1728 lines
67 KiB
Rust
1728 lines
67 KiB
Rust
use crate::check::intrinsicck::InlineAsmCtxt;
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use crate::errors::{self, LinkageType};
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use super::compare_impl_item::check_type_bounds;
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use super::compare_impl_item::{compare_impl_method, compare_impl_ty};
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use super::*;
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use rustc_attr as attr;
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use rustc_errors::{Applicability, ErrorGuaranteed, MultiSpan};
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use rustc_hir as hir;
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use rustc_hir::def::{CtorKind, DefKind, Res};
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use rustc_hir::def_id::{DefId, LocalDefId, CRATE_DEF_ID};
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use rustc_hir::intravisit::Visitor;
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use rustc_hir::{ItemKind, Node, PathSegment};
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use rustc_infer::infer::opaque_types::ConstrainOpaqueTypeRegionVisitor;
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use rustc_infer::infer::outlives::env::OutlivesEnvironment;
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use rustc_infer::infer::{RegionVariableOrigin, TyCtxtInferExt};
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use rustc_infer::traits::{Obligation, TraitEngineExt as _};
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use rustc_lint_defs::builtin::REPR_TRANSPARENT_EXTERNAL_PRIVATE_FIELDS;
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use rustc_middle::hir::nested_filter;
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use rustc_middle::middle::stability::EvalResult;
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use rustc_middle::traits::DefiningAnchor;
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use rustc_middle::ty::fold::BottomUpFolder;
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use rustc_middle::ty::layout::{LayoutError, MAX_SIMD_LANES};
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use rustc_middle::ty::util::{Discr, IntTypeExt};
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use rustc_middle::ty::GenericArgKind;
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use rustc_middle::ty::{
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self, AdtDef, ParamEnv, RegionKind, Ty, TyCtxt, TypeSuperVisitable, TypeVisitable,
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TypeVisitableExt,
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};
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use rustc_session::lint::builtin::{UNINHABITED_STATIC, UNSUPPORTED_CALLING_CONVENTIONS};
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use rustc_span::symbol::sym;
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use rustc_span::{self, Span};
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use rustc_target::abi::FieldIdx;
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use rustc_target::spec::abi::Abi;
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use rustc_trait_selection::traits::error_reporting::on_unimplemented::OnUnimplementedDirective;
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use rustc_trait_selection::traits::error_reporting::TypeErrCtxtExt as _;
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use rustc_trait_selection::traits::outlives_bounds::InferCtxtExt as _;
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use rustc_trait_selection::traits::{self, ObligationCtxt, TraitEngine, TraitEngineExt as _};
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use rustc_type_ir::fold::TypeFoldable;
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use std::ops::ControlFlow;
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pub fn check_abi(tcx: TyCtxt<'_>, hir_id: hir::HirId, span: Span, abi: Abi) {
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match tcx.sess.target.is_abi_supported(abi) {
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Some(true) => (),
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Some(false) => {
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struct_span_err!(
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tcx.sess,
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span,
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E0570,
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"`{abi}` is not a supported ABI for the current target",
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)
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.emit();
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}
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None => {
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tcx.struct_span_lint_hir(
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UNSUPPORTED_CALLING_CONVENTIONS,
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hir_id,
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span,
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"use of calling convention not supported on this target",
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|lint| lint,
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);
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}
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}
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// This ABI is only allowed on function pointers
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if abi == Abi::CCmseNonSecureCall {
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struct_span_err!(
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tcx.sess,
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span,
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E0781,
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"the `\"C-cmse-nonsecure-call\"` ABI is only allowed on function pointers"
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)
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.emit();
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}
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}
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fn check_struct(tcx: TyCtxt<'_>, def_id: LocalDefId) {
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let def = tcx.adt_def(def_id);
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let span = tcx.def_span(def_id);
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def.destructor(tcx); // force the destructor to be evaluated
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if def.repr().simd() {
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check_simd(tcx, span, def_id);
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}
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check_transparent(tcx, def);
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check_packed(tcx, span, def);
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}
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fn check_union(tcx: TyCtxt<'_>, def_id: LocalDefId) {
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let def = tcx.adt_def(def_id);
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let span = tcx.def_span(def_id);
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def.destructor(tcx); // force the destructor to be evaluated
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check_transparent(tcx, def);
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check_union_fields(tcx, span, def_id);
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check_packed(tcx, span, def);
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}
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/// Check that the fields of the `union` do not need dropping.
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fn check_union_fields(tcx: TyCtxt<'_>, span: Span, item_def_id: LocalDefId) -> bool {
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let item_type = tcx.type_of(item_def_id).instantiate_identity();
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if let ty::Adt(def, args) = item_type.kind() {
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assert!(def.is_union());
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fn allowed_union_field<'tcx>(
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ty: Ty<'tcx>,
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tcx: TyCtxt<'tcx>,
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param_env: ty::ParamEnv<'tcx>,
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) -> bool {
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// We don't just accept all !needs_drop fields, due to semver concerns.
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match ty.kind() {
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ty::Ref(..) => true, // references never drop (even mutable refs, which are non-Copy and hence fail the later check)
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ty::Tuple(tys) => {
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// allow tuples of allowed types
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tys.iter().all(|ty| allowed_union_field(ty, tcx, param_env))
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}
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ty::Array(elem, _len) => {
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// Like `Copy`, we do *not* special-case length 0.
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allowed_union_field(*elem, tcx, param_env)
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}
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_ => {
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// Fallback case: allow `ManuallyDrop` and things that are `Copy`,
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// also no need to report an error if the type is unresolved.
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ty.ty_adt_def().is_some_and(|adt_def| adt_def.is_manually_drop())
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|| ty.is_copy_modulo_regions(tcx, param_env)
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|| ty.references_error()
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}
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}
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}
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let param_env = tcx.param_env(item_def_id);
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for field in &def.non_enum_variant().fields {
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let field_ty = tcx.normalize_erasing_regions(param_env, field.ty(tcx, args));
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if !allowed_union_field(field_ty, tcx, param_env) {
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let (field_span, ty_span) = match tcx.hir().get_if_local(field.did) {
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// We are currently checking the type this field came from, so it must be local.
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Some(Node::Field(field)) => (field.span, field.ty.span),
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_ => unreachable!("mir field has to correspond to hir field"),
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};
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tcx.sess.emit_err(errors::InvalidUnionField {
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field_span,
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sugg: errors::InvalidUnionFieldSuggestion {
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lo: ty_span.shrink_to_lo(),
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hi: ty_span.shrink_to_hi(),
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},
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note: (),
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});
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return false;
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} else if field_ty.needs_drop(tcx, param_env) {
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// This should never happen. But we can get here e.g. in case of name resolution errors.
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tcx.sess.delay_span_bug(span, "we should never accept maybe-dropping union fields");
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}
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}
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} else {
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span_bug!(span, "unions must be ty::Adt, but got {:?}", item_type.kind());
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}
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true
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}
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/// Check that a `static` is inhabited.
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fn check_static_inhabited(tcx: TyCtxt<'_>, def_id: LocalDefId) {
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// Make sure statics are inhabited.
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// Other parts of the compiler assume that there are no uninhabited places. In principle it
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// would be enough to check this for `extern` statics, as statics with an initializer will
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// have UB during initialization if they are uninhabited, but there also seems to be no good
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// reason to allow any statics to be uninhabited.
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let ty = tcx.type_of(def_id).instantiate_identity();
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let span = tcx.def_span(def_id);
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let layout = match tcx.layout_of(ParamEnv::reveal_all().and(ty)) {
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Ok(l) => l,
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// Foreign statics that overflow their allowed size should emit an error
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Err(LayoutError::SizeOverflow(_))
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if matches!(tcx.def_kind(def_id), DefKind::Static(_)
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if tcx.def_kind(tcx.local_parent(def_id)) == DefKind::ForeignMod) =>
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{
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tcx.sess.emit_err(errors::TooLargeStatic { span });
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return;
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}
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// Generic statics are rejected, but we still reach this case.
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Err(e) => {
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tcx.sess.delay_span_bug(span, format!("{e:?}"));
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return;
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}
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};
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if layout.abi.is_uninhabited() {
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tcx.struct_span_lint_hir(
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UNINHABITED_STATIC,
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tcx.hir().local_def_id_to_hir_id(def_id),
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span,
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"static of uninhabited type",
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|lint| {
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lint
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.note("uninhabited statics cannot be initialized, and any access would be an immediate error")
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},
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);
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}
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}
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/// Checks that an opaque type does not contain cycles and does not use `Self` or `T::Foo`
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/// projections that would result in "inheriting lifetimes".
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fn check_opaque(tcx: TyCtxt<'_>, id: hir::ItemId) {
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let item = tcx.hir().item(id);
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let hir::ItemKind::OpaqueTy(hir::OpaqueTy { origin, .. }) = item.kind else {
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tcx.sess.delay_span_bug(item.span, "expected opaque item");
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return;
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};
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// HACK(jynelson): trying to infer the type of `impl trait` breaks documenting
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// `async-std` (and `pub async fn` in general).
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// Since rustdoc doesn't care about the concrete type behind `impl Trait`, just don't look at it!
