diff options
Diffstat (limited to 'compiler/rustc_hir_analysis/src/collect.rs')
| -rw-r--r-- | compiler/rustc_hir_analysis/src/collect.rs | 134 |
1 files changed, 120 insertions, 14 deletions
diff --git a/compiler/rustc_hir_analysis/src/collect.rs b/compiler/rustc_hir_analysis/src/collect.rs index 0c4649cea14..b7f259668a1 100644 --- a/compiler/rustc_hir_analysis/src/collect.rs +++ b/compiler/rustc_hir_analysis/src/collect.rs @@ -17,6 +17,7 @@ use crate::astconv::AstConv; use crate::check::intrinsic::intrinsic_operation_unsafety; use crate::errors; +use hir::def::DefKind; use rustc_data_structures::captures::Captures; use rustc_data_structures::fx::{FxHashMap, FxHashSet}; use rustc_errors::{struct_span_err, Applicability, DiagnosticBuilder, ErrorGuaranteed, StashKey}; @@ -24,6 +25,8 @@ use rustc_hir as hir; use rustc_hir::def_id::{DefId, LocalDefId}; use rustc_hir::intravisit::{self, Visitor}; use rustc_hir::{GenericParamKind, Node}; +use rustc_infer::infer::TyCtxtInferExt; +use rustc_infer::traits::ObligationCause; use rustc_middle::hir::nested_filter; use rustc_middle::ty::query::Providers; use rustc_middle::ty::util::{Discr, IntTypeExt}; @@ -31,7 +34,9 @@ use rustc_middle::ty::{self, AdtKind, Const, IsSuggestable, ToPredicate, Ty, TyC use rustc_span::symbol::{kw, sym, Ident, Symbol}; use rustc_span::Span; use rustc_target::spec::abi; +use rustc_trait_selection::infer::InferCtxtExt; use rustc_trait_selection::traits::error_reporting::suggestions::NextTypeParamName; +use rustc_trait_selection::traits::ObligationCtxt; use std::iter; mod generics_of; @@ -208,7 +213,7 @@ pub(crate) fn placeholder_type_error_diag<'tcx>( is_fn = true; // Check if parent is const or static - let parent_id = tcx.hir().get_parent_node(hir_ty.hir_id); + let parent_id = tcx.hir().parent_id(hir_ty.hir_id); let parent_node = tcx.hir().get(parent_id); is_const_or_static = matches!( @@ -500,9 +505,9 @@ impl<'tcx> AstConv<'tcx> for ItemCtxt<'tcx> { } } - fn normalize_ty(&self, _span: Span, ty: Ty<'tcx>) -> Ty<'tcx> { - // Types in item signatures are not normalized to avoid undue dependencies. - ty + fn probe_adt(&self, _span: Span, ty: Ty<'tcx>) -> Option<ty::AdtDef<'tcx>> { + // FIXME(#103640): Should we handle the case where `ty` is a projection? + ty.ty_adt_def() } fn set_tainted_by_errors(&self, _: ErrorGuaranteed) { @@ -839,7 +844,7 @@ fn convert_variant( ) } -fn adt_def<'tcx>(tcx: TyCtxt<'tcx>, def_id: DefId) -> ty::AdtDef<'tcx> { +fn adt_def(tcx: TyCtxt<'_>, def_id: DefId) -> ty::AdtDef<'_> { use rustc_hir::*; let def_id = def_id.expect_local(); @@ -1059,7 +1064,7 @@ fn is_suggestable_infer_ty(ty: &hir::Ty<'_>) -> bool { is_suggestable_infer_ty(ty) || matches!(length, hir::ArrayLen::Infer(_, _)) } Tup(tys) => tys.iter().any(is_suggestable_infer_ty), - Ptr(mut_ty) | Rptr(_, mut_ty) => is_suggestable_infer_ty(mut_ty.ty), + Ptr(mut_ty) | Ref(_, mut_ty) => is_suggestable_infer_ty(mut_ty.ty), OpaqueDef(_, generic_args, _) => are_suggestable_generic_args(generic_args), Path(hir::QPath::TypeRelative(ty, segment)) => { is_suggestable_infer_ty(ty) || are_suggestable_generic_args(segment.args().args) @@ -1104,7 +1109,7 @@ fn fn_sig(tcx: TyCtxt<'_>, def_id: DefId) -> ty::PolyFnSig<'_> { ImplItem(hir::ImplItem { kind: ImplItemKind::Fn(sig, _), generics, .. }) => { // Do not try to infer the return type for a impl method coming from a trait if let Item(hir::Item { kind: ItemKind::Impl(i), .. }) = - tcx.hir().get(tcx.hir().get_parent_node(hir_id)) + tcx.hir().get_parent(hir_id) && i.of_trait.is_some() { <dyn AstConv<'_>>::ty_of_fn( @@ -1191,12 +1196,11 @@ fn infer_return_ty_for_fn_sig<'tcx>( ty::ReErased => tcx.lifetimes.re_static, _ => r, }); - let fn_sig = ty::Binder::dummy(fn_sig); let mut visitor = HirPlaceholderCollector::default(); visitor.visit_ty(ty); let mut diag = bad_placeholder(tcx, visitor.0, "return type"); - let ret_ty = fn_sig.skip_binder().output(); + let ret_ty = fn_sig.output(); if ret_ty.is_suggestable(tcx, false) { diag.span_suggestion( ty.span, @@ -1219,16 +1223,26 @@ fn infer_return_ty_for_fn_sig<'tcx>( Applicability::MachineApplicable, ); } + } else