Update to nightly-2026-05-01

crates/rustc_plugin/examples/print-all-items/rust-toolchain.toml

@@ -1,3 +1,3 @@
 [toolchain]
-channel = "nightly-2025-08-20"
+channel = "nightly-2026-05-01"
 components = ["rust-src", "rustc-dev", "llvm-tools-preview"]

crates/rustc_plugin/examples/print-all-items/src/bin/cargo-print-all-items.rs

@@ -1,6 +1,6 @@
 #![feature(rustc_private)]
 
-fn main() {
+fn main() -> std::process::ExitCode {
   env_logger::init();
-  rustc_plugin::cli_main(print_all_items::PrintAllItemsPlugin);
+  rustc_plugin::cli_main(print_all_items::PrintAllItemsPlugin)
 }

crates/rustc_plugin/examples/print-all-items/src/bin/print-all-items-driver.rs

@@ -1,6 +1,6 @@
 #![feature(rustc_private)]
 
-fn main() {
+fn main() -> std::process::ExitCode {
   env_logger::init();
-  rustc_plugin::driver_main(print_all_items::PrintAllItemsPlugin);
+  rustc_plugin::driver_main(print_all_items::PrintAllItemsPlugin)
 }

crates/rustc_plugin/src/cli.rs

@@ -1,7 +1,7 @@
 use std::{
   env, fs,
   path::PathBuf,
-  process::{Command, Stdio, exit},
+  process::{Command, ExitCode, Stdio},
 };
 
 use cargo_metadata::camino::Utf8Path;
@@ -15,10 +15,10 @@ pub const SPECIFIC_TARGET: &str = "SPECIFIC_TARGET";
 pub const CARGO_VERBOSE: &str = "CARGO_VERBOSE";
 
 /// The top-level function that should be called in your user-facing binary.
-pub fn cli_main<T: RustcPlugin>(plugin: T) {
+pub fn cli_main<T: RustcPlugin>(plugin: T) -> ExitCode {
   if env::args().any(|arg| arg == "-V") {
     println!("{}", plugin.version());
-    return;
+    return ExitCode::SUCCESS;
   }
 
   let metadata = cargo_metadata::MetadataCommand::new()
@@ -95,7 +95,10 @@ pub fn cli_main<T: RustcPlugin>(plugin: T) {
 
   let exit_status = cmd.status().expect("failed to wait for cargo?");
 
-  exit(exit_status.code().unwrap_or(-1));
+  match exit_status.code() {
+    Some(code) => ExitCode::from(u8::try_from(code).unwrap()),
+    None => ExitCode::FAILURE,
+  }
 }
 
 fn only_run_on_file(

crates/rustc_plugin/src/driver.rs

@@ -2,7 +2,7 @@ use std::{
   env,
   ops::Deref,
   path::{Path, PathBuf},
-  process::{Command, exit},
+  process::{Command, ExitCode, exit},
 };
 
 use rustc_session::{EarlyDiagCtxt, config::ErrorOutputType};
@@ -99,11 +99,11 @@ struct DefaultCallbacks;
 impl rustc_driver::Callbacks for DefaultCallbacks {}
 
 /// The top-level function that should be called by your internal driver binary.
-pub fn driver_main<T: RustcPlugin>(plugin: T) {
+pub fn driver_main<T: RustcPlugin>(plugin: T) -> ExitCode {
   let early_dcx = EarlyDiagCtxt::new(ErrorOutputType::default());
   rustc_driver::init_rustc_env_logger(&early_dcx);
 
-  exit(rustc_driver::catch_with_exit_code(move || {
+  rustc_driver::catch_with_exit_code(move || {
     let mut orig_args: Vec<String> = env::args().collect();
 
     let (have_sys_root_arg, sys_root) = get_sysroot(&orig_args);
@@ -157,7 +157,7 @@ is_target_crate={is_target_crate}"
       );
       rustc_driver::run_compiler(&args, &mut DefaultCallbacks);
     }
-  }))
+  })
 }
 
 fn is_target_crate(args: &[String]) -> bool {

crates/rustc_utils/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "rustc_utils"
-version = "0.14.3-nightly-2025-08-20"
+version = "0.15.0-nightly-2026-05-01"
 edition = "2024"
 authors = ["Will Crichton <crichton.will@gmail.com>"]
 description = "Utilities for working with the Rust compiler"

crates/rustc_utils/src/hir/ty.rs

@@ -41,7 +41,7 @@ impl<'tcx> TyExt<'tcx> for Ty<'tcx> {
     use rustc_infer::traits::EvaluationResult;
 
