Auto merge of #53816 - zackmdavis:elided_lifetimes_in_paths_field_day…

…, r=nikomatsakis

don't elide lifetimes in paths in librustc/

In light of the "Apply to rustc" checkbox on #44524 and @nikomatsakis's [recent comment about regularly wanting visual indication of elided lifetimes in types](#44524 (comment)), I was curious to see what it would look like if we turned the `elided_lifetimes_in_path` lint on in at least one crate in the codebase (I chose librustc). Given that I couldn't figure out how to get `cargo fix` work with the build system, this arguably wasn't a very efficient use of my time, but once I started, the conjunction of moral law and the sunk cost fallacy forced me to continue.

This is mostly applying the `<'_>` suggestions issued by the lint, but there were a few places where I named the lifetimes (_e.g._, `<'a, 'gcx, 'tcx>` on `TyCtxt`) in order to match style with surrounding code.

r? @nikomatsakis

src/librustc/dep_graph/dep_node.rs

@@ -331,7 +331,7 @@ macro_rules! define_dep_nodes {
             /// refers to something from the previous compilation session that
             /// has been removed.
             #[inline]
-            pub fn extract_def_id(&self, tcx: TyCtxt) -> Option<DefId> {
+            pub fn extract_def_id(&self, tcx: TyCtxt<'_, '_, '_>) -> Option<DefId> {
                 if self.kind.can_reconstruct_query_key() {
                     let def_path_hash = DefPathHash(self.hash);
                     tcx.def_path_hash_to_def_id.as_ref()?
@@ -386,7 +386,7 @@ macro_rules! define_dep_nodes {
 }
 
 impl fmt::Debug for DepNode {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         write!(f, "{:?}", self.kind)?;
 
         if !self.kind.has_params() && !self.kind.is_anon() {
@@ -424,7 +424,7 @@ impl DefPathHash {
 
 impl DefId {
     #[inline]
-    pub fn to_dep_node(self, tcx: TyCtxt, kind: DepKind) -> DepNode {
+    pub fn to_dep_node(self, tcx: TyCtxt<'_, '_, '_>, kind: DepKind) -> DepNode {
         DepNode::from_def_path_hash(kind, tcx.def_path_hash(self))
     }
 }
@@ -714,7 +714,7 @@ impl<'a, 'gcx: 'tcx + 'a, 'tcx: 'a, T> DepNodeParams<'a, 'gcx, 'tcx> for T
 impl<'a, 'gcx: 'tcx + 'a, 'tcx: 'a> DepNodeParams<'a, 'gcx, 'tcx> for DefId {
     const CAN_RECONSTRUCT_QUERY_KEY: bool = true;
 
-    fn to_fingerprint(&self, tcx: TyCtxt) -> Fingerprint {
+    fn to_fingerprint(&self, tcx: TyCtxt<'_, '_, '_>) -> Fingerprint {
         tcx.def_path_hash(*self).0
     }
 
@@ -726,7 +726,7 @@ impl<'a, 'gcx: 'tcx + 'a, 'tcx: 'a> DepNodeParams<'a, 'gcx, 'tcx> for DefId {
 impl<'a, 'gcx: 'tcx + 'a, 'tcx: 'a> DepNodeParams<'a, 'gcx, 'tcx> for DefIndex {
     const CAN_RECONSTRUCT_QUERY_KEY: bool = true;
 
-    fn to_fingerprint(&self, tcx: TyCtxt) -> Fingerprint {
+    fn to_fingerprint(&self, tcx: TyCtxt<'_, '_, '_>) -> Fingerprint {
         tcx.hir.definitions().def_path_hash(*self).0
     }
 
@@ -738,7 +738,7 @@ impl<'a, 'gcx: 'tcx + 'a, 'tcx: 'a> DepNodeParams<'a, 'gcx, 'tcx> for DefIndex {
 impl<'a, 'gcx: 'tcx + 'a, 'tcx: 'a> DepNodeParams<'a, 'gcx, 'tcx> for CrateNum {
     const CAN_RECONSTRUCT_QUERY_KEY: bool = true;
 