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// See https://github.com/rust-lang/rust/issues/75100
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if tcx.sess.opts.actually_rustdoc {
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return;
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}
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let args = GenericArgs::identity_for_item(tcx, item.owner_id);
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let span = tcx.def_span(item.owner_id.def_id);
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if !tcx.features().impl_trait_projections {
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check_opaque_for_inheriting_lifetimes(tcx, item.owner_id.def_id, span);
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}
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if tcx.type_of(item.owner_id.def_id).instantiate_identity().references_error() {
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return;
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}
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if check_opaque_for_cycles(tcx, item.owner_id.def_id, args, span, &origin).is_err() {
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return;
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}
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let _ = check_opaque_meets_bounds(tcx, item.owner_id.def_id, span, &origin);
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}
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/// Checks that an opaque type does not use `Self` or `T::Foo` projections that would result
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/// in "inheriting lifetimes".
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#[instrument(level = "debug", skip(tcx, span))]
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pub(super) fn check_opaque_for_inheriting_lifetimes(
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tcx: TyCtxt<'_>,
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def_id: LocalDefId,
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span: Span,
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) {
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let item = tcx.hir().expect_item(def_id);
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debug!(?item, ?span);
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struct ProhibitOpaqueVisitor<'tcx> {
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tcx: TyCtxt<'tcx>,
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opaque_identity_ty: Ty<'tcx>,
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parent_count: u32,
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references_parent_regions: bool,
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selftys: Vec<(Span, Option<String>)>,
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}
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impl<'tcx> ty::visit::TypeVisitor<TyCtxt<'tcx>> for ProhibitOpaqueVisitor<'tcx> {
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type BreakTy = Ty<'tcx>;
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fn visit_ty(&mut self, t: Ty<'tcx>) -> ControlFlow<Self::BreakTy> {
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debug!(?t, "root_visit_ty");
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if t == self.opaque_identity_ty {
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ControlFlow::Continue(())
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} else {
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t.visit_with(&mut ConstrainOpaqueTypeRegionVisitor {
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tcx: self.tcx,
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op: |region| {
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if let ty::ReEarlyBound(ty::EarlyBoundRegion { index, .. }) = *region
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&& index < self.parent_count
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{
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self.references_parent_regions= true;
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}
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},
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});
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if self.references_parent_regions {
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ControlFlow::Break(t)
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} else {
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ControlFlow::Continue(())
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}
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}
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}
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}
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impl<'tcx> Visitor<'tcx> for ProhibitOpaqueVisitor<'tcx> {
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type NestedFilter = nested_filter::OnlyBodies;
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fn nested_visit_map(&mut self) -> Self::Map {
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self.tcx.hir()
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}
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fn visit_ty(&mut self, arg: &'tcx hir::Ty<'tcx>) {
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match arg.kind {
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hir::TyKind::Path(hir::QPath::Resolved(None, path)) => match &path.segments {
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[PathSegment { res: Res::SelfTyParam { .. }, .. }] => {
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let impl_ty_name = None;
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self.selftys.push((path.span, impl_ty_name));
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}
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[PathSegment { res: Res::SelfTyAlias { alias_to: def_id, .. }, .. }] => {
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let impl_ty_name = Some(self.tcx.def_path_str(*def_id));
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self.selftys.push((path.span, impl_ty_name));
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}
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_ => {}
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},
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_ => {}
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}
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hir::intravisit::walk_ty(self, arg);
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}
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}
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if let ItemKind::OpaqueTy(&hir::OpaqueTy {
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origin: hir::OpaqueTyOrigin::AsyncFn(..) | hir::OpaqueTyOrigin::FnReturn(..),
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..
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}) = item.kind
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{
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let args = GenericArgs::identity_for_item(tcx, def_id);
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let opaque_identity_ty = Ty::new_opaque(tcx, def_id.to_def_id(), args);
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let mut visitor = ProhibitOpaqueVisitor {
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opaque_identity_ty,
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parent_count: tcx.generics_of(def_id).parent_count as u32,
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references_parent_regions: false,
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tcx,
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selftys: vec![],
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};
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let prohibit_opaque = tcx
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.explicit_item_bounds(def_id)
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.instantiate_identity_iter_copied()
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.try_for_each(|(predicate, _)| predicate.visit_with(&mut visitor));
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if let Some(ty) = prohibit_opaque.break_value() {
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visitor.visit_item(&item);
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let is_async = match item.kind {
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ItemKind::OpaqueTy(hir::OpaqueTy { origin, .. }) => {
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matches!(origin, hir::OpaqueTyOrigin::AsyncFn(..))
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}
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_ => unreachable!(),
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};
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let mut err = feature_err(
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&tcx.sess.parse_sess,
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sym::impl_trait_projections,
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span,
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format!(
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"`{}` return type cannot contain a projection or `Self` that references \
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lifetimes from a parent scope",
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if is_async { "async fn" } else { "impl Trait" },
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),
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);
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for (span, name) in visitor.selftys {
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err.span_suggestion(
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span,
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"consider spelling out the type instead",
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name.unwrap_or_else(|| format!("{ty:?}")),
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Applicability::MaybeIncorrect,
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);
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}
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err.emit();
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}
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}
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}
|
|
|
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/// Checks that an opaque type does not contain cycles.
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pub(super) fn check_opaque_for_cycles<'tcx>(
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tcx: TyCtxt<'tcx>,
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def_id: LocalDefId,
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args: GenericArgsRef<'tcx>,
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|
span: Span,
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|
origin: &hir::OpaqueTyOrigin,
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) -> Result<(), ErrorGuaranteed> {
|
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if tcx.try_expand_impl_trait_type(def_id.to_def_id(), args).is_err() {
|
|
let reported = match origin {
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|
hir::OpaqueTyOrigin::AsyncFn(..) => async_opaque_type_cycle_error(tcx, span),
|
|
_ => opaque_type_cycle_error(tcx, def_id, span),
|
|
};
|
|
Err(reported)
|
|
} else {
|
|
Ok(())
|
|
}
|
|
}
|
|
|
|
/// Check that the concrete type behind `impl Trait` actually implements `Trait`.
|
|
///
|
|
/// This is mostly checked at the places that specify the opaque type, but we
|
|
/// check those cases in the `param_env` of that function, which may have
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|
/// bounds not on this opaque type:
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|
///
|
|
/// ```ignore (illustrative)
|
|
/// type X<T> = impl Clone;
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|
/// fn f<T: Clone>(t: T) -> X<T> {
|
|
/// t
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/// }
|
|
/// ```
|
|
///
|
|
/// Without this check the above code is incorrectly accepted: we would ICE if
|
|
/// some tried, for example, to clone an `Option<X<&mut ()>>`.
|
|
#[instrument(level = "debug", skip(tcx))]
|
|
fn check_opaque_meets_bounds<'tcx>(
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|
tcx: TyCtxt<'tcx>,
|
|
def_id: LocalDefId,
|
|
span: Span,
|
|
origin: &hir::OpaqueTyOrigin,
|
|
) -> Result<(), ErrorGuaranteed> {
|
|
let defining_use_anchor = match *origin {
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|
hir::OpaqueTyOrigin::FnReturn(did) | hir::OpaqueTyOrigin::AsyncFn(did) => did,
|
|
hir::OpaqueTyOrigin::TyAlias { .. } => tcx.impl_trait_parent(def_id),
|
|
};
|
|
let param_env = tcx.param_env(defining_use_anchor);
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|
|
|
let infcx = tcx
|
|
.infer_ctxt()
|
|
.with_opaque_type_inference(DefiningAnchor::Bind(defining_use_anchor))
|
|
.build();
|
|
let ocx = ObligationCtxt::new(&infcx);
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|
|
|
let args = GenericArgs::identity_for_item(tcx, def_id.to_def_id());
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|
let opaque_ty = Ty::new_opaque(tcx, def_id.to_def_id(), args);
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|
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|
// `ReErased` regions appear in the "parent_args" of closures/generators.
|
|
// We're ignoring them here and replacing them with fresh region variables.
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|
// See tests in ui/type-alias-impl-trait/closure_{parent_args,wf_outlives}.rs.
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|
//
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|
// FIXME: Consider wrapping the hidden type in an existential `Binder` and instantiating it
|
|
// here rather than using ReErased.
