Rework precise capturing syntax

compiler/rustc_hir_analysis/src/check/check.rs

@@ -481,9 +481,12 @@ fn sanity_check_found_hidden_type<'tcx>(
 /// 2. Checking that all lifetimes that are implicitly captured are mentioned.
 /// 3. Asserting that all parameters mentioned in the captures list are invariant.
 fn check_opaque_precise_captures<'tcx>(tcx: TyCtxt<'tcx>, opaque_def_id: LocalDefId) {
-    let hir::OpaqueTy { precise_capturing_args, .. } =
+    let hir::OpaqueTy { bounds, .. } =
         *tcx.hir_node_by_def_id(opaque_def_id).expect_item().expect_opaque_ty();
-    let Some((precise_capturing_args, _)) = precise_capturing_args else {
+    let Some(precise_capturing_args) = bounds.iter().find_map(|bound| match *bound {
+        hir::GenericBound::Use(bounds, ..) => Some(bounds),
+        _ => None,
+    }) else {
         // No precise capturing args; nothing to validate
         return;
     };

compiler/rustc_hir_analysis/src/hir_ty_lowering/bounds.rs

@@ -178,6 +178,9 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
                         lifetime.ident.span,
                     );
                 }
+                hir::GenericBound::Use(..) => {
+                    // We don't actually lower `use` into the type layer.
+                }
             }
         }
     }