diff options
Diffstat (limited to 'compiler/rustc_middle/src/ty/diagnostics.rs')
| -rw-r--r-- | compiler/rustc_middle/src/ty/diagnostics.rs | 126 |
1 files changed, 99 insertions, 27 deletions
diff --git a/compiler/rustc_middle/src/ty/diagnostics.rs b/compiler/rustc_middle/src/ty/diagnostics.rs index fd807882e0f..604f1da26c6 100644 --- a/compiler/rustc_middle/src/ty/diagnostics.rs +++ b/compiler/rustc_middle/src/ty/diagnostics.rs @@ -1,11 +1,12 @@ //! Diagnostics related methods for `Ty`. -use std::borrow::Cow; use std::fmt::Write; use std::ops::ControlFlow; use rustc_data_structures::fx::FxHashMap; -use rustc_errors::{Applicability, Diag, DiagArgValue, IntoDiagArg, into_diag_arg_using_display}; +use rustc_errors::{ + Applicability, Diag, DiagArgValue, IntoDiagArg, into_diag_arg_using_display, pluralize, +}; use rustc_hir::def::DefKind; use rustc_hir::def_id::DefId; use rustc_hir::{self as hir, LangItem, PredicateOrigin, WherePredicateKind}; @@ -161,7 +162,7 @@ pub fn suggest_arbitrary_trait_bound<'tcx>( true } -#[derive(Debug)] +#[derive(Debug, Clone, Copy)] enum SuggestChangingConstraintsMessage<'a> { RestrictBoundFurther, RestrictType { ty: &'a str }, @@ -172,7 +173,7 @@ enum SuggestChangingConstraintsMessage<'a> { fn suggest_changing_unsized_bound( generics: &hir::Generics<'_>, - suggestions: &mut Vec<(Span, String, SuggestChangingConstraintsMessage<'_>)>, + suggestions: &mut Vec<(Span, String, String, SuggestChangingConstraintsMessage<'_>)>, param: &hir::GenericParam<'_>, def_id: Option<DefId>, ) { @@ -207,7 +208,8 @@ fn suggest_changing_unsized_bound( continue; } - let mut push_suggestion = |sp, msg| suggestions.push((sp, String::new(), msg)); + let mut push_suggestion = + |sp, msg| suggestions.push((sp, "Sized".to_string(), String::new(), msg)); if predicate.bounds.len() == unsized_bounds.len() { // All the bounds are unsized bounds, e.g. @@ -278,8 +280,25 @@ pub fn suggest_constraining_type_params<'a>( span_to_replace: Option<Span>, ) -> bool { let mut grouped = FxHashMap::default(); + let mut unstable_suggestion = false; param_names_and_constraints.for_each(|(param_name, constraint, def_id)| { - grouped.entry(param_name).or_insert(Vec::new()).push((constraint, def_id)) + let stable = match def_id { + Some(def_id) => match tcx.lookup_stability(def_id) { + Some(s) => s.level.is_stable(), + None => true, + }, + None => true, + }; + if stable || tcx.sess.is_nightly_build() { + grouped.entry(param_name).or_insert(Vec::new()).push(( + constraint, + def_id, + if stable { "" } else { "unstable " }, + )); + if !stable { + unstable_suggestion = true; + } + } }); let mut applicability = Applicability::MachineApplicable; @@ -290,16 +309,21 @@ pub fn suggest_constraining_type_params<'a>( let Some(param) = param else { return false }; { - let mut sized_constraints = constraints.extract_if(|(_, def_id)| { + let mut sized_constraints = constraints.extract_if(|(_, def_id, _)| { def_id.is_some_and(|def_id| tcx.is_lang_item(def_id, LangItem::Sized)) }); - if let Some((_, def_id)) = sized_constraints.next() { + if let Some((_, def_id, _)) = sized_constraints.next() { applicability = Applicability::MaybeIncorrect; err.span_label(param.span, "this type parameter needs to be `Sized`"); suggest_changing_unsized_bound(generics, &mut suggestions, param, def_id); } } + let bound_message = if constraints.iter().any(|(_, def_id, _)| def_id.is_none()) { + SuggestChangingConstraintsMessage::RestrictBoundFurther + } else { + SuggestChangingConstraintsMessage::RestrictTypeFurther { ty: param_name } + }; // in the scenario like impl has stricter requirements than trait, // we should not suggest restrict bound on the impl, here we double check @@ -312,15 +336,54 @@ pub fn suggest_constraining_type_params<'a>( .collect(); constraints - .retain(|(_, def_id)| def_id.map_or(true, |def| !bound_trait_defs.contains(&def))); + .retain(|(_, def_id, _)| def_id.map_or(true, |def| !bound_trait_defs.contains(&def))); if constraints.is_empty() { continue; } - let mut constraint = constraints.iter().map(|&(c, _)| c).collect::<Vec<_>>(); + let mut constraint = constraints.iter().map(|&(c, _, _)| c).collect::<Vec<_>>(); constraint.sort(); constraint.dedup(); + let all_known = constraints.iter().all(|&(_, def_id, _)| def_id.is_some()); + let all_stable = constraints.iter().all(|&(_, _, stable)| stable.is_empty()); + let all_unstable = constraints.iter().all(|&(_, _, stable)| !stable.is_empty()); + let post = if all_stable || all_unstable { + // Don't redundantly say "trait `X`, trait `Y`", instead "traits `X` and `Y`" + let mut trait_names = constraints + .iter() + .map(|&(c, def_id, _)| match def_id { + None => format!("`{c}`"), + Some(def_id) => format!("`{}`", tcx.item_name(def_id)), + }) + .collect::<Vec<_>>(); + trait_names.sort(); + trait_names.dedup(); + let n = trait_names.len(); + let stable = if all_stable { "" } else { "unstable " }; + let trait_ = if all_known { format!("trait{}", pluralize!(n)) } else { String::new() }; + format!("{stable}{trait_}{}", match &trait_names[..] { + [t] => format!(" {t}"), + [ts @ .., last] => format!