Rollup of 10 pull requests

compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs

@@ -3376,10 +3376,15 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
 
         let (sugg_span, suggestion) = match tcx.sess.source_map().span_to_snippet(args_span) {
             Ok(string) => {
-                let coro_prefix = if string.starts_with("async") {
-                    // `async` is 5 chars long. Not using `.len()` to avoid the cast from `usize`
-                    // to `u32`.
-                    Some(5)
+                let coro_prefix = if let Some(sub) = string.strip_prefix("async") {
+                    let trimmed_sub = sub.trim_end();
+                    if trimmed_sub.ends_with("gen") {
+                        // `async` is 5 chars long.
+                        Some((trimmed_sub.len() + 5) as _)
+                    } else {
+                        // `async` is 5 chars long.
+                        Some(5)
+                    }
                 } else if string.starts_with("gen") {
                     // `gen` is 3 chars long
                     Some(3)

compiler/rustc_hir_analysis/src/hir_ty_lowering/errors.rs

@@ -204,8 +204,7 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
             .iter()
             .flat_map(|trait_def_id| tcx.associated_items(*trait_def_id).in_definition_order())
             .filter_map(|item| {
-                (!item.is_impl_trait_in_trait() && item.as_tag() == assoc_tag)
-                    .then_some(item.name())
+                (!item.is_impl_trait_in_trait() && item.as_tag() == assoc_tag).then(|| item.name())
             })
             .collect();
 

compiler/rustc_mir_dataflow/src/framework/graphviz.rs

@@ -122,7 +122,7 @@ impl RustcMirAttrs {
                 })
             } else if attr.has_name(sym::borrowck_graphviz_format) {
                 Self::set_field(&mut ret.formatter, tcx, &attr, |s| match s {
-                    sym::gen_kill | sym::two_phase => Ok(s),
+                    sym::two_phase => Ok(s),
                     _ => {
                         tcx.dcx().emit_err(UnknownFormatter { span: attr.span() });
                         Err(())

compiler/rustc_session/src/code_stats.rs

@@ -72,7 +72,7 @@ pub struct TypeSizeInfo {
 
 #[derive(Default)]
 pub struct CodeStats {
-    type_sizes: Lock<FxHashSet<TypeSizeInfo>>,
+    pub type_sizes: Lock<FxHashSet<TypeSizeInfo>>,
 }
 
 impl CodeStats {

compiler/rustc_session/src/config.rs

@@ -14,6 +14,7 @@ use std::str::{self, FromStr};
 use std::sync::LazyLock;
 use std::{cmp, fmt, fs, iter};
 
+use externs::{ExternOpt, split_extern_opt};
 use rustc_data_structures::fx::{FxHashSet, FxIndexMap};
 use rustc_data_structures::stable_hasher::{StableOrd, ToStableHashKey};
 use rustc_errors::emitter::HumanReadableErrorType;
@@ -39,6 +40,7 @@ use crate::utils::CanonicalizedPath;
 use crate::{EarlyDiagCtxt, HashStableContext, Session, filesearch, lint};
 
 mod cfg;
+mod externs;
 mod native_libs;
 pub mod sigpipe;
 
@@ -2205,44 +2207,13 @@ pub fn parse_externs(
     matches: &getopts::Matches,
     unstable_opts: &UnstableOptions,
 ) -> Externs {
-    fn is_ascii_ident(string: &str) -> bool {
-        let mut chars = string.chars();
-        if let Some(start) = chars.next()
-            && (start.is_ascii_alphabetic() || start == '_')
-        {
-            chars.all(|char| char.is_ascii_alphanumeric() || char == '_')
-        } else {
-            false
-        }
-    }
-
     let is_unstable_enabled = unstable_opts.unstable_options;
     let mut externs: BTreeMap<String, ExternEntry> = BTreeMap::new();
     for arg in matches.opt_strs("extern") {
-        let (name, path) = match arg.split_once('=') {
-            None => (arg, None),
-            Some((name, path)) => (name.to_string(), Some(Path::new(path))),
-        };
-        let (options, name) = match name.split_once(':') {
-            None => (None, name),
-            Some((opts, name)) => (Some(opts), name.to_string()),
-        };
-
-        if !is_ascii_ident(&name) {
-            let mut error = early_dcx.early_struct_fatal(format!(
-                "crate name `{name}` passed to `--extern` is not a valid ASCII identifier"
-            ));
-            let adjusted_name = name.replace('-', "_");
-            if is_ascii_ident(&adjusted_name) {
-                #[allow(rustc::diagnostic_outside_of_impl)] // FIXME
-                error.help(format!(
-                    "consider replacing the dashes with underscores: `{adjusted_name}`"
-                ));
-            }
-            error.emit();
-        }
+        let ExternOpt { crate_name: name, path, options } =
+            split_extern_opt(early_dcx, unstable_opts, &arg).unwrap_or_else(|e| e.emit());
 