     let infcx = tcx.infer_ctxt().build(TypingMode::non_body_analysis());
-    let ty = tcx.erase_regions(self);
+    let ty = tcx.erase_and_anonymize_regions(self);
     let result = infcx.type_implements_trait(trait_def_id, [ty], param_env);
     matches!(
       result,
@@ -50,7 +50,7 @@ impl<'tcx> TyExt<'tcx> for Ty<'tcx> {
   }
 
   fn is_copyable(self, tcx: TyCtxt<'tcx>, typing_env: TypingEnv<'tcx>) -> bool {
-    let ty = tcx.erase_regions(self);
+    let ty = tcx.erase_and_anonymize_regions(self);
     tcx.type_is_copy_modulo_regions(typing_env, ty)
   }
 }

crates/rustc_utils/src/lib.rs

@@ -12,13 +12,8 @@
 
 #![feature(
   rustc_private,
-  negative_impls,        // for !Send
   min_specialization,    // for rustc_index::newtype_index 
-  type_alias_impl_trait, // for iterators in traits
   box_patterns,          // for ergonomics
-  exact_size_is_empty,   // for graphviz module
-  impl_trait_in_assoc_type,
-  doc_auto_cfg,          // for feature gates in documentation
 )]
 #![warn(clippy::pedantic)]
 #![allow(

crates/rustc_utils/src/mir/body.rs

@@ -7,13 +7,12 @@ use std::{
 };
 
 use anyhow::{Result, ensure};
-use pretty::PrettyPrintMirOptions;
 use rustc_data_structures::fx::FxHashMap as HashMap;
 use rustc_hir::{CoroutineDesugaring, CoroutineKind, HirId, def_id::DefId};
 use rustc_middle::{
   mir::{
     BasicBlock, Body, Local, Location, Place, SourceInfo, TerminatorKind,
-    VarDebugInfoContents, pretty, pretty::write_mir_fn,
+    VarDebugInfoContents, pretty::MirWriter,
   },
   ty::{Region, Ty, TyCtxt},
 };
@@ -118,15 +117,7 @@ impl<'tcx> BodyExt<'tcx> for Body<'tcx> {
 
   fn to_string(&self, tcx: TyCtxt<'tcx>) -> Result<String> {
     let mut buffer = Vec::new();
-    write_mir_fn(
-      tcx,
-      self,
-      &mut |_, _| Ok(()),
-      &mut buffer,
-      PrettyPrintMirOptions {
-        include_extra_comments: false,
-      },
-    )?;
+    MirWriter::new(tcx).write_mir_fn(self, &mut buffer)?;
     Ok(String::from_utf8(buffer)?)
   }
 

crates/rustc_utils/src/mir/borrowck_facts.rs

@@ -6,11 +6,10 @@ use rustc_borrowck::consumers::{BodyWithBorrowckFacts, ConsumerOptions};
 use rustc_data_structures::fx::FxHashSet as HashSet;
 use rustc_hir::def_id::LocalDefId;
 use rustc_middle::{
-  mir::{Body, ConcreteOpaqueTypes, StatementKind, TerminatorKind},
+  mir::{Body, StatementKind, TerminatorKind},
   ty::TyCtxt,
   util::Providers,
 };
-use rustc_span::ErrorGuaranteed;
 
 use crate::{BodyExt, block_timer, cache::Cache};
 
@@ -61,7 +60,7 @@ pub fn enable_mir_simplification() {
 /// For why we need to do override mir_borrowck, see:
 /// <https://github.com/rust-lang/rust/blob/485ced56b8753ec86936903f2a8c95e9be8996a1/src/test/run-make-fulldeps/obtain-borrowck/driver.rs>
 pub fn override_queries(_session: &rustc_session::Session, local: &mut Providers) {
-  local.mir_borrowck = mir_borrowck;
+  local.queries.mir_borrowck = mir_borrowck;
 }
 
 thread_local! {
@@ -71,7 +70,7 @@ thread_local! {
 fn mir_borrowck(
   tcx: TyCtxt<'_>,
   def_id: LocalDefId,
-) -> Result<&ConcreteOpaqueTypes<'_>, ErrorGuaranteed> {
+) -> rustc_middle::queries::mir_borrowck::ProvidedValue<'_> {
   block_timer!(&format!(
     "get_bodies_with_borrowck_facts for {}",
     tcx.def_path_debug_str(def_id.to_def_id())
@@ -96,8 +95,8 @@ fn mir_borrowck(
     });
   }
   let mut providers = Providers::default();
-  rustc_borrowck::provide(&mut providers);
-  let original_mir_borrowck = providers.mir_borrowck;
+  rustc_borrowck::provide(&mut providers.queries);
+  let original_mir_borrowck = providers.queries.mir_borrowck;
   original_mir_borrowck(tcx, def_id)
 }
 

