebsd: 1h 11m -> 1h 32m (+30.0%)
x86_64-msvc-2: 2h 25m -> 1h 48m (-25.2%)
dist-i686-msvc: 2h 1m -> 1h 32m (-23.8%)
dist-powerpc64-linux-gnu: 1h 16m -> 1h 33m (+22.1%)
dist-armhf-linux: 1h 11m -> 1h 25m (+20.9%)

How to interpret the job duration changes?

Job durations can vary a lot, based on the actual runner instance
that executed the job, system noise, invalidated caches, etc. The table above is provided
mostly for t-infra members, for simpler debugging of potential CI slow-downs.

rust-timer · 2026-06-26T22:23:31Z

Finished benchmarking commit (ce9954c): comparison URL.

Overall result: ✅ improvements - no action needed

@rustbot label: -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
Improvements ✅ (primary)	-0.2%	[-0.2%, -0.2%]	1
Improvements ✅ (secondary)	-0.1%	[-0.1%, -0.1%]	1
All ❌✅ (primary)	-0.2%	[-0.2%, -0.2%]	1

Max RSS (memory usage)

Results (primary 2.0%, secondary 2.0%)

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

	mean	range	count
Regressions ❌ (primary)	2.0%	[1.1%, 2.7%]	3
Regressions ❌ (secondary)	2.0%	[1.6%, 2.1%]	6
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	2.0%	[1.1%, 2.7%]	3

Cycles

Results (secondary 0.9%)

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)	4.2%	[1.4%, 10.8%]	6
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-3.1%	[-3.8%, -2.3%]	5
All ❌✅ (primary)	-	-	0

Binary size

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

Bootstrap: 485.381s -> 486.597s (0.25%)
Artifact size: 392.99 MiB -> 395.64 MiB (0.67%)

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. T-libs Relevant to the library team, which will review and decide on the PR/issue. labels Apr 19, 2026

rustbot assigned davidtwco Apr 19, 2026

Urgau mentioned this pull request Apr 19, 2026

Add lint about redefining runtime symbols #146505

Closed