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taint fcx on selection errors during unsizing

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This commit is contained in:
Lukas Markeffsky 2025-01-02 18:31:40 +01:00
parent bf6f8a4d32
commit 93bb639ad6
5 changed files with 119 additions and 14 deletions
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7
compiler/rustc_hir_typeck/src/coercion.rs
View file

@ -666,7 +666,12 @@ impl<'f, 'tcx> Coerce<'f, 'tcx> {
// Dyn-compatibility violations or miscellaneous.
Err(err) => {
self.err_ctxt().report_selection_error(obligation.clone(), &obligation, &err);
let guar = self.err_ctxt().report_selection_error(
obligation.clone(),
&obligation,
&err,
);
self.fcx.set_tainted_by_errors(guar);
// Treat this like an obligation and follow through
// with the unsizing - the lack of a coercion should
// be silent, as it causes a type mismatch later.

13
tests/crashes/130521.rs
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@ -1,13 +0,0 @@
//@ known-bug: #130521
#![feature(dyn_compatible_for_dispatch)]
struct Vtable(dyn Cap<'static>);
trait Cap<'a> {}
union Transmute {
t: u128,
u: &'static Vtable,
}
const G: &Copy = unsafe { Transmute { t: 1 }.u };

71
tests/ui/dyn-compatibility/taint-const-eval.curr.stderr Normal file
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@ -0,0 +1,71 @@
error[E0038]: the trait `Qux` cannot be made into an object
--> $DIR/taint-const-eval.rs:11:15
|
LL | static FOO: &(dyn Qux + Sync) = "desc";
| ^^^^^^^^^^^^^^ `Qux` cannot be made into an object
|
note: for a trait to be "dyn-compatible" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
--> $DIR/taint-const-eval.rs:8:8
|
LL | trait Qux {
| --- this trait cannot be made into an object...
LL | fn bar();
| ^^^ ...because associated function `bar` has no `self` parameter
help: consider turning `bar` into a method by giving it a `&self` argument
|
LL | fn bar(&self);
| +++++
help: alternatively, consider constraining `bar` so it does not apply to trait objects
|
LL | fn bar() where Self: Sized;
| +++++++++++++++++
error[E0038]: the trait `Qux` cannot be made into an object
--> $DIR/taint-const-eval.rs:11:33
|
LL | static FOO: &(dyn Qux + Sync) = "desc";
| ^^^^^^ `Qux` cannot be made into an object
|
note: for a trait to be "dyn-compatible" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
--> $DIR/taint-const-eval.rs:8:8
|
LL | trait Qux {
| --- this trait cannot be made into an object...
LL | fn bar();
| ^^^ ...because associated function `bar` has no `self` parameter
= note: required for the cast from `&'static str` to `&'static (dyn Qux + Sync + 'static)`
help: consider turning `bar` into a method by giving it a `&self` argument
|
LL | fn bar(&self);
| +++++
help: alternatively, consider constraining `bar` so it does not apply to trait objects
|
LL | fn bar() where Self: Sized;
| +++++++++++++++++
error[E0038]: the trait `Qux` cannot be made into an object
--> $DIR/taint-const-eval.rs:11:15
|
LL | static FOO: &(dyn Qux + Sync) = "desc";
| ^^^^^^^^^^^^^^ `Qux` cannot be made into an object
|
note: for a trait to be "dyn-compatible" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
--> $DIR/taint-const-eval.rs:8:8
|
LL | trait Qux {
| --- this trait cannot be made into an object...
LL | fn bar();
| ^^^ ...because associated function `bar` has no `self` parameter
= note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
help: consider turning `bar` into a method by giving it a `&self` argument
|
LL | fn bar(&self);
| +++++
help: alternatively, consider constraining `bar` so it does not apply to trait objects
|
LL | fn bar() where Self: Sized;
| +++++++++++++++++
error: aborting due to 3 previous errors
For more information about this error, try `rustc --explain E0038`.

26
tests/ui/dyn-compatibility/taint-const-eval.dyn_compatible_for_dispatch.stderr Normal file
View file

@ -0,0 +1,26 @@
error[E0038]: the trait `Qux` cannot be made into an object
--> $DIR/taint-const-eval.rs:11:33
|
LL | static FOO: &(dyn Qux + Sync) = "desc";
| ^^^^^^ `Qux` cannot be made into an object
|
note: for a trait to be "dyn-compatible" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
--> $DIR/taint-const-eval.rs:8:8
|
LL | trait Qux {
| --- this trait cannot be made into an object...
LL | fn bar();
| ^^^ ...because associated function `bar` has no `self` parameter
= note: required for the cast from `&'static str` to `&'static (dyn Qux + Sync + 'static)`
help: consider turning `bar` into a method by giving it a `&self` argument
|
LL | fn bar(&self);
| +++++
help: alternatively, consider constraining `bar` so it does not apply to trait objects
|
LL | fn bar() where Self: Sized;
| +++++++++++++++++
error: aborting due to 1 previous error
For more information about this error, try `rustc --explain E0038`.

16
tests/ui/dyn-compatibility/taint-const-eval.rs Normal file
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@ -0,0 +1,16 @@
// Test that we do not attempt to create dyn-incompatible trait objects in const eval.
//@ revisions: curr dyn_compatible_for_dispatch
#![cfg_attr(dyn_compatible_for_dispatch, feature(dyn_compatible_for_dispatch))]
trait Qux {
fn bar();
}
static FOO: &(dyn Qux + Sync) = "desc";
//~^ the trait `Qux` cannot be made into an object
//[curr]~| the trait `Qux` cannot be made into an object
//[curr]~| the trait `Qux` cannot be made into an object
fn main() {}