Auto merge of #102150 - matthiaskrgr:rollup-6xmd8f3, r=matthiaskrgr

Rollup of 10 pull requests

Successful merges:

 - #102113 (OpTy: fix a method taking self rather than &self)
 - #102118 (rustdoc: clean up line numbers on code examples)
 - #102123 (Add note to clippy::non_expressive_names doc)
 - #102125 (rustdoc: remove no-op CSS `.content .item-info { position: relative }`)
 - #102127 (Use appropriate variable names)
 - #102128 (Const unification is already infallible, remove the error handling logic)
 - #102133 (Use valtrees for comparison)
 - #102135 (Improve some AllTypes fields name)
 - #102144 (Extend const_convert with const {FormResidual, Try} for ControlFlow.)
 - #102147 (rustdoc: remove no-op CSS `.location:empty { border: none }`)

Failed merges:

r? `@ghost`
`@rustbot` modify labels: rollup

5 files changed, 20 insertions, 42 deletions

diff --git a/compiler/rustc_const_eval/src/interpret/place.rs b/compiler/rustc_const_eval/src/interpret/place.rs
index b328892906d..bc1aa43b73a 100644
--- a/compiler/rustc_const_eval/src/interpret/place.rs
+++ b/compiler/rustc_const_eval/src/interpret/place.rs
@@ -280,7 +280,7 @@ impl<'tcx, Prov: Provenance> PlaceTy<'tcx, Prov> {
 
     #[inline(always)]
     #[cfg_attr(debug_assertions, track_caller)] // only in debug builds due to perf (see #98980)
-    pub fn assert_mem_place(self) -> MPlaceTy<'tcx, Prov> {
+    pub fn assert_mem_place(&self) -> MPlaceTy<'tcx, Prov> {
         self.try_as_mplace().unwrap()
     }
 }
diff --git a/compiler/rustc_infer/src/infer/combine.rs b/compiler/rustc_infer/src/infer/combine.rs
index c406df9e411..682ad02da86 100644
--- a/compiler/rustc_infer/src/infer/combine.rs
+++ b/compiler/rustc_infer/src/infer/combine.rs
@@ -147,11 +147,7 @@ impl<'infcx, 'tcx> InferCtxt<'infcx, 'tcx> {
                 ty::ConstKind::Infer(InferConst::Var(a_vid)),
                 ty::ConstKind::Infer(InferConst::Var(b_vid)),
             ) => {
-                self.inner
-                    .borrow_mut()
-                    .const_unification_table()
-                    .unify_var_var(a_vid, b_vid)
-                    .map_err(|e| const_unification_error(a_is_expected, e))?;
+                self.inner.borrow_mut().const_unification_table().union(a_vid, b_vid);
                 return Ok(a);
             }
 
@@ -246,21 +242,17 @@ impl<'infcx, 'tcx> InferCtxt<'infcx, 'tcx> {
         let value = ConstInferUnifier { infcx: self, span, param_env, for_universe, target_vid }
             .relate(ct, ct)?;
 
-        self.inner
-            .borrow_mut()
-            .const_unification_table()
-            .unify_var_value(
-                target_vid,
-                ConstVarValue {
-                    origin: ConstVariableOrigin {
-                        kind: ConstVariableOriginKind::ConstInference,
-                        span: DUMMY_SP,
-                    },
-                    val: ConstVariableValue::Known { value },
+        self.inner.borrow_mut().const_unification_table().union_value(
+            target_vid,
+            ConstVarValue {
+                origin: ConstVariableOrigin {
+                    kind: ConstVariableOriginKind::ConstInference,
+                    span: DUMMY_SP,
                 },
-            )
-            .map(|()| value)
-            .map_err(|e| const_unification_error(vid_is_expected, e))
+                val: ConstVariableValue::Known { value },
+            },
+        );
+        Ok(value)
     }
 
     fn unify_integral_variable(
@@ -768,13 +760,6 @@ pub trait ConstEquateRelation<'tcx>: TypeRelation<'tcx> {
     fn const_equate_obligation(&mut self, a: ty::Const<'tcx>, b: ty::Const<'tcx>);
 }
 
