diff options
Diffstat (limited to 'compiler/rustc_middle/src')
| -rw-r--r-- | compiler/rustc_middle/src/ty/layout.rs | 21 |
1 files changed, 21 insertions, 0 deletions
diff --git a/compiler/rustc_middle/src/ty/layout.rs b/compiler/rustc_middle/src/ty/layout.rs index bbb8a9fa671..2a058addf15 100644 --- a/compiler/rustc_middle/src/ty/layout.rs +++ b/compiler/rustc_middle/src/ty/layout.rs @@ -229,11 +229,32 @@ impl fmt::Display for ValidityRequirement { #[derive(Copy, Clone, Debug, HashStable, TyEncodable, TyDecodable)] pub enum LayoutError<'tcx> { + /// A type doesn't have a sensible layout. + /// + /// This variant is used for layout errors that don't necessarily cause + /// compile errors. + /// + /// For example, this can happen if a struct contains an unsized type in a + /// non-tail field, but has an unsatisfiable bound like `str: Sized`. Unknown(Ty<'tcx>), + /// The size of a type exceeds [`TargetDataLayout::obj_size_bound`]. SizeOverflow(Ty<'tcx>), + /// The layout can vary due to a generic parameter. + /// + /// Unlike `Unknown`, this variant is a "soft" error and indicates that the layout + /// may become computable after further instantiating the generic parameter(s). TooGeneric(Ty<'tcx>), + /// An alias failed to normalize. + /// + /// This variant is necessary, because, due to trait solver incompleteness, it is + /// possible than an alias that was rigid during analysis fails to normalize after + /// revealing opaque types. + /// + /// See `tests/ui/layout/normalization-failure.rs` for an example. NormalizationFailure(Ty<'tcx>, NormalizationError<'tcx>), + /// A non-layout error is reported elsewhere. ReferencesError(ErrorGuaranteed), + /// A type has cyclic layout, i.e. the type contains itself without indirection. Cycle(ErrorGuaranteed), } |