1516 lines
60 KiB
Rust
1516 lines
60 KiB
Rust
use super::coercion::CoerceMany;
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use super::compare_method::check_type_bounds;
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use super::compare_method::{compare_const_impl, compare_impl_method, compare_ty_impl};
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use super::*;
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use rustc_attr as attr;
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use rustc_errors::{Applicability, ErrorReported};
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use rustc_hir as hir;
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use rustc_hir::def_id::{DefId, LocalDefId, LOCAL_CRATE};
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use rustc_hir::lang_items::LangItem;
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use rustc_hir::{ItemKind, Node};
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use rustc_infer::infer::type_variable::{TypeVariableOrigin, TypeVariableOriginKind};
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use rustc_infer::infer::{RegionVariableOrigin, TyCtxtInferExt};
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use rustc_middle::ty::fold::TypeFoldable;
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use rustc_middle::ty::subst::GenericArgKind;
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use rustc_middle::ty::util::{Discr, IntTypeExt, Representability};
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use rustc_middle::ty::{self, ParamEnv, RegionKind, ToPredicate, Ty, TyCtxt};
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use rustc_session::config::EntryFnType;
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use rustc_session::lint::builtin::UNINHABITED_STATIC;
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use rustc_span::symbol::sym;
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use rustc_span::{self, MultiSpan, Span};
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use rustc_target::spec::abi::Abi;
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use rustc_trait_selection::opaque_types::InferCtxtExt as _;
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use rustc_trait_selection::traits::error_reporting::InferCtxtExt as _;
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use rustc_trait_selection::traits::{self, ObligationCauseCode};
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use std::ops::ControlFlow;
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pub fn check_wf_new(tcx: TyCtxt<'_>) {
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let visit = wfcheck::CheckTypeWellFormedVisitor::new(tcx);
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tcx.hir().krate().par_visit_all_item_likes(&visit);
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}
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pub(super) fn check_abi(tcx: TyCtxt<'_>, span: Span, abi: Abi) {
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if !tcx.sess.target.is_abi_supported(abi) {
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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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"The ABI `{}` is not supported for the current target",
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abi
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)
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.emit()
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}
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}
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/// Helper used for fns and closures. Does the grungy work of checking a function
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/// body and returns the function context used for that purpose, since in the case of a fn item
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/// there is still a bit more to do.
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///
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/// * ...
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/// * inherited: other fields inherited from the enclosing fn (if any)
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pub(super) fn check_fn<'a, 'tcx>(
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inherited: &'a Inherited<'a, 'tcx>,
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param_env: ty::ParamEnv<'tcx>,
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fn_sig: ty::FnSig<'tcx>,
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decl: &'tcx hir::FnDecl<'tcx>,
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fn_id: hir::HirId,
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body: &'tcx hir::Body<'tcx>,
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can_be_generator: Option<hir::Movability>,
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) -> (FnCtxt<'a, 'tcx>, Option<GeneratorTypes<'tcx>>) {
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let mut fn_sig = fn_sig;
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debug!("check_fn(sig={:?}, fn_id={}, param_env={:?})", fn_sig, fn_id, param_env);
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// Create the function context. This is either derived from scratch or,
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// in the case of closures, based on the outer context.
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let mut fcx = FnCtxt::new(inherited, param_env, body.value.hir_id);
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*fcx.ps.borrow_mut() = UnsafetyState::function(fn_sig.unsafety, fn_id);
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let tcx = fcx.tcx;
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let sess = tcx.sess;
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let hir = tcx.hir();
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let declared_ret_ty = fn_sig.output();
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let revealed_ret_ty =
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fcx.instantiate_opaque_types_from_value(fn_id, declared_ret_ty, decl.output.span());
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debug!("check_fn: declared_ret_ty: {}, revealed_ret_ty: {}", declared_ret_ty, revealed_ret_ty);
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fcx.ret_coercion = Some(RefCell::new(CoerceMany::new(revealed_ret_ty)));
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fcx.ret_type_span = Some(decl.output.span());
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if let ty::Opaque(..) = declared_ret_ty.kind() {
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fcx.ret_coercion_impl_trait = Some(declared_ret_ty);
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}
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fn_sig = tcx.mk_fn_sig(
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fn_sig.inputs().iter().cloned(),
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revealed_ret_ty,
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fn_sig.c_variadic,
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fn_sig.unsafety,
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fn_sig.abi,
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);
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let span = body.value.span;
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fn_maybe_err(tcx, span, fn_sig.abi);
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if fn_sig.abi == Abi::RustCall {
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let expected_args = if let ImplicitSelfKind::None = decl.implicit_self { 1 } else { 2 };
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let err = || {
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let item = match tcx.hir().get(fn_id) {
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Node::Item(hir::Item { kind: ItemKind::Fn(header, ..), .. }) => Some(header),
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Node::ImplItem(hir::ImplItem {
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kind: hir::ImplItemKind::Fn(header, ..), ..
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}) => Some(header),
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// Closures are RustCall, but they tuple their arguments, so shouldn't be checked
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Node::Expr(hir::Expr { kind: hir::ExprKind::Closure(..), .. }) => None,
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node => bug!("Item being checked wasn't a function/closure: {:?}", node),
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};
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if let Some(header) = item {
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tcx.sess.span_err(header.span, "A function with the \"rust-call\" ABI must take a single non-self argument that is a tuple")
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}
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};
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if fn_sig.inputs().len() != expected_args {
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err()
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} else {
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// FIXME(CraftSpider) Add a check on parameter expansion, so we don't just make the ICE happen later on
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// This will probably require wide-scale changes to support a TupleKind obligation
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// We can't resolve this without knowing the type of the param
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if !matches!(fn_sig.inputs()[expected_args - 1].kind(), ty::Tuple(_) | ty::Param(_)) {
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err()
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}
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}
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}
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if body.generator_kind.is_some() && can_be_generator.is_some() {
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let yield_ty = fcx
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.next_ty_var(TypeVariableOrigin { kind: TypeVariableOriginKind::TypeInference, span });
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fcx.require_type_is_sized(yield_ty, span, traits::SizedYieldType);
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// Resume type defaults to `()` if the generator has no argument.
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let resume_ty = fn_sig.inputs().get(0).copied().unwrap_or_else(|| tcx.mk_unit());
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fcx.resume_yield_tys = Some((resume_ty, yield_ty));
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}
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let outer_def_id = tcx.closure_base_def_id(hir.local_def_id(fn_id).to_def_id()).expect_local();
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let outer_hir_id = hir.local_def_id_to_hir_id(outer_def_id);
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GatherLocalsVisitor::new(&fcx, outer_hir_id).visit_body(body);
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// C-variadic fns also have a `VaList` input that's not listed in `fn_sig`
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// (as it's created inside the body itself, not passed in from outside).