-pub fn const_unification_error<'tcx>(
-    a_is_expected: bool,
-    (a, b): (ty::Const<'tcx>, ty::Const<'tcx>),
-) -> TypeError<'tcx> {
-    TypeError::ConstMismatch(ExpectedFound::new(a_is_expected, a, b))
-}
-
 fn int_unification_error<'tcx>(
     a_is_expected: bool,
     v: (ty::IntVarValue, ty::IntVarValue),
diff --git a/compiler/rustc_middle/src/infer/unify_key.rs b/compiler/rustc_middle/src/infer/unify_key.rs
index f2627885d03..41d8c7ffdb9 100644
--- a/compiler/rustc_middle/src/infer/unify_key.rs
+++ b/compiler/rustc_middle/src/infer/unify_key.rs
@@ -129,7 +129,7 @@ impl<'tcx> UnifyKey for ty::ConstVid<'tcx> {
 }
 
 impl<'tcx> UnifyValue for ConstVarValue<'tcx> {
-    type Error = (ty::Const<'tcx>, ty::Const<'tcx>);
+    type Error = NoError;
 
     fn unify_values(&value1: &Self, &value2: &Self) -> Result<Self, Self::Error> {
         Ok(match (value1.val, value2.val) {
diff --git a/compiler/rustc_middle/src/ty/fast_reject.rs b/compiler/rustc_middle/src/ty/fast_reject.rs
index 8d019a3bad8..41bb3c71401 100644
--- a/compiler/rustc_middle/src/ty/fast_reject.rs
+++ b/compiler/rustc_middle/src/ty/fast_reject.rs
@@ -384,14 +384,7 @@ impl DeepRejectCtxt {
             // they might unify with any value.
             ty::ConstKind::Unevaluated(_) | ty::ConstKind::Error(_) => true,
             ty::ConstKind::Value(obl) => match k {
-                ty::ConstKind::Value(imp) => {
-                    // FIXME(valtrees): Once we have valtrees, we can just
-                    // compare them directly here.
-                    match (obl.try_to_scalar_int(), imp.try_to_scalar_int()) {
-                        (Some(obl), Some(imp)) => obl == imp,
-                        _ => true,
-                    }
-                }
+                ty::ConstKind::Value(imp) => obl == imp,
                 _ => true,
             },
 
diff --git a/compiler/rustc_passes/src/check_attr.rs b/compiler/rustc_passes/src/check_attr.rs
index b3f15ba7cbf..f112f1274b8 100644
--- a/compiler/rustc_passes/src/check_attr.rs
+++ b/compiler/rustc_passes/src/check_attr.rs
@@ -35,8 +35,8 @@ pub(crate) fn target_from_impl_item<'tcx>(
     match impl_item.kind {
         hir::ImplItemKind::Const(..) => Target::AssocConst,
         hir::ImplItemKind::Fn(..) => {
-            let parent_hir_id = tcx.hir().get_parent_item(impl_item.hir_id());
-            let containing_item = tcx.hir().expect_item(parent_hir_id);
+            let parent_def_id = tcx.hir().get_parent_item(impl_item.hir_id());
+            let containing_item = tcx.hir().expect_item(parent_def_id);
             let containing_impl_is_for_trait = match &containing_item.kind {
                 hir::ItemKind::Impl(impl_) => impl_.of_trait.is_some(),
                 _ => bug!("parent of an ImplItem must be an Impl"),
@@ -640,8 +640,8 @@ impl CheckAttrVisitor<'_> {
         let span = meta.span();
         if let Some(location) = match target {
             Target::AssocTy => {
-                let parent_hir_id = self.tcx.hir().get_parent_item(hir_id);
-                let containing_item = self.tcx.hir().expect_item(parent_hir_id);
+                let parent_def_id = self.tcx.hir().get_parent_item(hir_id);
+                let containing_item = self.tcx.hir().expect_item(parent_def_id);
                 if Target::from_item(containing_item) == Target::Impl {
                     Some("type alias in implementation block")
                 } else {
@@ -649,8 +649,8 @@ impl CheckAttrVisitor<'_> {
                 }
             }
             Target::AssocConst => {
-                let parent_hir_id = self.tcx.hir().get_parent_item(hir_id);
-                let containing_item = self.tcx.hir().expect_item(parent_hir_id);
+                let parent_def_id = self.tcx.hir().get_parent_item(hir_id);
+                let containing_item = self.tcx.hir().expect_item(parent_def_id);
                 // We can't link to trait impl's consts.
                 let err = "associated constant in trait implementation block";
                 match containing_item.kind {