Auto merge of #118661 - fee1-dead-contrib:restore-const-partialEq, r=compiler-errors

Restore `const PartialEq`

And thus fixes a number of tests. There is a bug that still needs to be fixed, so WIP for now.

r? `@compiler-errors`

5 files changed, 31 insertions, 14 deletions

diff --git a/clippy_lints/src/derive.rs b/clippy_lints/src/derive.rs
index 61faaa10b8a..d8abe411030 100644
--- a/clippy_lints/src/derive.rs
+++ b/clippy_lints/src/derive.rs
@@ -450,12 +450,12 @@ fn check_partial_eq_without_eq<'tcx>(cx: &LateContext<'tcx>, span: Span, trait_r
         && let Some(def_id) = trait_ref.trait_def_id()
         && cx.tcx.is_diagnostic_item(sym::PartialEq, def_id)
         && let param_env = param_env_for_derived_eq(cx.tcx, adt.did(), eq_trait_def_id)
-        && !implements_trait_with_env(cx.tcx, param_env, ty, eq_trait_def_id, &[])
+        && !implements_trait_with_env(cx.tcx, param_env, ty, eq_trait_def_id, adt.did(),&[])
         // If all of our fields implement `Eq`, we can implement `Eq` too
         && adt
             .all_fields()
             .map(|f| f.ty(cx.tcx, args))
-            .all(|ty| implements_trait_with_env(cx.tcx, param_env, ty, eq_trait_def_id, &[]))
+            .all(|ty| implements_trait_with_env(cx.tcx, param_env, ty, eq_trait_def_id, adt.did(), &[]))
     {
         span_lint_and_sugg(
             cx,
diff --git a/clippy_lints/src/implied_bounds_in_impls.rs b/clippy_lints/src/implied_bounds_in_impls.rs
index 9a66cbde53c..4811691c80d 100644
--- a/clippy_lints/src/implied_bounds_in_impls.rs
+++ b/clippy_lints/src/implied_bounds_in_impls.rs
@@ -194,6 +194,10 @@ fn is_same_generics<'tcx>(
         .enumerate()
         .skip(1) // skip `Self` implicit arg
         .all(|(arg_index, arg)| {
+            if [implied_by_generics.host_effect_index, implied_generics.host_effect_index].contains(&Some(arg_index)) {
+                // skip host effect params in determining whether generics are same
+                return true;
+            }
             if let Some(ty) = arg.as_type() {
                 if let &ty::Param(ty::ParamTy { index, .. }) = ty.kind()
                     // `index == 0` means that it's referring to `Self`,
diff --git a/clippy_lints/src/loops/explicit_iter_loop.rs b/clippy_lints/src/loops/explicit_iter_loop.rs
index 1c2b7a169fc..c7980060807 100644
--- a/clippy_lints/src/loops/explicit_iter_loop.rs
+++ b/clippy_lints/src/loops/explicit_iter_loop.rs
@@ -118,7 +118,7 @@ fn is_ref_iterable<'tcx>(
             .liberate_late_bound_regions(fn_id, cx.tcx.fn_sig(fn_id).skip_binder())
         && let &[req_self_ty, req_res_ty] = &**sig.inputs_and_output
         && let param_env = cx.tcx.param_env(fn_id)
-        && implements_trait_with_env(cx.tcx, param_env, req_self_ty, trait_id, &[])
+        && implements_trait_with_env(cx.tcx, param_env, req_self_ty, trait_id, fn_id, &[])
         && let Some(into_iter_ty) =
             make_normalized_projection_with_regions(cx.tcx, param_env, trait_id, sym!(IntoIter), [req_self_ty])
         && let req_res_ty = normalize_with_regions(cx.tcx, param_env, req_res_ty)
diff --git a/clippy_lints/src/needless_pass_by_value.rs b/clippy_lints/src/needless_pass_by_value.rs
index 27da44812eb..2c5c3dcaa75 100644
--- a/clippy_lints/src/needless_pass_by_value.rs
+++ b/clippy_lints/src/needless_pass_by_value.rs
@@ -186,6 +186,7 @@ impl<'tcx> LateLintPass<'tcx> for NeedlessPassByValue {
                         cx.param_env,
                         ty,
                         t,
+                        None,
                         [Option::<ty::GenericArg<'tcx>>::None],
                     )
                 })
diff --git a/clippy_utils/src/ty.rs b/clippy_utils/src/ty.rs
index 1e748a46922..868c92f2f54 100644
--- a/clippy_utils/src/ty.rs
+++ b/clippy_utils/src/ty.rs
@@ -214,7 +214,8 @@ pub fn implements_trait<'tcx>(
     trait_id: DefId,
     args: &[GenericArg<'tcx>],
 ) -> bool {
-    implements_trait_with_env_from_iter(cx.tcx, cx.param_env, ty, trait_id, args.iter().map(|&x| Some(x)))
+    let callee_id = cx.enclosing_body.map(|body| cx.tcx.hir().body_owner(body).owner.to_def_id());
+    implements_trait_with_env_from_iter(cx.tcx, cx.param_env, ty, trait_id, callee_id, args.iter().map(|&x| Some(x)))
 }
 
