Auto merge of #154716 - JonathanBrouwer:rollup-mjhodpw, r=JonathanBrouwer

Rollup of 21 pull requests

Successful merges:

 - #153105 (Compute the result of a projection type with region errors)
 - #153286 (various fixes for scalable vectors)
 - #153532 (Attributes containing rustc)
 - #153960 (Make `layout_of` cycles fatal errors)
 - #154527 (Emit pre-expansion feature gate warnings for negative impls and specialization)
 - #154666 (Remove `StableHashContext` impls)
 - #154669 (Introduce #[diagnostic::on_move] on `Arc`)
 - #154710 (opaque_generic_const_args -> generic_const_args)
 - #154712 (Revert "`-Znext-solver` Remove the forced ambiguity hack from search graph")
 - #154713 (Stop compiling when we get resolving crate failure)
 - #154213 (tidy-alphabetical: fix line number in error message)
 - #154425 (Migrate transmute tests)
 - #154442 (Export `derive` at the crate root: `core::derive` and `std::derive`)
 - #154469 (mGCA: Lower spans for literal const args)
 - #154578 (Rename `probe_ty_var` to `try_resolve_ty_var`)
 - #154615 (Moving issues)
 - #154644 (rustdoc: seperate methods and associated functions in sidebar)
 - #154660 (Avoid creating async return opaques for foreign async fns)
 - #154671 (Add a test for a past ICE when calling a const fn of an unresolved type with the wrong number of args)
 - #154680 ([rustdoc] Replace `DocContext` with `TyCtxt` wherever possible)
 - #154709 (Revert `Ty` type alias in `rustc_type_ir`)

Author: bors

compiler/rustc_abi/src/layout.rs

@@ -10,8 +10,8 @@ use tracing::{debug, trace};
 
 use crate::{
     AbiAlign, Align, BackendRepr, FieldsShape, HasDataLayout, IndexSlice, IndexVec, Integer,
-    LayoutData, Niche, NonZeroUsize, Primitive, ReprOptions, Scalar, Size, StructKind, TagEncoding,
-    TargetDataLayout, Variants, WrappingRange,
+    LayoutData, Niche, NonZeroUsize, NumScalableVectors, Primitive, ReprOptions, Scalar, Size,
+    StructKind, TagEncoding, TargetDataLayout, Variants, WrappingRange,
 };
 
 mod coroutine;
@@ -204,13 +204,19 @@ impl<Cx: HasDataLayout> LayoutCalculator<Cx> {
         &self,
         element: F,
         count: u64,
+        number_of_vectors: NumScalableVectors,
     ) -> LayoutCalculatorResult<FieldIdx, VariantIdx, F>
     where
         FieldIdx: Idx,
         VariantIdx: Idx,
         F: AsRef<LayoutData<FieldIdx, VariantIdx>> + fmt::Debug,
     {
-        vector_type_layout(SimdVectorKind::Scalable, self.cx.data_layout(), element, count)
+        vector_type_layout(
+            SimdVectorKind::Scalable(number_of_vectors),
+            self.cx.data_layout(),
+            element,
+            count,
+        )
     }
 
     pub fn simd_type<FieldIdx, VariantIdx, F>(
@@ -1526,7 +1532,7 @@ impl<Cx: HasDataLayout> LayoutCalculator<Cx> {
 
 enum SimdVectorKind {
     /// `#[rustc_scalable_vector]`
-    Scalable,
+    Scalable(NumScalableVectors),
     /// `#[repr(simd, packed)]`
     PackedFixed,
     /// `#[repr(simd)]`
@@ -1559,9 +1565,10 @@ where
     let size =
         elt.size.checked_mul(count, dl).ok_or_else(|| LayoutCalculatorError::SizeOverflow)?;
     let (repr, align) = match kind {
-        SimdVectorKind::Scalable => {
-            (BackendRepr::SimdScalableVector { element, count }, dl.llvmlike_vector_align(size))
-        }
+        SimdVectorKind::Scalable(number_of_vectors) => (
+            BackendRepr::SimdScalableVector { element, count, number_of_vectors },
+            dl.llvmlike_vector_align(size),
+        ),
         // Non-power-of-two vectors have padding up to the next power-of-two.
         // If we're a packed repr, remove the padding while keeping the alignment as close
         // to a vector as possible.

compiler/rustc_abi/src/lib.rs

@@ -67,12 +67,6 @@ pub use layout::{FIRST_VARIANT, FieldIdx, LayoutCalculator, LayoutCalculatorErro
 #[cfg(feature = "nightly")]
 pub use layout::{Layout, TyAbiInterface, TyAndLayout};
 
-/// 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)]
 #[cfg_attr(
     feature = "nightly",
@@ -1702,6 +1696,28 @@ impl AddressSpace {
     pub const ZERO: Self = AddressSpace(0);
 }
 
