Auto merge of #82153 - jonas-schievink:rollup-ls5r943, r=jonas-schievink

Rollup of 19 pull requests

Successful merges:

 - #81503 (Suggest to create a new `const` item if the `fn` in the array is a `const fn`)
 - #81897 (Add match pattern diagnostics regression test)
 - #81975 (Seal the CommandExt, OsStrExt and OsStringExt traits)
 - #82009 (const_generics: Dont evaluate array length const when handling errors)
 - #82060 (Fix typos in BTreeSet::{first, last} docs)
 - #82061 (CTFE validation: catch ReadPointerAsBytes and better error)
 - #82063 (Fixed minor typo in catch_unwind docs)
 - #82067 (const_generics: Fix incorrect ty::ParamEnv::empty() usage)
 - #82077 (Edit `rustc_arena::DropArena` docs)
 - #82096 (Fix a typo)
 - #82106 (Remove unnecessary `Option` in `default_doc`)
 - #82107 (expand: Some cleanup)
 - #82118 (Add missing env!-decl variant)
 - #82119 (Fix typo in link to CreateSymbolicLinkW documentation.)
 - #82120 (Stabilize Arguments::as_str)
 - #82129 (Remove redundant bool_to_option feature gate)
 - #82133 (Update link for extern prelude.)
 - #82141 (32-bit ARM: Emit `lr` instead of `r14` when specified as an `asm!` output register.)
 - #82147 (⬆️ rust-analyzer)

Failed merges:

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

compiler/rustc_middle/src/mir/interpret/queries.rs

@@ -31,6 +31,7 @@ impl<'tcx> TyCtxt<'tcx> {
     /// constant `bar::<T>()` requires a substitution for `T`, if the substitution for `T` is still
     /// too generic for the constant to be evaluated then `Err(ErrorHandled::TooGeneric)` is
     /// returned.
+    #[instrument(level = "debug", skip(self))]
     pub fn const_eval_resolve(
         self,
         param_env: ty::ParamEnv<'tcx>,

compiler/rustc_middle/src/traits/mod.rs

@@ -228,7 +228,10 @@ pub enum ObligationCauseCode<'tcx> {
     /// Inline asm operand type must be `Sized`.
     InlineAsmSized,
     /// `[T, ..n]` implies that `T` must be `Copy`.
-    RepeatVec,
+    /// If the function in the array repeat expression is a `const fn`,
+    /// display a help message suggesting to move the function call to a
+    /// new `const` item while saying that `T` doesn't implement `Copy`.
+    RepeatVec(bool),
 
     /// Types of fields (other than the last, except for packed structs) in a struct must be sized.
     FieldSized {

compiler/rustc_middle/src/ty/error.rs

@@ -228,12 +228,17 @@ impl<'tcx> ty::TyS<'tcx> {
             ty::Adt(def, _) => format!("{} `{}`", def.descr(), tcx.def_path_str(def.did)).into(),
             ty::Foreign(def_id) => format!("extern type `{}`", tcx.def_path_str(def_id)).into(),
             ty::Array(t, n) => {
-                let n = tcx.lift(n).unwrap();
-                match n.try_eval_usize(tcx, ty::ParamEnv::empty()) {
-                    _ if t.is_simple_ty() => format!("array `{}`", self).into(),
-                    Some(n) => format!("array of {} element{}", n, pluralize!(n)).into(),
-                    None => "array".into(),
+                if t.is_simple_ty() {
+                    return format!("array `{}`", self).into();
                 }
+
+                let n = tcx.lift(n).unwrap();
+                if let ty::ConstKind::Value(v) = n.val {
+                    if let Some(n) = v.try_to_machine_usize(tcx) {
+                        return format!("array of {} element{}", n, pluralize!(n)).into();
+                    }
+                }
+                "array".into()
             }
             ty::Slice(ty) if ty.is_simple_ty() => format!("slice `{}`", self).into(),
             ty::Slice(_) => "slice".into(),

compiler/rustc_middle/src/ty/instance.rs

@@ -347,6 +347,7 @@ impl<'tcx> Instance<'tcx> {
     }
 
     // This should be kept up to date with `resolve`.
+    #[instrument(level = "debug", skip(tcx))]
     pub fn resolve_opt_const_arg(
         tcx: TyCtxt<'tcx>,
         param_env: ty::ParamEnv<'tcx>,