-    fn to_fingerprint(&self, tcx: TyCtxt) -> Fingerprint {
+    fn to_fingerprint(&self, tcx: TyCtxt<'_, '_, '_>) -> Fingerprint {
         let def_id = DefId {
             krate: *self,
             index: CRATE_DEF_INDEX,
@@ -757,7 +757,7 @@ impl<'a, 'gcx: 'tcx + 'a, 'tcx: 'a> DepNodeParams<'a, 'gcx, 'tcx> for (DefId, De
     // We actually would not need to specialize the implementation of this
     // method but it's faster to combine the hashes than to instantiate a full
     // hashing context and stable-hashing state.
-    fn to_fingerprint(&self, tcx: TyCtxt) -> Fingerprint {
+    fn to_fingerprint(&self, tcx: TyCtxt<'_, '_, '_>) -> Fingerprint {
         let (def_id_0, def_id_1) = *self;
 
         let def_path_hash_0 = tcx.def_path_hash(def_id_0);
@@ -781,7 +781,7 @@ impl<'a, 'gcx: 'tcx + 'a, 'tcx: 'a> DepNodeParams<'a, 'gcx, 'tcx> for HirId {
     // We actually would not need to specialize the implementation of this
     // method but it's faster to combine the hashes than to instantiate a full
     // hashing context and stable-hashing state.
-    fn to_fingerprint(&self, tcx: TyCtxt) -> Fingerprint {
+    fn to_fingerprint(&self, tcx: TyCtxt<'_, '_, '_>) -> Fingerprint {
         let HirId {
             owner,
             local_id: ItemLocalId(local_id),

src/librustc/hir/def_id.rs

@@ -36,7 +36,7 @@ pub enum CrateNum {
 }
 
 impl ::std::fmt::Debug for CrateNum {
-    fn fmt(&self, fmt: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
+    fn fmt(&self, fmt: &mut ::std::fmt::Formatter<'_>) -> ::std::fmt::Result {
         match self {
             CrateNum::Index(id) => write!(fmt, "crate{}", id.private),
             CrateNum::Invalid => write!(fmt, "invalid crate"),
@@ -97,7 +97,7 @@ impl CrateNum {
 }
 
 impl fmt::Display for CrateNum {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match self {
             CrateNum::Index(id) => fmt::Display::fmt(&id.private, f),
             CrateNum::Invalid => write!(f, "invalid crate"),
@@ -132,7 +132,7 @@ pub struct DefIndex(u32);
 pub const CRATE_DEF_INDEX: DefIndex = DefIndex(0);
 
 impl fmt::Debug for DefIndex {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         write!(f,
                "DefIndex({}:{})",
                self.address_space().index(),
@@ -224,7 +224,7 @@ pub struct DefId {
 }
 
 impl fmt::Debug for DefId {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         write!(f, "DefId({:?}/{}:{}",
                self.krate.index(),
                self.index.address_space().index(),
@@ -288,7 +288,7 @@ impl LocalDefId {
 }
 
 impl fmt::Debug for LocalDefId {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         self.to_def_id().fmt(f)
     }
 }

src/librustc/hir/lowering.rs

@@ -686,7 +686,7 @@ impl<'a> LoweringContext<'a> {
         f: F,
     ) -> (Vec<hir::GenericParam>, T)
     where
-        F: FnOnce(&mut LoweringContext) -> (Vec<hir::GenericParam>, T),
+        F: FnOnce(&mut LoweringContext<'_>) -> (Vec<hir::GenericParam>, T),
     {
         assert!(!self.is_collecting_in_band_lifetimes);
         assert!(self.lifetimes_to_define.is_empty());
@@ -788,7 +788,7 @@ impl<'a> LoweringContext<'a> {
     // for them.
     fn with_in_scope_lifetime_defs<T, F>(&mut self, params: &[GenericParam], f: F) -> T
     where
-        F: FnOnce(&mut LoweringContext) -> T,
+        F: FnOnce(&mut LoweringContext<'_>) -> T,
     {
         let old_len = self.in_scope_lifetimes.len();
         let lt_def_names = params.iter().filter_map(|param| match param.kind {
@@ -812,7 +812,7 @@ impl<'a> LoweringContext<'a> {
         params: &HirVec<hir::GenericParam>,
         f: F
     ) -> T where
-        F: FnOnce(&mut LoweringContext) -> T,
+        F: FnOnce(&mut LoweringContext<'_>) -> T,
     {
         let old_len = self.in_scope_lifetimes.len();
         let lt_def_names = params.iter().filter_map(|param| match param.kind {
@@ -841,7 +841,7 @@ impl<'a> LoweringContext<'a> {
         f: F,
     ) -> (hir::Generics, T)
     where
-        F: FnOnce(&mut LoweringContext, &mut Vec<hir::GenericParam>) -> T,
+        F: FnOnce(&mut LoweringContext<'_>, &mut Vec<hir::GenericParam>) -> T,
     {
         let (in_band_defs, (mut lowered_generics, res)) = self.with_in_scope_lifetime_defs(
             &generics.params,
@@ -870,7 +870,7 @@ impl<'a> LoweringContext<'a> {
 
