Rollup of 6 pull requests

compiler/rustc_abi/src/extern_abi.rs

@@ -261,6 +261,7 @@ impl StableOrd for ExternAbi {
 rustc_error_messages::into_diag_arg_using_display!(ExternAbi);
 
 #[cfg(feature = "nightly")]
+#[derive(Debug)]
 pub enum CVariadicStatus {
     NotSupported,
     Stable,

compiler/rustc_ast_lowering/src/asm.rs

@@ -5,7 +5,7 @@ use rustc_data_structures::fx::{FxHashMap, FxHashSet, FxIndexMap};
 use rustc_errors::msg;
 use rustc_hir as hir;
 use rustc_hir::def::{DefKind, Res};
-use rustc_session::parse::feature_err;
+use rustc_session::errors::feature_err;
 use rustc_span::{Span, sym};
 use rustc_target::asm;
 

compiler/rustc_ast_lowering/src/expr.rs

@@ -1693,7 +1693,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
             && !self.tcx.features().coroutines()
             && !self.tcx.features().gen_blocks()
         {
-            rustc_session::parse::feature_err(
+            rustc_session::errors::feature_err(
                 &self.tcx.sess,
                 sym::yield_expr,
                 span,

compiler/rustc_ast_lowering/src/lib.rs

@@ -62,7 +62,7 @@ use rustc_macros::extension;
 use rustc_middle::hir::{self as mid_hir};
 use rustc_middle::span_bug;
 use rustc_middle::ty::{DelegationInfo, ResolverAstLowering, TyCtxt};
-use rustc_session::parse::add_feature_diagnostics;
+use rustc_session::errors::add_feature_diagnostics;
 use rustc_span::symbol::{Ident, Symbol, kw, sym};
 use rustc_span::{DUMMY_SP, DesugaringKind, Span};
 use smallvec::SmallVec;

compiler/rustc_ast_lowering/src/path.rs

@@ -6,7 +6,7 @@ use rustc_hir::def::{DefKind, PartialRes, PerNS, Res};
 use rustc_hir::def_id::DefId;
 use rustc_hir::{self as hir, GenericArg};
 use rustc_middle::{span_bug, ty};
-use rustc_session::parse::add_feature_diagnostics;
+use rustc_session::errors::add_feature_diagnostics;
 use rustc_span::{BytePos, DUMMY_SP, DesugaringKind, Ident, Span, Symbol, sym};
 use smallvec::smallvec;
 use tracing::{debug, instrument};

compiler/rustc_ast_lowering/src/stability.rs

@@ -3,7 +3,7 @@ use std::fmt;
 use rustc_abi::ExternAbi;
 use rustc_feature::Features;
 use rustc_session::Session;
-use rustc_session::parse::feature_err;
+use rustc_session::errors::feature_err;
 use rustc_span::symbol::sym;
 use rustc_span::{Span, Symbol};
 