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let maybe_va_list = if fn_sig.c_variadic {
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let span = body.params.last().unwrap().span;
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let va_list_did = tcx.require_lang_item(LangItem::VaList, Some(span));
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let region = fcx.next_region_var(RegionVariableOrigin::MiscVariable(span));
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Some(tcx.type_of(va_list_did).subst(tcx, &[region.into()]))
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} else {
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None
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};
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// Add formal parameters.
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let inputs_hir = hir.fn_decl_by_hir_id(fn_id).map(|decl| &decl.inputs);
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let inputs_fn = fn_sig.inputs().iter().copied();
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for (idx, (param_ty, param)) in inputs_fn.chain(maybe_va_list).zip(body.params).enumerate() {
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// Check the pattern.
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let ty_span = try { inputs_hir?.get(idx)?.span };
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fcx.check_pat_top(¶m.pat, param_ty, ty_span, false);
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// Check that argument is Sized.
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// The check for a non-trivial pattern is a hack to avoid duplicate warnings
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// for simple cases like `fn foo(x: Trait)`,
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// where we would error once on the parameter as a whole, and once on the binding `x`.
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if param.pat.simple_ident().is_none() && !tcx.features().unsized_fn_params {
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fcx.require_type_is_sized(param_ty, param.pat.span, traits::SizedArgumentType(ty_span));
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}
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fcx.write_ty(param.hir_id, param_ty);
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}
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inherited.typeck_results.borrow_mut().liberated_fn_sigs_mut().insert(fn_id, fn_sig);
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fcx.in_tail_expr = true;
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if let ty::Dynamic(..) = declared_ret_ty.kind() {
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// FIXME: We need to verify that the return type is `Sized` after the return expression has
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// been evaluated so that we have types available for all the nodes being returned, but that
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// requires the coerced evaluated type to be stored. Moving `check_return_expr` before this
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// causes unsized errors caused by the `declared_ret_ty` to point at the return expression,
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// while keeping the current ordering we will ignore the tail expression's type because we
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// don't know it yet. We can't do `check_expr_kind` while keeping `check_return_expr`
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// because we will trigger "unreachable expression" lints unconditionally.
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// Because of all of this, we perform a crude check to know whether the simplest `!Sized`
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// case that a newcomer might make, returning a bare trait, and in that case we populate
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// the tail expression's type so that the suggestion will be correct, but ignore all other
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// possible cases.
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fcx.check_expr(&body.value);
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fcx.require_type_is_sized(declared_ret_ty, decl.output.span(), traits::SizedReturnType);
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tcx.sess.delay_span_bug(decl.output.span(), "`!Sized` return type");
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} else {
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fcx.require_type_is_sized(declared_ret_ty, decl.output.span(), traits::SizedReturnType);
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fcx.check_return_expr(&body.value);
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}
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fcx.in_tail_expr = false;
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// We insert the deferred_generator_interiors entry after visiting the body.
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// This ensures that all nested generators appear before the entry of this generator.
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// resolve_generator_interiors relies on this property.
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let gen_ty = if let (Some(_), Some(gen_kind)) = (can_be_generator, body.generator_kind) {
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let interior = fcx
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.next_ty_var(TypeVariableOrigin { kind: TypeVariableOriginKind::MiscVariable, span });
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fcx.deferred_generator_interiors.borrow_mut().push((body.id(), interior, gen_kind));
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let (resume_ty, yield_ty) = fcx.resume_yield_tys.unwrap();
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Some(GeneratorTypes {
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resume_ty,
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yield_ty,
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interior,
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movability: can_be_generator.unwrap(),
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})
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} else {
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None
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};
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// Finalize the return check by taking the LUB of the return types
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// we saw and assigning it to the expected return type. This isn't
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// really expected to fail, since the coercions would have failed
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// earlier when trying to find a LUB.
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//
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// However, the behavior around `!` is sort of complex. In the
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// event that the `actual_return_ty` comes back as `!`, that
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// indicates that the fn either does not return or "returns" only
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// values of type `!`. In this case, if there is an expected
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// return type that is *not* `!`, that should be ok. But if the
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// return type is being inferred, we want to "fallback" to `!`:
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//
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// let x = move || panic!();
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//
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// To allow for that, I am creating a type variable with diverging
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// fallback. This was deemed ever so slightly better than unifying
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// the return value with `!` because it allows for the caller to
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// make more assumptions about the return type (e.g., they could do
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//
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// let y: Option<u32> = Some(x());
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//
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// which would then cause this return type to become `u32`, not
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// `!`).
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let coercion = fcx.ret_coercion.take().unwrap().into_inner();
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let mut actual_return_ty = coercion.complete(&fcx);
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if actual_return_ty.is_never() {
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actual_return_ty = fcx.next_diverging_ty_var(TypeVariableOrigin {
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kind: TypeVariableOriginKind::DivergingFn,
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span,
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});
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}
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fcx.demand_suptype(span, revealed_ret_ty, actual_return_ty);
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// Check that the main return type implements the termination trait.