-        let path = path.map(|p| CanonicalizedPath::new(p));
+        let path = path.map(|p| CanonicalizedPath::new(p.as_path()));
 
         let entry = externs.entry(name.to_owned());
 

compiler/rustc_session/src/config/externs.rs

@@ -0,0 +1,79 @@
+//! This module contains code to help parse and manipulate `--extern` arguments.
+
+use std::path::PathBuf;
+
+use rustc_errors::{Diag, FatalAbort};
+
+use super::UnstableOptions;
+use crate::EarlyDiagCtxt;
+
+#[cfg(test)]
+mod tests;
+
+/// Represents the pieces of an `--extern` argument.
+pub(crate) struct ExternOpt {
+    pub(crate) crate_name: String,
+    pub(crate) path: Option<PathBuf>,
+    pub(crate) options: Option<String>,
+}
+
+/// Breaks out the major components of an `--extern` argument.
+///
+/// The options field will be a string containing comma-separated options that will need further
+/// parsing and processing.
+pub(crate) fn split_extern_opt<'a>(
+    early_dcx: &'a EarlyDiagCtxt,
+    unstable_opts: &UnstableOptions,
+    extern_opt: &str,
+) -> Result<ExternOpt, Diag<'a, FatalAbort>> {
+    let (name, path) = match extern_opt.split_once('=') {
+        None => (extern_opt.to_string(), None),
+        Some((name, path)) => (name.to_string(), Some(PathBuf::from(path))),
+    };
+    let (options, crate_name) = match name.split_once(':') {
+        None => (None, name),
+        Some((opts, crate_name)) => {
+            if unstable_opts.namespaced_crates && crate_name.starts_with(':') {
+                // If the name starts with `:`, we know this was actually something like `foo::bar` and
+                // not a set of options. We can just use the original name as the crate name.
+                (None, name)
+            } else {
+                (Some(opts.to_string()), crate_name.to_string())
+            }
+        }
+    };
+
+    if !valid_crate_name(&crate_name, unstable_opts) {
+        let mut error = early_dcx.early_struct_fatal(format!(
+            "crate name `{crate_name}` passed to `--extern` is not a valid ASCII identifier"
+        ));
+        let adjusted_name = crate_name.replace('-', "_");
+        if is_ascii_ident(&adjusted_name) {
+            #[allow(rustc::diagnostic_outside_of_impl)] // FIXME
+            error
+                .help(format!("consider replacing the dashes with underscores: `{adjusted_name}`"));
+        }
+        return Err(error);
+    }
+
+    Ok(ExternOpt { crate_name, path, options })
+}
+
+fn valid_crate_name(name: &str, unstable_opts: &UnstableOptions) -> bool {
+    match name.split_once("::") {
+        Some((a, b)) if unstable_opts.namespaced_crates => is_ascii_ident(a) && is_ascii_ident(b),
+        Some(_) => false,
+        None => is_ascii_ident(name),
+    }
+}
+
+fn is_ascii_ident(string: &str) -> bool {
+    let mut chars = string.chars();
+    if let Some(start) = chars.next()
+        && (start.is_ascii_alphabetic() || start == '_')
+    {
+        chars.all(|char| char.is_ascii_alphanumeric() || char == '_')
+    } else {
+        false
+    }
+}

