Remove superfluous traversable impl for mir::Local

Author: eggyal

compiler/rustc_middle/src/mir/syntax.rs

@@ -1033,7 +1033,7 @@ pub enum ProjectionElem<V, T> {
     ///
     /// The `x[i]` is turned into a `Deref` followed by an `Index`, not just an `Index`. The same
     /// thing is true of the `ConstantIndex` and `Subslice` projections below.
-    Index(V),
+    Index(#[skip_traversal(because_boring)] V),
 
     /// These indices are generated by slice patterns. Easiest to explain
     /// by example:

compiler/rustc_middle/src/ty/structural_impls.rs

@@ -421,7 +421,6 @@ TrivialLiftImpls! {
 // provide any traversal implementations, we need to provide a traversal
 // implementation (only for TyCtxt<'_> interners).
 TrivialTypeTraversalImpls! {
-    crate::mir::Local,
     crate::ty::BoundConstness,
     ::rustc_span::Span,
     ::rustc_errors::ErrorGuaranteed,