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fix: Do not ICE on normalization failure of an extern static item #149210

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Merged
merged 1 commit into from
Nov 25, 2025
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Merged

fix: Do not ICE on normalization failure of an extern static item #149210

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15 changes: 11 additions & 4 deletions compiler/rustc_hir_analysis/src/check/wfcheck.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -1186,14 +1186,21 @@ pub(crate) fn check_static_item<'tcx>(
) -> Result<(), ErrorGuaranteed> {
enter_wf_checking_ctxt(tcx, item_id, |wfcx| {
let span = tcx.ty_span(item_id);
let item_ty = wfcx.deeply_normalize(span, Some(WellFormedLoc::Ty(item_id)), ty);
let loc = Some(WellFormedLoc::Ty(item_id));
let item_ty = wfcx.deeply_normalize(span, loc, ty);

let is_foreign_item = tcx.is_foreign_item(item_id);
let is_structurally_foreign_item = || {
let tail = tcx.struct_tail_raw(
item_ty,
&ObligationCause::dummy(),
|ty| wfcx.deeply_normalize(span, loc, ty),
|| {},
);

let forbid_unsized = !is_foreign_item || {
let tail = tcx.struct_tail_for_codegen(item_ty, wfcx.infcx.typing_env(wfcx.param_env));
!matches!(tail.kind(), ty::Foreign(_))
matches!(tail.kind(), ty::Foreign(_))
};
let forbid_unsized = !(is_foreign_item && is_structurally_foreign_item());

wfcx.register_wf_obligation(span, Some(WellFormedLoc::Ty(item_id)), item_ty.into());
if forbid_unsized {
Expand Down
21 changes: 21 additions & 0 deletions tests/ui/static/extern-static-normalization-failure-issue-148161.rs
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Original file line number Diff line number Diff line change
@@ -0,0 +1,21 @@
// Regression test for https://github.com/rust-lang/rust/issues/148161
trait Trait {
type Assoc;
}

impl Trait for u8 {
type Assoc = i8;
}

struct Struct<T: Trait> {
member: T::Assoc,
}

unsafe extern "C" {
// This used to be an ICE due to normalization failure on `<Struct<i8> as Trait>::Assoc`
// while wf checking this static item.
static VAR: Struct<i8>;
//~^ ERROR: the trait bound `i8: Trait` is not satisfied
}

fn main() {}
20 changes: 20 additions & 0 deletions tests/ui/static/extern-static-normalization-failure-issue-148161.stderr
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Original file line number Diff line number Diff line change
@@ -0,0 +1,20 @@
error[E0277]: the trait bound `i8: Trait` is not satisfied
--> $DIR/extern-static-normalization-failure-issue-148161.rs:17:17
|
LL | static VAR: Struct<i8>;
| ^^^^^^^^^^ the trait `Trait` is not implemented for `i8`
|
help: the trait `Trait` is implemented for `u8`
--> $DIR/extern-static-normalization-failure-issue-148161.rs:6:1
|
LL | impl Trait for u8 {
| ^^^^^^^^^^^^^^^^^
note: required by a bound in `Struct`
--> $DIR/extern-static-normalization-failure-issue-148161.rs:10:18
|
LL | struct Struct<T: Trait> {
| ^^^^^ required by this bound in `Struct`

error: aborting due to 1 previous error

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