diff options
| -rw-r--r-- | compiler/rustc_middle/src/ty/layout.rs | 6 | ||||
| -rw-r--r-- | compiler/rustc_ty_utils/src/layout.rs | 6 | ||||
| -rw-r--r-- | tests/ui/layout/transmute-to-tail-with-err.rs | 8 | ||||
| -rw-r--r-- | tests/ui/layout/transmute-to-tail-with-err.stderr | 14 |
4 files changed, 32 insertions, 2 deletions
diff --git a/compiler/rustc_middle/src/ty/layout.rs b/compiler/rustc_middle/src/ty/layout.rs index 254ffc33c96..42fb5d031bb 100644 --- a/compiler/rustc_middle/src/ty/layout.rs +++ b/compiler/rustc_middle/src/ty/layout.rs @@ -730,7 +730,11 @@ where */ }; - let metadata = if let Some(metadata_def_id) = tcx.lang_items().metadata_type() { + let metadata = if let Some(metadata_def_id) = tcx.lang_items().metadata_type() + // Projection eagerly bails out when the pointee references errors, + // fall back to structurally deducing metadata. + && !pointee.references_error() + { let metadata = tcx.normalize_erasing_regions( cx.param_env(), tcx.mk_projection(metadata_def_id, [pointee]), diff --git a/compiler/rustc_ty_utils/src/layout.rs b/compiler/rustc_ty_utils/src/layout.rs index e3132fcc4c4..1788f544a7f 100644 --- a/compiler/rustc_ty_utils/src/layout.rs +++ b/compiler/rustc_ty_utils/src/layout.rs @@ -156,7 +156,11 @@ fn layout_of_uncached<'tcx>( let unsized_part = tcx.struct_tail_erasing_lifetimes(pointee, param_env); - let metadata = if let Some(metadata_def_id) = tcx.lang_items().metadata_type() { + let metadata = if let Some(metadata_def_id) = tcx.lang_items().metadata_type() + // Projection eagerly bails out when the pointee references errors, + // fall back to structurally deducing metadata. + && !pointee.references_error() + { let metadata_ty = tcx.normalize_erasing_regions( param_env, tcx.mk_projection(metadata_def_id, [pointee]), diff --git a/tests/ui/layout/transmute-to-tail-with-err.rs b/tests/ui/layout/transmute-to-tail-with-err.rs new file mode 100644 index 00000000000..6753ce15ed1 --- /dev/null +++ b/tests/ui/layout/transmute-to-tail-with-err.rs @@ -0,0 +1,8 @@ +trait Trait<T> {} + +struct Bar(Box<dyn Trait<T>>); +//~^ ERROR cannot find type `T` in this scope + +fn main() { + let x: Bar = unsafe { std::mem::transmute(()) }; +} diff --git a/tests/ui/layout/transmute-to-tail-with-err.stderr b/tests/ui/layout/transmute-to-tail-with-err.stderr new file mode 100644 index 00000000000..97ab59c398a --- /dev/null +++ b/tests/ui/layout/transmute-to-tail-with-err.stderr @@ -0,0 +1,14 @@ +error[E0412]: cannot find type `T` in this scope + --> $DIR/transmute-to-tail-with-err.rs:3:26 + | +LL | struct Bar(Box<dyn Trait<T>>); + | ^ not found in this scope + | +help: you might be missing a type parameter + | +LL | struct Bar<T>(Box<dyn Trait<T>>); + | +++ + +error: aborting due to previous error + +For more information about this error, try `rustc --explain E0412`. |