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if let Some(term_id) = tcx.lang_items().termination() {
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if let Some((def_id, EntryFnType::Main)) = tcx.entry_fn(LOCAL_CRATE) {
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let main_id = hir.local_def_id_to_hir_id(def_id);
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if main_id == fn_id {
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let substs = tcx.mk_substs_trait(declared_ret_ty, &[]);
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let trait_ref = ty::TraitRef::new(term_id, substs);
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let return_ty_span = decl.output.span();
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let cause = traits::ObligationCause::new(
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return_ty_span,
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fn_id,
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ObligationCauseCode::MainFunctionType,
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);
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inherited.register_predicate(traits::Obligation::new(
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cause,
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param_env,
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trait_ref.without_const().to_predicate(tcx),
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));
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}
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}
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}
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// Check that a function marked as `#[panic_handler]` has signature `fn(&PanicInfo) -> !`
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if let Some(panic_impl_did) = tcx.lang_items().panic_impl() {
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if panic_impl_did == hir.local_def_id(fn_id).to_def_id() {
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if let Some(panic_info_did) = tcx.lang_items().panic_info() {
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if *declared_ret_ty.kind() != ty::Never {
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sess.span_err(decl.output.span(), "return type should be `!`");
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}
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let inputs = fn_sig.inputs();
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let span = hir.span(fn_id);
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if inputs.len() == 1 {
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let arg_is_panic_info = match *inputs[0].kind() {
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ty::Ref(region, ty, mutbl) => match *ty.kind() {
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ty::Adt(ref adt, _) => {
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adt.did == panic_info_did
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&& mutbl == hir::Mutability::Not
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&& *region != RegionKind::ReStatic
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}
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_ => false,
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},
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_ => false,
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};
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if !arg_is_panic_info {
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sess.span_err(decl.inputs[0].span, "argument should be `&PanicInfo`");
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}
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if let Node::Item(item) = hir.get(fn_id) {
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if let ItemKind::Fn(_, ref generics, _) = item.kind {
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if !generics.params.is_empty() {
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sess.span_err(span, "should have no type parameters");
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}
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}
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}
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} else {
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let span = sess.source_map().guess_head_span(span);
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sess.span_err(span, "function should have one argument");
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}
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} else {
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sess.err("language item required, but not found: `panic_info`");
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}
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}
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}
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// Check that a function marked as `#[alloc_error_handler]` has signature `fn(Layout) -> !`
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if let Some(alloc_error_handler_did) = tcx.lang_items().oom() {
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if alloc_error_handler_did == hir.local_def_id(fn_id).to_def_id() {
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if let Some(alloc_layout_did) = tcx.lang_items().alloc_layout() {
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if *declared_ret_ty.kind() != ty::Never {
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sess.span_err(decl.output.span(), "return type should be `!`");
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}
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let inputs = fn_sig.inputs();
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let span = hir.span(fn_id);
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if inputs.len() == 1 {
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let arg_is_alloc_layout = match inputs[0].kind() {
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ty::Adt(ref adt, _) => adt.did == alloc_layout_did,
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_ => false,
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};
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if !arg_is_alloc_layout {
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sess.span_err(decl.inputs[0].span, "argument should be `Layout`");
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}
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if let Node::Item(item) = hir.get(fn_id) {
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if let ItemKind::Fn(_, ref generics, _) = item.kind {
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|
if !generics.params.is_empty() {
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sess.span_err(
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span,
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"`#[alloc_error_handler]` function should have no type \
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parameters",
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);
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}
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}
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}
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} else {
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let span = sess.source_map().guess_head_span(span);
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sess.span_err(span, "function should have one argument");
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}
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} else {
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sess.err("language item required, but not found: `alloc_layout`");
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}
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}
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|
}
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|
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|
(fcx, gen_ty)
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}
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|
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pub(super) fn check_struct(tcx: TyCtxt<'_>, id: hir::HirId, span: Span) {
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let def_id = tcx.hir().local_def_id(id);
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let def = tcx.adt_def(def_id);
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def.destructor(tcx); // force the destructor to be evaluated
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check_representable(tcx, span, def_id);
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|
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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, span, def);
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check_packed(tcx, span, def);
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}
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|
|
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fn check_union(tcx: TyCtxt<'_>, id: hir::HirId, span: Span) {
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let def_id = tcx.hir().local_def_id(id);
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let def = tcx.adt_def(def_id);
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def.destructor(tcx); // force the destructor to be evaluated
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check_representable(tcx, span, def_id);
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check_transparent(tcx, span, 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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|
}
|
|
|
|
/// 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);
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if let ty::Adt(def, substs) = item_type.kind() {
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assert!(def.is_union());
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let fields = &def.non_enum_variant().fields;
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let param_env = tcx.param_env(item_def_id);
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|
for field in fields {
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let field_ty = field.ty(tcx, substs);
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// We are currently checking the type this field came from, so it must be local.
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let field_span = tcx.hir().span_if_local(field.did).unwrap();
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|
if field_ty.needs_drop(tcx, param_env) {
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|
struct_span_err!(
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tcx.sess,
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|
field_span,
|
|
E0740,
|
|
"unions may not contain fields that need dropping"
|
|
)
|
|
.span_note(field_span, "`std::mem::ManuallyDrop` can be used to wrap the type")
|
|
.emit();
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return false;
|
|
}
|
|
}
|
|
} else {
|
|
span_bug!(span, "unions must be ty::Adt, but got {:?}", item_type.kind());
|
|
}
|
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true
|
|
}
|
|
|
|
/// Check that a `static` is inhabited.
|
|
fn check_static_inhabited<'tcx>(tcx: TyCtxt<'tcx>, def_id: LocalDefId, span: Span) {
|
|
// Make sure statics are inhabited.
|
|
// Other parts of the compiler assume that there are no uninhabited places. In principle it
|
|
// would be enough to check this for `extern` statics, as statics with an initializer will
|
|
// have UB during initialization if they are uninhabited, but there also seems to be no good
|
|
// reason to allow any statics to be uninhabited.
|
|
let ty = tcx.type_of(def_id);
|
|
let layout = match tcx.layout_of(ParamEnv::reveal_all().and(ty)) {
|
|
Ok(l) => l,
|
|
Err(_) => {
|
|
// Generic statics are rejected, but we still reach this case.
|
|
tcx.sess.delay_span_bug(span, "generic static must be rejected");
|
|
return;
|
|
}
|
|
};
|
|
if layout.abi.is_uninhabited() {
|
|
tcx.struct_span_lint_hir(
|
|
UNINHABITED_STATIC,
|
|
tcx.hir().local_def_id_to_hir_id(def_id),
|
|
span,
|
|
|lint| {
|
|
lint.build("static of uninhabited type")
|
|
.note("uninhabited statics cannot be initialized, and any access would be an immediate error")
|
|
.emit();
|
|
},
|
|
);
|
|
}
|
|
}
|
|
|
|
/// Checks that an opaque type does not contain cycles and does not use `Self` or `T::Foo`
|
|
/// projections that would result in "inheriting lifetimes".
|
|
pub(super) fn check_opaque<'tcx>(
|
|
tcx: TyCtxt<'tcx>,
|
|
def_id: LocalDefId,
|
|
substs: SubstsRef<'tcx>,
|
|
span: Span,
|
|
origin: &hir::OpaqueTyOrigin,
|
|
) {
|
|
check_opaque_for_inheriting_lifetimes(tcx, def_id, span);
|
|
if tcx.type_of(def_id).references_error() {
|
|
return;
|
|
}
|
|
if check_opaque_for_cycles(tcx, def_id, substs, span, origin).is_err() {
|
|
return;
|
|
}
|
|
check_opaque_meets_bounds(tcx, def_id, substs, span, origin);
|
|
}
|
|
|
|
/// Checks that an opaque type does not use `Self` or `T::Foo` projections that would result
|
|
/// in "inheriting lifetimes".
