From 6a2e15a6f08fa1869cd9aacb89c7b2d033c54e65 Mon Sep 17 00:00:00 2001 From: Oli Scherer Date: Fri, 31 May 2024 13:36:27 +0000 Subject: [PATCH] Only collect infer vars to error about in case infer vars are actually forbidden --- compiler/rustc_hir_analysis/src/collect.rs | 87 ++++++++++++++++- .../src/hir_ty_lowering/mod.rs | 93 ++----------------- compiler/rustc_hir_typeck/src/fn_ctxt/mod.rs | 16 ++++ 3 files changed, 111 insertions(+), 85 deletions(-) diff --git a/compiler/rustc_hir_analysis/src/collect.rs b/compiler/rustc_hir_analysis/src/collect.rs index 538d87a300d..f6e5aeb5396 100644 --- a/compiler/rustc_hir_analysis/src/collect.rs +++ b/compiler/rustc_hir_analysis/src/collect.rs @@ -19,10 +19,10 @@ use rustc_data_structures::captures::Captures; use rustc_data_structures::fx::{FxHashSet, FxIndexMap}; use rustc_data_structures::unord::UnordMap; use rustc_errors::{struct_span_code_err, Applicability, Diag, ErrorGuaranteed, StashKey, E0228}; -use rustc_hir as hir; use rustc_hir::def::DefKind; use rustc_hir::def_id::{DefId, LocalDefId}; -use rustc_hir::intravisit::{self, Visitor}; +use rustc_hir::intravisit::{self, walk_generics, Visitor}; +use rustc_hir::{self as hir}; use rustc_hir::{GenericParamKind, Node}; use rustc_infer::infer::{InferCtxt, TyCtxtInferExt}; use rustc_infer::traits::ObligationCause; @@ -529,6 +529,89 @@ impl<'tcx> HirTyLowerer<'tcx> for ItemCtxt<'tcx> { fn set_tainted_by_errors(&self, err: ErrorGuaranteed) { self.tainted_by_errors.set(Some(err)); } + + fn lower_fn_sig( + &self, + decl: &hir::FnDecl<'tcx>, + generics: Option<&hir::Generics<'_>>, + hir_id: rustc_hir::HirId, + hir_ty: Option<&hir::Ty<'_>>, + ) -> (Vec>, Ty<'tcx>) { + let tcx = self.tcx(); + // We proactively collect all the inferred type params to emit a single error per fn def. + let mut visitor = HirPlaceholderCollector::default(); + let mut infer_replacements = vec![]; + + if let Some(generics) = generics { + walk_generics(&mut visitor, generics); + } + + let input_tys = decl + .inputs + .iter() + .enumerate() + .map(|(i, a)| { + if let hir::TyKind::Infer = a.kind { + if let Some(suggested_ty) = + self.lowerer().suggest_trait_fn_ty_for_impl_fn_infer(hir_id, Some(i)) + { + infer_replacements.push((a.span, suggested_ty.to_string())); + return Ty::new_error_with_message(tcx, a.span, suggested_ty.to_string()); + } + } + + // Only visit the type looking for `_` if we didn't fix the type above + visitor.visit_ty(a); + self.lowerer().lower_arg_ty(a, None) + }) + .collect(); + + let output_ty = match decl.output { + hir::FnRetTy::Return(output) => { + if let hir::TyKind::Infer = output.kind + && let Some(suggested_ty) = + self.lowerer().suggest_trait_fn_ty_for_impl_fn_infer(hir_id, None) + { + infer_replacements.push((output.span, suggested_ty.to_string())); + Ty::new_error_with_message(tcx, output.span, suggested_ty.to_string()) + } else { + visitor.visit_ty(output); + self.lower_ty(output) + } + } + hir::FnRetTy::DefaultReturn(..) => tcx.types.unit, + }; + + if !(visitor.0.is_empty() && infer_replacements.is_empty()) { + // We check for the presence of + // `ident_span` to not emit an error twice when we have `fn foo(_: fn() -> _)`. + + let mut diag = crate::collect::placeholder_type_error_diag( + tcx, + generics, + visitor.0, + infer_replacements.iter().map(|(s, _)| *s).collect(), + true, + hir_ty, + "function", + ); + + if !infer_replacements.is_empty() { + diag.multipart_suggestion( + format!( + "try replacing `_` with the type{} in the corresponding trait method signature", + rustc_errors::pluralize!(infer_replacements.len()), + ), + infer_replacements, + Applicability::MachineApplicable, + ); + } + + self.set_tainted_by_errors(diag.emit()); + } + + (input_tys, output_ty) + } } /// Synthesize a new lifetime name that doesn't clash with any of the lifetimes already present. diff --git a/compiler/rustc_hir_analysis/src/hir_ty_lowering/mod.rs b/compiler/rustc_hir_analysis/src/hir_ty_lowering/mod.rs index 7076983284c..8f498fcdf36 100644 --- a/compiler/rustc_hir_analysis/src/hir_ty_lowering/mod.rs +++ b/compiler/rustc_hir_analysis/src/hir_ty_lowering/mod.rs @@ -20,7 +20,6 @@ mod lint; mod object_safety; use crate::bounds::Bounds; -use crate::collect::HirPlaceholderCollector; use crate::errors::{AmbiguousLifetimeBound, WildPatTy}; use crate::hir_ty_lowering::errors::{prohibit_assoc_item_constraint, GenericsArgsErrExtend}; use crate::hir_ty_lowering::generics::{check_generic_arg_count, lower_generic_args}; @@ -34,7 +33,6 @@ use rustc_errors::{ use rustc_hir as hir; use rustc_hir::def::{CtorOf, DefKind, Namespace, Res}; use rustc_hir::def_id::{DefId, LocalDefId}; -use rustc_hir::intravisit::{walk_generics, Visitor as _}; use rustc_hir::{GenericArg, GenericArgs, HirId}; use rustc_infer::infer::{InferCtxt, TyCtxtInferExt}; use rustc_infer::traits::ObligationCause; @@ -157,6 +155,14 @@ pub trait HirTyLowerer<'tcx> { poly_trait_ref: ty::PolyTraitRef<'tcx>, ) -> Ty<'tcx>; + fn lower_fn_sig( + &self, + decl: &hir::FnDecl<'tcx>, + generics: Option<&hir::Generics<'_>>, + hir_id: HirId, + hir_ty: Option<&hir::Ty<'_>>, + ) -> (Vec>, Ty<'tcx>); + /// Returns `AdtDef` if `ty` is an ADT. /// /// Note that `ty` might be a alias type that needs normalization. @@ -2306,92 +2312,13 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ { let bound_vars = tcx.late_bound_vars(hir_id); debug!