compiler/rustc_ast_passes/src/ast_validation.rs

@@ -30,11 +30,11 @@ use rustc_data_structures::fx::FxIndexMap;
 use rustc_errors::{DiagCtxtHandle, Diagnostic, LintBuffer};
 use rustc_feature::Features;
 use rustc_session::Session;
+use rustc_session::errors::feature_err;
 use rustc_session::lint::builtin::{
     DEPRECATED_WHERE_CLAUSE_LOCATION, MISSING_ABI, MISSING_UNSAFE_ON_EXTERN,
     PATTERNS_IN_FNS_WITHOUT_BODY, UNUSED_VISIBILITIES,
 };
-use rustc_session::parse::feature_err;
 use rustc_span::{Ident, Span, kw, sym};
 use rustc_target::spec::{AbiMap, AbiMapping};
 use thin_vec::thin_vec;
@@ -762,12 +762,23 @@ impl<'a> AstValidator<'a> {
         match fn_ctxt {
             FnCtxt::Foreign => return,
             FnCtxt::Free | FnCtxt::Assoc(_) => {
-                if !self.sess.target.supports_c_variadic_definitions() {
-                    self.dcx().emit_err(errors::CVariadicNotSupported {
-                        variadic_span: variadic_param.span,
-                        target: &*self.sess.target.llvm_target,
-                    });
-                    return;
+                match self.sess.target.supports_c_variadic_definitions() {
+                    CVariadicStatus::NotSupported => {
+                        self.dcx().emit_err(errors::CVariadicNotSupported {
+                            variadic_span: variadic_param.span,
+                            target: &*self.sess.target.llvm_target,
+                        });
+                        return;
+                    }
+                    CVariadicStatus::Unstable { feature } if !self.features.enabled(feature) => {
+                        let msg =
+                            format!("C-variadic function definitions on this target are unstable");
+                        feature_err(&self.sess, feature, variadic_param.span, msg).emit();
+                        return;
+                    }
+                    CVariadicStatus::Unstable { .. } | CVariadicStatus::Stable => {
+                        /* fall through */
+                    }
                 }
 
                 match sig.header.ext {

compiler/rustc_ast_passes/src/feature_gate.rs

@@ -6,7 +6,7 @@ use rustc_feature::{AttributeGate, BUILTIN_ATTRIBUTE_MAP, BuiltinAttribute, Feat
 use rustc_hir::Attribute;
 use rustc_hir::attrs::AttributeKind;
 use rustc_session::Session;
-use rustc_session::parse::{feature_err, feature_warn};
+use rustc_session::errors::{feature_err, feature_warn};
 use rustc_span::{Span, Spanned, Symbol, sym};
 use thin_vec::ThinVec;
 
@@ -510,6 +510,7 @@ pub fn check_crate(krate: &ast::Crate, sess: &Session, features: &Features) {
     gate_all!(try_blocks_heterogeneous, "`try bikeshed` expression is experimental");
     gate_all!(unsafe_binders, "unsafe binder types are experimental");
     gate_all!(unsafe_fields, "`unsafe` fields are experimental");
+    gate_all!(view_types, "view types are experimental");
     gate_all!(where_clause_attrs, "attributes in `where` clause are unstable");
     gate_all!(yeet_expr, "`do yeet` expression is experimental");
     // tidy-alphabetical-end

compiler/rustc_attr_parsing/src/attributes/cfg.rs

@@ -13,8 +13,9 @@ use rustc_parse::parser::{ForceCollect, Parser, Recovery};
 use rustc_parse::{exp, parse_in};
 use rustc_session::Session;
 use rustc_session::config::ExpectedValues;
+use rustc_session::errors::feature_err;
 use rustc_session::lint::builtin::UNEXPECTED_CFGS;
-use rustc_session::parse::{ParseSess, feature_err};
+use rustc_session::parse::ParseSess;
 use rustc_span::{ErrorGuaranteed, Span, Symbol, sym};
 use thin_vec::ThinVec;
 

compiler/rustc_attr_parsing/src/attributes/codegen_attrs.rs

@@ -1,5 +1,5 @@
 use rustc_hir::attrs::{CoverageAttrKind, OptimizeAttr, RtsanSetting, SanitizerSet, UsedBy};
-use rustc_session::parse::feature_err;
+use rustc_session::errors::feature_err;
 use rustc_span::edition::Edition::Edition2024;
 
 use super::prelude::*;

compiler/rustc_attr_parsing/src/attributes/doc.rs

@@ -5,7 +5,7 @@ use rustc_hir::Target;
 use rustc_hir::attrs::{
     AttributeKind, CfgEntry, CfgHideShow, CfgInfo, DocAttribute, DocInline, HideOrShow,
 };
-use rustc_session::parse::feature_err;
+use rustc_session::errors::feature_err;
 use rustc_span::{Span, Symbol, edition, sym};
 use thin_vec::ThinVec;
 