|
|
pub(super) fn check_opaque_for_inheriting_lifetimes(
|
|
tcx: TyCtxt<'tcx>,
|
|
def_id: LocalDefId,
|
|
span: Span,
|
|
) {
|
|
let item = tcx.hir().expect_item(tcx.hir().local_def_id_to_hir_id(def_id));
|
|
debug!(
|
|
"check_opaque_for_inheriting_lifetimes: def_id={:?} span={:?} item={:?}",
|
|
def_id, span, item
|
|
);
|
|
|
|
#[derive(Debug)]
|
|
struct ProhibitOpaqueVisitor<'tcx> {
|
|
opaque_identity_ty: Ty<'tcx>,
|
|
generics: &'tcx ty::Generics,
|
|
};
|
|
|
|
impl<'tcx> ty::fold::TypeVisitor<'tcx> for ProhibitOpaqueVisitor<'tcx> {
|
|
type BreakTy = Option<Ty<'tcx>>;
|
|
|
|
fn visit_ty(&mut self, t: Ty<'tcx>) -> ControlFlow<Self::BreakTy> {
|
|
debug!("check_opaque_for_inheriting_lifetimes: (visit_ty) t={:?}", t);
|
|
if t != self.opaque_identity_ty && t.super_visit_with(self).is_break() {
|
|
return ControlFlow::Break(Some(t));
|
|
}
|
|
ControlFlow::CONTINUE
|
|
}
|
|
|
|
fn visit_region(&mut self, r: ty::Region<'tcx>) -> ControlFlow<Self::BreakTy> {
|
|
debug!("check_opaque_for_inheriting_lifetimes: (visit_region) r={:?}", r);
|
|
if let RegionKind::ReEarlyBound(ty::EarlyBoundRegion { index, .. }) = r {
|
|
if *index < self.generics.parent_count as u32 {
|
|
return ControlFlow::Break(None);
|
|
} else {
|
|
return ControlFlow::CONTINUE;
|
|
}
|
|
}
|
|
|
|
r.super_visit_with(self)
|
|
}
|
|
|
|
fn visit_const(&mut self, c: &'tcx ty::Const<'tcx>) -> ControlFlow<Self::BreakTy> {
|
|
if let ty::ConstKind::Unevaluated(..) = c.val {
|
|
// FIXME(#72219) We currenctly don't detect lifetimes within substs
|
|
// which would violate this check. Even though the particular substitution is not used
|
|
// within the const, this should still be fixed.
|
|
return ControlFlow::CONTINUE;
|
|
}
|
|
c.super_visit_with(self)
|
|
}
|
|
}
|
|
|
|
if let ItemKind::OpaqueTy(hir::OpaqueTy {
|
|
origin: hir::OpaqueTyOrigin::AsyncFn | hir::OpaqueTyOrigin::FnReturn,
|
|
..
|
|
}) = item.kind
|
|
{
|
|
let mut visitor = ProhibitOpaqueVisitor {
|
|
opaque_identity_ty: tcx.mk_opaque(
|
|
def_id.to_def_id(),
|
|
InternalSubsts::identity_for_item(tcx, def_id.to_def_id()),
|
|
),
|
|
generics: tcx.generics_of(def_id),
|
|
};
|
|
let prohibit_opaque = tcx
|
|
.explicit_item_bounds(def_id)
|
|
.iter()
|
|
.try_for_each(|(predicate, _)| predicate.visit_with(&mut visitor));
|
|
debug!(
|
|
"check_opaque_for_inheriting_lifetimes: prohibit_opaque={:?}, visitor={:?}",
|
|
prohibit_opaque, visitor
|
|
);
|
|
|
|
if let Some(ty) = prohibit_opaque.break_value() {
|
|
let is_async = match item.kind {
|
|
ItemKind::OpaqueTy(hir::OpaqueTy { origin, .. }) => match origin {
|
|
hir::OpaqueTyOrigin::AsyncFn => true,
|
|
_ => false,
|
|
},
|
|
_ => unreachable!(),
|
|
};
|
|
|
|
let mut err = struct_span_err!(
|
|
tcx.sess,
|
|
span,
|
|
E0760,
|
|
"`{}` return type cannot contain a projection or `Self` that references lifetimes from \
|
|
a parent scope",
|
|
if is_async { "async fn" } else { "impl Trait" },
|
|
);
|
|
|
|
if let Ok(snippet) = tcx.sess.source_map().span_to_snippet(span) {
|
|
if snippet == "Self" {
|
|
if let Some(ty) = ty {
|
|
err.span_suggestion(
|
|
span,
|
|
"consider spelling out the type instead",
|
|
format!("{:?}", ty),
|
|
Applicability::MaybeIncorrect,
|
|
);
|
|
}
|
|
}
|
|
}
|
|
err.emit();
|
|
}
|
|
}
|
|
}
|
|
|
|
/// Checks that an opaque type does not contain cycles.
|
|
pub(super) fn check_opaque_for_cycles<'tcx>(
|
|
tcx: TyCtxt<'tcx>,
|
|
def_id: LocalDefId,
|
|
substs: SubstsRef<'tcx>,
|
|
span: Span,
|
|
origin: &hir::OpaqueTyOrigin,
|
|
) -> Result<(), ErrorReported> {
|
|
if let Err(partially_expanded_type) = tcx.try_expand_impl_trait_type(def_id.to_def_id(), substs)
|
|
{
|
|
match origin {
|
|
hir::OpaqueTyOrigin::AsyncFn => async_opaque_type_cycle_error(tcx, span),
|
|
hir::OpaqueTyOrigin::Binding => {
|
|
binding_opaque_type_cycle_error(tcx, def_id, span, partially_expanded_type)
|
|
}
|
|
_ => opaque_type_cycle_error(tcx, def_id, span),
|
|
}
|
|
Err(ErrorReported)
|
|
} 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
|
|
/// bounds not on this opaque type:
|
|
///
|
|
/// type X<T> = impl Clone
|
|
/// fn f<T: Clone>(t: T) -> X<T> {
|
|
/// t
|
|
/// }
|
|
///
|
|
/// Without this check the above code is incorrectly accepted: we would ICE if
|
|
/// some tried, for example, to clone an `Option<X<&mut ()>>`.
|
|
fn check_opaque_meets_bounds<'tcx>(
|
|
tcx: TyCtxt<'tcx>,
|
|
def_id: LocalDefId,
|
|
substs: SubstsRef<'tcx>,
|
|
span: Span,
|
|
origin: &hir::OpaqueTyOrigin,
|
|
) {
|
|
match origin {
|
|
// Checked when type checking the function containing them.
