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https://github.com/rust-lang/rust.git
synced 2024-10-30 14:01:51 +00:00
Modify existing bounds if they exist
This commit is contained in:
parent
044a28a409
commit
af5a37e844
@ -803,6 +803,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
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predicates
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.iter()
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.map(|(param, constraint)| (param.name.as_str(), &**constraint, None)),
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None,
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);
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}
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}
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@ -136,6 +136,7 @@ impl<'tcx> NonConstOp<'tcx> for FnCallNonConst<'tcx> {
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¶m_ty.name.as_str(),
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&constraint,
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None,
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None,
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);
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}
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}
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@ -176,6 +176,7 @@ fn visit_implementation_of_copy(tcx: TyCtxt<'_>, impl_did: LocalDefId) {
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bounds.iter().map(|(param, constraint, def_id)| {
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(param.as_str(), constraint.as_str(), *def_id)
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}),
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None,
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);
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err.emit();
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}
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@ -1385,6 +1385,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
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generics,
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diag,
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vec![(param.name.as_str(), "Clone", Some(clone_trait_did))].into_iter(),
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None,
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);
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} else {
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self.suggest_derive(diag, &[(trait_ref.to_predicate(self.tcx), None, None)]);
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@ -77,49 +77,86 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
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(ty::Param(p), ty::Alias(ty::Projection, proj)) | (ty::Alias(ty::Projection, proj), ty::Param(p))
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if tcx.def_kind(proj.def_id) != DefKind::ImplTraitPlaceholder =>
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{
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let generics = tcx.generics_of(body_owner_def_id);
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let p_span = tcx.def_span(generics.type_param(p, tcx).def_id);
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let p_def_id = tcx
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.generics_of(body_owner_def_id)
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.type_param(p, tcx)
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.def_id;
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let p_span = tcx.def_span(p_def_id);
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if !sp.contains(p_span) {
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diag.span_label(p_span, "this type parameter");
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}
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let hir = tcx.hir();
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let mut note = true;
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if let Some(generics) = generics
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.type_param(p, tcx)
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.def_id
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let parent = p_def_id
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.as_local()
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.map(|id| hir.local_def_id_to_hir_id(id))
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.and_then(|id| tcx.hir().find_parent(id))
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.as_ref()
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.and_then(|node| node.generics())
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.and_then(|id| {
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let local_id = hir.local_def_id_to_hir_id(id);
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let generics = tcx.hir().find_parent(local_id)?.generics()?;
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Some((id, generics))
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});
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if let Some((local_id, generics)) = parent
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{
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// Synthesize the associated type restriction `Add<Output = Expected>`.
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// FIXME: extract this logic for use in other diagnostics.
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let (trait_ref, assoc_substs) = proj.trait_ref_and_own_substs(tcx);
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let path =
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tcx.def_path_str_with_substs(trait_ref.def_id, trait_ref.substs);
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let item_name = tcx.item_name(proj.def_id);
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let item_args = self.format_generic_args(assoc_substs);
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let path = if path.ends_with('>') {
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format!(
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"{}, {}{} = {}>",
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&path[..path.len() - 1],
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item_name,
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item_args,
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p
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)
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// Here, we try to see if there's an existing
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// trait implementation that matches the one that
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// we're suggesting to restrict. If so, find the
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// "end", whether it be at the end of the trait
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// or the end of the generic arguments.
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let mut matching_span = None;
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let mut matched_end_of_args = false;
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for bound in generics.bounds_for_param(local_id) {
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let potential_spans = bound
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.bounds
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.iter()
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.find_map(|bound| {
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let bound_trait_path = bound.trait_ref()?.path;
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let def_id = bound_trait_path.res.opt_def_id()?;
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let generic_args = bound_trait_path.segments.iter().last().map(|path| path.args());
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(def_id == trait_ref.def_id).then_some((bound_trait_path.span, generic_args))
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});
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if let Some((end_of_trait, end_of_args)) = potential_spans {
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let args_span = end_of_args.and_then(|args| args.span());
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matched_end_of_args = args_span.is_some();
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matching_span = args_span
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.or_else(|| Some(end_of_trait))
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.map(|span| span.shrink_to_hi());
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break;
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}
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}
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if matched_end_of_args {
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// Append suggestion to the end of our args
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let path = format!(", {}{} = {}",item_name, item_args, p);
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note = !suggest_constraining_type_param(
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tcx,
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generics,
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diag,
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&format!("{}", proj.self_ty()),
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&path,
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None,
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matching_span,
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);
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} else {
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format!("{}<{}{} = {}>", path, item_name, item_args, p)
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};
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note = !suggest_constraining_type_param(
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tcx,
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generics,
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diag,
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&format!("{}", proj.self_ty()),
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&path,
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None,
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);
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// Suggest adding a bound to an existing trait
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// or if the trait doesn't exist, add the trait
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// and the suggested bounds.
