Auto merge of #154773 - matthiaskrgr:rollup-DMnqd9w, r=matthiaskrgr

Rollup of 7 pull requests

Successful merges:

 - #153286 (various fixes for scalable vectors)
 - #153592 (Add  `min_adt_const_params` gate)
 - #154675 (Improve shadowed private field diagnostics)
 - #154653 (Remove rustc_on_unimplemented's append_const_msg)
 - #154743 (Remove an unused `StableHash` impl.)
 - #154752 (Add comment to borrow-checker)
 - #154764 (Add tests for three ICEs that have already been fixed)

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

@@ -1696,6 +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.
@@ -1714,6 +1736,7 @@ pub enum BackendRepr {
     SimdScalableVector {
         element: Scalar,
         count: u64,
+        number_of_vectors: NumScalableVectors,
     },
     SimdVector {
         element: Scalar,
@@ -1820,8 +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,
+                }
             }
         }
     }
@@ -2161,7 +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_attr_parsing/src/attributes/diagnostic/mod.rs

@@ -3,8 +3,8 @@ use std::ops::Range;
 use rustc_errors::E0232;
 use rustc_hir::AttrPath;
 use rustc_hir::attrs::diagnostic::{
-    AppendConstMessage, Directive, FilterFormatString, Flag, FormatArg, FormatString, LitOrArg,
-    Name, NameValue, OnUnimplementedCondition, Piece, Predicate,
+    Directive, FilterFormatString, Flag, FormatArg, FormatString, LitOrArg, Name, NameValue,
+    OnUnimplementedCondition, Piece, Predicate,
 };
 use rustc_hir::lints::{AttributeLintKind, FormatWarning};
 use rustc_macros::Diagnostic;
@@ -92,7 +92,6 @@ fn parse_directive_items<'p, S: Stage>(
     let mut notes = ThinVec::new();
     let mut parent_label = None;
     let mut subcommands = ThinVec::new();
-    let mut append_const_msg = None;
 
     for item in items {
         let span = item.span();
@@ -131,7 +130,6 @@ fn parse_directive_items<'p, S: Stage>(
             let Some(ret) = (||{
                 Some($($code)*)
             })() else {
-
                 malformed!()
             };
             ret
@@ -159,8 +157,13 @@ fn parse_directive_items<'p, S: Stage>(
         let item: &MetaItemParser = or_malformed!(item.meta_item()?);
         let name = or_malformed!(item.ident()?).name;
 
-        // Some things like `message = "message"` must have a value.
-        // But with things like `append_const_msg` that is optional.
+        // Currently, as of April 2026, all arguments of all diagnostic attrs
+        // must have a value, like `message = "message"`. Thus in a well-formed
+        // diagnostic attribute this is never `None`.
+        //
+        // But we don't assert its presence yet because we don't want to mention it
+        // if someone does something like `#[diagnostic::on_unimplemented(doesnt_exist)]`.
+        // That happens in the big `match` below.
         let value: Option<Ident> = match item.args().name_value() {
             Some(nv) => Some(or_malformed!(nv.value_as_ident()?)),
             None => None,
@@ -223,14 +226,6 @@ fn parse_directive_items<'p, S: Stage>(
                 let value = or_malformed!(value?);
                 notes.push(parse_format(value))
             }
-
-            (Mode::RustcOnUnimplemented, sym::append_const_msg) => {
-                append_const_msg = if let Some(msg) = value {
-                    Some(AppendConstMessage::Custom(msg.name, item.span()))
-                } else {
-                    Some(AppendConstMessage::Default)
-                }
-            }
             (Mode::RustcOnUnimplemented, sym::parent_label) => {
                 let value = or_malformed!(value?);
                 if parent_label.is_none() {
@@ -290,7 +285,6 @@ fn parse_directive_items<'p, S: Stage>(
         label,
         notes,
         parent_label,
-        append_const_msg,
     })
 }
 

compiler/rustc_borrowck/src/type_check/mod.rs

@@ -447,6 +447,8 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
         let tcx = self.infcx.tcx;
 
         for proj in &user_ty.projs {
+            // Necessary for non-trivial patterns whose user-type annotation is an opaque type,
+            // e.g. `let (_a,): Tait = whatever`, see #105897
             if !self.infcx.next_trait_solver()
                 && let ty::Alias(ty::Opaque, ..) = curr_projected_ty.ty.kind()
             {

compiler/rustc_codegen_gcc/src/builder.rs

@@ -24,7 +24,8 @@ use rustc_data_structures::fx::FxHashSet;
 use rustc_middle::bug;
 use rustc_middle::middle::codegen_fn_attrs::CodegenFnAttrs;
 use rustc_middle::ty::layout::{
-    FnAbiError, FnAbiOfHelpers, FnAbiRequest, HasTyCtxt, HasTypingEnv, LayoutError, LayoutOfHelpers,
+    FnAbiError, FnAbiOfHelpers, FnAbiRequest, HasTyCtxt, HasTypingEnv, LayoutError,
+    LayoutOfHelpers, TyAndLayout,
 };
 use rustc_middle::ty::{self, AtomicOrdering, Instance, Ty, TyCtxt};
 use rustc_span::Span;
@@ -943,8 +944,8 @@ impl<'a, 'gcc, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'gcc, 'tcx> {
             .get_address(self.location)
     }
 
