diff options
Diffstat (limited to 'compiler/rustc_hir_analysis/src/coherence/builtin.rs')
| -rw-r--r-- | compiler/rustc_hir_analysis/src/coherence/builtin.rs | 212 |
1 files changed, 88 insertions, 124 deletions
diff --git a/compiler/rustc_hir_analysis/src/coherence/builtin.rs b/compiler/rustc_hir_analysis/src/coherence/builtin.rs index c930537d4..be70acfc3 100644 --- a/compiler/rustc_hir_analysis/src/coherence/builtin.rs +++ b/compiler/rustc_hir_analysis/src/coherence/builtin.rs @@ -1,11 +1,10 @@ //! Check properties that are required by built-in traits and set //! up data structures required by type-checking/codegen. -use crate::errors::{ - ConstParamTyImplOnNonAdt, CopyImplOnNonAdt, CopyImplOnTypeWithDtor, DropImplOnWrongItem, -}; +use crate::errors; + use rustc_data_structures::fx::FxHashSet; -use rustc_errors::{struct_span_err, ErrorGuaranteed, MultiSpan}; +use rustc_errors::{ErrorGuaranteed, MultiSpan}; use rustc_hir as hir; use rustc_hir::def_id::{DefId, LocalDefId}; use rustc_hir::lang_items::LangItem; @@ -65,7 +64,7 @@ fn visit_implementation_of_drop(tcx: TyCtxt<'_>, impl_did: LocalDefId) { let impl_ = tcx.hir().expect_item(impl_did).expect_impl(); - tcx.sess.emit_err(DropImplOnWrongItem { span: impl_.self_ty.span }); + tcx.sess.emit_err(errors::DropImplOnWrongItem { span: impl_.self_ty.span }); } fn visit_implementation_of_copy(tcx: TyCtxt<'_>, impl_did: LocalDefId) { @@ -91,10 +90,10 @@ fn visit_implementation_of_copy(tcx: TyCtxt<'_>, impl_did: LocalDefId) { infringing_fields_error(tcx, fields, LangItem::Copy, impl_did, span); } Err(CopyImplementationError::NotAnAdt) => { - tcx.sess.emit_err(CopyImplOnNonAdt { span }); + tcx.sess.emit_err(errors::CopyImplOnNonAdt { span }); } Err(CopyImplementationError::HasDestructor) => { - tcx.sess.emit_err(CopyImplOnTypeWithDtor { span }); + tcx.sess.emit_err(errors::CopyImplOnTypeWithDtor { span }); } } } @@ -117,7 +116,7 @@ fn visit_implementation_of_const_param_ty(tcx: TyCtxt<'_>, impl_did: LocalDefId) infringing_fields_error(tcx, fields, LangItem::ConstParamTy, impl_did, span); } Err(ConstParamTyImplementationError::NotAnAdtOrBuiltinAllowed) => { - tcx.sess.emit_err(ConstParamTyImplOnNonAdt { span }); + tcx.sess.emit_err(errors::ConstParamTyImplOnNonAdt { span }); } } } @@ -152,11 +151,17 @@ fn visit_implementation_of_dispatch_from_dyn(tcx: TyCtxt<'_>, impl_did: LocalDef let param_env = tcx.param_env(impl_did); - let create_err = |msg: &str| struct_span_err!(tcx.sess, span, E0378, "{}", msg); - let infcx = tcx.infer_ctxt().build(); let cause = ObligationCause::misc(span, impl_did); + // Later parts of the compiler rely on all DispatchFromDyn types to be ABI-compatible with raw + // pointers. This is enforced here: we only allow impls for references, raw pointers, and things + // that are effectively repr(transparent) newtypes around types that already hav a + // DispatchedFromDyn impl. We cannot literally use repr(transparent) on those tpyes since some + // of them support an allocator, but we ensure that for the cases where the type implements this + // trait, they *do* satisfy the repr(transparent) rules, and then we assume that everything else + // in the compiler (in particular, all the call ABI logic) will treat them as repr(transparent) + // even if they do not carry that attribute. use rustc_type_ir::sty::TyKind::*; match (source.kind(), target.kind()) { (&Ref(r_a, _, mutbl_a), Ref(r_b, _, mutbl_b)) @@ -168,22 +173,19 @@ fn visit_implementation_of_dispatch_from_dyn(tcx: TyCtxt<'_>, impl_did: LocalDef let source_path = tcx.def_path_str(def_a.did()); let target_path = tcx.def_path_str(def_b.did()); - create_err(&format!