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|
let hidden_ty = tcx.type_of(def_id.to_def_id()).instantiate(tcx, args);
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|
let hidden_ty = tcx.fold_regions(hidden_ty, |re, _dbi| match re.kind() {
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|
ty::ReErased => infcx.next_region_var(RegionVariableOrigin::MiscVariable(span)),
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|
_ => re,
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|
});
|
|
|
|
let misc_cause = traits::ObligationCause::misc(span, def_id);
|
|
|
|
match ocx.eq(&misc_cause, param_env, opaque_ty, hidden_ty) {
|
|
Ok(()) => {}
|
|
Err(ty_err) => {
|
|
let ty_err = ty_err.to_string(tcx);
|
|
return Err(tcx.sess.delay_span_bug(
|
|
span,
|
|
format!("could not unify `{hidden_ty}` with revealed type:\n{ty_err}"),
|
|
));
|
|
}
|
|
}
|
|
|
|
// Additionally require the hidden type to be well-formed with only the generics of the opaque type.
|
|
// Defining use functions may have more bounds than the opaque type, which is ok, as long as the
|
|
// hidden type is well formed even without those bounds.
|
|
let predicate =
|
|
ty::Binder::dummy(ty::PredicateKind::Clause(ty::ClauseKind::WellFormed(hidden_ty.into())));
|
|
ocx.register_obligation(Obligation::new(tcx, misc_cause.clone(), param_env, predicate));
|
|
|
|
// Check that all obligations are satisfied by the implementation's
|
|
// version.
|
|
let errors = ocx.select_all_or_error();
|
|
if !errors.is_empty() {
|
|
let guar = infcx.err_ctxt().report_fulfillment_errors(&errors);
|
|
return Err(guar);
|
|
}
|
|
match origin {
|
|
// Checked when type checking the function containing them.
|
|
hir::OpaqueTyOrigin::FnReturn(..) | hir::OpaqueTyOrigin::AsyncFn(..) => {}
|
|
// Nested opaque types occur only in associated types:
|
|
// ` type Opaque<T> = impl Trait<&'static T, AssocTy = impl Nested>; `
|
|
// They can only be referenced as `<Opaque<T> as Trait<&'static T>>::AssocTy`.
|
|
// We don't have to check them here because their well-formedness follows from the WF of
|
|
// the projection input types in the defining- and use-sites.
|
|
hir::OpaqueTyOrigin::TyAlias { .. }
|
|
if tcx.def_kind(tcx.parent(def_id.to_def_id())) == DefKind::OpaqueTy => {}
|
|
// Can have different predicates to their defining use
|
|
hir::OpaqueTyOrigin::TyAlias { .. } => {
|
|
let wf_tys = ocx.assumed_wf_types_and_report_errors(param_env, def_id)?;
|
|
let implied_bounds = infcx.implied_bounds_tys(param_env, def_id, wf_tys);
|
|
let outlives_env = OutlivesEnvironment::with_bounds(param_env, implied_bounds);
|
|
ocx.resolve_regions_and_report_errors(defining_use_anchor, &outlives_env)?;
|
|
}
|
|
}
|
|
// Check that any hidden types found during wf checking match the hidden types that `type_of` sees.
|
|
for (key, mut ty) in infcx.take_opaque_types() {
|
|
ty.hidden_type.ty = infcx.resolve_vars_if_possible(ty.hidden_type.ty);
|
|
sanity_check_found_hidden_type(tcx, key, ty.hidden_type, defining_use_anchor, origin)?;
|
|
}
|
|
Ok(())
|
|
}
|
|
|
|
fn sanity_check_found_hidden_type<'tcx>(
|
|
tcx: TyCtxt<'tcx>,
|
|
key: ty::OpaqueTypeKey<'tcx>,
|
|
mut ty: ty::OpaqueHiddenType<'tcx>,
|
|
defining_use_anchor: LocalDefId,
|
|
origin: &hir::OpaqueTyOrigin,
|
|
) -> Result<(), ErrorGuaranteed> {
|
|
if ty.ty.is_ty_var() {
|
|
// Nothing was actually constrained.
|
|
return Ok(());
|
|
}
|
|
if let ty::Alias(ty::Opaque, alias) = ty.ty.kind() {
|
|
if alias.def_id == key.def_id.to_def_id() && alias.args == key.args {
|
|
// Nothing was actually constrained, this is an opaque usage that was
|
|
// only discovered to be opaque after inference vars resolved.
|
|
return Ok(());
|
|
}
|
|
}
|
|
// Closures frequently end up containing erased lifetimes in their final representation.
|
|
// These correspond to lifetime variables that never got resolved, so we patch this up here.
|
|
ty.ty = ty.ty.fold_with(&mut BottomUpFolder {
|
|
tcx,
|
|
ty_op: |t| t,
|
|
ct_op: |c| c,
|
|
lt_op: |l| match l.kind() {
|
|
RegionKind::ReVar(_) => tcx.lifetimes.re_erased,
|
|
_ => l,
|
|
},
|
|
});
|
|
// Get the hidden type.
|
|
let mut hidden_ty = tcx.type_of(key.def_id).instantiate(tcx, key.args);
|
|
if let hir::OpaqueTyOrigin::FnReturn(..) | hir::OpaqueTyOrigin::AsyncFn(..) = origin {
|
|
if hidden_ty != ty.ty {
|
|
hidden_ty = find_and_apply_rpit_args(
|
|
tcx,
|
|
hidden_ty,
|
|
defining_use_anchor.to_def_id(),
|
|
key.def_id.to_def_id(),
|
|
)?;
|
|
}
|
|
}
|
|
|
|
// If the hidden types differ, emit a type mismatch diagnostic.
|
|
if hidden_ty == ty.ty {
|
|
Ok(())
|
|
} else {
|
|
let span = tcx.def_span(key.def_id);
|
|
let other = ty::OpaqueHiddenType { ty: hidden_ty, span };
|
|
Err(ty.report_mismatch(&other, key.def_id, tcx).emit())
|
|
}
|
|
}
|
|
|
|
/// In case it is in a nested opaque type, find that opaque type's
|
|
/// usage in the function signature and use the generic arguments from the usage site.
|
|
/// We need to do because RPITs ignore the lifetimes of the function,
|
|
/// as they have their own copies of all the lifetimes they capture.
|
|
/// So the only way to get the lifetimes represented in terms of the function,
|
|
/// is to look how they are used in the function signature (or do some other fancy
|
|
/// recording of this mapping at ast -> hir lowering time).
|
|
///
|
|
/// As an example:
|
|
/// ```text
|
|
/// trait Id {
|
|
/// type Assoc;
|
|
/// }
|
|
/// impl<'a> Id for &'a () {
|
|
/// type Assoc = &'a ();
|
|
/// }
|
|
/// fn func<'a>(x: &'a ()) -> impl Id<Assoc = impl Sized + 'a> { x }
|
|
/// // desugared to
|
|
/// fn func<'a>(x: &'a () -> Outer<'a> where <Outer<'a> as Id>::Assoc = Inner<'a> {
|
|
/// // Note that in contrast to other nested items, RPIT type aliases can
|
|
/// // access their parents' generics.
|
|
///
|
|
/// // hidden type is `&'aDupOuter ()`
|
|
/// // During wfcheck the hidden type of `Inner<'aDupOuter>` is `&'a ()`, but
|
|
/// // `typeof(Inner<'aDupOuter>) = &'aDupOuter ()`.
|
|
/// // So we walk the signature of `func` to find the use of `Inner<'a>`
|
|
/// // and then use that to replace the lifetimes in the hidden type, obtaining
|
|
/// // `&'a ()`.
|
|
/// type Outer<'aDupOuter> = impl Id<Assoc = Inner<'aDupOuter>>;
|
|
///
|
|
/// // hidden type is `&'aDupInner ()`
|
|
/// type Inner<'aDupInner> = impl Sized + 'aDupInner;
|
|
///
|
|
/// x
|
|
/// }
|
|
/// ```
|
|
fn find_and_apply_rpit_args<'tcx>(
|
|
tcx: TyCtxt<'tcx>,
|
|
mut hidden_ty: Ty<'tcx>,
|
|
function: DefId,
|
|
opaque: DefId,
|
|
) -> Result<Ty<'tcx>, ErrorGuaranteed> {
|
|
// Find use of the RPIT in the function signature and thus find the right args to
|
|
// convert it into the parameter space of the function signature. This is needed,
|
|
// because that's what `type_of` returns, against which we compare later.
|
|
let ret = tcx.fn_sig(function).instantiate_identity().output();
|
|
struct Visitor<'tcx> {
|
|
tcx: TyCtxt<'tcx>,
|
|
opaque: DefId,
|
|
seen: FxHashSet<DefId>,
|
|
}
|
|
impl<'tcx> ty::TypeVisitor<TyCtxt<'tcx>> for Visitor<'tcx> {
|
|
type BreakTy = GenericArgsRef<'tcx>;
|
|
|
|
#[instrument(level = "trace", skip(self), ret)]
|
|
fn visit_ty(&mut self, t: Ty<'tcx>) -> ControlFlow<Self::BreakTy> {
|
|
trace!("{:#?}", t.kind());
|
|
match t.kind() {
|
|
ty::Alias(ty::Opaque, alias) => {
|
|
trace!(?alias.def_id);
|
|
if alias.def_id == self.opaque {
|
|
return ControlFlow::Break(alias.args);
|
|
} else if self.seen.insert(alias.def_id) {
|
|
for clause in self
|
|
.tcx
|
|
.explicit_item_bounds(alias.def_id)
|
|
.iter_instantiated_copied(self.tcx, alias.args)
|
|
{
|
|
trace!(?clause);
|
|
clause.visit_with(self)?;
|
|
}
|
|
}
|
|
}
|
|
ty::Alias(ty::Weak, alias) => {
|
|
self.tcx
|
|
.type_of(alias.def_id)
|
|
.instantiate(self.tcx, alias.args)
|
|
.visit_with(self)?;
|
|
}
|
|
_ => (),
|
|
}
|
|
|
|
t.super_visit_with(self)
|
|
}
|
|
}
|
|
if let ControlFlow::Break(args) =
|
|
ret.visit_with(&mut Visitor { tcx, opaque, seen: Default::default() })
|
|
{
|
|
trace!(?args);
|
|
trace!("expected: {hidden_ty:#?}");
|
|
hidden_ty = ty::EarlyBinder::bind(hidden_ty).instantiate(tcx, args);
|
|
trace!("expected: {hidden_ty:#?}");
|
|
} else {
|
|
tcx.sess
|
|
.delay_span_bug(tcx.def_span(function), format!("{ret:?} does not contain {opaque:?}"));
|
|
}
|
|
Ok(hidden_ty)
|
|
}
|
|
|
|
fn is_enum_of_nonnullable_ptr<'tcx>(
|
|
tcx: TyCtxt<'tcx>,
|
|
adt_def: AdtDef<'tcx>,
|
|
args: GenericArgsRef<'tcx>,
|
|
) -> bool {
|
|
if adt_def.repr().inhibit_enum_layout_opt() {
|
|
return false;
|
|
}
|
|
|
|
let [var_one, var_two] = &adt_def.variants().raw[..] else {
|
|
return false;
|
|
};
|
|
let (([], [field]) | ([field], [])) = (&var_one.fields.raw[..], &var_two.fields.raw[..]) else {
|
|
return false;
|
|
};
|
|
matches!(field.ty(tcx, args).kind(), ty::FnPtr(..) | ty::Ref(..))