|
|
hir::OpaqueTyOrigin::FnReturn | hir::OpaqueTyOrigin::AsyncFn => return,
|
|
// Can have different predicates to their defining use
|
|
hir::OpaqueTyOrigin::Binding | hir::OpaqueTyOrigin::Misc => {}
|
|
}
|
|
|
|
let hir_id = tcx.hir().local_def_id_to_hir_id(def_id);
|
|
let param_env = tcx.param_env(def_id);
|
|
|
|
tcx.infer_ctxt().enter(move |infcx| {
|
|
let inh = Inherited::new(infcx, def_id);
|
|
let infcx = &inh.infcx;
|
|
let opaque_ty = tcx.mk_opaque(def_id.to_def_id(), substs);
|
|
|
|
let misc_cause = traits::ObligationCause::misc(span, hir_id);
|
|
|
|
let (_, opaque_type_map) = inh.register_infer_ok_obligations(
|
|
infcx.instantiate_opaque_types(def_id, hir_id, param_env, opaque_ty, span),
|
|
);
|
|
|
|
for (def_id, opaque_defn) in opaque_type_map {
|
|
match infcx
|
|
.at(&misc_cause, param_env)
|
|
.eq(opaque_defn.concrete_ty, tcx.type_of(def_id).subst(tcx, opaque_defn.substs))
|
|
{
|
|
Ok(infer_ok) => inh.register_infer_ok_obligations(infer_ok),
|
|
Err(ty_err) => tcx.sess.delay_span_bug(
|
|
opaque_defn.definition_span,
|
|
&format!(
|
|
"could not unify `{}` with revealed type:\n{}",
|
|
opaque_defn.concrete_ty, ty_err,
|
|
),
|
|
),
|
|
}
|
|
}
|
|
|
|
// Check that all obligations are satisfied by the implementation's
|
|
// version.
|
|
if let Err(ref errors) = inh.fulfillment_cx.borrow_mut().select_all_or_error(&infcx) {
|
|
infcx.report_fulfillment_errors(errors, None, false);
|
|
}
|
|
|
|
// Finally, resolve all regions. This catches wily misuses of
|
|
// lifetime parameters.
|
|
let fcx = FnCtxt::new(&inh, param_env, hir_id);
|
|
fcx.regionck_item(hir_id, span, &[]);
|
|
});
|
|
}
|
|
|
|
pub fn check_item_type<'tcx>(tcx: TyCtxt<'tcx>, it: &'tcx hir::Item<'tcx>) {
|
|
debug!(
|
|
"check_item_type(it.hir_id={}, it.name={})",
|
|
it.hir_id,
|
|
tcx.def_path_str(tcx.hir().local_def_id(it.hir_id).to_def_id())
|
|
);
|
|
let _indenter = indenter();
|
|
match it.kind {
|
|
// Consts can play a role in type-checking, so they are included here.
|
|
hir::ItemKind::Static(..) => {
|
|
let def_id = tcx.hir().local_def_id(it.hir_id);
|
|
tcx.ensure().typeck(def_id);
|
|
maybe_check_static_with_link_section(tcx, def_id, it.span);
|
|
check_static_inhabited(tcx, def_id, it.span);
|
|
}
|
|
hir::ItemKind::Const(..) => {
|
|
tcx.ensure().typeck(tcx.hir().local_def_id(it.hir_id));
|
|
}
|
|
hir::ItemKind::Enum(ref enum_definition, _) => {
|
|
check_enum(tcx, it.span, &enum_definition.variants, it.hir_id);
|
|
}
|
|
hir::ItemKind::Fn(..) => {} // entirely within check_item_body
|
|
hir::ItemKind::Impl { ref items, .. } => {
|
|
debug!("ItemKind::Impl {} with id {}", it.ident, it.hir_id);
|
|
let impl_def_id = tcx.hir().local_def_id(it.hir_id);
|
|
if let Some(impl_trait_ref) = tcx.impl_trait_ref(impl_def_id) {
|
|
check_impl_items_against_trait(tcx, it.span, impl_def_id, impl_trait_ref, items);
|
|
let trait_def_id = impl_trait_ref.def_id;
|
|
check_on_unimplemented(tcx, trait_def_id, it);
|
|
}
|
|
}
|
|
hir::ItemKind::Trait(_, _, _, _, ref items) => {
|
|
let def_id = tcx.hir().local_def_id(it.hir_id);
|
|
check_on_unimplemented(tcx, def_id.to_def_id(), it);
|
|
|
|
for item in items.iter() {
|
|
let item = tcx.hir().trait_item(item.id);
|
|
match item.kind {
|
|
hir::TraitItemKind::Fn(ref sig, _) => {
|
|
let abi = sig.header.abi;
|
|
fn_maybe_err(tcx, item.ident.span, abi);
|
|
}
|
|
hir::TraitItemKind::Type(.., Some(_default)) => {
|
|
let item_def_id = tcx.hir().local_def_id(item.hir_id).to_def_id();
|
|
let assoc_item = tcx.associated_item(item_def_id);
|
|
let trait_substs =
|
|
InternalSubsts::identity_for_item(tcx, def_id.to_def_id());
|
|
let _: Result<_, rustc_errors::ErrorReported> = check_type_bounds(
|
|
tcx,
|
|
assoc_item,
|
|
assoc_item,
|
|
item.span,
|
|
ty::TraitRef { def_id: def_id.to_def_id(), substs: trait_substs },
|
|
);
|
|
}
|
|
_ => {}
|
|
}
|
|
}
|
|
}
|
|
hir::ItemKind::Struct(..) => {
|
|
check_struct(tcx, it.hir_id, it.span);
|
|
}
|
|
hir::ItemKind::Union(..) => {
|
|
check_union(tcx, it.hir_id, it.span);
|
|
}
|
|
hir::ItemKind::OpaqueTy(hir::OpaqueTy { origin, .. }) => {
|
|
// HACK(jynelson): trying to infer the type of `impl trait` breaks documenting
|
|
// `async-std` (and `pub async fn` in general).
|
|
// Since rustdoc doesn't care about the concrete type behind `impl Trait`, just don't look at it!
