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.

2 files changed, 12 insertions, 16 deletions

diff --git a/compiler/rustc_resolve/src/late.rs b/compiler/rustc_resolve/src/late.rs
index 08c4a485f26..08629090bb1 100644
--- a/compiler/rustc_resolve/src/late.rs
+++ b/compiler/rustc_resolve/src/late.rs
@@ -370,7 +370,7 @@ enum LifetimeRibKind {
 
 #[derive(Copy, Clone, Debug)]
 enum LifetimeBinderKind {
-    BareFnType,
+    FnPtrType,
     PolyTrait,
     WhereBound,
     Item,
@@ -384,7 +384,7 @@ impl LifetimeBinderKind {
     fn descr(self) -> &'static str {
         use LifetimeBinderKind::*;
         match self {
-            BareFnType => "type",
+            FnPtrType => "type",
             PolyTrait => "bound",
             WhereBound => "bound",
             Item | ConstItem => "item",
@@ -900,16 +900,16 @@ impl<'ast, 'ra, 'tcx> Visitor<'ast> for LateResolutionVisitor<'_, 'ast, 'ra, 'tc
                 self.diag_metadata.current_trait_object = Some(&bounds[..]);
                 visit::walk_ty(self, ty)
             }
-            TyKind::BareFn(bare_fn) => {
-                let span = ty.span.shrink_to_lo().to(bare_fn.decl_span.shrink_to_lo());
+            TyKind::FnPtr(fn_ptr) => {
+                let span = ty.span.shrink_to_lo().to(fn_ptr.decl_span.shrink_to_lo());
                 self.with_generic_param_rib(
-                    &bare_fn.generic_params,
+                    &fn_ptr.generic_params,
                     RibKind::Normal,
                     ty.id,
-                    LifetimeBinderKind::BareFnType,
+                    LifetimeBinderKind::FnPtrType,
                     span,
                     |this| {
-                        this.visit_generic_params(&bare_fn.generic_params, false);
+                        this.visit_generic_params(&fn_ptr.generic_params, false);
                         this.with_lifetime_rib(
                             LifetimeRibKind::AnonymousCreateParameter {
                                 binder: ty.id,
@@ -921,12 +921,8 @@ impl<'ast, 'ra, 'tcx> Visitor<'ast> for LateResolutionVisitor<'_, 'ast, 'ra, 'tc
                                     false,
                                     // We don't need to deal with patterns in parameters, because
                                     // they are not possible for foreign or bodiless functions.
-                                    bare_fn
-                                        .decl
-                                        .inputs
-                                        .iter()
-                                        .map(|Param { ty, .. }| (None, &**ty)),
-                                    &bare_fn.decl.output,
+                                    fn_ptr.decl.inputs.iter().map(|Param { ty, .. }| (None, &**ty)),
+                                    &fn_ptr.decl.output,
                                 )
                             },
                         );
@@ -939,7 +935,7 @@ impl<'ast, 'ra, 'tcx> Visitor<'ast> for LateResolutionVisitor<'_, 'ast, 'ra, 'tc
                     &unsafe_binder.generic_params,
                     RibKind::Normal,
                     ty.id,
-                    LifetimeBinderKind::BareFnType,
+                    LifetimeBinderKind::FnPtrType,
                     span,
                     |this| {
                         this.visit_generic_params(&unsafe_binder.generic_params, false);
@@ -2976,7 +2972,7 @@ impl<'a, 'ast, 'ra, 'tcx> LateResolutionVisitor<'a, 'ast, 'ra, 'tcx> {
             }
         }
 
-        if let LifetimeBinderKind::BareFnType
+        if let LifetimeBinderKind::FnPtrType
         | LifetimeBinderKind::WhereBound
         | LifetimeBinderKind::Function
         | LifetimeBinderKind::ImplBlock = generics_kind
diff --git a/compiler/rustc_resolve/src/late/diagnostics.rs b/compiler/rustc_resolve/src/late/diagnostics.rs
index a4022691995..fa04c8bc604 100644
--- a/compiler/rustc_resolve/src/late/diagnostics.rs
+++ b/compiler/rustc_resolve/src/late/diagnostics.rs
@@ -3177,7 +3177,7 @@ impl<'ast, 'ra, 'tcx> LateResolutionVisitor<'_, 'ast, 'ra, 'tcx> {
 
                     let higher_ranked = matches!(
                         kind,
-                        LifetimeBinderKind::BareFnType
+                        LifetimeBinderKind::FnPtrType
                             | LifetimeBinderKind::PolyTrait
                             | LifetimeBinderKind::WhereBound
                     );