|
|
}
|
|
|
|
fn check_static_linkage(tcx: TyCtxt<'_>, def_id: LocalDefId) {
|
|
if tcx.codegen_fn_attrs(def_id).import_linkage.is_some() {
|
|
if match tcx.type_of(def_id).instantiate_identity().kind() {
|
|
ty::RawPtr(_) => false,
|
|
ty::Adt(adt_def, args) => !is_enum_of_nonnullable_ptr(tcx, *adt_def, *args),
|
|
_ => true,
|
|
} {
|
|
tcx.sess.emit_err(LinkageType { span: tcx.def_span(def_id) });
|
|
}
|
|
}
|
|
}
|
|
|
|
fn check_item_type(tcx: TyCtxt<'_>, id: hir::ItemId) {
|
|
debug!(
|
|
"check_item_type(it.def_id={:?}, it.name={})",
|
|
id.owner_id,
|
|
tcx.def_path_str(id.owner_id)
|
|
);
|
|
let _indenter = indenter();
|
|
match tcx.def_kind(id.owner_id) {
|
|
DefKind::Static(..) => {
|
|
tcx.ensure().typeck(id.owner_id.def_id);
|
|
maybe_check_static_with_link_section(tcx, id.owner_id.def_id);
|
|
check_static_inhabited(tcx, id.owner_id.def_id);
|
|
check_static_linkage(tcx, id.owner_id.def_id);
|
|
}
|
|
DefKind::Const => {
|
|
tcx.ensure().typeck(id.owner_id.def_id);
|
|
}
|
|
DefKind::Enum => {
|
|
check_enum(tcx, id.owner_id.def_id);
|
|
}
|
|
DefKind::Fn => {} // entirely within check_item_body
|
|
DefKind::Impl { of_trait } => {
|
|
if of_trait && let Some(impl_trait_ref) = tcx.impl_trait_ref(id.owner_id) {
|
|
check_impl_items_against_trait(
|
|
tcx,
|
|
id.owner_id.def_id,
|
|
impl_trait_ref.instantiate_identity(),
|
|
);
|
|
check_on_unimplemented(tcx, id);
|
|
}
|
|
}
|
|
DefKind::Trait => {
|
|
let assoc_items = tcx.associated_items(id.owner_id);
|
|
check_on_unimplemented(tcx, id);
|
|
|
|
for &assoc_item in assoc_items.in_definition_order() {
|
|
match assoc_item.kind {
|
|
ty::AssocKind::Fn => {
|
|
let abi = tcx.fn_sig(assoc_item.def_id).skip_binder().abi();
|
|
fn_maybe_err(tcx, assoc_item.ident(tcx).span, abi);
|
|
}
|
|
ty::AssocKind::Type if assoc_item.defaultness(tcx).has_value() => {
|
|
let trait_args =
|
|
GenericArgs::identity_for_item(tcx, id.owner_id);
|
|
let _: Result<_, rustc_errors::ErrorGuaranteed> = check_type_bounds(
|
|
tcx,
|
|
assoc_item,
|
|
assoc_item,
|
|
ty::TraitRef::new(tcx, id.owner_id.to_def_id(), trait_args),
|
|
);
|
|
}
|
|
_ => {}
|
|
}
|
|
}
|
|
}
|
|
DefKind::Struct => {
|
|
check_struct(tcx, id.owner_id.def_id);
|
|
}
|
|
DefKind::Union => {
|
|
check_union(tcx, id.owner_id.def_id);
|
|
}
|
|
DefKind::OpaqueTy => {
|
|
let origin = tcx.opaque_type_origin(id.owner_id.def_id);
|
|
if let hir::OpaqueTyOrigin::FnReturn(fn_def_id) | hir::OpaqueTyOrigin::AsyncFn(fn_def_id) = origin
|
|
&& let hir::Node::TraitItem(trait_item) = tcx.hir().get_by_def_id(fn_def_id)
|
|
&& let (_, hir::TraitFn::Required(..)) = trait_item.expect_fn()
|
|
{
|
|
// Skip opaques from RPIT in traits with no default body.
|
|
} else {
|
|
check_opaque(tcx, id);
|
|
}
|
|
}
|
|
DefKind::TyAlias => {
|
|
let pty_ty = tcx.type_of(id.owner_id).instantiate_identity();
|
|
let generics = tcx.generics_of(id.owner_id);
|
|
check_type_params_are_used(tcx, &generics, pty_ty);
|
|
}
|
|
DefKind::ForeignMod => {
|
|
let it = tcx.hir().item(id);
|
|
let hir::ItemKind::ForeignMod { abi, items } = it.kind else {
|
|
return;
|
|
};
|
|
check_abi(tcx, it.hir_id(), it.span, abi);
|
|
|
|
match abi {
|
|
Abi::RustIntrinsic => {
|
|
for item in items {
|
|
let item = tcx.hir().foreign_item(item.id);
|
|
intrinsic::check_intrinsic_type(tcx, item);
|
|
}
|
|
}
|
|
|
|
Abi::PlatformIntrinsic => {
|
|
for item in items {
|
|
let item = tcx.hir().foreign_item(item.id);
|
|
intrinsic::check_platform_intrinsic_type(tcx, item);
|
|
}
|
|
}
|
|
|
|
_ => {
|
|
for item in items {
|
|
let def_id = item.id.owner_id.def_id;
|
|
let generics = tcx.generics_of(def_id);
|
|
let own_counts = generics.own_counts();
|
|
if generics.params.len() - own_counts.lifetimes != 0 {
|
|
let (kinds, kinds_pl, egs) = match (own_counts.types, own_counts.consts)
|
|
{
|
|
(_, 0) => ("type", "types", Some("u32")),
|
|
// We don't specify an example value, because we can't generate
|
|
// a valid value for any type.
|
|
(0, _) => ("const", "consts", None),
|
|
_ => ("type or const", "types or consts", None),
|
|
};
|
|
struct_span_err!(
|
|
tcx.sess,
|
|
item.span,
|
|
E0044,
|
|
"foreign items may not have {kinds} parameters",
|
|
)
|
|
.span_label(item.span, format!("can't have {kinds} parameters"))
|
|
.help(
|
|
// FIXME: once we start storing spans for type arguments, turn this
|
|
// into a suggestion.
|
|
format!(
|
|
"replace the {} parameters with concrete {}{}",
|
|
kinds,
|
|
kinds_pl,
|
|
egs.map(|egs| format!(" like `{egs}`")).unwrap_or_default(),
|
|
),
|
|
)
|
|
.emit();
|
|
}
|
|
|
|
let item = tcx.hir().foreign_item(item.id);
|
|
match &item.kind {
|
|
hir::ForeignItemKind::Fn(fn_decl, _, _) => {
|
|
require_c_abi_if_c_variadic(tcx, fn_decl, abi, item.span);
|
|
}
|
|
hir::ForeignItemKind::Static(..) => {
|
|
check_static_inhabited(tcx, def_id);
|
|
check_static_linkage(tcx, def_id);
|
|
}
|
|
_ => {}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
DefKind::GlobalAsm => {
|
|
let it = tcx.hir().item(id);
|
|
let hir::ItemKind::GlobalAsm(asm) = it.kind else { span_bug!(it.span, "DefKind::GlobalAsm but got {:#?}", it) };
|
|
InlineAsmCtxt::new_global_asm(tcx).check_asm(asm, id.owner_id.def_id);
|
|
}
|
|
_ => {}
|
|
}
|
|
}
|
|
|
|
pub(super) fn check_on_unimplemented(tcx: TyCtxt<'_>, item: hir::ItemId) {
|
|
// an error would be reported if this fails.
|
|
let _ = OnUnimplementedDirective::of_item(tcx, item.owner_id.to_def_id());
|
|
}
|
|
|
|
pub(super) fn check_specialization_validity<'tcx>(
|
|
tcx: TyCtxt<'tcx>,
|
|
trait_def: &ty::TraitDef,
|
|
trait_item: ty::AssocItem,
|
|
impl_id: DefId,
|
|
impl_item: DefId,
|
|
) {
|
|
let Ok(ancestors) = trait_def.ancestors(tcx, impl_id) else { return };
|
|
let mut ancestor_impls = ancestors.skip(1).filter_map(|parent| {
|
|
if parent.is_from_trait() {
|
|
None
|
|
} else {
|
|
Some((parent, parent.item(tcx, trait_item.def_id)))
|
|
}
|
|
});
|
|
|
|
let opt_result = ancestor_impls.find_map(|(parent_impl, parent_item)| {
|
|
match parent_item {
|
|
// Parent impl exists, and contains the parent item we're trying to specialize, but
|
|
// doesn't mark it `default`.
