Adapt clippy.

Author: cjgillot

src/tools/clippy/clippy_lints/src/eta_reduction.rs

@@ -111,8 +111,6 @@ impl<'tcx> LateLintPass<'tcx> for EtaReduction {
                 .map_or(callee_ty, |id| cx.tcx.type_of(id));
             if check_sig(cx, closure_ty, call_ty);
             let substs = cx.typeck_results().node_substs(callee.hir_id);
-            // This fixes some false positives that I don't entirely understand
-            if substs.is_empty() || !cx.typeck_results().expr_ty(expr).has_late_bound_regions();
             // A type param function ref like `T::f` is not 'static, however
             // it is if cast like `T::f as fn()`. This seems like a rustc bug.
             if !substs.types().any(|t| matches!(t.kind(), ty::Param(_)));
@@ -217,7 +215,7 @@ fn check_sig<'tcx>(cx: &LateContext<'tcx>, closure_ty: Ty<'tcx>, call_ty: Ty<'tc
         return false;
     };
     let closure_sig = cx.tcx.signature_unclosure(substs.as_closure().sig(), Unsafety::Normal);
-    cx.tcx.erase_late_bound_regions(closure_sig) == cx.tcx.erase_late_bound_regions(call_sig)
+    cx.tcx.anonymize_late_bound_regions(closure_sig) == cx.tcx.anonymize_late_bound_regions(call_sig)
 }
 
 fn get_ufcs_type_name(cx: &LateContext<'_>, method_def_id: DefId) -> String {

src/tools/clippy/clippy_lints/src/methods/unnecessary_to_owned.rs

@@ -486,7 +486,9 @@ fn is_to_string_on_string_like<'a>(
     }
 
     if let Some(substs) = cx.typeck_results().node_substs_opt(call_expr.hir_id)
-        && let [generic_arg] = substs.as_slice()
+        && let substs = substs.as_slice()
+        && let Some(generic_arg) = substs.get(0)
+        && substs.iter().skip(1).all(|arg| matches!(arg.unpack(), ty::GenericArgKind::Lifetime(_)))
         && let GenericArgKind::Type(ty) = generic_arg.unpack()
         && let Some(deref_trait_id) = cx.tcx.get_diagnostic_item(sym::Deref)
         && let Some(as_ref_trait_id) = cx.tcx.get_diagnostic_item(sym::AsRef)

src/tools/clippy/clippy_lints/src/only_used_in_recursion.rs

@@ -247,9 +247,12 @@ impl<'tcx> LateLintPass<'tcx> for OnlyUsedInRecursion {
                     && let Some(trait_ref) = cx.tcx.impl_trait_ref(item.def_id)
                     && let Some(trait_item_id) = cx.tcx.associated_item(def_id).trait_item_def_id
                 {
+                    let substs = ty::InternalSubsts::identity_for_item(cx.tcx, trait_item_id)
+                        .rebase_onto(cx.tcx, trait_ref.def_id, trait_ref.substs);
+                    let substs = cx.tcx.erase_regions(substs);
                     (
                         trait_item_id,
-                        FnKind::ImplTraitFn(cx.tcx.erase_regions(trait_ref.substs) as *const _ as usize),
+                        FnKind::ImplTraitFn(substs as *const _ as usize),
                         usize::from(sig.decl.implicit_self.has_implicit_self()),
                     )
                 } else {

src/tools/clippy/clippy_lints/src/pass_by_ref_or_value.rs

@@ -143,7 +143,7 @@ impl<'tcx> PassByRefOrValue {
             return;
         }
 
-        let fn_sig = cx.tcx.fn_sig(def_id);
+        let fn_sig = cx.tcx.type_of(def_id).fn_sig(cx.tcx);
         let fn_body = cx.enclosing_body.map(|id| cx.tcx.hir().body(id));
 
         // Gather all the lifetimes found in the output type which may affect whether