diff options
3 files changed, 19 insertions, 1 deletions
diff --git a/src/librustc_middle/traits/specialization_graph.rs b/src/librustc_middle/traits/specialization_graph.rs index f4961617b81..c9aae898007 100644 --- a/src/librustc_middle/traits/specialization_graph.rs +++ b/src/librustc_middle/traits/specialization_graph.rs @@ -1,5 +1,6 @@ use crate::ich::{self, StableHashingContext}; use crate::ty::fast_reject::SimplifiedType; +use crate::ty::fold::TypeFoldable; use crate::ty::{self, TyCtxt}; use rustc_data_structures::fx::FxHashMap; use rustc_data_structures::stable_hasher::{HashStable, StableHasher}; @@ -226,7 +227,8 @@ pub fn ancestors( start_from_impl: DefId, ) -> Result<Ancestors<'tcx>, ErrorReported> { let specialization_graph = tcx.specialization_graph_of(trait_def_id); - if specialization_graph.has_errored { + + if specialization_graph.has_errored || tcx.type_of(start_from_impl).references_error() { Err(ErrorReported) } else { Ok(Ancestors { diff --git a/src/test/ui/specialization/min_specialization/impl-on-nonexisting.rs b/src/test/ui/specialization/min_specialization/impl-on-nonexisting.rs new file mode 100644 index 00000000000..77a64320d6f --- /dev/null +++ b/src/test/ui/specialization/min_specialization/impl-on-nonexisting.rs @@ -0,0 +1,7 @@ +#![feature(min_specialization)] + +trait Trait {} +impl Trait for NonExistent {} +//~^ ERROR cannot find type `NonExistent` in this scope + +fn main() {} diff --git a/src/test/ui/specialization/min_specialization/impl-on-nonexisting.stderr b/src/test/ui/specialization/min_specialization/impl-on-nonexisting.stderr new file mode 100644 index 00000000000..b032ccbe53f --- /dev/null +++ b/src/test/ui/specialization/min_specialization/impl-on-nonexisting.stderr @@ -0,0 +1,9 @@ +error[E0412]: cannot find type `NonExistent` in this scope + --> $DIR/impl-on-nonexisting.rs:4:16 + | +LL | impl Trait for NonExistent {} + | ^^^^^^^^^^^ not found in this scope + +error: aborting due to previous error + +For more information about this error, try `rustc --explain E0412`. |