|
|
Some(parent_item) if traits::impl_item_is_final(tcx, &parent_item) => {
|
|
Some(Err(parent_impl.def_id()))
|
|
}
|
|
|
|
// Parent impl contains item and makes it specializable.
|
|
Some(_) => Some(Ok(())),
|
|
|
|
// Parent impl doesn't mention the item. This means it's inherited from the
|
|
// grandparent. In that case, if parent is a `default impl`, inherited items use the
|
|
// "defaultness" from the grandparent, else they are final.
|
|
None => {
|
|
if tcx.defaultness(parent_impl.def_id()).is_default() {
|
|
None
|
|
} else {
|
|
Some(Err(parent_impl.def_id()))
|
|
}
|
|
}
|
|
}
|
|
});
|
|
|
|
// If `opt_result` is `None`, we have only encountered `default impl`s that don't contain the
|
|
// item. This is allowed, the item isn't actually getting specialized here.
|
|
let result = opt_result.unwrap_or(Ok(()));
|
|
|
|
if let Err(parent_impl) = result {
|
|
if !tcx.is_impl_trait_in_trait(impl_item) {
|
|
report_forbidden_specialization(tcx, impl_item, parent_impl);
|
|
} else {
|
|
tcx.sess.delay_span_bug(
|
|
DUMMY_SP,
|
|
format!("parent item: {parent_impl:?} not marked as default"),
|
|
);
|
|
}
|
|
}
|
|
}
|
|
|
|
fn check_impl_items_against_trait<'tcx>(
|
|
tcx: TyCtxt<'tcx>,
|
|
impl_id: LocalDefId,
|
|
impl_trait_ref: ty::TraitRef<'tcx>,
|
|
) {
|
|
// If the trait reference itself is erroneous (so the compilation is going
|
|
// to fail), skip checking the items here -- the `impl_item` table in `tcx`
|
|
// isn't populated for such impls.
|
|
if impl_trait_ref.references_error() {
|
|
return;
|
|
}
|
|
|
|
let impl_item_refs = tcx.associated_item_def_ids(impl_id);
|
|
|
|
// Negative impls are not expected to have any items
|
|
match tcx.impl_polarity(impl_id) {
|
|
ty::ImplPolarity::Reservation | ty::ImplPolarity::Positive => {}
|
|
ty::ImplPolarity::Negative => {
|
|
if let [first_item_ref, ..] = impl_item_refs {
|
|
let first_item_span = tcx.def_span(first_item_ref);
|
|
struct_span_err!(
|
|
tcx.sess,
|
|
first_item_span,
|
|
E0749,
|
|
"negative impls cannot have any items"
|
|
)
|
|
.emit();
|
|
}
|
|
return;
|
|
}
|
|
}
|
|
|
|
let trait_def = tcx.trait_def(impl_trait_ref.def_id);
|
|
|
|
for &impl_item in impl_item_refs {
|
|
let ty_impl_item = tcx.associated_item(impl_item);
|
|
let ty_trait_item = if let Some(trait_item_id) = ty_impl_item.trait_item_def_id {
|
|
tcx.associated_item(trait_item_id)
|
|
} else {
|
|
// Checked in `associated_item`.
|
|
tcx.sess.delay_span_bug(tcx.def_span(impl_item), "missing associated item in trait");
|
|
continue;
|
|
};
|
|
match ty_impl_item.kind {
|
|
ty::AssocKind::Const => {
|
|
let _ = tcx.compare_impl_const((
|
|
impl_item.expect_local(),
|
|
ty_impl_item.trait_item_def_id.unwrap(),
|
|
));
|
|
}
|
|
ty::AssocKind::Fn => {
|
|
compare_impl_method(tcx, ty_impl_item, ty_trait_item, impl_trait_ref);
|
|
}
|
|
ty::AssocKind::Type => {
|
|
compare_impl_ty(tcx, ty_impl_item, ty_trait_item, impl_trait_ref);
|
|
}
|
|
}
|
|
|
|
check_specialization_validity(
|
|
tcx,
|
|
trait_def,
|
|
ty_trait_item,
|
|
impl_id.to_def_id(),
|
|
impl_item,
|
|
);
|
|
}
|
|
|
|
if let Ok(ancestors) = trait_def.ancestors(tcx, impl_id.to_def_id()) {
|
|
// Check for missing items from trait
|
|
let mut missing_items = Vec::new();
|
|
|
|
let mut must_implement_one_of: Option<&[Ident]> =
|
|
trait_def.must_implement_one_of.as_deref();
|
|
|
|
for &trait_item_id in tcx.associated_item_def_ids(impl_trait_ref.def_id) {
|
|
let leaf_def = ancestors.leaf_def(tcx, trait_item_id);
|
|
|
|
let is_implemented = leaf_def
|
|
.as_ref()
|
|
.is_some_and(|node_item| node_item.item.defaultness(tcx).has_value());
|
|
|
|
if !is_implemented && tcx.defaultness(impl_id).is_final() {
|
|
missing_items.push(tcx.associated_item(trait_item_id));
|
|
}
|
|
|
|
// true if this item is specifically implemented in this impl
|
|
let is_implemented_here =
|
|
leaf_def.as_ref().is_some_and(|node_item| !node_item.defining_node.is_from_trait());
|
|
|
|
if !is_implemented_here {
|
|
let full_impl_span =
|
|
tcx.hir().span_with_body(tcx.hir().local_def_id_to_hir_id(impl_id));
|
|
match tcx.eval_default_body_stability(trait_item_id, full_impl_span) {
|
|
EvalResult::Deny { feature, reason, issue, .. } => default_body_is_unstable(
|
|
tcx,
|
|
full_impl_span,
|
|
trait_item_id,
|
|
feature,
|
|
reason,
|
|
issue,
|
|
),
|
|
|
|
// Unmarked default bodies are considered stable (at least for now).
|
|
EvalResult::Allow | EvalResult::Unmarked => {}
|
|
}
|
|
}
|
|
|
|
if let Some(required_items) = &must_implement_one_of {
|
|
if is_implemented_here {
|
|
let trait_item = tcx.associated_item(trait_item_id);
|
|
if required_items.contains(&trait_item.ident(tcx)) {
|
|
must_implement_one_of = None;
|
|
}
|
|
}
|
|
}
|
|
|
|
if let Some(leaf_def) = &leaf_def
|
|
&& !leaf_def.is_final()
|
|
&& let def_id = leaf_def.item.def_id
|
|
&& tcx.impl_method_has_trait_impl_trait_tys(def_id)
|
|
{
|
|
let def_kind = tcx.def_kind(def_id);
|
|
let descr = tcx.def_kind_descr(def_kind, def_id);
|
|
let (msg, feature) = if tcx.asyncness(def_id).is_async() {
|
|
(
|
|
format!("async {descr} in trait cannot be specialized"),
|
|
sym::async_fn_in_trait,
|
|
)
|
|
} else {
|
|
(
|
|
format!(
|
|
"{descr} with return-position `impl Trait` in trait cannot be specialized"
|
|
),
|
|
sym::return_position_impl_trait_in_trait,
|
|
)
|
|
};
|
|
tcx.sess
|
|
.struct_span_err(tcx.def_span(def_id), msg)
|
|
.note(format!(
|
|
"specialization behaves in inconsistent and \
|
|
surprising ways with `#![feature({feature})]`, \
|
|
and for now is disallowed"
|
|
))
|
|
.emit();
|
|
}
|
|
}
|
|
|
|
if !missing_items.is_empty() {
|
|
let full_impl_span =
|
|
tcx.hir().span_with_body(tcx.hir().local_def_id_to_hir_id(impl_id));
|
|
missing_items_err(tcx, impl_id, &missing_items, full_impl_span);
|
|
}
|
|
|
|
if let Some(missing_items) = must_implement_one_of {
|
|
let attr_span = tcx
|
|
.get_attr(impl_trait_ref.def_id, sym::rustc_must_implement_one_of)
|
|
.map(|attr| attr.span);
|
|
|
|
missing_items_must_implement_one_of_err(
|
|
tcx,
|
|
tcx.def_span(impl_id),
|
|
missing_items,
|
|
attr_span,
|
|
);
|
|
}
|
|
}
|
|
}
|
|
|
|
pub fn check_simd(tcx: TyCtxt<'_>, sp: Span, def_id: LocalDefId) {
|
|
let t = tcx.type_of(def_id).instantiate_identity();
|
|
if let ty::Adt(def, args) = t.kind()
|
|
&& def.is_struct()
|
|
{
|
|
let fields = &def.non_enum_variant().fields;
|
|
if fields.is_empty() {
|
|
struct_span_err!(tcx.sess, sp, E0075, "SIMD vector cannot be empty").emit();
|
|
return;
|
|
}
|
|
let e = fields[FieldIdx::from_u32(0)].ty(tcx, args);
|
|
if !fields.iter().all(|f| f.ty(tcx, args) == e) {
|
|
struct_span_err!(tcx.sess, sp, E0076, "SIMD vector should be homogeneous")
|
|
.span_label(sp, "SIMD elements must have the same type")
|
|
.emit();
|
|
return;
|
|
}
|
|
|
|
let len = if let ty::Array(_ty, c) = e.kind() {
|
|
c.try_eval_target_usize(tcx, tcx.param_env(def.did()))
|
|
} else {
|
|
Some(fields.len() as u64)
|
|
};
|
|
if let Some(len) = len {
|
|
if len == 0 {
|
|
struct_span_err!(tcx.sess, sp, E0075, "SIMD vector cannot be empty").emit();
|
|
return;
|
|
} else if len > MAX_SIMD_LANES {
|
|
struct_span_err!(
|
|
tcx.sess,
|
|
sp,
|
|
E0075,
|
|
"SIMD vector cannot have more than {MAX_SIMD_LANES} elements",
|
|
)
|
|
.emit();
|
|
return;
|
|
}
|
|
}
|
|
|
