Rollup merge of #143544 - workingjubilee:rename-bare-fn, r=fmease

compiler: rename BareFn to FnPtr

At some point "BareFn" was the chosen name for a "bare" function, without the niceties of `~fn`, `&fn`, or a few other ways of writing a function type. However, at some point the syntax for a "bare function" and any other function diverged even more. We started calling them what they are: function pointers, denoted by their own syntax.

However, we never changed the *internal* name for these, as this divergence was very gradual. Personally, I have repeatedly searched for "FnPtr" and gotten confused until I find the name is BareFn, only to forget this until the next time, since I don't routinely interact with the higher-level AST and HIR. But even tools that interact with these internal types only touch on them in a few places, making a migration easy enough. Let's use a more intuitive and obvious name, as this 12+ year old name has little to do with current Rust.

Author: jhpratt

clippy_lints/src/dereference.rs

@@ -824,7 +824,7 @@ impl TyCoercionStability {
                 TyKind::Slice(_)
                 | TyKind::Array(..)
                 | TyKind::Ptr(_)
-                | TyKind::BareFn(_)
+                | TyKind::FnPtr(_)
                 | TyKind::Pat(..)
                 | TyKind::Never
                 | TyKind::Tup(_)

clippy_lints/src/lifetimes.rs

@@ -13,7 +13,7 @@ use rustc_hir::intravisit::{
     walk_poly_trait_ref, walk_trait_ref, walk_ty, walk_unambig_ty, walk_where_predicate,
 };
 use rustc_hir::{
-    AmbigArg, BareFnTy, BodyId, FnDecl, FnSig, GenericArg, GenericArgs, GenericBound, GenericParam, GenericParamKind,
+    AmbigArg, BodyId, FnDecl, FnPtrTy, FnSig, GenericArg, GenericArgs, GenericBound, GenericParam, GenericParamKind,
     Generics, HirId, Impl, ImplItem, ImplItemKind, Item, ItemKind, Lifetime, LifetimeKind, LifetimeParamKind, Node,
     PolyTraitRef, PredicateOrigin, TraitFn, TraitItem, TraitItemKind, Ty, TyKind, WhereBoundPredicate, WherePredicate,
     WherePredicateKind, lang_items,
@@ -480,7 +480,7 @@ impl<'tcx> Visitor<'tcx> for RefVisitor<'_, 'tcx> {
 
     fn visit_ty(&mut self, ty: &'tcx Ty<'_, AmbigArg>) {
         match ty.kind {
-            TyKind::BareFn(&BareFnTy { decl, .. }) => {
+            TyKind::FnPtr(&FnPtrTy { decl, .. }) => {
                 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());

clippy_lints/src/types/type_complexity.rs

@@ -50,7 +50,7 @@ impl<'tcx> Visitor<'tcx> for TypeComplexityVisitor {
             TyKind::Path(..) | TyKind::Slice(..) | TyKind::Tup(..) | TyKind::Array(..) => (10 * self.nest, 1),
 
             // function types bring a lot of overhead
-            TyKind::BareFn(bare) if bare.abi == ExternAbi::Rust => (50 * self.nest, 1),
+            TyKind::FnPtr(fn_ptr) if fn_ptr.abi == ExternAbi::Rust => (50 * self.nest, 1),
 
             TyKind::TraitObject(param_bounds, _) => {
                 let has_lifetime_parameters = param_bounds.iter().any(|bound| {

clippy_utils/src/ast_utils/mod.rs

@@ -838,7 +838,7 @@ pub fn eq_ty(l: &Ty, r: &Ty) -> bool {
         (PinnedRef(ll, l), PinnedRef(rl, r)) => {
             both(ll.as_ref(), rl.as_ref(), |l, r| eq_id(l.ident, r.ident)) && l.mutbl == r.mutbl && eq_ty(&l.ty, &r.ty)
         },
-        (BareFn(l), BareFn(r)) => {
+        (FnPtr(l), FnPtr(r)) => {
             l.safety == r.safety
                 && eq_ext(&l.ext, &r.ext)
                 && over(&l.generic_params, &r.generic_params, eq_generic_param)

clippy_utils/src/check_proc_macro.rs

@@ -372,17 +372,17 @@ fn ty_search_pat(ty: &Ty<'_>) -> (Pat, Pat) {
         TyKind::Slice(..) | TyKind::Array(..) => (Pat::Str("["), Pat::Str("]")),
         TyKind::Ptr(MutTy { ty, .. }) => (Pat::Str("*"), ty_search_pat(ty).1),
         TyKind::Ref(_, MutTy { ty, .. }) => (Pat::Str("&"), ty_search_pat(ty).1),
-        TyKind::BareFn(bare_fn) => (
-            if bare_fn.safety.is_unsafe() {
+        TyKind::FnPtr(fn_ptr) => (
+            if fn_ptr.safety.is_unsafe() {
                 Pat::Str("unsafe")
-            } else if bare_fn.abi != ExternAbi::Rust {
+            } else if fn_ptr.abi != ExternAbi::Rust {
                 Pat::Str("extern")
             } else {
                 Pat::MultiStr(&["fn", "extern"])
             },
-            match bare_fn.decl.output {
+            match fn_ptr.decl.output {
                 FnRetTy::DefaultReturn(_) => {
-                    if let [.., ty] = bare_fn.decl.inputs {
+                    if let [.., ty] = fn_ptr.decl.inputs {
                         ty_search_pat(ty).1
                     } else {
                         Pat::Str("(")

clippy_utils/src/hir_utils.rs

@@ -1283,20 +1283,20 @@ impl<'a, 'tcx> SpanlessHash<'a, 'tcx> {
                 self.hash_ty(mut_ty.ty);
                 mut_ty.mutbl.hash(&mut self.s);
             },
-            TyKind::BareFn(bfn) => {
-                bfn.safety.hash(&mut self.s);
-                bfn.abi.hash(&mut self.s);
-                for arg in bfn.decl.inputs {
+            TyKind::FnPtr(fn_ptr) => {
+                fn_ptr.safety.hash(&mut self.s);
+                fn_ptr.abi.hash(&mut self.s);
+                for arg in fn_ptr.decl.inputs {
                     self.hash_ty(arg);
                 }
-                std::mem::discriminant(&bfn.decl.output).hash(&mut self.s);
-                match bfn.decl.output {
+                std::mem::discriminant(&fn_ptr.decl.output).hash(&mut self.s);
+                match fn_ptr.decl.output {
                     FnRetTy::DefaultReturn(_) => {},
                     FnRetTy::Return(ty) => {
                         self.hash_ty(ty);
                     },
                 }
-                bfn.decl.c_variadic.hash(&mut self.s);
+                fn_ptr.decl.c_variadic.hash(&mut self.s);
             },
             TyKind::Tup(ty_list) => {
                 for ty in *ty_list {