|
|
// See https://github.com/rust-lang/rust/issues/75100
|
|
if !tcx.sess.opts.actually_rustdoc {
|
|
let def_id = tcx.hir().local_def_id(it.hir_id);
|
|
|
|
let substs = InternalSubsts::identity_for_item(tcx, def_id.to_def_id());
|
|
check_opaque(tcx, def_id, substs, it.span, &origin);
|
|
}
|
|
}
|
|
hir::ItemKind::TyAlias(..) => {
|
|
let def_id = tcx.hir().local_def_id(it.hir_id);
|
|
let pty_ty = tcx.type_of(def_id);
|
|
let generics = tcx.generics_of(def_id);
|
|
check_type_params_are_used(tcx, &generics, pty_ty);
|
|
}
|
|
hir::ItemKind::ForeignMod(ref m) => {
|
|
check_abi(tcx, it.span, m.abi);
|
|
|
|
if m.abi == Abi::RustIntrinsic {
|
|
for item in m.items {
|
|
intrinsic::check_intrinsic_type(tcx, item);
|
|
}
|
|
} else if m.abi == Abi::PlatformIntrinsic {
|
|
for item in m.items {
|
|
intrinsic::check_platform_intrinsic_type(tcx, item);
|
|
}
|
|
} else {
|
|
for item in m.items {
|
|
let def_id = tcx.hir().local_def_id(item.hir_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 {} parameters",
|
|
kinds,
|
|
)
|
|
.span_label(item.span, &format!("can't have {} parameters", kinds))
|
|
.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();
|
|
}
|
|
|
|
match item.kind {
|
|
hir::ForeignItemKind::Fn(ref fn_decl, _, _) => {
|
|
require_c_abi_if_c_variadic(tcx, fn_decl, m.abi, item.span);
|
|
}
|
|
hir::ForeignItemKind::Static(..) => {
|
|
check_static_inhabited(tcx, def_id, item.span);
|
|
}
|
|
_ => {}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
_ => { /* nothing to do */ }
|
|
}
|
|
}
|
|
|
|
pub(super) fn check_on_unimplemented(tcx: TyCtxt<'_>, trait_def_id: DefId, item: &hir::Item<'_>) {
|
|
let item_def_id = tcx.hir().local_def_id(item.hir_id);
|
|
// an error would be reported if this fails.
|
|
let _ = traits::OnUnimplementedDirective::of_item(tcx, trait_def_id, item_def_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: &hir::ImplItem<'_>,
|
|
) {
|
|
let kind = match impl_item.kind {
|
|
hir::ImplItemKind::Const(..) => ty::AssocKind::Const,
|
|
hir::ImplItemKind::Fn(..) => ty::AssocKind::Fn,
|
|
hir::ImplItemKind::TyAlias(_) => ty::AssocKind::Type,
|
|
};
|
|
|
|
let ancestors = match trait_def.ancestors(tcx, impl_id) {
|
|
Ok(ancestors) => ancestors,
|
|
Err(_) => 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.ident, kind, trait_def.def_id)))
|
|
}
|
|
})
|
|
.peekable();
|
|
|
|
if ancestor_impls.peek().is_none() {
|
|
// No parent, nothing to specialize.
|
|
return;
|
|
}
|
|
|
|
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.impl_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 {
|
|
report_forbidden_specialization(tcx, impl_item, parent_impl);
|
|
}
|
|
}
|
|
|
|
pub(super) fn check_impl_items_against_trait<'tcx>(
|
|
tcx: TyCtxt<'tcx>,
|
|
full_impl_span: Span,
|
|
impl_id: LocalDefId,
|
|
impl_trait_ref: ty::TraitRef<'tcx>,
|
|
impl_item_refs: &[hir::ImplItemRef<'_>],
|
|
) {
|
|
let impl_span = tcx.sess.source_map().guess_head_span(full_impl_span);
|
|
|
|
// 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;
|
|
}
|
|
|
|
// 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.hir().impl_item(first_item_ref.id).span;
|
|
struct_span_err!(
|
|
tcx.sess,
|
|
first_item_span,
|
|
E0749,
|
|
"negative impls cannot have any items"
|
|
)
|
|
.emit();
|
|
}
|
|
return;
|
|
}
|
|
}
|
|
|
|
// Locate trait definition and items
|
|
let trait_def = tcx.trait_def(impl_trait_ref.def_id);
|
|
|
|
let impl_items = || impl_item_refs.iter().map(|iiref| tcx.hir().impl_item(iiref.id));
|
|
|
|
// Check existing impl methods to see if they are both present in trait
|
|
// and compatible with trait signature
|
|
for impl_item in impl_items() {
|
|
let namespace = impl_item.kind.namespace();
|
|
let ty_impl_item = tcx.associated_item(tcx.hir().local_def_id(impl_item.hir_id));
|
|
let ty_trait_item = tcx
|
|
.associated_items(impl_trait_ref.def_id)
|
|
.find_by_name_and_namespace(tcx, ty_impl_item.ident, namespace, impl_trait_ref.def_id)
|
|
.or_else(|| {
|
|
// Not compatible, but needed for the error message
|
|
tcx.associated_items(impl_trait_ref.def_id)
|
|
.filter_by_name(tcx, ty_impl_item.ident, impl_trait_ref.def_id)
|
|
.next()
|
|
});
|
|
|
|
// Check that impl definition matches trait definition
|
|
if let Some(ty_trait_item) = ty_trait_item {
|
|
match impl_item.kind {
|
|
hir::ImplItemKind::Const(..) => {
|
|
// Find associated const definition.
|
|
if ty_trait_item.kind == ty::AssocKind::Const {
|
|
compare_const_impl(
|
|
tcx,
|
|
&ty_impl_item,
|
|
impl_item.span,
|
|
&ty_trait_item,
|
|
impl_trait_ref,
|
|
);
|
|
} else {
|
|
let mut err = struct_span_err!(
|
|
tcx.sess,
|
|
impl_item.span,
|
|
E0323,
|
|
"item `{}` is an associated const, \
|
|
which doesn't match its trait `{}`",
|
|
ty_impl_item.ident,
|
|
impl_trait_ref.print_only_trait_path()
|
|
);
|
|
err.span_label(impl_item.span, "does not match trait");
|
|
// We can only get the spans from local trait definition
|
|
// Same for E0324 and E0325
|
|
if let Some(trait_span) = tcx.hir().span_if_local(ty_trait_item.def_id) {
|
|
err.span_label(trait_span, "item in trait");
|
|
}
|
|
err.emit()
|
|
}
|
|
}
|
|
hir::ImplItemKind::Fn(..) => {
|
|
let opt_trait_span = tcx.hir().span_if_local(ty_trait_item.def_id);
