Auto merge of rust-lang#132005 - matthiaskrgr:rollup-ced4upi, r=matth…

…iaskrgr

Rollup of 7 pull requests

Successful merges:

 - rust-lang#130350 (stabilize Strict Provenance and Exposed Provenance APIs)
 - rust-lang#131737 (linkchecker: add a reminder on broken links to add new/renamed pages to `SUMMARY.md` for mdBooks)
 - rust-lang#131991 (test: Add test for trait in FQS cast, issue rust-lang#98565)
 - rust-lang#131997 (Make `rustc_abi` compile on stable again)
 - rust-lang#131999 (Improve test coverage for `unit_bindings` lint)
 - rust-lang#132001 (fix coherence error for very large tuples™)
 - rust-lang#132003 (update ABI compatibility docs for new option-like rules)

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

compiler/rustc_abi/src/callconv.rs

@@ -3,18 +3,23 @@ mod abi {
     pub(crate) use crate::Variants;
 }
 
+#[cfg(feature = "nightly")]
 use rustc_macros::HashStable_Generic;
 
-use crate::{Abi, Align, FieldsShape, HasDataLayout, Size, TyAbiInterface, TyAndLayout};
+#[cfg(feature = "nightly")]
+use crate::{Abi, FieldsShape, TyAbiInterface, TyAndLayout};
+use crate::{Align, HasDataLayout, Size};
 
-#[derive(Copy, Clone, PartialEq, Eq, Hash, Debug, HashStable_Generic)]
+#[cfg_attr(feature = "nightly", derive(HashStable_Generic))]
+#[derive(Copy, Clone, PartialEq, Eq, Hash, Debug)]
 pub enum RegKind {
     Integer,
     Float,
     Vector,
 }
 
-#[derive(Copy, Clone, PartialEq, Eq, Hash, Debug, HashStable_Generic)]
+#[cfg_attr(feature = "nightly", derive(HashStable_Generic))]
+#[derive(Copy, Clone, PartialEq, Eq, Hash, Debug)]
 pub struct Reg {
     pub kind: RegKind,
     pub size: Size,
@@ -108,15 +113,8 @@ impl HomogeneousAggregate {
     }
 }
 
+#[cfg(feature = "nightly")]
 impl<'a, Ty> TyAndLayout<'a, Ty> {
-    /// Returns `true` if this is an aggregate type (including a ScalarPair!)
-    pub fn is_aggregate(&self) -> bool {
-        match self.abi {
-            Abi::Uninhabited | Abi::Scalar(_) | Abi::Vector { .. } => false,
-            Abi::ScalarPair(..) | Abi::Aggregate { .. } => true,
-        }
-    }
-
     /// Returns `Homogeneous` if this layout is an aggregate containing fields of
     /// only a single type (e.g., `(u32, u32)`). Such aggregates are often
     /// special-cased in ABIs.

compiler/rustc_abi/src/layout.rs

@@ -11,8 +11,10 @@ use crate::{
     Variants, WrappingRange,
 };
 
+#[cfg(feature = "nightly")]
 mod ty;
 
+#[cfg(feature = "nightly")]
 pub use ty::{FIRST_VARIANT, FieldIdx, Layout, TyAbiInterface, TyAndLayout, VariantIdx};
 
 // A variant is absent if it's uninhabited and only has ZST fields.

compiler/rustc_abi/src/lib.rs

@@ -29,14 +29,14 @@ mod layout;
 mod tests;
 
 pub use callconv::{Heterogeneous, HomogeneousAggregate, Reg, RegKind};
-pub use layout::{
-    FIRST_VARIANT, FieldIdx, Layout, LayoutCalculator, LayoutCalculatorError, TyAbiInterface,
-    TyAndLayout, VariantIdx,
-};
+#[cfg(feature = "nightly")]
+pub use layout::{FIRST_VARIANT, FieldIdx, Layout, TyAbiInterface, TyAndLayout, VariantIdx};
+pub use layout::{LayoutCalculator, LayoutCalculatorError};
 
 /// Requirements for a `StableHashingContext` to be used in this crate.
 /// This is a hack to allow using the `HashStable_Generic` derive macro
 /// instead of implementing everything in `rustc_middle`.
+#[cfg(feature = "nightly")]
 pub trait HashStableContext {}
 