|
// Check that we use types valid for use in the lanes of a SIMD "vector register"
|
|
// These are scalar types which directly match a "machine" type
|
|
// Yes: Integers, floats, "thin" pointers
|
|
// No: char, "fat" pointers, compound types
|
|
match e.kind() {
|
|
ty::Param(_) => (), // pass struct<T>(T, T, T, T) through, let monomorphization catch errors
|
|
ty::Int(_) | ty::Uint(_) | ty::Float(_) | ty::RawPtr(_) => (), // struct(u8, u8, u8, u8) is ok
|
|
ty::Array(t, _) if matches!(t.kind(), ty::Param(_)) => (), // pass struct<T>([T; N]) through, let monomorphization catch errors
|
|
ty::Array(t, _clen)
|
|
if matches!(
|
|
t.kind(),
|
|
ty::Int(_) | ty::Uint(_) | ty::Float(_) | ty::RawPtr(_)
|
|
) =>
|
|
{ /* struct([f32; 4]) is ok */ }
|
|
_ => {
|
|
struct_span_err!(
|
|
tcx.sess,
|
|
sp,
|
|
E0077,
|
|
"SIMD vector element type should be a \
|
|
primitive scalar (integer/float/pointer) type"
|
|
)
|
|
.emit();
|
|
return;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
pub(super) fn check_packed(tcx: TyCtxt<'_>, sp: Span, def: ty::AdtDef<'_>) {
|
|
let repr = def.repr();
|
|
if repr.packed() {
|
|
for attr in tcx.get_attrs(def.did(), sym::repr) {
|
|
for r in attr::parse_repr_attr(&tcx.sess, attr) {
|
|
if let attr::ReprPacked(pack) = r
|
|
&& let Some(repr_pack) = repr.pack
|
|
&& pack as u64 != repr_pack.bytes()
|
|
{
|
|
struct_span_err!(
|
|
tcx.sess,
|
|
sp,
|
|
E0634,
|
|
"type has conflicting packed representation hints"
|
|
)
|
|
.emit();
|
|
}
|
|
}
|
|
}
|
|
if repr.align.is_some() {
|
|
struct_span_err!(
|
|
tcx.sess,
|
|
sp,
|
|
E0587,
|
|
"type has conflicting packed and align representation hints"
|
|
)
|
|
.emit();
|
|
} else {
|
|
if let Some(def_spans) = check_packed_inner(tcx, def.did(), &mut vec![]) {
|
|
let mut err = struct_span_err!(
|
|
tcx.sess,
|
|
sp,
|
|
E0588,
|
|
"packed type cannot transitively contain a `#[repr(align)]` type"
|
|
);
|
|
|
|
err.span_note(
|
|
tcx.def_span(def_spans[0].0),
|
|
format!("`{}` has a `#[repr(align)]` attribute", tcx.item_name(def_spans[0].0)),
|
|
);
|
|
|
|
if def_spans.len() > 2 {
|
|
let mut first = true;
|
|
for (adt_def, span) in def_spans.iter().skip(1).rev() {
|
|
let ident = tcx.item_name(*adt_def);
|
|
err.span_note(
|
|
*span,
|
|
if first {
|
|
format!(
|
|
"`{}` contains a field of type `{}`",
|
|
tcx.type_of(def.did()).instantiate_identity(),
|
|
ident
|
|
)
|
|
} else {
|
|
format!("...which contains a field of type `{ident}`")
|
|
},
|
|
);
|
|
first = false;
|
|
}
|
|
}
|
|
|
|
err.emit();
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
pub(super) fn check_packed_inner(
|
|
tcx: TyCtxt<'_>,
|
|
def_id: DefId,
|
|
stack: &mut Vec<DefId>,
|
|
) -> Option<Vec<(DefId, Span)>> {
|
|
if let ty::Adt(def, args) = tcx.type_of(def_id).instantiate_identity().kind() {
|
|
if def.is_struct() || def.is_union() {
|
|
if def.repr().align.is_some() {
|
|
return Some(vec![(def.did(), DUMMY_SP)]);
|
|
}
|
|
|
|
stack.push(def_id);
|
|
for field in &def.non_enum_variant().fields {
|
|
if let ty::Adt(def, _) = field.ty(tcx, args).kind()
|
|
&& !stack.contains(&def.did())
|
|
&& let Some(mut defs) = check_packed_inner(tcx, def.did(), stack)
|
|
{
|
|
defs.push((def.did(), field.ident(tcx).span));
|
|
return Some(defs);
|
|
}
|
|
}
|
|
stack.pop();
|
|
}
|
|
}
|
|
|
|
None
|
|
}
|
|
|
|
pub(super) fn check_transparent<'tcx>(tcx: TyCtxt<'tcx>, adt: ty::AdtDef<'tcx>) {
|
|
if !adt.repr().transparent() {
|
|
return;
|
|
}
|
|
|
|
if adt.is_union() && !tcx.features().transparent_unions {
|
|
feature_err(
|
|
&tcx.sess.parse_sess,
|
|
sym::transparent_unions,
|
|
tcx.def_span(adt.did()),
|
|
"transparent unions are unstable",
|
|
)
|
|
.emit();
|
|
}
|
|
|
|
if adt.variants().len() != 1 {
|
|
bad_variant_count(tcx, adt, tcx.def_span(adt.did()), adt.did());
|
|
// Don't bother checking the fields.
|
|
return;
|
|
}
|
|
|
|
// For each field, figure out if it's known to be a ZST and align(1), with "known"
|
|
// respecting #[non_exhaustive] attributes.
|
|
let field_infos = adt.all_fields().map(|field| {
|
|
let ty = field.ty(tcx, GenericArgs::identity_for_item(tcx, field.did));
|
|
let param_env = tcx.param_env(field.did);
|
|
let layout = tcx.layout_of(param_env.and(ty));
|
|
// We are currently checking the type this field came from, so it must be local
|
|
let span = tcx.hir().span_if_local(field.did).unwrap();
|
|
let zst = layout.is_ok_and(|layout| layout.is_zst());
|
|
let align = layout.ok().map(|layout| layout.align.abi.bytes());
|
|
if !zst {
|
|
return (span, zst, align, None);
|
|
}
|
|
|
|
fn check_non_exhaustive<'tcx>(
|
|
tcx: TyCtxt<'tcx>,
|
|
t: Ty<'tcx>,
|
|
) -> ControlFlow<(&'static str, DefId, GenericArgsRef<'tcx>, bool)> {
|
|
match t.kind() {
|
|
ty::Tuple(list) => list.iter().try_for_each(|t| check_non_exhaustive(tcx, t)),
|
|
ty::Array(ty, _) => check_non_exhaustive(tcx, *ty),
|
|
ty::Adt(def, subst) => {
|
|
if !def.did().is_local() {
|
|
let non_exhaustive = def.is_variant_list_non_exhaustive()
|
|
|| def
|
|
.variants()
|
|
.iter()
|
|
.any(ty::VariantDef::is_field_list_non_exhaustive);
|
|
let has_priv = def.all_fields().any(|f| !f.vis.is_public());
|
|
if non_exhaustive || has_priv {
|
|
return ControlFlow::Break((
|
|
def.descr(),
|
|
def.did(),
|
|
subst,
|
|
non_exhaustive,
|
|
));
|
|
}
|
|
}
|
|
def.all_fields()
|
|
.map(|field| field.ty(tcx, subst))
|
|
.try_for_each(|t| check_non_exhaustive(tcx, t))
|
|
}
|
|
_ => ControlFlow::Continue(()),
|
|
}
|
|
}
|
|
|
|
(span, zst, align, check_non_exhaustive(tcx, ty).break_value())
|
|
});
|
|
|
|
let non_zst_fields = field_infos
|
|
.clone()
|
|
.filter_map(|(span, zst, _align, _non_exhaustive)| if !zst { Some(span) } else { None });
|
|
let non_zst_count = non_zst_fields.clone().count();
|
|
if non_zst_count >= 2 {
|
|
bad_non_zero_sized_fields(tcx, adt, non_zst_count, non_zst_fields, tcx.def_span(adt.did()));
|
|
}
|
|
let incompatible_zst_fields =
|
|
field_infos.clone().filter(|(_, _, _, opt)| opt.is_some()).count();
|
|
let incompat = incompatible_zst_fields + non_zst_count >= 2 && non_zst_count < 2;
|
|
for (span, zst, align, non_exhaustive) in field_infos {
|
|
if zst && align != Some(1) {
|
|
let mut err = struct_span_err!(
|
|
tcx.sess,
|
|
span,
|
|
E0691,
|
|
"zero-sized field in transparent {} has alignment larger than 1",
|
|
adt.descr(),
|
|
);
|
|
|
|
if let Some(align_bytes) = align {
|
|
err.span_label(
|
|
span,
|
|
format!("has alignment of {align_bytes}, which is larger than 1"),
|
|
);
|
|
} else {
|
|
err.span_label(span, "may have alignment larger than 1");
|
|
}
|
|
|
|
err.emit();
|
|
}
|
|
if incompat && let Some((descr, def_id, args, non_exhaustive)) = non_exhaustive {
|
|
tcx.struct_span_lint_hir(
|
|
REPR_TRANSPARENT_EXTERNAL_PRIVATE_FIELDS,
|
|
tcx.hir().local_def_id_to_hir_id(adt.did().expect_local()),
|
|
span,
|
|
"zero-sized fields in `repr(transparent)` cannot contain external non-exhaustive types",
|
|
|lint| {
|
|
let note = if non_exhaustive {
|
|
"is marked with `#[non_exhaustive]`"
|
|
} else {
|
|
"contains private fields"
|
|
};
|
|
let field_ty = tcx.def_path_str_with_args(def_id, args);
|
|
lint
|
|
.note(format!("this {descr} contains `{field_ty}`, which {note}, \
|
|
and makes it not a breaking change to become non-zero-sized in the future."))