compiler/rustc_attr_parsing/src/attributes/link_attrs.rs

@@ -3,8 +3,8 @@ use rustc_feature::Features;
 use rustc_hir::attrs::AttributeKind::{LinkName, LinkOrdinal, LinkSection};
 use rustc_hir::attrs::*;
 use rustc_session::Session;
+use rustc_session::errors::feature_err;
 use rustc_session::lint::builtin::ILL_FORMED_ATTRIBUTE_INPUT;
-use rustc_session::parse::feature_err;
 use rustc_span::edition::Edition::Edition2024;
 use rustc_span::kw;
 use rustc_target::spec::{Arch, BinaryFormat};

compiler/rustc_codegen_llvm/src/va_arg.rs

@@ -1,4 +1,4 @@
-use rustc_abi::{Align, BackendRepr, Endian, HasDataLayout, Primitive, Size};
+use rustc_abi::{Align, BackendRepr, CVariadicStatus, Endian, HasDataLayout, Primitive, Size};
 use rustc_codegen_ssa::MemFlags;
 use rustc_codegen_ssa::common::IntPredicate;
 use rustc_codegen_ssa::mir::operand::OperandRef;
@@ -1038,6 +1038,8 @@ pub(super) fn emit_va_arg<'ll, 'tcx>(
     assert!(!bx.layout_of(target_ty).is_zst());
 
     let target = &bx.cx.tcx.sess.target;
+    let stability = target.supports_c_variadic_definitions();
+
     match target.arch {
         Arch::X86 => emit_ptr_va_arg(
             bx,
@@ -1094,6 +1096,7 @@ pub(super) fn emit_va_arg<'ll, 'tcx>(
             ForceRightAdjust::Yes,
         ),
         Arch::RiscV32 if target.llvm_abiname == LlvmAbi::Ilp32e => {
+            std::assert_matches!(stability, CVariadicStatus::Unstable { .. });
             // FIXME: clang manually adjusts the alignment for this ABI. It notes:
             //
             // > To be compatible with GCC's behaviors, we force arguments with
@@ -1215,10 +1218,15 @@ pub(super) fn emit_va_arg<'ll, 'tcx>(
         Arch::SpirV => bug!("spirv does not support c-variadic functions"),
 
         Arch::Sparc | Arch::Avr | Arch::M68k | Arch::Msp430 => {
+            std::assert_matches!(stability, CVariadicStatus::Unstable { .. });
+
             // Clang uses the LLVM implementation for these architectures.
             bx.va_arg(addr.immediate(), bx.cx.layout_of(target_ty).llvm_type(bx.cx))
         }
+
         Arch::Other(ref arch) => {
+            std::assert_matches!(stability, CVariadicStatus::Unstable { .. });
+
             // Just to be safe we error out explicitly here, instead of crossing our fingers that
             // the default LLVM implementation has the correct behavior for this target.
             bug!("c-variadic functions are not currently implemented for custom target {arch}")

compiler/rustc_codegen_ssa/src/codegen_attrs.rs

@@ -12,8 +12,8 @@ use rustc_middle::middle::codegen_fn_attrs::{
 use rustc_middle::mono::Visibility;
 use rustc_middle::query::Providers;
 use rustc_middle::ty::{self as ty, TyCtxt};
+use rustc_session::errors::feature_err;
 use rustc_session::lint;
-use rustc_session::parse::feature_err;
 use rustc_span::{Span, sym};
 use rustc_target::spec::Os;
 

compiler/rustc_codegen_ssa/src/target_features.rs

@@ -7,8 +7,8 @@ use rustc_middle::middle::codegen_fn_attrs::{TargetFeature, TargetFeatureKind};
 use rustc_middle::query::Providers;
 use rustc_middle::ty::TyCtxt;
 use rustc_session::Session;
+use rustc_session::errors::feature_err;
 use rustc_session::lint::builtin::AARCH64_SOFTFLOAT_NEON;
-use rustc_session::parse::feature_err;
 use rustc_span::{Span, Symbol, edit_distance, sym};
 use rustc_target::spec::{Arch, SanitizerSet};
 use rustc_target::target_features::{RUSTC_SPECIFIC_FEATURES, Stability};

