Auto merge of #112718 - oli-obk:SIMD-destructure_mir_const, r=cjgillot

Make simd_shuffle_indices use valtrees

This removes the second-to-last user of the `destructure_mir_constant` query. So in a follow-up we can remove the query and just move the query provider function directly into pretty printing (which is the last user).

cc `@rust-lang/clippy` there's a small functional change, but I think it is correct?

2 files changed, 62 insertions, 14 deletions

diff --git a/clippy_lints/src/non_copy_const.rs b/clippy_lints/src/non_copy_const.rs
index 58590df1fed..ac49ccdb501 100644
--- a/clippy_lints/src/non_copy_const.rs
+++ b/clippy_lints/src/non_copy_const.rs
@@ -15,12 +15,14 @@ use rustc_hir::{
 };
 use rustc_hir_analysis::hir_ty_to_ty;
 use rustc_lint::{LateContext, LateLintPass, Lint};
-use rustc_middle::mir;
-use rustc_middle::mir::interpret::{ConstValue, ErrorHandled};
+use rustc_middle::mir::interpret::ErrorHandled;
 use rustc_middle::ty::adjustment::Adjust;
-use rustc_middle::ty::{self, Ty};
+use rustc_middle::ty::{self, Ty, TyCtxt};
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 use rustc_span::{sym, InnerSpan, Span};
+use rustc_target::abi::VariantIdx;
+use rustc_middle::mir::interpret::EvalToValTreeResult;
+use rustc_middle::mir::interpret::GlobalId;
 
 // FIXME: this is a correctness problem but there's no suitable
 // warn-by-default category.
@@ -141,21 +143,35 @@ fn is_unfrozen<'tcx>(cx: &LateContext<'tcx>, ty: Ty<'tcx>) -> bool {
 
 fn is_value_unfrozen_raw<'tcx>(
     cx: &LateContext<'tcx>,
-    result: Result<ConstValue<'tcx>, ErrorHandled>,
+    result: Result<Option<ty::ValTree<'tcx>>, ErrorHandled>,
     ty: Ty<'tcx>,
 ) -> bool {
-    fn inner<'tcx>(cx: &LateContext<'tcx>, val: mir::ConstantKind<'tcx>) -> bool {
-        match val.ty().kind() {
+    fn inner<'tcx>(cx: &LateContext<'tcx>, val: ty::ValTree<'tcx>, ty: Ty<'tcx>) -> bool {
+        match *ty.kind() {
             // the fact that we have to dig into every structs to search enums
             // leads us to the point checking `UnsafeCell` directly is the only option.
             ty::Adt(ty_def, ..) if ty_def.is_unsafe_cell() => true,
             // As of 2022-09-08 miri doesn't track which union field is active so there's no safe way to check the
             // contained value.
             ty::Adt(def, ..) if def.is_union() => false,
-            ty::Array(..) | ty::Adt(..) | ty::Tuple(..) => {
-                let val = cx.tcx.destructure_mir_constant(cx.param_env, val);
-                val.fields.iter().any(|field| inner(cx, *field))
+            ty::Array(ty, _)  => {
+                val.unwrap_branch().iter().any(|field| inner(cx, *field, ty))
             },
+            ty::Adt(def, _) if def.is_union() => false,
+            ty::Adt(def, substs) if def.is_enum() => {
+                let (&variant_index, fields) = val.unwrap_branch().split_first().unwrap();
+                let variant_index =
+                    VariantIdx::from_u32(variant_index.unwrap_leaf().try_to_u32().ok().unwrap());
+                fields.iter().copied().zip(
+                    def.variants()[variant_index]
+                        .fields
+                        .iter()
+                        .map(|field| field.ty(cx.tcx, substs))).any(|(field, ty)| inner(cx, field, ty))
+            }
+            ty::Adt(def, substs) => {
+                val.unwrap_branch().iter().zip(def.non_enum_variant().fields.iter().map(|field| field.ty(cx.tcx, substs))).any(|(field, ty)| inner(cx, *field, ty))
+            }
+            ty::Tuple(tys) => val.unwrap_branch().iter().zip(tys).any(|(field, ty)| inner(cx, *field, ty)),
             _ => false,
         }
     }
@@ -184,24 +200,44 @@ fn is_value_unfrozen_raw<'tcx>(
             // I chose this way because unfrozen enums as assoc consts are rare (or, hopefully, none).
             err == ErrorHandled::TooGeneric
         },
-        |val| inner(cx, mir::ConstantKind::from_value(val, ty)),
+        |val| val.map_or(true, |val| inner(cx, val, ty)),
     )
 }
 
 fn is_value_unfrozen_poly<'tcx>(cx: &LateContext<'tcx>, body_id: BodyId, ty: Ty<'tcx>) -> bool {
-    let result = cx.tcx.const_eval_poly(body_id.hir_id.owner.to_def_id());
+    let def_id = body_id.hir_id.owner.to_def_id();
+    let substs = ty::InternalSubsts::identity_for_item(cx.tcx, def_id);
+    let instance = ty::Instance::new(def_id, substs);
+    let cid = rustc_middle::mir::interpret::GlobalId { instance, promoted: None };
+    let param_env = cx.tcx.param_env(def_id).with_reveal_all_normalized(cx.tcx);
+    let result = cx.tcx.const_eval_global_id_for_typeck(param_env, cid, None);
     is_value_unfrozen_raw(cx, result, ty)
 }
 
 fn is_value_unfrozen_expr<'tcx>(cx: &LateContext<'tcx>, hir_id: HirId, def_id: DefId, ty: Ty<'tcx>) -> bool {
     let substs = cx.typeck_results().node_substs(hir_id);
 
-    let result = cx
-        .tcx
-        .const_eval_resolve(cx.param_env, mir::UnevaluatedConst::new(def_id, substs), None);
+    let result = const_eval_resolve(cx.tcx, cx.param_env, ty::UnevaluatedConst::new(def_id, substs), None);
     is_value_unfrozen_raw(cx, result, ty)
 }
 
+
+pub fn const_eval_resolve<'tcx>(
+    tcx: TyCtxt<'tcx>,
+    param_env: ty::ParamEnv<'tcx>,
+    ct: ty::UnevaluatedConst<'tcx>,
+    span: Option<Span>,
+) -> EvalToValTreeResult<'tcx> {
+    match ty::Instance::resolve(tcx, param_env, ct.def, ct.substs) {
+        Ok(Some(instance)) => {
+            let cid = GlobalId { instance, promoted: None };
+            tcx.const_eval_global_id_for_typeck(param_env, cid, span)
+        }
+        Ok(None) => Err(ErrorHandled::TooGeneric),
+        Err(err) => Err(ErrorHandled::Reported(err.into())),
+    }
+}
+
 #[derive(Copy, Clone)]
 enum Source {
     Item { item: Span },
diff --git a/tests/ui/crashes/ice-9445.stderr b/tests/ui/crashes/ice-9445.stderr
new file mode 100644
index 00000000000..a59d098e5ac
--- /dev/null
+++ b/tests/ui/crashes/ice-9445.stderr
@@ -0,0 +1,12 @@
+error: a `const` item should never be interior mutable
+  --> $DIR/ice-9445.rs:1:1
+   |
+LL | const UNINIT: core::mem::MaybeUninit<core::cell::Cell<&'static ()>> = core::mem::MaybeUninit::uninit();
+   | -----^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   | |
+   | make this a static item (maybe with lazy_static)
+   |
+   = note: `-D clippy::declare-interior-mutable-const` implied by `-D warnings`
+
+error: aborting due to previous error
+