 #[derive(Clone, Copy, PartialEq, Eq, Default)]
@@ -1644,6 +1644,14 @@ pub struct LayoutS<FieldIdx: Idx, VariantIdx: Idx> {
 }
 
 impl<FieldIdx: Idx, VariantIdx: Idx> LayoutS<FieldIdx, VariantIdx> {
+    /// Returns `true` if this is an aggregate type (including a ScalarPair!)
+    pub fn is_aggregate(&self) -> bool {
+        match self.abi {
+            Abi::Uninhabited | Abi::Scalar(_) | Abi::Vector { .. } => false,
+            Abi::ScalarPair(..) | Abi::Aggregate { .. } => true,
+        }
+    }
+
     pub fn scalar<C: HasDataLayout>(cx: &C, scalar: Scalar) -> Self {
         let largest_niche = Niche::from_scalar(cx, Size::ZERO, scalar);
         let size = scalar.size(cx);

compiler/rustc_arena/src/lib.rs

@@ -23,7 +23,6 @@
 #![feature(maybe_uninit_slice)]
 #![feature(rustc_attrs)]
 #![feature(rustdoc_internals)]
-#![feature(strict_provenance)]
 #![warn(unreachable_pub)]
 // tidy-alphabetical-end
 

compiler/rustc_codegen_ssa/src/lib.rs

@@ -11,7 +11,6 @@
 #![feature(let_chains)]
 #![feature(negative_impls)]
 #![feature(rustdoc_internals)]
-#![feature(strict_provenance)]
 #![feature(trait_alias)]
 #![feature(try_blocks)]
 #![warn(unreachable_pub)]

compiler/rustc_codegen_ssa/src/mir/rvalue.rs

@@ -361,12 +361,16 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
             (Int(..) | Float(_), Int(..) | Float(_)) => bx.bitcast(imm, to_backend_ty),
             (Pointer(..), Pointer(..)) => bx.pointercast(imm, to_backend_ty),
             (Int(..), Pointer(..)) => bx.ptradd(bx.const_null(bx.type_ptr()), imm),
-            (Pointer(..), Int(..)) => bx.ptrtoint(imm, to_backend_ty),
+            (Pointer(..), Int(..)) => {
+                // FIXME: this exposes the provenance, which shouldn't be necessary.
+                bx.ptrtoint(imm, to_backend_ty)
+            }
             (Float(_), Pointer(..)) => {
                 let int_imm = bx.bitcast(imm, bx.cx().type_isize());
                 bx.ptradd(bx.const_null(bx.type_ptr()), int_imm)
             }
             (Pointer(..), Float(_)) => {
+                // FIXME: this exposes the provenance, which shouldn't be necessary.
                 let int_imm = bx.ptrtoint(imm, bx.cx().type_isize());
                 bx.bitcast(int_imm, to_backend_ty)
             }

compiler/rustc_const_eval/src/lib.rs

@@ -10,7 +10,6 @@
 #![feature(never_type)]
 #![feature(rustdoc_internals)]
 #![feature(slice_ptr_get)]
-#![feature(strict_provenance)]
 #![feature(trait_alias)]
 #![feature(try_blocks)]
 #![feature(unqualified_local_imports)]

compiler/rustc_data_structures/src/lib.rs

@@ -33,7 +33,6 @@
 #![feature(ptr_alignment_type)]
 #![feature(rustc_attrs)]
 #![feature(rustdoc_internals)]
-#![feature(strict_provenance)]
 #![feature(test)]
 #![feature(thread_id_value)]
 #![feature(type_alias_impl_trait)]

compiler/rustc_feature/src/unstable.rs

@@ -595,7 +595,7 @@ declare_features! (
     /// Allows attributes on expressions and non-item statements.
     (unstable, stmt_expr_attributes, "1.6.0", Some(15701)),
     /// Allows lints part of the strict provenance effort.
-    (unstable, strict_provenance, "1.61.0", Some(95228)),
+    (unstable, strict_provenance_lints, "1.61.0", Some(130351)),
     /// Allows string patterns to dereference values to match them.
     (unstable, string_deref_patterns, "1.67.0", Some(87121)),
     /// Allows the use of `#[target_feature]` on safe functions.