|
|
if ty_trait_item.kind == ty::AssocKind::Fn {
|
|
compare_impl_method(
|
|
tcx,
|
|
&ty_impl_item,
|
|
impl_item.span,
|
|
&ty_trait_item,
|
|
impl_trait_ref,
|
|
opt_trait_span,
|
|
);
|
|
} else {
|
|
let mut err = struct_span_err!(
|
|
tcx.sess,
|
|
impl_item.span,
|
|
E0324,
|
|
"item `{}` is an associated method, \
|
|
which doesn't match its trait `{}`",
|
|
ty_impl_item.ident,
|
|
impl_trait_ref.print_only_trait_path()
|
|
);
|
|
err.span_label(impl_item.span, "does not match trait");
|
|
if let Some(trait_span) = opt_trait_span {
|
|
err.span_label(trait_span, "item in trait");
|
|
}
|
|
err.emit()
|
|
}
|
|
}
|
|
hir::ImplItemKind::TyAlias(_) => {
|
|
let opt_trait_span = tcx.hir().span_if_local(ty_trait_item.def_id);
|
|
if ty_trait_item.kind == ty::AssocKind::Type {
|
|
compare_ty_impl(
|
|
tcx,
|
|
&ty_impl_item,
|
|
impl_item.span,
|
|
&ty_trait_item,
|
|
impl_trait_ref,
|
|
opt_trait_span,
|
|
);
|
|
} else {
|
|
let mut err = struct_span_err!(
|
|
tcx.sess,
|
|
impl_item.span,
|
|
E0325,
|
|
"item `{}` is an associated type, \
|
|
which doesn't match its trait `{}`",
|
|
ty_impl_item.ident,
|
|
impl_trait_ref.print_only_trait_path()
|
|
);
|
|
err.span_label(impl_item.span, "does not match trait");
|
|
if let Some(trait_span) = opt_trait_span {
|
|
err.span_label(trait_span, "item in trait");
|
|
}
|
|
err.emit()
|
|
}
|
|
}
|
|
}
|
|
|
|
check_specialization_validity(
|
|
tcx,
|
|
trait_def,
|
|
&ty_trait_item,
|
|
impl_id.to_def_id(),
|
|
impl_item,
|
|
);
|
|
}
|
|
}
|
|
|
|
// Check for missing items from trait
|
|
let mut missing_items = Vec::new();
|
|
if let Ok(ancestors) = trait_def.ancestors(tcx, impl_id.to_def_id()) {
|
|
for trait_item in tcx.associated_items(impl_trait_ref.def_id).in_definition_order() {
|
|
let is_implemented = ancestors
|
|
.leaf_def(tcx, trait_item.ident, trait_item.kind)
|
|
.map(|node_item| !node_item.defining_node.is_from_trait())
|
|
.unwrap_or(false);
|
|
|
|
if !is_implemented && tcx.impl_defaultness(impl_id).is_final() {
|
|
if !trait_item.defaultness.has_value() {
|
|
missing_items.push(*trait_item);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
if !missing_items.is_empty() {
|
|
missing_items_err(tcx, impl_span, &missing_items, full_impl_span);
|
|
}
|
|
}
|
|
|
|
/// Checks whether a type can be represented in memory. In particular, it
|
|
/// identifies types that contain themselves without indirection through a
|
|
/// pointer, which would mean their size is unbounded.
|
|
pub(super) fn check_representable(tcx: TyCtxt<'_>, sp: Span, item_def_id: LocalDefId) -> bool {
|
|
let rty = tcx.type_of(item_def_id);
|
|
|
|
// Check that it is possible to represent this type. This call identifies
|
|
// (1) types that contain themselves and (2) types that contain a different
|
|
// recursive type. It is only necessary to throw an error on those that
|
|
// contain themselves. For case 2, there must be an inner type that will be
|
|
// caught by case 1.
|
|
match rty.is_representable(tcx, sp) {
|
|
Representability::SelfRecursive(spans) => {
|
|
recursive_type_with_infinite_size_error(tcx, item_def_id.to_def_id(), spans);
|
|
return false;
|
|
}
|
|
Representability::Representable | Representability::ContainsRecursive => (),
|
|
}
|
|
true
|
|
}
|
|
|
|
pub fn check_simd(tcx: TyCtxt<'_>, sp: Span, def_id: LocalDefId) {
|
|
let t = tcx.type_of(def_id);
|
|
if let ty::Adt(def, substs) = t.kind() {
|
|
if 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[0].ty(tcx, substs);
|
|
if !fields.iter().all(|f| f.ty(tcx, substs) == 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;
|
|
}
|
|
match e.kind() {
|
|
ty::Param(_) => { /* struct<T>(T, T, T, T) is ok */ }
|
|
_ if e.is_machine() => { /* struct(u8, u8, u8, u8) is ok */ }
|
|
_ => {
|
|
struct_span_err!(
|
|
tcx.sess,
|
|
sp,
|
|
E0077,
|
|
"SIMD vector element type should be machine 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).iter() {
|
|
for r in attr::find_repr_attrs(&tcx.sess, attr) {
|
|
if let attr::ReprPacked(pack) = r {
|
|
if let Some(repr_pack) = repr.pack {
|
|
if 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),
|
|
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, substs) = tcx.type_of(def_id).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, substs).kind() {
|
|
if !stack.contains(&def.did) {
|
|
if let Some(mut defs) = check_packed_inner(tcx, def.did, stack) {
|
|
defs.push((def.did, field.ident.span));
|
|
return Some(defs);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
stack.pop();
|
|
}
|
|
}
|
|
|
|
None
|
|
}
|
|
|
|
pub(super) fn check_transparent<'tcx>(tcx: TyCtxt<'tcx>, sp: Span, adt: &'tcx ty::AdtDef) {
|
|
if !adt.repr.transparent() {
|
|
return;
|
|
}
|
|
let sp = tcx.sess.source_map().guess_head_span(sp);
|
|
|
|
if adt.is_union() && !tcx.features().transparent_unions {
|
|
feature_err(
|
|
&tcx.sess.parse_sess,
|
|
sym::transparent_unions,
|
|
sp,
|
|
"transparent unions are unstable",
|
|
)
|
|
.emit();
|
|
}
|
|
|
|
if adt.variants.len() != 1 {
|
|
bad_variant_count(tcx, adt, sp, adt.did);
|
|
if adt.variants.is_empty() {
|
|
// Don't bother checking the fields. No variants (and thus no fields) exist.