crates/rustc_utils/src/mir/operand.rs

@@ -12,7 +12,7 @@ impl<'tcx> OperandExt<'tcx> for Operand<'tcx> {
   fn as_place(&self) -> Option<Place<'tcx>> {
     match self {
       Operand::Copy(place) | Operand::Move(place) => Some(*place),
-      Operand::Constant(_) => None,
+      Operand::Constant(_) | Operand::RuntimeChecks(_) => None,
     }
   }
 }

crates/rustc_utils/src/mir/place.rs

@@ -6,18 +6,15 @@ use log::{trace, warn};
 use rustc_abi::{FieldIdx, VariantIdx};
 use rustc_data_structures::fx::{FxHashMap as HashMap, FxHashSet as HashSet};
 use rustc_hir::def_id::DefId;
-use rustc_infer::infer::TyCtxtInferExt;
 use rustc_middle::{
   mir::{
     Body, HasLocalDecls, Local, Location, Mutability, Place, PlaceElem, PlaceRef,
     ProjectionElem, RETURN_PLACE, VarDebugInfo, VarDebugInfoContents,
     visit::{PlaceContext, Visitor},
   },
-  traits::ObligationCause,
   ty::{self, AdtKind, Region, RegionKind, RegionVid, Ty, TyCtxt, TyKind, TypeVisitor},
 };
-use rustc_trait_selection::traits::NormalizeExt;
-use rustc_type_ir::TypingMode;
+use rustc_type_ir::Unnormalized;
 
 use crate::{AdtDefExt, SpanExt};
 
@@ -285,7 +282,7 @@ impl<'tcx> PlaceExt<'tcx> for Place<'tcx> {
         }
         ProjectionElem::Downcast(sym, _) => {
           let variant = sym.map(|s| s.to_string()).unwrap_or_else(|| "??".into());
-          (ElemPosition::Suffix, format!("@{variant}",).into())
+          (ElemPosition::Suffix, format!("@{variant}").into())
         }
 
         ProjectionElem::Index(_) => (ElemPosition::Suffix, "[_]".into()),
@@ -319,16 +316,10 @@ impl<'tcx> PlaceExt<'tcx> for Place<'tcx> {
   }
 
   fn normalize(&self, tcx: TyCtxt<'tcx>, def_id: DefId) -> Place<'tcx> {
-    let param_env = tcx.param_env(def_id);
-    let place = tcx.erase_regions(*self);
-    let infcx = tcx.infer_ctxt().build(TypingMode::post_borrowck_analysis(
-      tcx,
-      def_id.expect_local(),
-    ));
-    let place = infcx
-      .at(&ObligationCause::dummy(), param_env)
-      .normalize(place)
-      .value;
+    let place = tcx.normalize_erasing_regions(
+      tcx.typing_env_normalized_for_post_analysis(def_id),
+      Unnormalized::new_wip(*self),
+    );
 
     let projection = place
       .projection

crates/rustc_utils/src/source_map/filename.rs

@@ -1,11 +1,37 @@
-use std::path::PathBuf;
+use std::{fmt, path::PathBuf};
+
+use rustc_index::Idx;
 
 #[derive(Debug, Clone, Hash, PartialEq, Eq)]
 pub struct Filename(pub PathBuf);
 
-rustc_index::newtype_index! {
-  #[cfg_attr(feature = "serde", derive(serde::Serialize))]
-  #[cfg_attr(feature = "ts-rs", derive(ts_rs::TS))]
-  #[debug_format = "f{}"]
-  pub struct FilenameIndex {}
+#[derive(Clone, Copy, PartialEq, Eq, Hash)]
+#[cfg_attr(feature = "serde", derive(serde::Serialize))]
+#[cfg_attr(feature = "ts-rs", derive(ts_rs::TS))]
+pub struct FilenameIndex(usize);
+
+impl fmt::Debug for FilenameIndex {
+  fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+    write!(f, "f{}", self.0)
+  }
 }
+
+impl Idx for FilenameIndex {
+  fn new(idx: usize) -> Self {
+    FilenameIndex(idx)
+  }
+
+  fn index(self) -> usize {
+    self.0
+  }
+}
+
+// NOTE(nightly-2026-05-01): the newtype_index has been commented out below
+// bc it uses some wacky `T is range` type that isn't implemented by serde or ts_rs.
+
+// rustc_index::newtype_index! {
+//   #[cfg_attr(feature = "serde", derive(serde::Serialize))]
+//   #[cfg_attr(feature = "ts-rs", derive(ts_rs::TS))]
+//   #[debug_format = "f{}"]
+//   pub struct FilenameIndex {}
+// }