compiler/rustc_lint_defs/src/builtin.rs

@@ -2667,7 +2667,6 @@ declare_lint! {
     /// ### Example
     ///
     /// ```rust
-    /// #![feature(strict_provenance)]
     /// #![warn(fuzzy_provenance_casts)]
     ///
     /// fn main() {
@@ -2701,7 +2700,7 @@ declare_lint! {
     pub FUZZY_PROVENANCE_CASTS,
     Allow,
     "a fuzzy integer to pointer cast is used",
-    @feature_gate = strict_provenance;
+    @feature_gate = strict_provenance_lints;
 }
 
 declare_lint! {
@@ -2711,7 +2710,6 @@ declare_lint! {
     /// ### Example
     ///
     /// ```rust
-    /// #![feature(strict_provenance)]
     /// #![warn(lossy_provenance_casts)]
     ///
     /// fn main() {
@@ -2747,7 +2745,7 @@ declare_lint! {
     pub LOSSY_PROVENANCE_CASTS,
     Allow,
     "a lossy pointer to integer cast is used",
-    @feature_gate = strict_provenance;
+    @feature_gate = strict_provenance_lints;
 }
 
 declare_lint! {

compiler/rustc_middle/src/lib.rs

@@ -56,7 +56,6 @@
 #![feature(ptr_alignment_type)]
 #![feature(rustc_attrs)]
 #![feature(rustdoc_internals)]
-#![feature(strict_provenance)]
 #![feature(trait_upcasting)]
 #![feature(trusted_len)]
 #![feature(try_blocks)]

compiler/rustc_next_trait_solver/src/solve/eval_ctxt/canonical.rs

@@ -16,7 +16,7 @@ use rustc_type_ir::fold::TypeFoldable;
 use rustc_type_ir::inherent::*;
 use rustc_type_ir::relate::solver_relating::RelateExt;
 use rustc_type_ir::{self as ty, Canonical, CanonicalVarValues, InferCtxtLike, Interner};
-use tracing::{instrument, trace};
+use tracing::{debug, instrument, trace};
 
 use crate::canonicalizer::{CanonicalizeMode, Canonicalizer};
 use crate::delegate::SolverDelegate;
@@ -165,12 +165,22 @@ where
         // HACK: We bail with overflow if the response would have too many non-region
         // inference variables. This tends to only happen if we encounter a lot of
         // ambiguous alias types which get replaced with fresh inference variables
-        // during generalization. This prevents a hang in nalgebra.
-        let num_non_region_vars = canonical.variables.iter().filter(|c| !c.is_region()).count();
-        if num_non_region_vars > self.cx().recursion_limit() {
-            return Ok(self.make_ambiguous_response_no_constraints(MaybeCause::Overflow {
-                suggest_increasing_limit: true,
-            }));
+        // during generalization. This prevents hangs caused by an exponential blowup,
+        // see tests/ui/traits/next-solver/coherence-alias-hang.rs.
+        //
+        // We don't do so for `NormalizesTo` goals as we erased the expected term and
+        // bailing with overflow here would prevent us from detecting a type-mismatch,
+        // causing a coherence error in diesel, see #131969. We still bail with verflow
+        // when later returning from the parent AliasRelate goal.
+        if !self.is_normalizes_to_goal {
+            let num_non_region_vars =
+                canonical.variables.iter().filter(|c| !c.is_region() && c.is_existential()).count();
+            if num_non_region_vars > self.cx().recursion_limit() {
+                debug!(?num_non_region_vars, "too many inference variables -> overflow");
+                return Ok(self.make_ambiguous_response_no_constraints(MaybeCause::Overflow {
+                    suggest_increasing_limit: true,
+                }));
+            }
         }
 
         Ok(canonical)

compiler/rustc_span/src/symbol.rs

@@ -1913,7 +1913,7 @@ symbols! {
         str_trim,
         str_trim_end,
         str_trim_start,
-        strict_provenance,
+        strict_provenance_lints,
         string_as_mut_str,
         string_as_str,
         string_deref_patterns,

compiler/rustc_trait_selection/src/traits/coherence.rs

@@ -298,6 +298,7 @@ fn equate_impl_headers<'tcx>(
 }
 
 /// The result of [fn impl_intersection_has_impossible_obligation].
+#[derive(Debug)]
 enum IntersectionHasImpossibleObligations<'tcx> {
     Yes,
     No {
@@ -328,6 +329,7 @@ enum IntersectionHasImpossibleObligations<'tcx> {
 /// of the two impls above to be empty.
 ///
 /// Importantly, this works even if there isn't a `impl !Error for MyLocalType`.
+#[instrument(level = "debug", skip(selcx), ret)]
 fn impl_intersection_has_impossible_obligation<'a, 'cx, 'tcx>(
     selcx: &mut SelectionContext<'cx, 'tcx>,
     obligations: &'a [PredicateObligation<'tcx>],