compiler/rustc_session/src/config/externs/tests.rs

@@ -0,0 +1,92 @@
+use std::path::PathBuf;
+
+use super::split_extern_opt;
+use crate::EarlyDiagCtxt;
+use crate::config::UnstableOptions;
+
+/// Verifies split_extern_opt handles the supported cases.
+#[test]
+fn test_split_extern_opt() {
+    let early_dcx = EarlyDiagCtxt::new(<_>::default());
+    let unstable_opts = &UnstableOptions::default();
+
+    let extern_opt =
+        split_extern_opt(&early_dcx, unstable_opts, "priv,noprelude:foo=libbar.rlib").unwrap();
+    assert_eq!(extern_opt.crate_name, "foo");
+    assert_eq!(extern_opt.path, Some(PathBuf::from("libbar.rlib")));
+    assert_eq!(extern_opt.options, Some("priv,noprelude".to_string()));
+
+    let extern_opt = split_extern_opt(&early_dcx, unstable_opts, "priv,noprelude:foo").unwrap();
+    assert_eq!(extern_opt.crate_name, "foo");
+    assert_eq!(extern_opt.path, None);
+    assert_eq!(extern_opt.options, Some("priv,noprelude".to_string()));
+
+    let extern_opt = split_extern_opt(&early_dcx, unstable_opts, "foo=libbar.rlib").unwrap();
+    assert_eq!(extern_opt.crate_name, "foo");
+    assert_eq!(extern_opt.path, Some(PathBuf::from("libbar.rlib")));
+    assert_eq!(extern_opt.options, None);
+
+    let extern_opt = split_extern_opt(&early_dcx, unstable_opts, "foo").unwrap();
+    assert_eq!(extern_opt.crate_name, "foo");
+    assert_eq!(extern_opt.path, None);
+    assert_eq!(extern_opt.options, None);
+}
+
+/// Tests some invalid cases for split_extern_opt.
+#[test]
+fn test_split_extern_opt_invalid() {
+    let early_dcx = EarlyDiagCtxt::new(<_>::default());
+    let unstable_opts = &UnstableOptions::default();
+
+    // too many `:`s
+    let result = split_extern_opt(&early_dcx, unstable_opts, "priv:noprelude:foo=libbar.rlib");
+    assert!(result.is_err());
+    let _ = result.map_err(|e| e.cancel());
+
+    // can't nest externs without the unstable flag
+    let result = split_extern_opt(&early_dcx, unstable_opts, "noprelude:foo::bar=libbar.rlib");
+    assert!(result.is_err());
+    let _ = result.map_err(|e| e.cancel());
+}
+
+/// Tests some cases for split_extern_opt with nested crates like `foo::bar`.
+#[test]
+fn test_split_extern_opt_nested() {
+    let early_dcx = EarlyDiagCtxt::new(<_>::default());
+    let unstable_opts = &UnstableOptions { namespaced_crates: true, ..Default::default() };
+
+    let extern_opt =
+        split_extern_opt(&early_dcx, unstable_opts, "priv,noprelude:foo::bar=libbar.rlib").unwrap();
+    assert_eq!(extern_opt.crate_name, "foo::bar");
+    assert_eq!(extern_opt.path, Some(PathBuf::from("libbar.rlib")));
+    assert_eq!(extern_opt.options, Some("priv,noprelude".to_string()));
+
+    let extern_opt =
+        split_extern_opt(&early_dcx, unstable_opts, "priv,noprelude:foo::bar").unwrap();
+    assert_eq!(extern_opt.crate_name, "foo::bar");
+    assert_eq!(extern_opt.path, None);
+    assert_eq!(extern_opt.options, Some("priv,noprelude".to_string()));
+
+    let extern_opt = split_extern_opt(&early_dcx, unstable_opts, "foo::bar=libbar.rlib").unwrap();
+    assert_eq!(extern_opt.crate_name, "foo::bar");
+    assert_eq!(extern_opt.path, Some(PathBuf::from("libbar.rlib")));
+    assert_eq!(extern_opt.options, None);
+
+    let extern_opt = split_extern_opt(&early_dcx, unstable_opts, "foo::bar").unwrap();
+    assert_eq!(extern_opt.crate_name, "foo::bar");
+    assert_eq!(extern_opt.path, None);
+    assert_eq!(extern_opt.options, None);
+}
+
+/// Tests some invalid cases for split_extern_opt with nested crates like `foo::bar`.
+#[test]
+fn test_split_extern_opt_nested_invalid() {
+    let early_dcx = EarlyDiagCtxt::new(<_>::default());
+    let unstable_opts = &UnstableOptions { namespaced_crates: true, ..Default::default() };
+
+    // crates can only be nested one deep.
+    let result =
+        split_extern_opt(&early_dcx, unstable_opts, "priv,noprelude:foo::bar::baz=libbar.rlib");
+    assert!(result.is_err());
+    let _ = result.map_err(|e| e.cancel());
+}

compiler/rustc_session/src/options.rs

@@ -2331,6 +2331,8 @@ options! {
         "the size at which the `large_assignments` lint starts to be emitted"),
     mutable_noalias: bool = (true, parse_bool, [TRACKED],
         "emit noalias metadata for mutable references (default: yes)"),
+    namespaced_crates: bool = (false, parse_bool, [TRACKED],
+        "allow crates to be namespaced by other crates (default: no)"),
     next_solver: NextSolverConfig = (NextSolverConfig::default(), parse_next_solver_config, [TRACKED],
         "enable and configure the next generation trait solver used by rustc"),
     nll_facts: bool = (false, parse_bool, [UNTRACKED],