+/// How many scalable vectors are in a `BackendRepr::ScalableVector`?
+#[derive(Clone, Copy, PartialEq, Eq, Hash, Debug)]
+#[cfg_attr(feature = "nightly", derive(HashStable_Generic))]
+pub struct NumScalableVectors(pub u8);
+
+impl NumScalableVectors {
+    /// Returns a `NumScalableVector` for a non-tuple scalable vector (e.g. a single vector).
+    pub fn for_non_tuple() -> Self {
+        NumScalableVectors(1)
+    }
+
+    // Returns `NumScalableVectors` for values of two through eight, which are a valid number of
+    // fields for a tuple of scalable vectors to have. `1` is a valid value of `NumScalableVectors`
+    // but not for a tuple which would have a field count.
+    pub fn from_field_count(count: usize) -> Option<Self> {
+        match count {
+            2..8 => Some(NumScalableVectors(count as u8)),
+            _ => None,
+        }
+    }
+}
+
 /// The way we represent values to the backend
 ///
 /// Previously this was conflated with the "ABI" a type is given, as in the platform-specific ABI.
@@ -1720,6 +1736,7 @@ pub enum BackendRepr {
     SimdScalableVector {
         element: Scalar,
         count: u64,
+        number_of_vectors: NumScalableVectors,
     },
     SimdVector {
         element: Scalar,
@@ -1826,8 +1843,12 @@ impl BackendRepr {
                 BackendRepr::SimdVector { element: element.to_union(), count }
             }
             BackendRepr::Memory { .. } => BackendRepr::Memory { sized: true },
-            BackendRepr::SimdScalableVector { element, count } => {
-                BackendRepr::SimdScalableVector { element: element.to_union(), count }
+            BackendRepr::SimdScalableVector { element, count, number_of_vectors } => {
+                BackendRepr::SimdScalableVector {
+                    element: element.to_union(),
+                    count,
+                    number_of_vectors,
+                }
             }
         }
     }
@@ -2167,7 +2188,7 @@ impl<FieldIdx: Idx, VariantIdx: Idx> LayoutData<FieldIdx, VariantIdx> {
     }
 
     /// Returns `true` if the size of the type is only known at runtime.
-    pub fn is_runtime_sized(&self) -> bool {
+    pub fn is_scalable_vector(&self) -> bool {
         matches!(self.backend_repr, BackendRepr::SimdScalableVector { .. })
     }
 

compiler/rustc_ast/src/ast.rs

@@ -31,7 +31,8 @@ use rustc_data_structures::tagged_ptr::Tag;
 use rustc_macros::{Decodable, Encodable, HashStable_Generic, Walkable};
 pub use rustc_span::AttrId;
 use rustc_span::{
-    ByteSymbol, DUMMY_SP, ErrorGuaranteed, Ident, Span, Spanned, Symbol, kw, respan, sym,
+    ByteSymbol, DUMMY_SP, ErrorGuaranteed, HashStableContext, Ident, Span, Spanned, Symbol, kw,
+    respan, sym,
 };
 use thin_vec::{ThinVec, thin_vec};
 
@@ -120,7 +121,7 @@ impl PartialEq<&[Symbol]> for Path {
     }
 }
 
-impl<Hcx: rustc_span::HashStableContext> HashStable<Hcx> for Path {
+impl<Hcx: HashStableContext> HashStable<Hcx> for Path {
     fn hash_stable(&self, hcx: &mut Hcx, hasher: &mut StableHasher) {
         self.segments.len().hash_stable(hcx, hasher);
         for segment in &self.segments {

compiler/rustc_ast/src/lib.rs

@@ -36,8 +36,3 @@ pub mod visit;
 
 pub use self::ast::*;
 pub use self::ast_traits::{AstNodeWrapper, HasAttrs, HasNodeId, HasTokens};
-
-/// 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`.
-pub trait HashStableContext: rustc_span::HashStableContext {}

compiler/rustc_ast/src/tokenstream.rs

@@ -14,7 +14,7 @@ use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
 use rustc_data_structures::sync;
 use rustc_macros::{Decodable, Encodable, HashStable_Generic, Walkable};
 use rustc_serialize::{Decodable, Encodable};
-use rustc_span::{DUMMY_SP, Span, SpanDecoder, SpanEncoder, Symbol, sym};
+use rustc_span::{DUMMY_SP, HashStableContext, Span, SpanDecoder, SpanEncoder, Symbol, sym};
 use thin_vec::ThinVec;
 
 use crate::ast::AttrStyle;
@@ -826,7 +826,7 @@ impl FromIterator<TokenTree> for TokenStream {
 
 impl<Hcx> HashStable<Hcx> for TokenStream
 where
-    Hcx: crate::HashStableContext,
+    Hcx: HashStableContext,
 {
     fn hash_stable(&self, hcx: &mut Hcx, hasher: &mut StableHasher) {
         for sub_tt in self.iter() {

compiler/rustc_ast_lowering/src/lib.rs

@@ -2683,7 +2683,7 @@ impl<'hir, R: ResolverAstLoweringExt<'hir>> LoweringContext<'_, 'hir, R> {
                 overly_complex_const(self)
             }
             ExprKind::Lit(literal) => {
-                let span = expr.span;
+                let span = self.lower_span(expr.span);
                 let literal = self.lower_lit(literal, span);
 
                 ConstArg {
@@ -2695,7 +2695,7 @@ impl<'hir, R: ResolverAstLoweringExt<'hir>> LoweringContext<'_, 'hir, R> {
             ExprKind::Unary(UnOp::Neg, inner_expr)
                 if let ExprKind::Lit(literal) = &inner_expr.kind =>
             {
-                let span = expr.span;
+                let span = self.lower_span(expr.span);
                 let literal = self.lower_lit(literal, span);
 
                 if !matches!(literal.node, LitKind::Int(..)) {