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Auto merge of #96806 - cjgillot:codegen-fulfill-nice, r=oli-obk

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Gracefully fail to resolve associated items instead of `delay_span_bug`.

`codegen_fulfill_obligation` is used during instance resolution for trait items.

In case of insufficient normalization issues during MIR inlining, it caused ICEs.
It's better to gracefully refuse to resolve the associated item, and let the caller decide what to do with this.

Split from https://github.com/rust-lang/rust/pull/91743
Closes #69121
Closes #73021
Closes #88599
Closes #93008
Closes #93248
Closes #94680
Closes #96170
r? `@oli-obk`
This commit is contained in:
bors 2022-05-11 21:39:02 +00:00
commit cb9cb4d4e1
12 changed files with 108 additions and 88 deletions
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2
compiler/rustc_middle/src/query/mod.rs
View file

@ -1145,7 +1145,7 @@ rustc_queries! {
query codegen_fulfill_obligation(
key: (ty::ParamEnv<'tcx>, ty::PolyTraitRef<'tcx>)
) -> Result<&'tcx ImplSource<'tcx, ()>, ErrorGuaranteed> {
) -> Result<&'tcx ImplSource<'tcx, ()>, traits::CodegenObligationError> {
cache_on_disk_if { true }
desc { |tcx|
"checking if `{}` fulfills its obligations",

18
compiler/rustc_middle/src/traits/mod.rs
View file

@ -963,3 +963,21 @@ pub enum MethodViolationCode {
/// the method's receiver (`self` argument) can't be dispatched on
UndispatchableReceiver,
}
/// These are the error cases for `codegen_fulfill_obligation`.
#[derive(Copy, Clone, Debug, Hash, HashStable, Encodable, Decodable)]
pub enum CodegenObligationError {
/// Ambiguity can happen when monomorphizing during trans
/// expands to some humongous type that never occurred
/// statically -- this humongous type can then overflow,
/// leading to an ambiguous result. So report this as an
/// overflow bug, since I believe this is the only case
/// where ambiguity can result.
Ambiguity,
/// This can trigger when we probe for the source of a `'static` lifetime requirement
/// on a trait object: `impl Foo for dyn Trait {}` has an implicit `'static` bound.
/// This can also trigger when we have a global bound that is not actually satisfied,
/// but was included during typeck due to the trivial_bounds feature.
Unimplemented,
FulfillmentError,
}