use rustc_hir::FnRetTy::Return;
use rustc_hir::{
BareFnTy, BodyId, FnDecl, GenericArg, GenericBound, GenericParam, GenericParamKind, Generics, Impl, ImplItem,
- ImplItemKind, Item, ItemKind, LangItem, Lifetime, LifetimeName, ParamName, PolyTraitRef, TraitBoundModifier,
- TraitFn, TraitItem, TraitItemKind, Ty, TyKind, WherePredicate,
+ ImplItemKind, Item, ItemKind, LangItem, Lifetime, LifetimeName, ParamName, PolyTraitRef, PredicateOrigin,
+ TraitBoundModifier, TraitFn, TraitItem, TraitItemKind, Ty, TyKind, WherePredicate,
};
use rustc_lint::{LateContext, LateLintPass};
use rustc_middle::hir::nested_filter as middle_nested_filter;
+use rustc_middle::ty::TyCtxt;
use rustc_session::{declare_lint_pass, declare_tool_lint};
+use rustc_span::def_id::LocalDefId;
use rustc_span::source_map::Span;
use rustc_span::symbol::{kw, Ident, Symbol};
///
/// ### Example
/// ```rust
- /// // Bad: unnecessary lifetime annotations
+ /// // Unnecessary lifetime annotations
/// fn in_and_out<'a>(x: &'a u8, y: u8) -> &'a u8 {
/// x
/// }
+ /// ```
///
- /// // Good
+ /// Use instead:
+ /// ```rust
/// fn elided(x: &u8, y: u8) -> &u8 {
/// x
/// }
///
/// ### Example
/// ```rust
- /// // Bad: unnecessary lifetimes
+ /// // unnecessary lifetimes
/// fn unused_lifetime<'a>(x: u8) {
/// // ..
/// }
+ /// ```
///
- /// // Good
+ /// Use instead:
+ /// ```rust
/// fn no_lifetime(x: u8) {
/// // ...
/// }
if let ItemKind::Fn(ref sig, generics, id) = item.kind {
check_fn_inner(cx, sig.decl, Some(id), None, generics, item.span, true);
} else if let ItemKind::Impl(impl_) = item.kind {
- report_extra_impl_lifetimes(cx, impl_);
+ if !item.span.from_expansion() {
+ report_extra_impl_lifetimes(cx, impl_);
+ }
}
}
enum RefLt {
Unnamed,
Static,
- Named(Symbol),
+ Named(LocalDefId),
}
fn check_fn_inner<'tcx>(
.filter(|param| matches!(param.kind, GenericParamKind::Type { .. }));
for typ in types {
for pred in generics.bounds_for_param(cx.tcx.hir().local_def_id(typ.hir_id)) {
- if pred.in_where_clause {
+ if pred.origin == PredicateOrigin::WhereClause {
// has_where_lifetimes checked that this predicate contains no lifetime.
continue;
}
// level of the current item.
// check named LTs
- let allowed_lts = allowed_lts_from(named_generics);
+ let allowed_lts = allowed_lts_from(cx.tcx, named_generics);
// these will collect all the lifetimes for references in arg/return types
let mut input_visitor = RefVisitor::new(cx);
return false;
}
- if allowed_lts
- .intersection(
- &input_visitor
- .nested_elision_site_lts
- .iter()
- .chain(output_visitor.nested_elision_site_lts.iter())
- .cloned()
- .filter(|v| matches!(v, RefLt::Named(_)))
- .collect(),
- )
- .next()
- .is_some()
- {
- return false;
- }
-
let input_lts = input_visitor.lts;
let output_lts = output_visitor.lts;
}
}
+ // check for higher-ranked trait bounds
+ if !input_visitor.nested_elision_site_lts.is_empty() || !output_visitor.nested_elision_site_lts.is_empty() {
+ let allowed_lts: FxHashSet<_> = allowed_lts
+ .iter()
+ .filter_map(|lt| match lt {
+ RefLt::Named(def_id) => Some(cx.tcx.item_name(def_id.to_def_id())),
+ _ => None,
+ })
+ .collect();
+ for lt in input_visitor.nested_elision_site_lts {
+ if let RefLt::Named(def_id) = lt {
+ if allowed_lts.contains(&cx.tcx.item_name(def_id.to_def_id())) {
+ return false;
+ }
+ }
+ }
+ for lt in output_visitor.nested_elision_site_lts {
+ if let RefLt::Named(def_id) = lt {
+ if allowed_lts.contains(&cx.tcx.item_name(def_id.to_def_id())) {
+ return false;
+ }
+ }
+ }
+ }
+
// no input lifetimes? easy case!