|
|
},
|
|
)
|
|
}
|
|
}
|
|
}
|
|
|
|
#[allow(trivial_numeric_casts)]
|
|
fn check_enum(tcx: TyCtxt<'_>, def_id: LocalDefId) {
|
|
let def = tcx.adt_def(def_id);
|
|
def.destructor(tcx); // force the destructor to be evaluated
|
|
|
|
if def.variants().is_empty() {
|
|
if let Some(attr) = tcx.get_attrs(def_id, sym::repr).next() {
|
|
struct_span_err!(
|
|
tcx.sess,
|
|
attr.span,
|
|
E0084,
|
|
"unsupported representation for zero-variant enum"
|
|
)
|
|
.span_label(tcx.def_span(def_id), "zero-variant enum")
|
|
.emit();
|
|
}
|
|
}
|
|
|
|
let repr_type_ty = def.repr().discr_type().to_ty(tcx);
|
|
if repr_type_ty == tcx.types.i128 || repr_type_ty == tcx.types.u128 {
|
|
if !tcx.features().repr128 {
|
|
feature_err(
|
|
&tcx.sess.parse_sess,
|
|
sym::repr128,
|
|
tcx.def_span(def_id),
|
|
"repr with 128-bit type is unstable",
|
|
)
|
|
.emit();
|
|
}
|
|
}
|
|
|
|
for v in def.variants() {
|
|
if let ty::VariantDiscr::Explicit(discr_def_id) = v.discr {
|
|
tcx.ensure().typeck(discr_def_id.expect_local());
|
|
}
|
|
}
|
|
|
|
if def.repr().int.is_none() {
|
|
let is_unit = |var: &ty::VariantDef| matches!(var.ctor_kind(), Some(CtorKind::Const));
|
|
let has_disr = |var: &ty::VariantDef| matches!(var.discr, ty::VariantDiscr::Explicit(_));
|
|
|
|
let has_non_units = def.variants().iter().any(|var| !is_unit(var));
|
|
let disr_units = def.variants().iter().any(|var| is_unit(&var) && has_disr(&var));
|
|
let disr_non_unit = def.variants().iter().any(|var| !is_unit(&var) && has_disr(&var));
|
|
|
|
if disr_non_unit || (disr_units && has_non_units) {
|
|
let mut err = struct_span_err!(
|
|
tcx.sess,
|
|
tcx.def_span(def_id),
|
|
E0732,
|
|
"`#[repr(inttype)]` must be specified"
|
|
);
|
|
err.emit();
|
|
}
|
|
}
|
|
|
|
detect_discriminant_duplicate(tcx, def);
|
|
check_transparent(tcx, def);
|
|
}
|
|
|
|
/// Part of enum check. Given the discriminants of an enum, errors if two or more discriminants are equal
|
|
fn detect_discriminant_duplicate<'tcx>(tcx: TyCtxt<'tcx>, adt: ty::AdtDef<'tcx>) {
|
|
// Helper closure to reduce duplicate code. This gets called everytime we detect a duplicate.
|
|
// Here `idx` refers to the order of which the discriminant appears, and its index in `vs`
|
|
let report = |dis: Discr<'tcx>, idx, err: &mut Diagnostic| {
|
|
let var = adt.variant(idx); // HIR for the duplicate discriminant
|
|
let (span, display_discr) = match var.discr {
|
|
ty::VariantDiscr::Explicit(discr_def_id) => {
|
|
// In the case the discriminant is both a duplicate and overflowed, let the user know
|
|
if let hir::Node::AnonConst(expr) = tcx.hir().get_by_def_id(discr_def_id.expect_local())
|
|
&& let hir::ExprKind::Lit(lit) = &tcx.hir().body(expr.body).value.kind
|
|
&& let rustc_ast::LitKind::Int(lit_value, _int_kind) = &lit.node
|
|
&& *lit_value != dis.val
|
|
{
|
|
(tcx.def_span(discr_def_id), format!("`{dis}` (overflowed from `{lit_value}`)"))
|
|
} else {
|
|
// Otherwise, format the value as-is
|
|
(tcx.def_span(discr_def_id), format!("`{dis}`"))
|
|
}
|
|
}
|
|
// This should not happen.
|
|
ty::VariantDiscr::Relative(0) => (tcx.def_span(var.def_id), format!("`{dis}`")),
|
|
ty::VariantDiscr::Relative(distance_to_explicit) => {
|
|
// At this point we know this discriminant is a duplicate, and was not explicitly
|
|
// assigned by the user. Here we iterate backwards to fetch the HIR for the last
|
|
// explicitly assigned discriminant, and letting the user know that this was the
|
|
// increment startpoint, and how many steps from there leading to the duplicate
|
|
if let Some(explicit_idx) =
|
|
idx.as_u32().checked_sub(distance_to_explicit).map(VariantIdx::from_u32)
|
|
{
|
|
let explicit_variant = adt.variant(explicit_idx);
|
|
let ve_ident = var.name;
|
|
let ex_ident = explicit_variant.name;
|
|
let sp = if distance_to_explicit > 1 { "variants" } else { "variant" };
|
|
|
|
err.span_label(
|
|
tcx.def_span(explicit_variant.def_id),
|
|
format!(
|
|
"discriminant for `{ve_ident}` incremented from this startpoint \
|
|
(`{ex_ident}` + {distance_to_explicit} {sp} later \
|
|
=> `{ve_ident}` = {dis})"
|
|
),
|
|
);
|
|
}
|
|
|
|
(tcx.def_span(var.def_id), format!("`{dis}`"))
|
|
}
|
|
};
|
|
|
|
err.span_label(span, format!("{display_discr} assigned here"));
|
|
};
|
|
|
|
let mut discrs = adt.discriminants(tcx).collect::<Vec<_>>();
|
|
|
|
// Here we loop through the discriminants, comparing each discriminant to another.
|
|
// When a duplicate is detected, we instantiate an error and point to both
|
|
// initial and duplicate value. The duplicate discriminant is then discarded by swapping
|
|
// it with the last element and decrementing the `vec.len` (which is why we have to evaluate
|
|
// `discrs.len()` anew every iteration, and why this could be tricky to do in a functional
|
|
// style as we are mutating `discrs` on the fly).
|
|
let mut i = 0;
|
|
while i < discrs.len() {
|
|
let var_i_idx = discrs[i].0;
|
|
let mut error: Option<DiagnosticBuilder<'_, _>> = None;
|
|
|
|
let mut o = i + 1;
|
|
while o < discrs.len() {
|
|
let var_o_idx = discrs[o].0;
|
|
|
|
if discrs[i].1.val == discrs[o].1.val {
|
|
let err = error.get_or_insert_with(|| {
|
|
let mut ret = struct_span_err!(
|
|
tcx.sess,
|
|
tcx.def_span(adt.did()),
|
|
E0081,
|
|
"discriminant value `{}` assigned more than once",
|
|
discrs[i].1,
|
|
);
|
|
|
|
report(discrs[i].1, var_i_idx, &mut ret);
|
|
|
|
ret
|
|
});
|
|
|
|
report(discrs[o].1, var_o_idx, err);
|
|
|
|
// Safe to unwrap here, as we wouldn't reach this point if `discrs` was empty
|
|
discrs[o] = *discrs.last().unwrap();
|
|
discrs.pop();
|
|
} else {
|
|
o += 1;
|
|
}
|
|
}
|
|
|
|
if let Some(mut e) = error {
|
|
e.emit();
|
|
}
|
|
|
|
i += 1;
|
|
}
|
|
}
|
|
|
|
pub(super) fn check_type_params_are_used<'tcx>(
|
|
tcx: TyCtxt<'tcx>,
|
|
generics: &ty::Generics,
|
|
ty: Ty<'tcx>,
|
|
) {
|
|
debug!("check_type_params_are_used(generics={:?}, ty={:?})", generics, ty);
|
|
|
|
assert_eq!(generics.parent, None);
|
|
|
|
if generics.own_counts().types == 0 {
|
|
return;
|
|
}
|
|
|
|
let mut params_used = BitSet::new_empty(generics.params.len());
|
|
|
|
if ty.references_error() {
|
|
// If there is already another error, do not emit
|
|
// an error for not using a type parameter.