compiler/rustc_span/src/symbol.rs

@@ -1068,7 +1068,6 @@ symbols! {
         ge,
         gen_blocks,
         gen_future,
-        gen_kill,
         generator_clone,
         generators,
         generic_arg_infer,

src/bootstrap/src/core/build_steps/compile.rs

@@ -155,7 +155,7 @@ impl Step for Std {
 
         // When using `download-rustc`, we already have artifacts for the host available. Don't
         // recompile them.
-        if builder.download_rustc() && builder.is_builder_target(target)
+        if builder.download_rustc() && builder.config.is_host_target(target)
             // NOTE: the beta compiler may generate different artifacts than the downloaded compiler, so
             // its artifacts can't be reused.
             && compiler.stage != 0
@@ -229,7 +229,7 @@ impl Step for Std {
         // The LLD wrappers and `rust-lld` are self-contained linking components that can be
         // necessary to link the stdlib on some targets. We'll also need to copy these binaries to
         // the `stage0-sysroot` to ensure the linker is found when bootstrapping on such a target.
-        if compiler.stage == 0 && builder.is_builder_target(compiler.host) {
+        if compiler.stage == 0 && builder.config.is_host_target(compiler.host) {
             trace!(
                 "(build == host) copying linking components to `stage0-sysroot` for bootstrapping"
             );
@@ -1374,7 +1374,7 @@ pub fn rustc_cargo_env(
 /// Pass down configuration from the LLVM build into the build of
 /// rustc_llvm and rustc_codegen_llvm.
 fn rustc_llvm_env(builder: &Builder<'_>, cargo: &mut Cargo, target: TargetSelection) {
-    if builder.is_rust_llvm(target) {
+    if builder.config.is_rust_llvm(target) {
         cargo.env("LLVM_RUSTLLVM", "1");
     }
     if builder.config.llvm_enzyme {
@@ -2182,7 +2182,7 @@ impl Step for Assemble {
         debug!("copying codegen backends to sysroot");
         copy_codegen_backends_to_sysroot(builder, build_compiler, target_compiler);
 
-        if builder.config.lld_enabled {
+        if builder.config.lld_enabled && !builder.config.is_system_llvm(target_compiler.host) {
             builder.ensure(crate::core::build_steps::tool::LldWrapper {
                 build_compiler,
                 target_compiler,
@@ -2532,7 +2532,9 @@ pub fn strip_debug(builder: &Builder<'_>, target: TargetSelection, path: &Path)
     // FIXME: to make things simpler for now, limit this to the host and target where we know
     // `strip -g` is both available and will fix the issue, i.e. on a x64 linux host that is not
     // cross-compiling. Expand this to other appropriate targets in the future.
-    if target != "x86_64-unknown-linux-gnu" || !builder.is_builder_target(target) || !path.exists()
+    if target != "x86_64-unknown-linux-gnu"
+        || !builder.config.is_host_target(target)
+        || !path.exists()
     {
         return;
     }

src/bootstrap/src/core/build_steps/dist.rs

@@ -612,7 +612,7 @@ impl Step for DebuggerScripts {
 fn skip_host_target_lib(builder: &Builder<'_>, compiler: Compiler) -> bool {
     // The only true set of target libraries came from the build triple, so
     // let's reduce redundant work by only producing archives from that host.
-    if !builder.is_builder_target(compiler.host) {
+    if !builder.config.is_host_target(compiler.host) {
         builder.info("\tskipping, not a build host");
         true
     } else {
@@ -671,7 +671,8 @@ fn copy_target_libs(
                 &self_contained_dst.join(path.file_name().unwrap()),
                 FileType::NativeLibrary,
             );
-        } else if dependency_type == DependencyType::Target || builder.is_builder_target(target) {
+        } else if dependency_type == DependencyType::Target || builder.config.is_host_target(target)
+        {
             builder.copy_link(&path, &dst.join(path.file_name().unwrap()), FileType::NativeLibrary);
         }
     }
@@ -824,7 +825,7 @@ impl Step for Analysis {
     fn run(self, builder: &Builder<'_>) -> Option<GeneratedTarball> {
         let compiler = self.compiler;
         let target = self.target;
-        if !builder.is_builder_target(compiler.host) {
+        if !builder.config.is_host_target(compiler.host) {
             return None;
         }
 
@@ -2118,7 +2119,7 @@ fn maybe_install_llvm(
     //
     // If the LLVM is coming from ourselves (just from CI) though, we
     // still want to install it, as it otherwise won't be available.
-    if builder.is_system_llvm(target) {
+    if builder.config.is_system_llvm(target) {
         trace!("system LLVM requested, no install");
         return false;
     }