     fn with_catch_scope<T, F>(&mut self, catch_id: NodeId, f: F) -> T
     where
-        F: FnOnce(&mut LoweringContext) -> T,
+        F: FnOnce(&mut LoweringContext<'_>) -> T,
     {
         let len = self.catch_scopes.len();
         self.catch_scopes.push(catch_id);
@@ -892,7 +892,7 @@ impl<'a> LoweringContext<'a> {
         capture_clause: CaptureBy,
         closure_node_id: NodeId,
         ret_ty: Option<&Ty>,
-        body: impl FnOnce(&mut LoweringContext) -> hir::Expr,
+        body: impl FnOnce(&mut LoweringContext<'_>) -> hir::Expr,
     ) -> hir::ExprKind {
         let prev_is_generator = mem::replace(&mut self.is_generator, true);
         let body_expr = body(self);
@@ -929,7 +929,7 @@ impl<'a> LoweringContext<'a> {
 
     fn lower_body<F>(&mut self, decl: Option<&FnDecl>, f: F) -> hir::BodyId
     where
-        F: FnOnce(&mut LoweringContext) -> hir::Expr,
+        F: FnOnce(&mut LoweringContext<'_>) -> hir::Expr,
     {
         let prev = mem::replace(&mut self.is_generator, false);
         let result = f(self);
@@ -940,7 +940,7 @@ impl<'a> LoweringContext<'a> {
 
     fn with_loop_scope<T, F>(&mut self, loop_id: NodeId, f: F) -> T
     where
-        F: FnOnce(&mut LoweringContext) -> T,
+        F: FnOnce(&mut LoweringContext<'_>) -> T,
     {
         // We're no longer in the base loop's condition; we're in another loop.
         let was_in_loop_condition = self.is_in_loop_condition;
@@ -965,7 +965,7 @@ impl<'a> LoweringContext<'a> {
 
     fn with_loop_condition_scope<T, F>(&mut self, f: F) -> T
     where
-        F: FnOnce(&mut LoweringContext) -> T,
+        F: FnOnce(&mut LoweringContext<'_>) -> T,
     {
         let was_in_loop_condition = self.is_in_loop_condition;
         self.is_in_loop_condition = true;
@@ -979,7 +979,7 @@ impl<'a> LoweringContext<'a> {
 
     fn with_new_scopes<T, F>(&mut self, f: F) -> T
     where
-        F: FnOnce(&mut LoweringContext) -> T,
+        F: FnOnce(&mut LoweringContext<'_>) -> T,
     {
         let was_in_loop_condition = self.is_in_loop_condition;
         self.is_in_loop_condition = false;
@@ -1094,7 +1094,8 @@ impl<'a> LoweringContext<'a> {
         }
     }
 
-    fn lower_ty_binding(&mut self, b: &TypeBinding, itctx: ImplTraitContext) -> hir::TypeBinding {
+    fn lower_ty_binding(&mut self, b: &TypeBinding,
+                        itctx: ImplTraitContext<'_>) -> hir::TypeBinding {
         hir::TypeBinding {
             id: self.lower_node_id(b.id).node_id,
             ident: b.ident,
@@ -1105,19 +1106,19 @@ impl<'a> LoweringContext<'a> {
 
     fn lower_generic_arg(&mut self,
                         arg: &ast::GenericArg,
-                        itctx: ImplTraitContext)
+                        itctx: ImplTraitContext<'_>)
                         -> hir::GenericArg {
         match arg {
             ast::GenericArg::Lifetime(lt) => GenericArg::Lifetime(self.lower_lifetime(&lt)),
             ast::GenericArg::Type(ty) => GenericArg::Type(self.lower_ty_direct(&ty, itctx)),
         }
     }
 