if input_lts.is_empty() {
false
}
}
-fn allowed_lts_from(named_generics: &[GenericParam<'_>]) -> FxHashSet<RefLt> {
+fn allowed_lts_from(tcx: TyCtxt<'_>, named_generics: &[GenericParam<'_>]) -> FxHashSet<RefLt> {
let mut allowed_lts = FxHashSet::default();
for par in named_generics.iter() {
if let GenericParamKind::Lifetime { .. } = par.kind {
- allowed_lts.insert(RefLt::Named(par.name.ident().name));
+ allowed_lts.insert(RefLt::Named(tcx.hir().local_def_id(par.hir_id)));
}
}
allowed_lts.insert(RefLt::Unnamed);
if let Some(ref lt) = *lifetime {
if lt.name == LifetimeName::Static {
self.lts.push(RefLt::Static);
- } else if let LifetimeName::Param(ParamName::Fresh(_)) = lt.name {
+ } else if let LifetimeName::Param(_, ParamName::Fresh) = lt.name {
// Fresh lifetimes generated should be ignored.
+ self.lts.push(RefLt::Unnamed);
} else if lt.is_elided() {
self.lts.push(RefLt::Unnamed);
+ } else if let LifetimeName::Param(def_id, _) = lt.name {
+ self.lts.push(RefLt::Named(def_id));
} else {
- self.lts.push(RefLt::Named(lt.name.ident().name));
+ self.lts.push(RefLt::Unnamed);
}
} else {
self.lts.push(RefLt::Unnamed);
TyKind::OpaqueDef(item, bounds) => {
let map = self.cx.tcx.hir();
let item = map.item(item);
+ let len = self.lts.len();
walk_item(self, item);
- walk_ty(self, ty);
+ self.lts.truncate(len);
self.lts.extend(bounds.iter().filter_map(|bound| match bound {
- GenericArg::Lifetime(l) => Some(RefLt::Named(l.name.ident().name)),
+ GenericArg::Lifetime(l) => Some(if let LifetimeName::Param(def_id, _) = l.name {
+ RefLt::Named(def_id)
+ } else {
+ RefLt::Unnamed
+ }),
_ => None,
}));
},
let mut sub_visitor = RefVisitor::new(self.cx);
sub_visitor.visit_fn_decl(decl);
self.nested_elision_site_lts.append(&mut sub_visitor.all_lts());
- return;
},
TyKind::TraitObject(bounds, ref lt, _) => {
if !lt.is_elided() {
for bound in bounds {
self.visit_poly_trait_ref(bound, TraitBoundModifier::None);
}
- return;
},
- _ => (),
+ _ => walk_ty(self, ty),
}
- walk_ty(self, ty);
}
}
return true;
}
// if the bounds define new lifetimes, they are fine to occur
- let allowed_lts = allowed_lts_from(pred.bound_generic_params);
+ let allowed_lts = allowed_lts_from(cx.tcx, pred.bound_generic_params);
// now walk the bounds
for bound in pred.bounds.iter() {
walk_param_bound(&mut visitor, bound);
impl<'tcx> Visitor<'tcx> for BodyLifetimeChecker {
// for lifetimes as parameters of generics
fn visit_lifetime(&mut self, lifetime: &'tcx Lifetime) {
- if lifetime.name.ident().name != kw::Empty && lifetime.name.ident().name != kw::StaticLifetime {
+ if lifetime.name.ident().name != kw::UnderscoreLifetime && lifetime.name.ident().name != kw::StaticLifetime {
self.lifetimes_used_in_body = true;
}
}
projects / rust.git / blobdiff