compiler/rustc_const_eval/src/check_consts/ops.rs

@@ -14,7 +14,7 @@ use rustc_middle::ty::{
     self, AssocContainer, Closure, FnDef, FnPtr, GenericArgKind, GenericArgsRef, Param, TraitRef,
     Ty, suggest_constraining_type_param,
 };
-use rustc_session::parse::add_feature_diagnostics;
+use rustc_session::errors::add_feature_diagnostics;
 use rustc_span::{BytePos, Pos, Span, Symbol, sym};
 use rustc_trait_selection::error_reporting::traits::call_kind::{
     CallDesugaringKind, CallKind, call_kind,

compiler/rustc_const_eval/src/interpret/operand.rs

@@ -216,14 +216,11 @@ impl<Prov: Provenance> std::fmt::Display for ImmTy<'_, Prov> {
         ty::tls::with(|tcx| {
             match self.imm {
                 Immediate::Scalar(s) => {
-                    if let Some(ty) = tcx.lift(self.layout.ty) {
-                        let s = FmtPrinter::print_string(tcx, Namespace::ValueNS, |p| {
-                            print_scalar(p, s, ty)
-                        })?;
-                        f.write_str(&s)?;
-                        return Ok(());
-                    }
-                    write!(f, "{:x}: {}", s, self.layout.ty)
+                    let ty = tcx.lift(self.layout.ty);
+                    let s = FmtPrinter::print_string(tcx, Namespace::ValueNS, |p| {
+                        print_scalar(p, s, ty)
+                    })?;
+                    f.write_str(&s)
                 }
                 Immediate::ScalarPair(a, b) => {
                     // FIXME(oli-obk): at least print tuples and slices nicely

compiler/rustc_expand/src/config.rs

@@ -27,7 +27,7 @@ use rustc_hir::{
 };
 use rustc_parse::parser::Recovery;
 use rustc_session::Session;
-use rustc_session::parse::feature_err;
+use rustc_session::errors::feature_err;
 use rustc_span::{STDLIB_STABLE_CRATES, Span, Symbol, sym};
 use tracing::instrument;
 

compiler/rustc_expand/src/expand.rs

@@ -30,8 +30,8 @@ use rustc_parse::parser::{
     RecoverColon, RecoverComma, Recovery, token_descr,
 };
 use rustc_session::Session;
+use rustc_session::errors::feature_err;
 use rustc_session::lint::builtin::{UNUSED_ATTRIBUTES, UNUSED_DOC_COMMENTS};
-use rustc_session::parse::feature_err;
 use rustc_span::hygiene::SyntaxContext;
 use rustc_span::{ErrorGuaranteed, FileName, Ident, LocalExpnId, Span, Symbol, sym};
 use smallvec::SmallVec;

compiler/rustc_expand/src/mbe/macro_rules.rs

@@ -23,7 +23,8 @@ use rustc_lint_defs::builtin::{
 use rustc_parse::exp;
 use rustc_parse::parser::{Parser, Recovery};
 use rustc_session::Session;
-use rustc_session::parse::{ParseSess, feature_err};
+use rustc_session::errors::feature_err;
+use rustc_session::parse::ParseSess;
 use rustc_span::edition::Edition;
 use rustc_span::hygiene::Transparency;
 use rustc_span::{Ident, Span, Symbol, kw, sym};