-    fn lower_ty(&mut self, t: &Ty, itctx: ImplTraitContext) -> P<hir::Ty> {
+    fn lower_ty(&mut self, t: &Ty, itctx: ImplTraitContext<'_>) -> P<hir::Ty> {
         P(self.lower_ty_direct(t, itctx))
     }
 
-    fn lower_ty_direct(&mut self, t: &Ty, mut itctx: ImplTraitContext) -> hir::Ty {
+    fn lower_ty_direct(&mut self, t: &Ty, mut itctx: ImplTraitContext<'_>) -> hir::Ty {
         let kind = match t.node {
             TyKind::Infer => hir::TyKind::Infer,
             TyKind::Err => hir::TyKind::Err,
@@ -1289,7 +1290,7 @@ impl<'a> LoweringContext<'a> {
         span: Span,
         fn_def_id: Option<DefId>,
         exist_ty_node_id: NodeId,
-        lower_bounds: impl FnOnce(&mut LoweringContext) -> hir::GenericBounds,
+        lower_bounds: impl FnOnce(&mut LoweringContext<'_>) -> hir::GenericBounds,
     ) -> hir::TyKind {
         // Make sure we know that some funky desugaring has been going on here.
         // This is a first: there is code in other places like for loop
@@ -1567,7 +1568,7 @@ impl<'a> LoweringContext<'a> {
         qself: &Option<QSelf>,
         p: &Path,
         param_mode: ParamMode,
-        mut itctx: ImplTraitContext,
+        mut itctx: ImplTraitContext<'_>,
     ) -> hir::QPath {
         let qself_position = qself.as_ref().map(|q| q.position);
         let qself = qself.as_ref().map(|q| self.lower_ty(&q.ty, itctx.reborrow()));
@@ -1762,7 +1763,7 @@ impl<'a> LoweringContext<'a> {
         param_mode: ParamMode,
         expected_lifetimes: usize,
         parenthesized_generic_args: ParenthesizedGenericArgs,
-        itctx: ImplTraitContext,
+        itctx: ImplTraitContext<'_>,
     ) -> hir::PathSegment {
         let (mut generic_args, infer_types) = if let Some(ref generic_args) = segment.args {
             let msg = "parenthesized parameters may only be used with a trait";
@@ -1844,7 +1845,7 @@ impl<'a> LoweringContext<'a> {
         &mut self,
         data: &AngleBracketedArgs,
         param_mode: ParamMode,
-        mut itctx: ImplTraitContext,
+        mut itctx: ImplTraitContext<'_>,
     ) -> (hir::GenericArgs, bool) {
         let &AngleBracketedArgs { ref args, ref bindings, .. } = data;
         let has_types = args.iter().any(|arg| match arg {
@@ -1871,7 +1872,7 @@ impl<'a> LoweringContext<'a> {
         self.with_anonymous_lifetime_mode(
             AnonymousLifetimeMode::PassThrough,
             |this| {
-                const DISALLOWED: ImplTraitContext = ImplTraitContext::Disallowed;
+                const DISALLOWED: ImplTraitContext<'_> = ImplTraitContext::Disallowed;
                 let &ParenthesisedArgs { ref inputs, ref output, span } = data;
                 let inputs = inputs.iter().map(|ty| this.lower_ty_direct(ty, DISALLOWED)).collect();
                 let mk_tup = |this: &mut Self, tys, span| {
@@ -2250,7 +2251,7 @@ impl<'a> LoweringContext<'a> {
     fn lower_param_bound(
         &mut self,
         tpb: &GenericBound,
-        itctx: ImplTraitContext,
+        itctx: ImplTraitContext<'_>,
     ) -> hir::GenericBound {
         match *tpb {
             GenericBound::Trait(ref ty, modifier) => hir::GenericBound::Trait(
@@ -2304,7 +2305,7 @@ impl<'a> LoweringContext<'a> {
         &mut self,
         params: &[GenericParam],
         add_bounds: &NodeMap<Vec<GenericBound>>,
-        mut itctx: ImplTraitContext,
+        mut itctx: ImplTraitContext<'_>,
     ) -> hir::HirVec<hir::GenericParam> {
         params.iter().map(|param| {
             self.lower_generic_param(param, add_bounds, itctx.reborrow())
@@ -2314,7 +2315,7 @@ impl<'a> LoweringContext<'a> {
     fn lower_generic_param(&mut self,
                            param: &GenericParam,
                            add_bounds: &NodeMap<Vec<GenericBound>>,
-                           mut itctx: ImplTraitContext)
+                           mut itctx: ImplTraitContext<'_>)
                            -> hir::GenericParam {
         let mut bounds = self.lower_param_bounds(&param.bounds, itctx.reborrow());
         match param.kind {
@@ -2383,7 +2384,7 @@ impl<'a> LoweringContext<'a> {
     fn lower_generics(
         &mut self,
         generics: &Generics,
-        itctx: ImplTraitContext)
+        itctx: ImplTraitContext<'_>)
         -> hir::Generics
     {
         // Collect `?Trait` bounds in where clause and move them to parameter definitions.
@@ -2536,7 +2537,7 @@ impl<'a> LoweringContext<'a> {
         }
     }
 