crates/rustc_utils/src/source_map/range.rs

@@ -11,7 +11,9 @@ use rustc_hir::{
 };
 use rustc_index::IndexVec;
 use rustc_middle::ty::TyCtxt;
-use rustc_span::{FileName, RealFileName, SourceFile, Span, source_map::SourceMap};
+use rustc_span::{
+  FileName, RemapPathScopeComponents, SourceFile, Span, source_map::SourceMap,
+};
 #[cfg(feature = "serde")]
 use serde::Serialize;
 #[cfg(feature = "ts-rs")]
@@ -141,9 +143,10 @@ impl FilenameIndex {
             .find(|name| match &name {
               // rustc seems to store relative paths to files in the workspace, so if filename is absolute,
               // we can compare them using Path::ends_with
-              FileName::Real(RealFileName::LocalPath(other)) => {
+              FileName::Real(real_file_name) => {
+                let other = real_file_name.path(RemapPathScopeComponents::DOCUMENTATION).to_path_buf();
                 let canonical = other.canonicalize();
-                let other = canonical.as_ref().unwrap_or(other);
+                let other = canonical.as_ref().unwrap_or(&other);
                 filename.ends_with(other)
               }
               _ => false,
@@ -155,8 +158,8 @@ impl FilenameIndex {
                 files
                   .iter()
                   .filter_map(|file| match &file.name {
-                    FileName::Real(RealFileName::LocalPath(other)) =>
-                      Some(format!("{}", other.display())),
+                    FileName::Real(other) =>
+                      Some(other.path(RemapPathScopeComponents::DOCUMENTATION).display().to_string()),
                     _ => None,
                   })
                   .collect::<Vec<_>>()
@@ -269,8 +272,9 @@ impl ByteRange {
       log::trace!("Converting to range: {span:?}");
       let file = source_map.lookup_source_file(span.lo());
       let filename = match &file.name {
-        FileName::Real(RealFileName::LocalPath(filename)) => {
-          Filename(filename.clone()).intern_with_ctx(&mut ctx)
+        FileName::Real(real_file_name) => {
+          let filename = real_file_name.path(RemapPathScopeComponents::DOCUMENTATION);
+          Filename(filename.to_path_buf()).intern_with_ctx(&mut ctx)
         }
         filename => bail!("Range::from_span doesn't support {filename:?}"),
       };

crates/rustc_utils/src/source_map/spanner/mod.rs

@@ -9,7 +9,7 @@ use rustc_middle::{
   },
   ty::TyCtxt,
 };
-use rustc_span::{Span, SpanData, source_map::Spanned};
+use rustc_span::{Span, SpanData, Spanned};
 
 pub use self::hir_span::EnclosingHirSpans;
 use self::{

crates/rustc_utils/src/source_map/spanner/span_tree.rs

@@ -1,5 +1,5 @@
 use intervaltree::IntervalTree;
-use rustc_span::{BytePos, SpanData, source_map::Spanned};
+use rustc_span::{BytePos, SpanData, Spanned};
 
 /// Interval tree data structure specialized to spans.
 pub struct SpanTree<T> {

crates/rustc_utils/src/test_utils.rs

@@ -46,6 +46,10 @@ impl FileLoader for StringLoader {
   fn read_binary_file(&self, path: &Path) -> io::Result<Arc<[u8]>> {
     Ok(fs::read(path)?.into())
   }
+
+  fn current_directory(&self) -> io::Result<std::path::PathBuf> {
+    Ok(std::env::current_dir().unwrap())
+  }
 }
 
 static SYSROOT: LazyLock<String> = LazyLock::new(|| {

rust-toolchain.toml

@@ -1,3 +1,3 @@
 [toolchain]
-channel = "nightly-2025-08-20"
+channel = "nightly-2026-05-01"
 components = ["clippy", "rust-src", "rustc-dev", "llvm-tools-preview"]