|
|
return;
|
|
}
|
|
}
|
|
|
|
// For each field, figure out if it's known to be a ZST and align(1)
|
|
let field_infos = adt.all_fields().map(|field| {
|
|
let ty = field.ty(tcx, InternalSubsts::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.map(|layout| layout.is_zst()).unwrap_or(false);
|
|
let align1 = layout.map(|layout| layout.align.abi.bytes() == 1).unwrap_or(false);
|
|
(span, zst, align1)
|
|
});
|
|
|
|
let non_zst_fields =
|
|
field_infos.clone().filter_map(|(span, zst, _align1)| if !zst { Some(span) } else { None });
|
|
let non_zst_count = non_zst_fields.clone().count();
|
|
if non_zst_count != 1 {
|
|
bad_non_zero_sized_fields(tcx, adt, non_zst_count, non_zst_fields, sp);
|
|
}
|
|
for (span, zst, align1) in field_infos {
|
|
if zst && !align1 {
|
|
struct_span_err!(
|
|
tcx.sess,
|
|
span,
|
|
E0691,
|
|
"zero-sized field in transparent {} has alignment larger than 1",
|
|
adt.descr(),
|
|
)
|
|
.span_label(span, "has alignment larger than 1")
|
|
.emit();
|
|
}
|
|
}
|
|
}
|
|
|
|
#[allow(trivial_numeric_casts)]
|
|
pub fn check_enum<'tcx>(
|
|
tcx: TyCtxt<'tcx>,
|
|
sp: Span,
|
|
vs: &'tcx [hir::Variant<'tcx>],
|
|
id: hir::HirId,
|
|
) {
|
|
let def_id = tcx.hir().local_def_id(id);
|
|
let def = tcx.adt_def(def_id);
|
|
def.destructor(tcx); // force the destructor to be evaluated
|
|
|
|
if vs.is_empty() {
|
|
let attributes = tcx.get_attrs(def_id.to_def_id());
|
|
if let Some(attr) = tcx.sess.find_by_name(&attributes, sym::repr) {
|
|
struct_span_err!(
|
|
tcx.sess,
|
|
attr.span,
|
|
E0084,
|
|
"unsupported representation for zero-variant enum"
|
|
)
|
|
.span_label(sp, "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,
|
|
sp,
|
|
"repr with 128-bit type is unstable",
|
|
)
|
|
.emit();
|
|
}
|
|
}
|
|
|
|
for v in vs {
|
|
if let Some(ref e) = v.disr_expr {
|
|
tcx.ensure().typeck(tcx.hir().local_def_id(e.hir_id));
|
|
}
|
|
}
|
|
|
|
if tcx.adt_def(def_id).repr.int.is_none() && tcx.features().arbitrary_enum_discriminant {
|
|
let is_unit = |var: &hir::Variant<'_>| match var.data {
|
|
hir::VariantData::Unit(..) => true,
|
|
_ => false,
|
|
};
|
|
|
|
let has_disr = |var: &hir::Variant<'_>| var.disr_expr.is_some();
|
|
let has_non_units = vs.iter().any(|var| !is_unit(var));
|
|
let disr_units = vs.iter().any(|var| is_unit(&var) && has_disr(&var));
|
|
let disr_non_unit = vs.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, sp, E0732, "`#[repr(inttype)]` must be specified");
|
|
err.emit();
|
|
}
|
|
}
|
|
|
|
let mut disr_vals: Vec<Discr<'tcx>> = Vec::with_capacity(vs.len());
|
|
for ((_, discr), v) in def.discriminants(tcx).zip(vs) {
|
|
// Check for duplicate discriminant values
|
|
if let Some(i) = disr_vals.iter().position(|&x| x.val == discr.val) {
|
|
let variant_did = def.variants[VariantIdx::new(i)].def_id;
|
|
let variant_i_hir_id = tcx.hir().local_def_id_to_hir_id(variant_did.expect_local());
|
|
let variant_i = tcx.hir().expect_variant(variant_i_hir_id);
|
|
let i_span = match variant_i.disr_expr {
|
|
Some(ref expr) => tcx.hir().span(expr.hir_id),
|
|
None => tcx.hir().span(variant_i_hir_id),
|
|
};
|
|
let span = match v.disr_expr {
|
|
Some(ref expr) => tcx.hir().span(expr.hir_id),
|
|
None => v.span,
|
|
};
|
|
struct_span_err!(
|
|
tcx.sess,
|
|
span,
|
|
E0081,
|
|
"discriminant value `{}` already exists",
|
|
disr_vals[i]
|
|
)
|
|
.span_label(i_span, format!("first use of `{}`", disr_vals[i]))
|
|
.span_label(span, format!("enum already has `{}`", disr_vals[i]))
|
|
.emit();
|
|
}
|
|
disr_vals.push(discr);
|
|
}
|
|
|
|
check_representable(tcx, sp, def_id);
|
|
check_transparent(tcx, sp, def);
|
|
}
|
|
|
|
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());
|
|
return;
|
|
}
|
|
|
|
for leaf in ty.walk() {
|
|
if let GenericArgKind::Type(leaf_ty) = leaf.unpack() {
|
|
if 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) {
|
|
if 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) {
|
|
tcx.hir().visit_item_likes_in_module(module_def_id, &mut CheckItemTypesVisitor { tcx });
|
|
}
|
|
|
|
pub(super) fn check_item_well_formed(tcx: TyCtxt<'_>, def_id: LocalDefId) {
|
|
wfcheck::check_item_well_formed(tcx, def_id);
|
|
}
|
|
|
|
pub(super) fn check_trait_item_well_formed(tcx: TyCtxt<'_>, def_id: LocalDefId) {
|
|
wfcheck::check_trait_item(tcx, def_id);
|
|
}
|
|
|
|
pub(super) fn check_impl_item_well_formed(tcx: TyCtxt<'_>, def_id: LocalDefId) {
|
|
wfcheck::check_impl_item(tcx, def_id);
|
|
}
|
|
|
|
fn async_opaque_type_cycle_error(tcx: TyCtxt<'tcx>, span: Span) {
|
|
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`")
|
|
.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<'tcx>, def_id: LocalDefId, span: Span) {
|
|
let mut err = struct_span_err!(tcx.sess, span, E0720, "cannot resolve opaque type");
|
|
|
|
let mut label = false;
|
|
if let Some((hir_id, visitor)) = get_owner_return_paths(tcx, def_id) {
|
|
let typeck_results = tcx.typeck(tcx.hir().local_def_id(hir_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".to_string());
|
|
}
|
|
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))
|
|
{
|
|
struct VisitTypes(Vec<DefId>);
|
|
impl<'tcx> ty::fold::TypeVisitor<'tcx> for VisitTypes {
|
|
fn visit_ty(&mut self, t: Ty<'tcx>) -> ControlFlow<Self::BreakTy> {
|
|
match *t.kind() {
|
|
ty::Opaque(def, _) => {
|
|
self.0.push(def);
|
|
ControlFlow::CONTINUE
|
|
}
|
|
_ => t.super_visit_with(self),
|
|
}
|
|
}
|
|
}
|
|
let mut visitor = VisitTypes(vec![]);
|
|
ty.visit_with(&mut visitor);
|
|
for def_id in visitor.0 {
|
|
let ty_span = tcx.def_span(def_id);
|
|
if !seen.contains(&ty_span) {
|
|
err.span_label(ty_span, &format!("returning this opaque type `{}`", ty));
|
|
seen.insert(ty_span);
|
|
}
|
|
err.span_label(sp, &format!("returning here with type `{}`", ty));
|
|
}
|
|
}
|
|
}
|
|
}
|
|
if !label {
|
|
err.span_label(span, "cannot resolve opaque type");
|
|
}
|
|
err.emit();
|
|
}
|