Auto merge of rust-lang#129999 - matthiaskrgr:rollup-pzr9c8p, r=matthiaskrgr

Rollup of 11 pull requests

Successful merges:

 - rust-lang#128919 (Add an internal lint that warns when accessing untracked data)
 - rust-lang#129472 (fix ICE when `asm_const` and `const_refs_to_static` are combined)
 - rust-lang#129653 (clarify that addr_of creates read-only pointers)
 - rust-lang#129775 (bootstrap: Try to track down why `initial_libdir` sometimes fails)
 - rust-lang#129939 (explain why Rvalue::Len still exists)
 - rust-lang#129942 (copy rustc rustlib artifacts from ci-rustc)
 - rust-lang#129943 (use the bootstrapped compiler for `test-float-parse` test)
 - rust-lang#129944 (Add compat note for trait solver change)
 - rust-lang#129947 (Add digit separators in `Duration` examples)
 - rust-lang#129955 (Temporarily remove fmease from the review rotation)
 - rust-lang#129957 (forward linker option to lint-docs)

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

Author: bors

RELEASES.md

@@ -100,6 +100,9 @@ Compatibility Notes
   The reason is that these types have different roles: `std::panic::PanicHookInfo` is the argument to the [panic hook](https://doc.rust-lang.org/stable/std/panic/fn.set_hook.html) in std context (where panics can have an arbitrary payload), while `core::panic::PanicInfo` is the argument to the [`#[panic_handler]`](https://doc.rust-lang.org/nomicon/panic-handler.html) in no_std context (where panics always carry a formatted *message*). Separating these types allows us to add more useful methods to these types, such as `std::panic::PanicHookInfo::payload_as_str()` and `core::panic::PanicInfo::message()`.
 
 * The new sort implementations may panic if a type's implementation of [`Ord`](https://doc.rust-lang.org/std/cmp/trait.Ord.html) (or the given comparison function) does not implement a [total order](https://en.wikipedia.org/wiki/Total_order) as the trait requires. `Ord`'s supertraits (`PartialOrd`, `Eq`, and `PartialEq`) must also be consistent. The previous implementations would not "notice" any problem, but the new implementations have a good chance of detecting inconsistencies, throwing a panic rather than returning knowingly unsorted data.
+* [In very rare cases, a change in the internal evaluation order of the trait
+  solver may result in new fatal overflow errors.](https://github.com/rust-lang/rust/pull/126128)
+
 
 <a id="1.81.0-Internal-Changes"></a>
 

compiler/rustc_borrowck/src/lib.rs

@@ -2522,7 +2522,7 @@ mod diags {
         }
 
         pub(crate) fn emit_errors(&mut self) -> Option<ErrorGuaranteed> {
-            let mut res = None;
+            let mut res = self.infcx.tainted_by_errors();
 
             // Buffer any move errors that we collected and de-duplicated.
             for (_, (_, diag)) in std::mem::take(&mut self.diags.buffered_move_errors) {

compiler/rustc_borrowck/src/universal_regions.rs

@@ -29,7 +29,8 @@ use rustc_macros::extension;
 use rustc_middle::ty::fold::TypeFoldable;
 use rustc_middle::ty::print::with_no_trimmed_paths;
 use rustc_middle::ty::{
-    self, GenericArgs, GenericArgsRef, InlineConstArgs, InlineConstArgsParts, RegionVid, Ty, TyCtxt,
+    self, GenericArgs, GenericArgsRef, InlineConstArgs, InlineConstArgsParts, RegionVid, Ty,
+    TyCtxt, TypeVisitableExt,
 };
 use rustc_middle::{bug, span_bug};
 use rustc_span::symbol::{kw, sym};
@@ -688,7 +689,8 @@ impl<'cx, 'tcx> UniversalRegionsBuilder<'cx, 'tcx> {
         defining_ty: DefiningTy<'tcx>,
     ) -> ty::Binder<'tcx, &'tcx ty::List<Ty<'tcx>>> {
         let tcx = self.infcx.tcx;
-        match defining_ty {
+
+        let inputs_and_output = match defining_ty {
             DefiningTy::Closure(def_id, args) => {
                 assert_eq!(self.mir_def.to_def_id(), def_id);
                 let closure_sig = args.as_closure().sig();
@@ -798,6 +800,7 @@ impl<'cx, 'tcx> UniversalRegionsBuilder<'cx, 'tcx> {
                 // "output" (the type of the constant).
                 assert_eq!(self.mir_def.to_def_id(), def_id);
                 let ty = tcx.type_of(self.mir_def).instantiate_identity();
+
                 let ty = indices.fold_to_region_vids(tcx, ty);
                 ty::Binder::dummy(tcx.mk_type_list(&[ty]))
             }
@@ -807,7 +810,14 @@ impl<'cx, 'tcx> UniversalRegionsBuilder<'cx, 'tcx> {
                 let ty = args.as_inline_const().ty();
                 ty::Binder::dummy(tcx.mk_type_list(&[ty]))
             }
+        };
+
+        // FIXME(#129952): We probably want a more principled approach here.
+        if let Err(terr) = inputs_and_output.skip_binder().error_reported() {
+            self.infcx.set_tainted_by_errors(terr);
         }
+
+        inputs_and_output
     }
 }
 

compiler/rustc_data_structures/src/steal.rs

@@ -57,6 +57,7 @@ impl<T> Steal<T> {
     ///
     /// This should not be used within rustc as it leaks information not tracked
     /// by the query system, breaking incremental compilation.
+    #[cfg_attr(not(bootstrap), rustc_lint_untracked_query_information)]
     pub fn is_stolen(&self) -> bool {
         self.value.borrow().is_none()
     }