if let Some(sugg) = suggest_impl_trait(tcx, ret_ty, ty.span, hir_id, def_id) { + diag.span_suggestion( + ty.span, + "replace with an appropriate return type", + sugg, + Applicability::MachineApplicable, + ); } else if ret_ty.is_closure() { - // We're dealing with a closure, so we should suggest using `impl Fn` or trait bounds - // to prevent the user from getting a papercut while trying to use the unique closure - // syntax (e.g. `[closure@src/lib.rs:2:5: 2:9]`). diag.help("consider using an `Fn`, `FnMut`, or `FnOnce` trait bound"); - diag.note("for more information on `Fn` traits and closure types, see https://doc.rust-lang.org/book/ch13-01-closures.html"); + } + // Also note how `Fn` traits work just in case! + if ret_ty.is_closure() { + diag.note( + "for more information on `Fn` traits and closure types, see \ + https://doc.rust-lang.org/book/ch13-01-closures.html", + ); } diag.emit(); - fn_sig + ty::Binder::dummy(fn_sig) } None => <dyn AstConv<'_>>::ty_of_fn( icx, @@ -1242,6 +1256,98 @@ fn infer_return_ty_for_fn_sig<'tcx>( } } +fn suggest_impl_trait<'tcx>( + tcx: TyCtxt<'tcx>, + ret_ty: Ty<'tcx>, + span: Span, + hir_id: hir::HirId, + def_id: LocalDefId, +) -> Option<String> { + let format_as_assoc: fn(_, _, _, _, _) -> _ = + |tcx: TyCtxt<'tcx>, + _: ty::SubstsRef<'tcx>, + trait_def_id: DefId, + assoc_item_def_id: DefId, + item_ty: Ty<'tcx>| { + let trait_name = tcx.item_name(trait_def_id); + let assoc_name = tcx.item_name(assoc_item_def_id); + Some(format!("impl {trait_name}<{assoc_name} = {item_ty}>")) + }; + let format_as_parenthesized: fn(_, _, _, _, _) -> _ = + |tcx: TyCtxt<'tcx>, + substs: ty::SubstsRef<'tcx>, + trait_def_id: DefId, + _: DefId, + item_ty: Ty<'tcx>| { + let trait_name = tcx.item_name(trait_def_id); + let args_tuple = substs.type_at(1); + let ty::Tuple(types) = *args_tuple.kind() else { return None; }; + if !types.is_suggestable(tcx, false) { + return None; + } + let maybe_ret = + if item_ty.is_unit() { String::new() } else { format!(" -> {item_ty}") }; + Some(format!( + "impl {trait_name}({}){maybe_ret}", + types.iter().map(|ty| ty.to_string()).collect::<Vec<_>>().join(", ") + )) + }; + + for (trait_def_id, assoc_item_def_id, formatter) in [ + ( + tcx.get_diagnostic_item(sym::Iterator), + tcx.get_diagnostic_item(sym::IteratorItem), + format_as_assoc, + ), + ( + tcx.lang_items().future_trait(), + tcx.get_diagnostic_item(sym::FutureOutput), + format_as_assoc, + ), + (tcx.lang_items().fn_trait(), tcx.lang_items().fn_once_output(), format_as_parenthesized), + ( + tcx.lang_items().fn_mut_trait(), + tcx.lang_items().fn_once_output(), + format_as_parenthesized, + ), + ( + tcx.lang_items().fn_once_trait(), + tcx.lang_items().fn_once_output(), + format_as_parenthesized, + ), + ] { + let Some(trait_def_id) = trait_def_id else { continue; }; + let Some(assoc_item_def_id) = assoc_item_def_id else { continue; }; + if tcx.def_kind(assoc_item_def_id) != DefKind::AssocTy { + continue; + } + let param_env = tcx.param_env(def_id); + let infcx = tcx.infer_ctxt().build(); + let substs = ty::InternalSubsts::for_item(tcx, trait_def_id, |param, _| { + if param.index == 0 { ret_ty.into() } else { infcx.var_for_def(span, param) } + }); + if !infcx.type_implements_trait(trait_def_id, substs, param_env).must_apply_modulo_regions() + { + continue; + } + let ocx = ObligationCtxt::new_in_snapshot(&infcx); + let item_ty = ocx.normalize( + &ObligationCause::misc(span, hir_id), + param_env, + tcx.mk_projection(assoc_item_def_id, substs), + ); + // FIXME(compiler-errors): We may benefit from resolving regions here. + if ocx.select_where_possible().is_empty() + && let item_ty = infcx.resolve_vars_if_possible(item_ty) + && item_ty.is_suggestable(tcx, false) + && let Some(sugg) = formatter(tcx, infcx.resolve_vars_if_possible(substs), trait_def_id, assoc_item_def_id, item_ty) + { + return Some(sugg); + } + } + None +} + fn impl_trait_ref(tcx: TyCtxt<'_>, def_id: DefId) -> Option<ty::TraitRef<'_>> { let icx = ItemCtxt::new(tcx, def_id); let item = tcx.hir().expect_item(def_id.expect_local()); |