( - "the trait `DispatchFromDyn` may only be implemented \ - for a coercion between structures with the same \ - definition; expected `{source_path}`, found `{target_path}`", - )) - .emit(); + tcx.sess.emit_err(errors::DispatchFromDynCoercion { + span, + trait_name: "DispatchFromDyn", + note: true, + source_path, + target_path, + }); return; } if def_a.repr().c() || def_a.repr().packed() { - create_err( - "structs implementing `DispatchFromDyn` may not have \ - `#[repr(packed)]` or `#[repr(C)]`", - ) - .emit(); + tcx.sess.emit_err(errors::DispatchFromDynRepr { span }); } let fields = &def_a.non_enum_variant().fields; @@ -195,8 +197,8 @@ fn visit_implementation_of_dispatch_from_dyn(tcx: TyCtxt<'_>, impl_did: LocalDef let ty_b = field.ty(tcx, args_b); if let Ok(layout) = tcx.layout_of(param_env.and(ty_a)) { - if layout.is_zst() && layout.align.abi.bytes() == 1 { - // ignore ZST fields with alignment of 1 byte + if layout.is_1zst() { + // ignore 1-ZST fields return false; } } @@ -205,16 +207,11 @@ fn visit_implementation_of_dispatch_from_dyn(tcx: TyCtxt<'_>, impl_did: LocalDef infcx.at(&cause, param_env).eq(DefineOpaqueTypes::No, ty_a, ty_b) { if ok.obligations.is_empty() { - create_err( - "the trait `DispatchFromDyn` may only be implemented \ - for structs containing the field being coerced, \ - ZST fields with 1 byte alignment, and nothing else", - ) - .note(format!( - "extra field `{}` of type `{}` is not allowed", - field.name, ty_a, - )) - .emit(); + tcx.sess.emit_err(errors::DispatchFromDynZST { + span, + name: field.name, + ty: ty_a, + }); return false; } @@ -225,36 +222,29 @@ fn visit_implementation_of_dispatch_from_dyn(tcx: TyCtxt<'_>, impl_did: LocalDef .collect::<Vec<_>>(); if coerced_fields.is_empty() { - create_err( - "the trait `DispatchFromDyn` may only be implemented \ - for a coercion between structures with a single field \ - being coerced, none found", - ) - .emit(); + tcx.sess.emit_err(errors::DispatchFromDynSingle { + span, + trait_name: "DispatchFromDyn", + note: true, + }); } else if coerced_fields.len() > 1 { - create_err("implementing the `DispatchFromDyn` trait requires multiple coercions") - .note( - "the trait `DispatchFromDyn` may only be implemented \ - for a coercion between structures with a single field \ - being coerced", - ) - .note(format!( - "currently, {} fields need coercions: {}", - coerced_fields.len(), - coerced_fields - .iter() - .map(|field| { - format!( - "`{}` (`{}` to `{}`)", - field.name, - field.ty(tcx, args_a), - field.ty(tcx, args_b), - ) - }) - .collect::<Vec<_>>() - .join(", ") - )) - .emit(); + tcx.sess.emit_err(errors::DispatchFromDynMulti { + span, + coercions_note: true, + number: coerced_fields.len(), + coercions: coerced_fields + .iter() + .map(|field| { + format!( + "`{}` (`{}` to `{}`)", + field.name, + field.ty(tcx, args_a), + field.ty(tcx, args_b), + ) + }) + .collect::<Vec<_>>() + .join(", "), + }); } else { let ocx = ObligationCtxt::new(&infcx); for field in coerced_fields { @@ -280,11 +270,7 @@ fn visit_implementation_of_dispatch_from_dyn(tcx: TyCtxt<'_>, impl_did: LocalDef } } _ => { - create_err( - "the trait `DispatchFromDyn` may only be implemented \ - for a coercion between structures", - ) - .emit(); + tcx.sess.emit_err(errors::CoerceUnsizedMay { span, trait_name: "DispatchFromDyn" }); } } } @@ -351,17 +337,13 @@ pub fn coerce_unsized_info<'tcx>(tcx: TyCtxt<'tcx>, impl_did: LocalDefId) -> Coe if def_a != def_b { let source_path = tcx.def_path_str(def_a.did()); let target_path = tcx.def_path_str(def_b.did()); - struct_span_err!