 /// Same as `implements_trait` but allows using a `ParamEnv` different from the lint context.
@@ -223,9 +224,10 @@ pub fn implements_trait_with_env<'tcx>(
     param_env: ParamEnv<'tcx>,
     ty: Ty<'tcx>,
     trait_id: DefId,
+    callee_id: DefId,
     args: &[GenericArg<'tcx>],
 ) -> bool {
-    implements_trait_with_env_from_iter(tcx, param_env, ty, trait_id, args.iter().map(|&x| Some(x)))
+    implements_trait_with_env_from_iter(tcx, param_env, ty, trait_id, Some(callee_id), args.iter().map(|&x| Some(x)))
 }
 
 /// Same as `implements_trait_from_env` but takes the arguments as an iterator.
@@ -234,6 +236,7 @@ pub fn implements_trait_with_env_from_iter<'tcx>(
     param_env: ParamEnv<'tcx>,
     ty: Ty<'tcx>,
     trait_id: DefId,
+    callee_id: Option<DefId>,
     args: impl IntoIterator<Item = impl Into<Option<GenericArg<'tcx>>>>,
 ) -> bool {
     // Clippy shouldn't have infer types
@@ -245,20 +248,29 @@ pub fn implements_trait_with_env_from_iter<'tcx>(
     }
 
     let infcx = tcx.infer_ctxt().build();
+    let args = args.into_iter().map(|arg| {
+        arg.into().unwrap_or_else(|| {
+            let orig = TypeVariableOrigin {
+                kind: TypeVariableOriginKind::MiscVariable,
+                span: DUMMY_SP,
+            };
+            infcx.next_ty_var(orig).into()
+        })
+    }).collect::<Vec<_>>();
+
+    // If an effect arg was not specified, we need to specify it.
+    let effect_arg = if tcx.generics_of(trait_id).host_effect_index.is_some_and(|x| args.get(x - 1).is_none()) {
+        Some(GenericArg::from(callee_id.map(|def_id| tcx.expected_host_effect_param_for_body(def_id)).unwrap_or(tcx.consts.true_)))
+    } else {
+        None
+    };
+
     let trait_ref = TraitRef::new(
         tcx,
         trait_id,
         Some(GenericArg::from(ty))
             .into_iter()
-            .chain(args.into_iter().map(|arg| {
-                arg.into().unwrap_or_else(|| {
-                    let orig = TypeVariableOrigin {
-                        kind: TypeVariableOriginKind::MiscVariable,
-                        span: DUMMY_SP,
-                    };
-                    infcx.next_ty_var(orig).into()
-                })
-            })),
+            .chain(args).chain(effect_arg),
     );
 
     debug_assert_matches!(