Implement .use keyword as an alias of clone

2 files changed, 11 insertions, 0 deletions

diff --git a/compiler/rustc_middle/src/thir.rs b/compiler/rustc_middle/src/thir.rs
index e5592de81cd..c9e7331660f 100644
--- a/compiler/rustc_middle/src/thir.rs
+++ b/compiler/rustc_middle/src/thir.rs
@@ -312,6 +312,14 @@ pub enum ExprKind<'tcx> {
         /// (e.g. `foo(a, b)` in `x.foo(a, b)`).
         fn_span: Span,
     },
+    /// A use expression `x.use`.
+    ByUse {
+        /// The expression on which use is applied.
+        expr: ExprId,
+        /// The span of use, without the dot and receiver
+        /// (e.g. `use` in `x.use`).
+        span: Span,
+    },
     /// A *non-overloaded* dereference.
     Deref {
         arg: ExprId,
diff --git a/compiler/rustc_middle/src/thir/visit.rs b/compiler/rustc_middle/src/thir/visit.rs
index a9df4d1625b..d208692f4e7 100644
--- a/compiler/rustc_middle/src/thir/visit.rs
+++ b/compiler/rustc_middle/src/thir/visit.rs
@@ -59,6 +59,9 @@ pub fn walk_expr<'thir, 'tcx: 'thir, V: Visitor<'thir, 'tcx>>(
                 visitor.visit_expr(&visitor.thir()[arg]);
             }
         }
+        ByUse { expr, span: _ } => {
+            visitor.visit_expr(&visitor.thir()[expr]);
+        }
         Deref { arg } => visitor.visit_expr(&visitor.thir()[arg]),
         Binary { lhs, rhs, op: _ } | LogicalOp { lhs, rhs, op: _ } => {
             visitor.visit_expr(&visitor.thir()[lhs]);