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let path = format!("<{}{} = {}>", item_name, item_args, p);
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note = !suggest_constraining_type_param(
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tcx,
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generics,
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diag,
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&format!("{}", proj.self_ty()),
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&path,
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None,
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matching_span,
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);
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}
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}
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if note {
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diag.note("you might be missing a type parameter or trait bound");
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@ -193,6 +193,9 @@ fn suggest_removing_unsized_bound(
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}
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/// Suggest restricting a type param with a new bound.
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///
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/// If `span_to_replace` is provided, then that span will be replaced with the
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/// `constraint`. If one wasn't provided, then the full bound will be suggested.
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pub fn suggest_constraining_type_param(
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tcx: TyCtxt<'_>,
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generics: &hir::Generics<'_>,
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@ -200,12 +203,14 @@ pub fn suggest_constraining_type_param(
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param_name: &str,
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constraint: &str,
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def_id: Option<DefId>,
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span_to_replace: Option<Span>,
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) -> bool {
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suggest_constraining_type_params(
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tcx,
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generics,
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err,
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[(param_name, constraint, def_id)].into_iter(),
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span_to_replace,
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)
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}
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@ -215,6 +220,7 @@ pub fn suggest_constraining_type_params<'a>(
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generics: &hir::Generics<'_>,
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err: &mut Diagnostic,
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param_names_and_constraints: impl Iterator<Item = (&'a str, &'a str, Option<DefId>)>,
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span_to_replace: Option<Span>,
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) -> bool {
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let mut grouped = FxHashMap::default();
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param_names_and_constraints.for_each(|(param_name, constraint, def_id)| {
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@ -253,7 +259,9 @@ pub fn suggest_constraining_type_params<'a>(
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let mut suggest_restrict = |span, bound_list_non_empty| {
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suggestions.push((
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span,
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if bound_list_non_empty {
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if span_to_replace.is_some() {
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constraint.clone()
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} else if bound_list_non_empty {
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format!(" + {}", constraint)
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} else {
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format!(" {}", constraint)
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@ -262,6 +270,11 @@ pub fn suggest_constraining_type_params<'a>(
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))
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};
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if let Some(span) = span_to_replace {
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suggest_restrict(span, true);
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continue;
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}
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// When the type parameter has been provided bounds
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//
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// Message:
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@ -679,6 +679,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
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¶m_name,
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&constraint,
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Some(trait_pred.def_id()),
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None,
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) {
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return;
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}
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@ -1087,6 +1088,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
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param.name.as_str(),
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"Clone",
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Some(clone_trait),
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None,
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);
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}
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err.span_suggestion_verbose(
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@ -16,8 +16,8 @@ LL | for<'b> <Self as UnsafeCopy<'b, T>>::Item: std::ops::Deref<Target = T>,
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| ^^^^^^^^^^ required by this bound in `UnsafeCopy`
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help: consider further restricting this bound
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LL | impl<T: Copy + std::ops::Deref + Deref<Target = T>> UnsafeCopy<'_, T> for T {
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| +++++++++++++++++++
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LL | impl<T: Copy + std::ops::Deref<Target = T>> UnsafeCopy<'_, T> for T {
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| ++++++++++++
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error: aborting due to previous error
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@ -15,8 +15,8 @@ LL | type Item<'a>: std::ops::Deref<Target = T>;
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| ^^^^^^^^^^ required by this bound in `UnsafeCopy::Item`
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help: consider further restricting this bound
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LL | impl<T: Copy + std::ops::Deref + Deref<Target = T>> UnsafeCopy<T> for T {
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| +++++++++++++++++++
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LL | impl<T: Copy + std::ops::Deref<Target = T>> UnsafeCopy<T> for T {
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| ++++++++++++
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error: aborting due to previous error
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@ -4,7 +4,7 @@ use std::ops::Add;
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struct A<B>(B);
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impl<B> Add for A<B> where B: Add + Add<Output = B> {
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impl<B> Add for A<B> where B: Add<Output = B> {
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type Output = Self;
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fn add(self, rhs: Self) -> Self {
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@ -14,7 +14,7 @@ impl<B> Add for A<B> where B: Add + Add<Output = B> {
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struct C<B>(B);
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impl<B: Add + Add<Output = B>> Add for C<B> {
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impl<B: Add<Output = B>> Add for C<B> {
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type Output = Self;
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fn add(self, rhs: Self) -> Self {
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@ -34,7 +34,7 @@ impl<B: std::ops::Add<Output = B>> Add for D<B> {
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struct E<B>(B);