compiler/rustc_expand/src/mbe/quoted.rs

@@ -5,7 +5,7 @@ use rustc_ast_pretty::pprust;
 use rustc_errors::Applicability;
 use rustc_feature::Features;
 use rustc_session::Session;
-use rustc_session::parse::feature_err;
+use rustc_session::errors::feature_err;
 use rustc_span::edition::Edition;
 use rustc_span::{Ident, Span, kw, sym};
 

compiler/rustc_feature/src/unstable.rs

@@ -420,6 +420,9 @@ declare_features! (
     (unstable, bpf_target_feature, "1.54.0", Some(150247)),
     /// Allows using C-variadics.
     (unstable, c_variadic, "1.34.0", Some(44930)),
+    /// Allows defining c-variadic functions on targets where this feature has not yet
+    /// undergone sufficient testing for stabilization.
+    (unstable, c_variadic_experimental_arch, "CURRENT_RUSTC_VERSION", Some(155973)),
     /// Allows defining c-variadic naked functions with any extern ABI that is allowed
     /// on c-variadic foreign functions.
     (unstable, c_variadic_naked_functions, "1.93.0", Some(148767)),
@@ -750,6 +753,8 @@ declare_features! (
     (internal, unsized_fn_params, "1.49.0", Some(48055)),
     /// Allows using the `#[used(linker)]` (or `#[used(compiler)]`) attribute.
     (unstable, used_with_arg, "1.60.0", Some(93798)),
+    /// Allows view types.
+    (unstable, view_types, "CURRENT_RUSTC_VERSION", Some(155938)),
     /// Target features on wasm.
     (unstable, wasm_target_feature, "1.30.0", Some(150260)),
     /// Allows use of attributes in `where` clauses.

compiler/rustc_hir_analysis/src/check/mod.rs

@@ -92,7 +92,7 @@ use rustc_middle::ty::{
     Unnormalized,
 };
 use rustc_middle::{bug, span_bug};
-use rustc_session::parse::feature_err;
+use rustc_session::errors::feature_err;
 use rustc_span::def_id::CRATE_DEF_ID;
 use rustc_span::{BytePos, DUMMY_SP, Ident, Span, Symbol, kw, sym};
 use rustc_trait_selection::error_reporting::InferCtxtErrorExt;
@@ -312,7 +312,7 @@ fn default_body_is_unstable(
     });
 
     let inject_span = item_did.is_local().then(|| tcx.crate_level_attribute_injection_span());
-    rustc_session::parse::add_feature_diagnostics_for_issue(
+    rustc_session::errors::add_feature_diagnostics_for_issue(
         &mut err,
         &tcx.sess,
         feature,

compiler/rustc_hir_analysis/src/check/wfcheck.rs

@@ -27,7 +27,7 @@ use rustc_middle::ty::{
     Unnormalized, Upcast,
 };
 use rustc_middle::{bug, span_bug};
-use rustc_session::parse::feature_err;
+use rustc_session::errors::feature_err;
 use rustc_span::{DUMMY_SP, Span, sym};
 use rustc_trait_selection::error_reporting::InferCtxtErrorExt;
 use rustc_trait_selection::regions::{InferCtxtRegionExt, OutlivesEnvironmentBuildExt};

compiler/rustc_hir_analysis/src/coherence/mod.rs

@@ -11,7 +11,7 @@ use rustc_hir::LangItem;
 use rustc_hir::def_id::{DefId, LocalDefId};
 use rustc_middle::query::Providers;
 use rustc_middle::ty::{self, TyCtxt, TypeVisitableExt, elaborate};
-use rustc_session::parse::feature_err;
+use rustc_session::errors::feature_err;
 use rustc_span::{ErrorGuaranteed, sym};
 use tracing::debug;
 