|
|
assert!(tcx.sess.has_errors().is_some());
|
|
return;
|
|
}
|
|
|
|
for leaf in ty.walk() {
|
|
if let GenericArgKind::Type(leaf_ty) = leaf.unpack()
|
|
&& let ty::Param(param) = leaf_ty.kind()
|
|
{
|
|
debug!("found use of ty param {:?}", param);
|
|
params_used.insert(param.index);
|
|
}
|
|
}
|
|
|
|
for param in &generics.params {
|
|
if !params_used.contains(param.index)
|
|
&& let ty::GenericParamDefKind::Type { .. } = param.kind
|
|
{
|
|
let span = tcx.def_span(param.def_id);
|
|
struct_span_err!(
|
|
tcx.sess,
|
|
span,
|
|
E0091,
|
|
"type parameter `{}` is unused",
|
|
param.name,
|
|
)
|
|
.span_label(span, "unused type parameter")
|
|
.emit();
|
|
}
|
|
}
|
|
}
|
|
|
|
pub(super) fn check_mod_item_types(tcx: TyCtxt<'_>, module_def_id: LocalDefId) {
|
|
let module = tcx.hir_module_items(module_def_id);
|
|
for id in module.items() {
|
|
check_item_type(tcx, id);
|
|
}
|
|
if module_def_id == CRATE_DEF_ID {
|
|
super::entry::check_for_entry_fn(tcx);
|
|
}
|
|
}
|
|
|
|
fn async_opaque_type_cycle_error(tcx: TyCtxt<'_>, span: Span) -> ErrorGuaranteed {
|
|
struct_span_err!(tcx.sess, span, E0733, "recursion in an `async fn` requires boxing")
|
|
.span_label(span, "recursive `async fn`")
|
|
.note("a recursive `async fn` must be rewritten to return a boxed `dyn Future`")
|
|
.note(
|
|
"consider using the `async_recursion` crate: https://crates.io/crates/async_recursion",
|
|
)
|
|
.emit()
|
|
}
|
|
|
|
/// Emit an error for recursive opaque types.
|
|
///
|
|
/// If this is a return `impl Trait`, find the item's return expressions and point at them. For
|
|
/// direct recursion this is enough, but for indirect recursion also point at the last intermediary
|
|
/// `impl Trait`.
|
|
///
|
|
/// If all the return expressions evaluate to `!`, then we explain that the error will go away
|
|
/// after changing it. This can happen when a user uses `panic!()` or similar as a placeholder.
|
|
fn opaque_type_cycle_error(
|
|
tcx: TyCtxt<'_>,
|
|
opaque_def_id: LocalDefId,
|
|
span: Span,
|
|
) -> ErrorGuaranteed {
|
|
let mut err = struct_span_err!(tcx.sess, span, E0720, "cannot resolve opaque type");
|
|
|
|
let mut label = false;
|
|
if let Some((def_id, visitor)) = get_owner_return_paths(tcx, opaque_def_id) {
|
|
let typeck_results = tcx.typeck(def_id);
|
|
if visitor
|
|
.returns
|
|
.iter()
|
|
.filter_map(|expr| typeck_results.node_type_opt(expr.hir_id))
|
|
.all(|ty| matches!(ty.kind(), ty::Never))
|
|
{
|
|
let spans = visitor
|
|
.returns
|
|
.iter()
|
|
.filter(|expr| typeck_results.node_type_opt(expr.hir_id).is_some())
|
|
.map(|expr| expr.span)
|
|
.collect::<Vec<Span>>();
|
|
let span_len = spans.len();
|
|
if span_len == 1 {
|
|
err.span_label(spans[0], "this returned value is of `!` type");
|
|
} else {
|
|
let mut multispan: MultiSpan = spans.clone().into();
|
|
for span in spans {
|
|
multispan.push_span_label(span, "this returned value is of `!` type");
|
|
}
|
|
err.span_note(multispan, "these returned values have a concrete \"never\" type");
|
|
}
|
|
err.help("this error will resolve once the item's body returns a concrete type");
|
|
} else {
|
|
let mut seen = FxHashSet::default();
|
|
seen.insert(span);
|
|
err.span_label(span, "recursive opaque type");
|
|
label = true;
|
|
for (sp, ty) in visitor
|
|
.returns
|
|
.iter()
|
|
.filter_map(|e| typeck_results.node_type_opt(e.hir_id).map(|t| (e.span, t)))
|
|
.filter(|(_, ty)| !matches!(ty.kind(), ty::Never))
|
|
{
|
|
#[derive(Default)]
|
|
struct OpaqueTypeCollector {
|
|
opaques: Vec<DefId>,
|
|
closures: Vec<DefId>,
|
|
}
|
|
impl<'tcx> ty::visit::TypeVisitor<TyCtxt<'tcx>> for OpaqueTypeCollector {
|
|
fn visit_ty(&mut self, t: Ty<'tcx>) -> ControlFlow<Self::BreakTy> {
|
|
match *t.kind() {
|
|
ty::Alias(ty::Opaque, ty::AliasTy { def_id: def, .. }) => {
|
|
self.opaques.push(def);
|
|
ControlFlow::Continue(())
|
|
}
|
|
ty::Closure(def_id, ..) | ty::Generator(def_id, ..) => {
|
|
self.closures.push(def_id);
|
|
t.super_visit_with(self)
|
|
}
|
|
_ => t.super_visit_with(self),
|
|
}
|
|
}
|
|
}
|
|
|
|
let mut visitor = OpaqueTypeCollector::default();
|
|
ty.visit_with(&mut visitor);
|
|
for def_id in visitor.opaques {
|
|
let ty_span = tcx.def_span(def_id);
|
|
if !seen.contains(&ty_span) {
|
|
let descr = if ty.is_impl_trait() { "opaque " } else { "" };
|
|
err.span_label(ty_span, format!("returning this {descr}type `{ty}`"));
|
|
seen.insert(ty_span);
|
|
}
|
|
err.span_label(sp, format!("returning here with type `{ty}`"));
|
|
}
|
|
|
|
for closure_def_id in visitor.closures {
|
|
let Some(closure_local_did) = closure_def_id.as_local() else {
|
|
continue;
|
|
};
|
|
let typeck_results = tcx.typeck(closure_local_did);
|
|
|
|
let mut label_match = |ty: Ty<'_>, span| {
|
|
for arg in ty.walk() {
|
|
if let ty::GenericArgKind::Type(ty) = arg.unpack()
|
|
&& let ty::Alias(ty::Opaque, ty::AliasTy { def_id: captured_def_id, .. }) = *ty.kind()
|
|
&& captured_def_id == opaque_def_id.to_def_id()
|
|
{
|
|
err.span_label(
|
|
span,
|
|
format!(
|
|
"{} captures itself here",
|
|
tcx.def_descr(closure_def_id)
|
|
),
|
|
);
|
|
}
|
|
}
|
|
};
|
|
|
|
// Label any closure upvars that capture the opaque
|
|
for capture in typeck_results.closure_min_captures_flattened(closure_local_did)
|
|
{
|
|
label_match(capture.place.ty(), capture.get_path_span(tcx));
|
|
}
|
|
// Label any generator locals that capture the opaque
|
|
for interior_ty in
|
|
typeck_results.generator_interior_types.as_ref().skip_binder()
|
|
{
|
|
label_match(interior_ty.ty, interior_ty.span);
|
|
}
|
|
if tcx.sess.opts.unstable_opts.drop_tracking_mir
|
|
&& let DefKind::Generator = tcx.def_kind(closure_def_id)
|
|
&& let Some(generator_layout) = tcx.mir_generator_witnesses(closure_def_id)
|
|
{
|
|
for interior_ty in &generator_layout.field_tys {
|
|
label_match(interior_ty.ty, interior_ty.source_info.span);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
if !label {
|
|
err.span_label(span, "cannot resolve opaque type");
|
|
}
|
|
err.emit()
|
|
}
|
|
|
|
pub(super) fn check_generator_obligations(tcx: TyCtxt<'_>, def_id: LocalDefId) {
|
|
debug_assert!(tcx.sess.opts.unstable_opts.drop_tracking_mir);
|
|
debug_assert!(matches!(tcx.def_kind(def_id), DefKind::Generator));
|
|
|
|
let typeck = tcx.typeck(def_id);
|
|
let param_env = tcx.param_env(def_id);
|
|
|
|
let generator_interior_predicates = &typeck.generator_interior_predicates[&def_id];
|
|
debug!(?generator_interior_predicates);
|
|
|
|
let infcx = tcx
|
|
.infer_ctxt()
|
|
// typeck writeback gives us predicates with their regions erased.
|
|
// As borrowck already has checked lifetimes, we do not need to do it again.
|
|
.ignoring_regions()
|
|
// Bind opaque types to `def_id` as they should have been checked by borrowck.
|
|
.with_opaque_type_inference(DefiningAnchor::Bind(def_id))
|
|
.build();
|
|
|
|
let mut fulfillment_cx = <dyn TraitEngine<'_>>::new(&infcx);
|
|
for (predicate, cause) in generator_interior_predicates {
|
|
let obligation = Obligation::new(tcx, cause.clone(), param_env, *predicate);
|
|
fulfillment_cx.register_predicate_obligation(&infcx, obligation);
|
|
}
|
|
let errors = fulfillment_cx.select_all_or_error(&infcx);
|
|
debug!(?errors);
|
|
if !errors.is_empty() {
|
|
infcx.err_ctxt().report_fulfillment_errors(&errors);
|
|
}
|
|
}
|