-    fn scalable_alloca(&mut self, _elt: u64, _align: Align, _element_ty: Ty<'_>) -> RValue<'gcc> {
-        todo!()
+    fn alloca_with_ty(&mut self, ty: TyAndLayout<'tcx>) -> RValue<'gcc> {
+        self.alloca(ty.layout.size, ty.layout.align.abi)
     }
 
     fn load(&mut self, pointee_ty: Type<'gcc>, ptr: RValue<'gcc>, align: Align) -> RValue<'gcc> {

compiler/rustc_codegen_gcc/src/common.rs

@@ -145,6 +145,10 @@ impl<'gcc, 'tcx> ConstCodegenMethods for CodegenCx<'gcc, 'tcx> {
         self.const_int(self.type_i32(), i as i64)
     }
 
+    fn const_i64(&self, i: i64) -> RValue<'gcc> {
+        self.const_int(self.type_i64(), i)
+    }
+
     fn const_int(&self, typ: Type<'gcc>, int: i64) -> RValue<'gcc> {
         self.gcc_int(typ, int)
     }

compiler/rustc_codegen_llvm/src/builder.rs

@@ -7,8 +7,7 @@ pub(crate) mod autodiff;
 pub(crate) mod gpu_offload;
 
 use libc::{c_char, c_uint};
-use rustc_abi as abi;
-use rustc_abi::{Align, Size, WrappingRange};
+use rustc_abi::{self as abi, Align, Size, WrappingRange};
 use rustc_codegen_ssa::MemFlags;
 use rustc_codegen_ssa::common::{IntPredicate, RealPredicate, SynchronizationScope, TypeKind};
 use rustc_codegen_ssa::mir::operand::{OperandRef, OperandValue};
@@ -616,21 +615,14 @@ impl<'a, 'll, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'll, 'tcx> {
         }
     }
 
-    fn scalable_alloca(&mut self, elt: u64, align: Align, element_ty: Ty<'_>) -> Self::Value {
+    fn alloca_with_ty(&mut self, layout: TyAndLayout<'tcx>) -> Self::Value {
         let mut bx = Builder::with_cx(self.cx);
         bx.position_at_start(unsafe { llvm::LLVMGetFirstBasicBlock(self.llfn()) });
-        let llvm_ty = match element_ty.kind() {
-            ty::Bool => bx.type_i1(),
-            ty::Int(int_ty) => self.cx.type_int_from_ty(*int_ty),
-            ty::Uint(uint_ty) => self.cx.type_uint_from_ty(*uint_ty),
-            ty::Float(float_ty) => self.cx.type_float_from_ty(*float_ty),
-            _ => unreachable!("scalable vectors can only contain a bool, int, uint or float"),
-        };
+        let scalable_vector_ty = layout.llvm_type(self.cx);
 
         unsafe {
-            let ty = llvm::LLVMScalableVectorType(llvm_ty, elt.try_into().unwrap());
-            let alloca = llvm::LLVMBuildAlloca(&bx.llbuilder, ty, UNNAMED);
-            llvm::LLVMSetAlignment(alloca, align.bytes() as c_uint);
+            let alloca = llvm::LLVMBuildAlloca(&bx.llbuilder, scalable_vector_ty, UNNAMED);
+            llvm::LLVMSetAlignment(alloca, layout.align.abi.bytes() as c_uint);
             alloca
         }
     }

compiler/rustc_codegen_llvm/src/common.rs

@@ -159,6 +159,10 @@ impl<'ll, 'tcx> ConstCodegenMethods for CodegenCx<'ll, 'tcx> {
         self.const_int(self.type_i32(), i as i64)
     }
 
+    fn const_i64(&self, i: i64) -> &'ll Value {
+        self.const_int(self.type_i64(), i as i64)
+    }
+
     fn const_int(&self, t: &'ll Type, i: i64) -> &'ll Value {
         debug_assert!(
             self.type_kind(t) == TypeKind::Integer,

compiler/rustc_codegen_llvm/src/debuginfo/dwarf_const.rs

@@ -35,6 +35,14 @@ declare_constant!(DW_OP_plus_uconst: u64);
 /// Double-checked by a static assertion in `RustWrapper.cpp`.
 #[allow(non_upper_case_globals)]
 pub(crate) const DW_OP_LLVM_fragment: u64 = 0x1000;
+#[allow(non_upper_case_globals)]
+pub(crate) const DW_OP_constu: u64 = 0x10;
+#[allow(non_upper_case_globals)]
+pub(crate) const DW_OP_minus: u64 = 0x1c;
+#[allow(non_upper_case_globals)]
+pub(crate) const DW_OP_mul: u64 = 0x1e;
+#[allow(non_upper_case_globals)]
+pub(crate) const DW_OP_bregx: u64 = 0x92;
 // It describes the actual value of a source variable which might not exist in registers or in memory.
 #[allow(non_upper_case_globals)]
 pub(crate) const DW_OP_stack_value: u64 = 0x9f;