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impl<B: Add + Add<Output = B>> Add for E<B> where B: Add<Output = B> {
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impl<B: Add<Output = B>> Add for E<B> where B: Add<Output = B> {
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//~^ ERROR equality constraints are not yet supported in `where` clauses
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type Output = Self;
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@ -37,8 +37,8 @@ LL | struct A<B>(B);
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| ^
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help: consider further restricting this bound
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LL | impl<B> Add for A<B> where B: Add + Add<Output = B> {
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| +++++++++++++++++
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LL | impl<B> Add for A<B> where B: Add<Output = B> {
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| ++++++++++++
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error[E0308]: mismatched types
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--> $DIR/missing-bounds.rs:21:14
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@ -60,8 +60,8 @@ LL | struct C<B>(B);
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| ^
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help: consider further restricting this bound
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LL | impl<B: Add + Add<Output = B>> Add for C<B> {
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| +++++++++++++++++
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LL | impl<B: Add<Output = B>> Add for C<B> {
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| ++++++++++++
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error[E0369]: cannot add `B` to `B`
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--> $DIR/missing-bounds.rs:31:21
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@ -96,8 +96,8 @@ LL | struct E<B>(B);
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| ^
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help: consider further restricting this bound
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LL | impl<B: Add + Add<Output = B>> Add for E<B> where <B as Add>::Output = B {
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| +++++++++++++++++
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LL | impl<B: Add<Output = B>> Add for E<B> where <B as Add>::Output = B {
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| ++++++++++++
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error: aborting due to 5 previous errors
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30
tests/ui/suggestions/restrict-existing-type-bounds.rs
Normal file
30
tests/ui/suggestions/restrict-existing-type-bounds.rs
Normal file
@ -0,0 +1,30 @@
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pub trait TryAdd<Rhs = Self> {
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type Error;
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type Output;
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fn try_add(self, rhs: Rhs) -> Result<Self::Output, Self::Error>;
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}
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impl<T: TryAdd> TryAdd for Option<T> {
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type Error = <T as TryAdd>::Error;
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type Output = Option<<T as TryAdd>::Output>;
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fn try_add(self, rhs: Self) -> Result<Self::Output, Self::Error> {
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Ok(self) //~ ERROR mismatched types
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}
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}
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struct Other<A>(A);
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struct X;
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impl<T: TryAdd<Error = X>> TryAdd for Other<T> {
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type Error = <T as TryAdd>::Error;
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type Output = Other<<T as TryAdd>::Output>;
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fn try_add(self, rhs: Self) -> Result<Self::Output, Self::Error> {
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Ok(self) //~ ERROR mismatched types
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}
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}
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fn main() {}
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57
tests/ui/suggestions/restrict-existing-type-bounds.stderr
Normal file
57
tests/ui/suggestions/restrict-existing-type-bounds.stderr
Normal file
@ -0,0 +1,57 @@
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error[E0308]: mismatched types
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--> $DIR/restrict-existing-type-bounds.rs:13:12
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LL | impl<T: TryAdd> TryAdd for Option<T> {
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| - this type parameter
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...
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LL | Ok(self)
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| -- ^^^^ expected `Option<<T as TryAdd>::Output>`, found `Option<T>`
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| |
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| arguments to this enum variant are incorrect
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|
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= note: expected enum `Option<<T as TryAdd>::Output>`
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found enum `Option<T>`
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help: the type constructed contains `Option<T>` due to the type of the argument passed
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--> $DIR/restrict-existing-type-bounds.rs:13:9
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|
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LL | Ok(self)
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| ^^^----^
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| |
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| this argument influences the type of `Ok`
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note: tuple variant defined here
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--> $SRC_DIR/core/src/result.rs:LL:COL
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help: consider further restricting this bound
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|
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LL | impl<T: TryAdd<Output = T>> TryAdd for Option<T> {
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| ++++++++++++
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error[E0308]: mismatched types
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--> $DIR/restrict-existing-type-bounds.rs:26:12
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|
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LL | impl<T: TryAdd<Error = X>> TryAdd for Other<T> {
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| - this type parameter
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...
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LL | Ok(self)
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| -- ^^^^ expected `Other<<T as TryAdd>::Output>`, found `Other<T>`
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| |
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| arguments to this enum variant are incorrect
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|
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= note: expected struct `Other<<T as TryAdd>::Output>`
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found struct `Other<T>`
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help: the type constructed contains `Other<T>` due to the type of the argument passed
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--> $DIR/restrict-existing-type-bounds.rs:26:9
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|
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LL | Ok(self)
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| ^^^----^
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| |
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| this argument influences the type of `Ok`
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note: tuple variant defined here
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--> $SRC_DIR/core/src/result.rs:LL:COL
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help: consider further restricting this bound
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|
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LL | impl<T: TryAdd<Error = X, Output = T>> TryAdd for Other<T> {
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| ++++++++++++
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error: aborting due to 2 previous errors
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For more information about this error, try `rustc --explain E0308`.
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