-    fn lower_trait_ref(&mut self, p: &TraitRef, itctx: ImplTraitContext) -> hir::TraitRef {
+    fn lower_trait_ref(&mut self, p: &TraitRef, itctx: ImplTraitContext<'_>) -> hir::TraitRef {
         let path = match self.lower_qpath(p.ref_id, &None, &p.path, ParamMode::Explicit, itctx) {
             hir::QPath::Resolved(None, path) => path.and_then(|path| path),
             qpath => bug!("lower_trait_ref: unexpected QPath `{:?}`", qpath),
@@ -2552,7 +2553,7 @@ impl<'a> LoweringContext<'a> {
     fn lower_poly_trait_ref(
         &mut self,
         p: &PolyTraitRef,
-        mut itctx: ImplTraitContext,
+        mut itctx: ImplTraitContext<'_>,
     ) -> hir::PolyTraitRef {
         let bound_generic_params =
             self.lower_generic_params(&p.bound_generic_params, &NodeMap(), itctx.reborrow());
@@ -2593,14 +2594,14 @@ impl<'a> LoweringContext<'a> {
         }
     }
 
-    fn lower_mt(&mut self, mt: &MutTy, itctx: ImplTraitContext) -> hir::MutTy {
+    fn lower_mt(&mut self, mt: &MutTy, itctx: ImplTraitContext<'_>) -> hir::MutTy {
         hir::MutTy {
             ty: self.lower_ty(&mt.ty, itctx),
             mutbl: self.lower_mutability(mt.mutbl),
         }
     }
 
-    fn lower_param_bounds(&mut self, bounds: &[GenericBound], mut itctx: ImplTraitContext)
+    fn lower_param_bounds(&mut self, bounds: &[GenericBound], mut itctx: ImplTraitContext<'_>)
         -> hir::GenericBounds {
         bounds.iter().map(|bound| self.lower_param_bound(bound, itctx.reborrow())).collect()
     }

src/librustc/hir/map/blocks.rs

@@ -143,7 +143,7 @@ impl<'a> ClosureParts<'a> {
 
 impl<'a> FnLikeNode<'a> {
     /// Attempts to construct a FnLikeNode from presumed FnLike node input.
-    pub fn from_node(node: Node) -> Option<FnLikeNode> {
+    pub fn from_node(node: Node<'_>) -> Option<FnLikeNode<'_>> {
         let fn_like = match node {
             map::Node::Item(item) => item.is_fn_like(),
             map::Node::TraitItem(tm) => tm.is_fn_like(),
@@ -173,15 +173,15 @@ impl<'a> FnLikeNode<'a> {
     }
 
     pub fn span(self) -> Span {
-        self.handle(|i: ItemFnParts| i.span,
+        self.handle(|i: ItemFnParts<'_>| i.span,
                     |_, _, _: &'a ast::MethodSig, _, _, span, _| span,
-                    |c: ClosureParts| c.span)
+                    |c: ClosureParts<'_>| c.span)
     }
 
     pub fn id(self) -> NodeId {
-        self.handle(|i: ItemFnParts| i.id,
+        self.handle(|i: ItemFnParts<'_>| i.id,
                     |id, _, _: &'a ast::MethodSig, _, _, _, _| id,
-                    |c: ClosureParts| c.id)
+                    |c: ClosureParts<'_>| c.id)
     }
 
     pub fn constness(self) -> ast::Constness {