Auto merge of #101241 - camsteffen:refactor-binding-annotations, r=cjgillot

`BindingAnnotation` refactor

* `ast::BindingMode` is deleted and replaced with `hir::BindingAnnotation` (which is moved to `ast`)
* `BindingAnnotation` is changed from an enum to a tuple struct e.g. `BindingAnnotation(ByRef::No, Mutability::Mut)`
* Associated constants added for convenience `BindingAnnotation::{NONE, REF, MUT, REF_MUT}`

One goal is to make it more clear that `BindingAnnotation` merely represents syntax `ref mut` and not the actual binding mode. This was especially confusing since we had `ast::BindingMode`->`hir::BindingAnnotation`->`thir::BindingMode`.

I wish there were more symmetry between `ByRef` and `Mutability` (variant) naming (maybe `Mutable::Yes`?), and I also don't love how long the name `BindingAnnotation` is, but this seems like the best compromise. Ideas welcome.

1 files changed, 2 insertions, 13 deletions

diff --git a/compiler/rustc_save_analysis/src/lib.rs b/compiler/rustc_save_analysis/src/lib.rs
index c58ccde4390..89bca39512f 100644
--- a/compiler/rustc_save_analysis/src/lib.rs
+++ b/compiler/rustc_save_analysis/src/lib.rs
@@ -866,23 +866,12 @@ impl<'l> Visitor<'l> for PathCollector<'l> {
             hir::PatKind::TupleStruct(ref path, ..) | hir::PatKind::Path(ref path) => {
                 self.collected_paths.push((p.hir_id, path));
             }
-            hir::PatKind::Binding(bm, _, ident, _) => {
+            hir::PatKind::Binding(hir::BindingAnnotation(_, mutbl), _, ident, _) => {
                 debug!(
                     "PathCollector, visit ident in pat {}: {:?} {:?}",
                     ident, p.span, ident.span
                 );
-                let immut = match bm {
-                    // Even if the ref is mut, you can't change the ref, only
-                    // the data pointed at, so showing the initialising expression
-                    // is still worthwhile.
-                    hir::BindingAnnotation::Unannotated | hir::BindingAnnotation::Ref => {
-                        hir::Mutability::Not
-                    }
-                    hir::BindingAnnotation::Mutable | hir::BindingAnnotation::RefMut => {
-                        hir::Mutability::Mut
-                    }
-                };
-                self.collected_idents.push((p.hir_id, ident, immut));
+                self.collected_idents.push((p.hir_id, ident, mutbl));
             }
             _ => {}
         }