library/alloc/benches/lib.rs

@@ -4,7 +4,8 @@
 #![feature(iter_next_chunk)]
 #![feature(repr_simd)]
 #![feature(slice_partition_dedup)]
-#![feature(strict_provenance)]
+#![cfg_attr(bootstrap, feature(strict_provenance))]
+#![cfg_attr(not(bootstrap), feature(strict_provenance_lints))]
 #![feature(test)]
 #![deny(fuzzy_provenance_casts)]
 

library/alloc/src/lib.rs

@@ -147,7 +147,6 @@
 #![feature(slice_range)]
 #![feature(std_internals)]
 #![feature(str_internals)]
-#![feature(strict_provenance)]
 #![feature(trusted_fused)]
 #![feature(trusted_len)]
 #![feature(trusted_random_access)]
@@ -162,6 +161,8 @@
 //
 // Language features:
 // tidy-alphabetical-start
+#![cfg_attr(bootstrap, feature(strict_provenance))]
+#![cfg_attr(not(bootstrap), feature(strict_provenance_lints))]
 #![cfg_attr(not(test), feature(coroutine_trait))]
 #![cfg_attr(test, feature(panic_update_hook))]
 #![cfg_attr(test, feature(test))]

library/alloc/tests/lib.rs

@@ -32,7 +32,8 @@
 #![feature(panic_update_hook)]
 #![feature(pointer_is_aligned_to)]
 #![feature(thin_box)]
-#![feature(strict_provenance)]
+#![cfg_attr(bootstrap, feature(strict_provenance))]
+#![cfg_attr(not(bootstrap), feature(strict_provenance_lints))]
 #![feature(drain_keep_rest)]
 #![feature(local_waker)]
 #![feature(vec_pop_if)]

library/core/src/intrinsics.rs

@@ -2794,7 +2794,6 @@ where
 /// #![feature(is_val_statically_known)]
 /// #![feature(core_intrinsics)]
 /// # #![allow(internal_features)]
-/// #![feature(strict_provenance)]
 /// use std::intrinsics::is_val_statically_known;
 ///
 /// fn foo(x: &i32) -> bool {

library/core/src/lib.rs

@@ -163,7 +163,6 @@
 #![feature(str_internals)]
 #![feature(str_split_inclusive_remainder)]
 #![feature(str_split_remainder)]
-#![feature(strict_provenance)]
 #![feature(ub_checks)]
 #![feature(unchecked_neg)]
 #![feature(unchecked_shifts)]
@@ -174,6 +173,8 @@
 //
 // Language features:
 // tidy-alphabetical-start
+#![cfg_attr(bootstrap, feature(strict_provenance))]
+#![cfg_attr(not(bootstrap), feature(strict_provenance_lints))]
 #![feature(abi_unadjusted)]
 #![feature(adt_const_params)]
 #![feature(allow_internal_unsafe)]

library/core/src/primitive_docs.rs

@@ -1784,9 +1784,11 @@ mod prim_ref {}
 ///   unique field that doesn't have size 0 and alignment 1 (if there is such a field).
 /// - `i32` is ABI-compatible with `NonZero<i32>`, and similar for all other integer types.
 /// - If `T` is guaranteed to be subject to the [null pointer
-///   optimization](option/index.html#representation), then `T` and `Option<T>` are ABI-compatible.
-///   Furthermore, if `U` satisfies the requirements [outlined here](result/index.html#representation),
-///   then `T` and `Result<T, U>` and `Result<U, T>` are all ABI-compatible.
+///   optimization](option/index.html#representation), and `E` is an enum satisfying the following
+///   requirements, then `T` and `E` are ABI-compatible. Such an enum `E` is called "option-like".
+///   - The enum `E` has exactly two variants.
+///   - One variant has exactly one field, of type `T`.
+///   - All fields of the other variant are zero-sized with 1-byte alignment.
 ///
 /// Furthermore, ABI compatibility satisfies the following general properties:
 ///