compiler/rustc_feature/src/builtin_attrs.rs

@@ -793,6 +793,12 @@ pub const BUILTIN_ATTRIBUTES: &[BuiltinAttribute] = &[
         rustc_lint_query_instability, Normal, template!(Word),
         WarnFollowing, EncodeCrossCrate::Yes, INTERNAL_UNSTABLE
     ),
+    // Used by the `rustc::untracked_query_information` lint to warn methods which
+    // might not be stable during incremental compilation.
+    rustc_attr!(
+        rustc_lint_untracked_query_information, Normal, template!(Word),
+        WarnFollowing, EncodeCrossCrate::Yes, INTERNAL_UNSTABLE
+    ),
     // Used by the `rustc::diagnostic_outside_of_impl` lints to assist in changes to diagnostic
     // APIs. Any function with this attribute will be checked by that lint.
     rustc_attr!(

compiler/rustc_lint/messages.ftl

@@ -699,6 +699,9 @@ lint_ptr_null_checks_ref = references are not nullable, so checking them for nul
 lint_query_instability = using `{$query}` can result in unstable query results
     .note = if you believe this case to be fine, allow this lint and add a comment explaining your rationale
 
+lint_query_untracked = `{$method}` accesses information that is not tracked by the query system
+    .note = if you believe this case to be fine, allow this lint and add a comment explaining your rationale
+
 lint_range_endpoint_out_of_range = range endpoint is out of range for `{$ty}`
 
 lint_range_use_inclusive_range = use an inclusive range instead

compiler/rustc_lint/src/internal.rs

@@ -17,8 +17,8 @@ use tracing::debug;
 
 use crate::lints::{
     BadOptAccessDiag, DefaultHashTypesDiag, DiagOutOfImpl, LintPassByHand, NonExistentDocKeyword,
-    NonGlobImportTypeIrInherent, QueryInstability, SpanUseEqCtxtDiag, TyQualified, TykindDiag,
-    TykindKind, TypeIrInherentUsage, UntranslatableDiag,
+    NonGlobImportTypeIrInherent, QueryInstability, QueryUntracked, SpanUseEqCtxtDiag, TyQualified,
+    TykindDiag, TykindKind, TypeIrInherentUsage, UntranslatableDiag,
 };
 use crate::{EarlyContext, EarlyLintPass, LateContext, LateLintPass, LintContext};
 
@@ -88,7 +88,18 @@ declare_tool_lint! {
     report_in_external_macro: true
 }
 
-declare_lint_pass!(QueryStability => [POTENTIAL_QUERY_INSTABILITY]);
+declare_tool_lint! {
+    /// The `untracked_query_information` lint detects use of methods which leak information not
+    /// tracked by the query system, such as whether a `Steal<T>` value has already been stolen. In
+    /// order not to break incremental compilation, such methods must be used very carefully or not
+    /// at all.
+    pub rustc::UNTRACKED_QUERY_INFORMATION,
+    Allow,
+    "require explicit opt-in when accessing information not tracked by the query system",
+    report_in_external_macro: true
+}
+
+declare_lint_pass!(QueryStability => [POTENTIAL_QUERY_INSTABILITY, UNTRACKED_QUERY_INFORMATION]);
 
 impl LateLintPass<'_> for QueryStability {
     fn check_expr(&mut self, cx: &LateContext<'_>, expr: &Expr<'_>) {
@@ -102,6 +113,13 @@ impl LateLintPass<'_> for QueryStability {
                     QueryInstability { query: cx.tcx.item_name(def_id) },
                 );
             }
+            if cx.tcx.has_attr(def_id, sym::rustc_lint_untracked_query_information) {
+                cx.emit_span_lint(
+                    UNTRACKED_QUERY_INFORMATION,
+                    span,
+                    QueryUntracked { method: cx.tcx.item_name(def_id) },
+                );
+            }
         }
     }
 }

compiler/rustc_lint/src/lib.rs

@@ -610,6 +610,7 @@ fn register_internals(store: &mut LintStore) {
         vec![
             LintId::of(DEFAULT_HASH_TYPES),
             LintId::of(POTENTIAL_QUERY_INSTABILITY),
+            LintId::of(UNTRACKED_QUERY_INFORMATION),
             LintId::of(USAGE_OF_TY_TYKIND),
             LintId::of(PASS_BY_VALUE),
             LintId::of(LINT_PASS_IMPL_WITHOUT_MACRO),

compiler/rustc_lint/src/lints.rs

@@ -894,6 +894,13 @@ pub(crate) struct QueryInstability {
     pub query: Symbol,
 }
 
+#[derive(LintDiagnostic)]
+#[diag(lint_query_untracked)]
+#[note]
+pub(crate) struct QueryUntracked {
+    pub method: Symbol,
+}
+
 #[derive(LintDiagnostic)]
 #[diag(lint_span_use_eq_ctxt)]
 pub(crate) struct SpanUseEqCtxtDiag;

compiler/rustc_middle/src/mir/syntax.rs

@@ -1307,6 +1307,9 @@ pub enum Rvalue<'tcx> {
     /// If the type of the place is an array, this is the array length. For slices (`[T]`, not
     /// `&[T]`) this accesses the place's metadata to determine the length. This rvalue is
     /// ill-formed for places of other types.
+    ///
+    /// This cannot be a `UnOp(PtrMetadata, _)` because that expects a value, and we only
+    /// have a place, and `UnOp(PtrMetadata, RawPtr(place))` is not a thing.
     Len(Place<'tcx>),
 
     /// Performs essentially all of the casts that can be performed via `as`.