( - tcx.sess, + tcx.sess.emit_err(errors::DispatchFromDynSame { span, - E0377, - "the trait `CoerceUnsized` may only be implemented \ - for a coercion between structures with the same \ - definition; expected `{}`, found `{}`", + trait_name: "CoerceUnsized", + note: true, source_path, - target_path - ) - .emit(); + target_path, + }); return err_info; } @@ -437,15 +419,11 @@ pub fn coerce_unsized_info<'tcx>(tcx: TyCtxt<'tcx>, impl_did: LocalDefId) -> Coe .collect::<Vec<_>>(); if diff_fields.is_empty() { - struct_span_err!( - tcx.sess, + tcx.sess.emit_err(errors::CoerceUnsizedOneField { span, - E0374, - "the trait `CoerceUnsized` may only be implemented \ - for a coercion between structures with one field \ - being coerced, none found" - ) - .emit(); + trait_name: "CoerceUnsized", + note: true, + }); return err_info; } else if diff_fields.len() > 1 { let item = tcx.hir().expect_item(impl_did); @@ -455,29 +433,17 @@ pub fn coerce_unsized_info<'tcx>(tcx: TyCtxt<'tcx>, impl_did: LocalDefId) -> Coe tcx.def_span(impl_did) }; - struct_span_err!( - tcx.sess, + tcx.sess.emit_err(errors::CoerceUnsizedMulti { span, - E0375, - "implementing the trait \ - `CoerceUnsized` requires multiple \ - coercions" - ) - .note( - "`CoerceUnsized` may only be implemented for \ - a coercion between structures with one field being coerced", - ) - .note(format!( - "currently, {} fields need coercions: {}", - diff_fields.len(), - diff_fields + coercions_note: true, + number: diff_fields.len(), + coercions: diff_fields .iter() - .map(|&(i, a, b)| { format!("`{}` (`{}` to `{}`)", fields[i].name, a, b) }) + .map(|&(i, a, b)| format!("`{}` (`{}` to `{}`)", fields[i].name, a, b)) .collect::<Vec<_>>() - .join(", ") - )) - .span_label(span, "requires multiple coercions") - .emit(); + .join(", "), + }); + return err_info; } @@ -487,14 +453,7 @@ pub fn coerce_unsized_info<'tcx>(tcx: TyCtxt<'tcx>, impl_did: LocalDefId) -> Coe } _ => { - struct_span_err!( - tcx.sess, - span, - E0376, - "the trait `CoerceUnsized` may only be implemented \ - for a coercion between structures" - ) - .emit(); + tcx.sess.emit_err(errors::DispatchFromDynStruct { span, trait_name: "CoerceUnsized" }); return err_info; } }; @@ -532,13 +491,6 @@ fn infringing_fields_error( let trait_name = tcx.def_path_str(trait_did); - let mut err = struct_span_err!( - tcx.sess, - impl_span, - E0204, - "the trait `{trait_name}` cannot be implemented for this type" - ); - // We'll try to suggest constraining type parameters to fulfill the requirements of // their `Copy` implementation. let mut errors: BTreeMap<_, Vec<_>> = Default::default(); @@ -546,14 +498,15 @@ fn infringing_fields_error( let mut seen_tys = FxHashSet::default(); + let mut label_spans = Vec::new(); + for (field, ty, reason) in fields { // Only report an error once per type. if !seen_tys.insert(ty) { continue; } - let field_span = tcx.def_span(field.did); - err.span_label(field_span, format!("this field does not implement `{trait_name}`")); + label_spans.push(tcx.def_span(field.did)); match reason { InfringingFieldsReason::Fulfill(fulfillment_errors) => { @@ -617,13 +570,24 @@ fn infringing_fields_error( } } } + let mut notes = Vec::new(); for ((ty, error_predicate), spans) in errors { let span: MultiSpan = spans.into(); - err.span_note( + notes.push(errors::ImplForTyRequires { span, - format!("the `{trait_name}` impl for `{ty}` requires that `{error_predicate}`"), - ); + error_predicate, + trait_name: trait_name.clone(), + ty, + }); } + + let mut err = tcx.sess.create_err(errors::TraitCannotImplForTy { + span: impl_span, + trait_name, + label_spans, + notes, + }); + suggest_constraining_type_params( tcx, tcx.hir().get_generics(impl_did).expect("impls always have generics"), |