compiler/rustc_hir_analysis/src/collect/resolve_bound_vars.rs

@@ -1272,7 +1272,7 @@ impl<'a, 'tcx> BoundVarContext<'a, 'tcx> {
                         && !self.tcx.asyncness(lifetime_ref.hir_id.owner.def_id).is_async()
                         && !self.tcx.features().anonymous_lifetime_in_impl_trait()
                     {
-                        let mut diag: rustc_errors::Diag<'_> = rustc_session::parse::feature_err(
+                        let mut diag: rustc_errors::Diag<'_> = rustc_session::errors::feature_err(
                             &self.tcx.sess,
                             sym::anonymous_lifetime_in_impl_trait,
                             lifetime_ref.ident.span,

compiler/rustc_hir_analysis/src/collect/type_of.rs

@@ -505,7 +505,7 @@ fn infer_placeholder_type<'tcx>(
 
 fn check_feature_inherent_assoc_ty(tcx: TyCtxt<'_>, span: Span) {
     if !tcx.features().inherent_associated_types() {
-        use rustc_session::parse::feature_err;
+        use rustc_session::errors::feature_err;
         use rustc_span::sym;
         feature_err(
             &tcx.sess,

compiler/rustc_hir_analysis/src/hir_ty_lowering/errors.rs

@@ -16,7 +16,7 @@ use rustc_middle::ty::{
     self, AdtDef, GenericParamDefKind, Ty, TyCtxt, TypeVisitableExt,
     suggest_constraining_type_param,
 };
-use rustc_session::parse::feature_err;
+use rustc_session::errors::feature_err;
 use rustc_span::edit_distance::find_best_match_for_name;
 use rustc_span::{BytePos, DUMMY_SP, Ident, Span, Symbol, kw, sym};
 use rustc_trait_selection::error_reporting::traits::report_dyn_incompatibility;

compiler/rustc_hir_analysis/src/hir_ty_lowering/mod.rs

@@ -43,8 +43,8 @@ use rustc_middle::ty::{
     const_lit_matches_ty, fold_regions,
 };
 use rustc_middle::{bug, span_bug};
+use rustc_session::errors::feature_err;
 use rustc_session::lint::builtin::AMBIGUOUS_ASSOCIATED_ITEMS;
-use rustc_session::parse::feature_err;
 use rustc_span::{DUMMY_SP, Ident, Span, kw, sym};
 use rustc_trait_selection::infer::InferCtxtExt;
 use rustc_trait_selection::traits::wf::object_region_bounds;

compiler/rustc_hir_analysis/src/lib.rs

@@ -89,7 +89,7 @@ use rustc_middle::mir::interpret::GlobalId;
 use rustc_middle::query::Providers;
 use rustc_middle::ty::{Const, Ty, TyCtxt};
 use rustc_middle::{middle, ty};
-use rustc_session::parse::feature_err;
+use rustc_session::errors::feature_err;
 use rustc_span::{ErrorGuaranteed, Span};
 use rustc_trait_selection::traits;
 

compiler/rustc_hir_typeck/src/expr.rs

@@ -30,8 +30,7 @@ use rustc_middle::ty::adjustment::{Adjust, Adjustment, AllowTwoPhase};
 use rustc_middle::ty::error::{ExpectedFound, TypeError};
 use rustc_middle::ty::{self, AdtKind, GenericArgsRef, Ty, TypeVisitableExt, Unnormalized};
 use rustc_middle::{bug, span_bug};
-use rustc_session::errors::ExprParenthesesNeeded;
-use rustc_session::parse::feature_err;
+use rustc_session::errors::{ExprParenthesesNeeded, feature_err};
 use rustc_span::edit_distance::find_best_match_for_name;
 use rustc_span::hygiene::DesugaringKind;
 use rustc_span::{Ident, Span, Spanned, Symbol, kw, sym};
@@ -3767,7 +3766,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                         self.tcx.adjust_ident_and_get_scope(field, container_def.did(), block);
 
                     if !self.tcx.features().offset_of_enum() {
-                        rustc_session::parse::feature_err(
+                        rustc_session::errors::feature_err(
                             &self.tcx.sess,
                             sym::offset_of_enum,
                             ident.span,