(?bound_vars); - // We proactively collect all the inferred type params to emit a single error per fn def. - let mut visitor = HirPlaceholderCollector::default(); - let mut infer_replacements = vec![]; - - if let Some(generics) = generics { - walk_generics(&mut visitor, generics); - } - - let input_tys: Vec<_> = decl - .inputs - .iter() - .enumerate() - .map(|(i, a)| { - if let hir::TyKind::Infer = a.kind - && !self.allow_infer() - { - if let Some(suggested_ty) = - self.suggest_trait_fn_ty_for_impl_fn_infer(hir_id, Some(i)) - { - infer_replacements.push((a.span, suggested_ty.to_string())); - return Ty::new_error_with_message( - self.tcx(), - a.span, - suggested_ty.to_string(), - ); - } - } - - // Only visit the type looking for `_` if we didn't fix the type above - visitor.visit_ty(a); - self.lower_arg_ty(a, None) - }) - .collect(); - - let output_ty = match decl.output { - hir::FnRetTy::Return(output) => { - if let hir::TyKind::Infer = output.kind - && !self.allow_infer() - && let Some(suggested_ty) = - self.suggest_trait_fn_ty_for_impl_fn_infer(hir_id, None) - { - infer_replacements.push((output.span, suggested_ty.to_string())); - Ty::new_error_with_message(self.tcx(), output.span, suggested_ty.to_string()) - } else { - visitor.visit_ty(output); - self.lower_ty(output) - } - } - hir::FnRetTy::DefaultReturn(..) => tcx.types.unit, - }; + let (input_tys, output_ty) = self.lower_fn_sig(decl, generics, hir_id, hir_ty); debug!(?output_ty); let fn_ty = tcx.mk_fn_sig(input_tys, output_ty, decl.c_variadic, safety, abi); let bare_fn_ty = ty::Binder::bind_with_vars(fn_ty, bound_vars); - if !self.allow_infer() && !(visitor.0.is_empty() && infer_replacements.is_empty()) { - // We always collect the spans for placeholder types when evaluating `fn`s, but we - // only want to emit an error complaining about them if infer types (`_`) are not - // allowed. `allow_infer` gates this behavior. We check for the presence of - // `ident_span` to not emit an error twice when we have `fn foo(_: fn() -> _)`. - - let mut diag = crate::collect::placeholder_type_error_diag( - tcx, - generics, - visitor.0, - infer_replacements.iter().map(|(s, _)| *s).collect(), - true, - hir_ty, - "function", - ); - - if !infer_replacements.is_empty() { - diag.multipart_suggestion( - format!( - "try replacing `_` with the type{} in the corresponding trait method signature", - rustc_errors::pluralize!(infer_replacements.len()), - ), - infer_replacements, - Applicability::MachineApplicable, - ); - } - - self.set_tainted_by_errors(diag.emit()); - } - // Find any late-bound regions declared in return type that do // not appear in the arguments. These are not well-formed. // @@ -2421,7 +2348,7 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ { /// corresponding function in the trait that the impl implements, if it exists. /// If arg_idx is Some, then it corresponds to an input type index, otherwise it /// corresponds to the return type. - fn suggest_trait_fn_ty_for_impl_fn_infer( + pub(super) fn suggest_trait_fn_ty_for_impl_fn_infer( &self, fn_hir_id: HirId, arg_idx: Option, diff --git a/compiler/rustc_hir_typeck/src/fn_ctxt/mod.rs b/compiler/rustc_hir_typeck/src/fn_ctxt/mod.rs index d250dee5113..e62c4639b43 100644 --- a/compiler/rustc_hir_typeck/src/fn_ctxt/mod.rs +++ b/compiler/rustc_hir_typeck/src/fn_ctxt/mod.rs @@ -355,6 +355,22 @@ impl<'a, 'tcx> HirTyLowerer<'tcx> for FnCtxt<'a, 'tcx> { fn set_tainted_by_errors(&self, e: ErrorGuaranteed) { self.infcx.set_tainted_by_errors(e) } + + fn lower_fn_sig( + &self, + decl: &rustc_hir::FnDecl<'tcx>, + _generics: Option<&rustc_hir::Generics<'_>>, + _hir_id: rustc_hir::HirId, + _hir_ty: Option<&hir::Ty<'_>>, + ) -> (Vec>, Ty<'tcx>) { + let input_tys = decl.inputs.iter().map(|a| self.lowerer().lower_arg_ty(a, None)).collect(); + + let output_ty = match decl.output { + hir::FnRetTy::Return(output) => self.lowerer().lower_ty(output), + hir::FnRetTy::DefaultReturn(..) => self.tcx().types.unit, + }; + (input_tys, output_ty) + } } /// The `ty` representation of a user-provided type. Depending on the use-site