(" {} and {last}", ts.join(", ")), + [] => return false, + },) + } else { + // We're more explicit when there's a mix of stable and unstable traits. + let mut trait_names = constraints + .iter() + .map(|&(c, def_id, stable)| match def_id { + None => format!("`{c}`"), + Some(def_id) => format!("{stable}trait `{}`", tcx.item_name(def_id)), + }) + .collect::<Vec<_>>(); + trait_names.sort(); + trait_names.dedup(); + match &trait_names[..] { + [t] => t.to_string(), + [ts @ .., last] => format!("{} and {last}", ts.join(", ")), + [] => return false, + } + }; let constraint = constraint.join(" + "); let mut suggest_restrict = |span, bound_list_non_empty, open_paren_sp| { let suggestion = if span_to_replace.is_some() { @@ -333,13 +396,11 @@ pub fn suggest_constraining_type_params<'a>( format!(" {constraint}") }; - use SuggestChangingConstraintsMessage::RestrictBoundFurther; - if let Some(open_paren_sp) = open_paren_sp { - suggestions.push((open_paren_sp, "(".to_string(), RestrictBoundFurther)); - suggestions.push((span, format!("){suggestion}"), RestrictBoundFurther)); + suggestions.push((open_paren_sp, post.clone(), "(".to_string(), bound_message)); + suggestions.push((span, post.clone(), format!("){suggestion}"), bound_message)); } else { - suggestions.push((span, suggestion, RestrictBoundFurther)); + suggestions.push((span, post.clone(), suggestion, bound_message)); } }; @@ -397,7 +458,8 @@ pub fn suggest_constraining_type_params<'a>( // - insert: `, X: Bar` suggestions.push(( generics.tail_span_for_predicate_suggestion(), - constraints.iter().fold(String::new(), |mut string, &(constraint, _)| { + post, + constraints.iter().fold(String::new(), |mut string, &(constraint, _, _)| { write!(string, ", {param_name}: {constraint}").unwrap(); string }), @@ -426,6 +488,7 @@ pub fn suggest_constraining_type_params<'a>( // default (`<T=Foo>`), so we suggest adding `where T: Bar`. suggestions.push(( generics.tail_span_for_predicate_suggestion(), + post, format!("{where_prefix} {param_name}: {constraint}"), SuggestChangingConstraintsMessage::RestrictTypeFurther { ty: param_name }, )); @@ -439,6 +502,7 @@ pub fn suggest_constraining_type_params<'a>( if let Some(colon_span) = param.colon_span { suggestions.push(( colon_span.shrink_to_hi(), + post, format!(" {constraint}"), SuggestChangingConstraintsMessage::RestrictType { ty: param_name }, )); @@ -451,6 +515,7 @@ pub fn suggest_constraining_type_params<'a>( // - help: consider restricting this type parameter with `T: Foo` suggestions.push(( param.span.shrink_to_hi(), + post, format!(": {constraint}"), SuggestChangingConstraintsMessage::RestrictType { ty: param_name }, )); @@ -459,39 +524,46 @@ pub fn suggest_constraining_type_params<'a>( // FIXME: remove the suggestions that are from derive, as the span is not correct suggestions = suggestions .into_iter() - .filter(|(span, _, _)| !span.in_derive_expansion()) + .filter(|(span, _, _, _)| !span.in_derive_expansion()) .collect::<Vec<_>>(); - + let suggested = !suggestions.is_empty(); if suggestions.len() == 1 { - let (span, suggestion, msg) = suggestions.pop().unwrap(); + let (span, post, suggestion, msg) = suggestions.pop().unwrap(); let msg = match msg { SuggestChangingConstraintsMessage::RestrictBoundFurther => { - Cow::from("consider further restricting this bound") + format!("consider further restricting this bound") + } + SuggestChangingConstraintsMessage::RestrictTypeFurther { ty } + | SuggestChangingConstraintsMessage::RestrictType { ty } + if ty.starts_with("impl ") => + { + format!("consider restricting opaque type `{ty}` with {post}") } SuggestChangingConstraintsMessage::RestrictType { ty } => { - Cow::from(format!("consider restricting type parameter `{ty}`")) + format!("consider restricting type parameter `{ty}` with {post}") } SuggestChangingConstraintsMessage::RestrictTypeFurther { ty } => { - Cow::from(format!("consider further restricting type parameter `{ty}`")) + format!("consider further restricting type parameter `{ty}` with {post}") } SuggestChangingConstraintsMessage::RemoveMaybeUnsized => { - Cow::from("consider removing the `?Sized` bound to make the type parameter `Sized`") + format!("consider removing the `?Sized` bound to make the type parameter `Sized`") } SuggestChangingConstraintsMessage::ReplaceMaybeUnsizedWithSized => { - Cow::from("consider replacing `?Sized` with `Sized`") + format!("consider replacing `?Sized` with `Sized`") } }; err.span_suggestion_verbose(span, msg, suggestion, applicability); } else if suggestions.len() > 1 { + let post = if unstable_suggestion { " (some of them are unstable traits)" } else { "" }; err.multipart_suggestion_verbose( - "consider restricting type parameters", - suggestions.into_iter().map(|(span, suggestion, _)| (span, suggestion)).collect(), + format!("consider restricting type parameters{post}"), + suggestions.into_iter().map(|(span, _, suggestion, _)| (span, suggestion)).collect(), applicability, ); } - true + suggested } /// Collect al types that have an implicit `'static` obligation that we could suggest `'_` for. |