Rollup of 8 pull requests

.github/workflows/post-merge.yml

@@ -35,8 +35,13 @@ jobs:
 
           cd src/ci/citool
 
-          echo "Post-merge analysis result" > output.log
+          printf "*This is an experimental post-merge analysis report. You can ignore it.*\n\n" > output.log
+          printf "<details>\n<summary>Post-merge report</summary>\n\n" >> output.log
+
           cargo run --release post-merge-report ${PARENT_COMMIT} ${{ github.sha }} >> output.log
+
+          printf "</details>\n" >> output.log
+
           cat output.log
 
           gh pr comment ${HEAD_PR} -F output.log

compiler/rustc_ast_lowering/src/lib.rs

@@ -1516,7 +1516,14 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
     fn lower_fn_params_to_names(&mut self, decl: &FnDecl) -> &'hir [Ident] {
         self.arena.alloc_from_iter(decl.inputs.iter().map(|param| match param.pat.kind {
             PatKind::Ident(_, ident, _) => self.lower_ident(ident),
-            _ => Ident::new(kw::Empty, self.lower_span(param.pat.span)),
+            PatKind::Wild => Ident::new(kw::Underscore, self.lower_span(param.pat.span)),
+            _ => {
+                self.dcx().span_delayed_bug(
+                    param.pat.span,
+                    "non-ident/wild param pat must trigger an error",
+                );
+                Ident::new(kw::Empty, self.lower_span(param.pat.span))
+            }
         }))
     }
 

compiler/rustc_codegen_llvm/src/consts.rs

@@ -5,16 +5,17 @@ use rustc_abi::{
 };
 use rustc_codegen_ssa::common;
 use rustc_codegen_ssa::traits::*;
+use rustc_hir::LangItem;
 use rustc_hir::def::DefKind;
 use rustc_hir::def_id::DefId;
 use rustc_middle::middle::codegen_fn_attrs::{CodegenFnAttrFlags, CodegenFnAttrs};
 use rustc_middle::mir::interpret::{
     Allocation, ConstAllocation, ErrorHandled, InitChunk, Pointer, Scalar as InterpScalar,
     read_target_uint,
 };
-use rustc_middle::mir::mono::MonoItem;
-use rustc_middle::ty::Instance;
+use rustc_middle::mir::mono::{Linkage, MonoItem};
 use rustc_middle::ty::layout::{HasTypingEnv, LayoutOf};
+use rustc_middle::ty::{self, Instance};
 use rustc_middle::{bug, span_bug};
 use tracing::{debug, instrument, trace};
 
@@ -171,8 +172,27 @@ fn check_and_apply_linkage<'ll, 'tcx>(
     if let Some(linkage) = attrs.import_linkage {
         debug!("get_static: sym={} linkage={:?}", sym, linkage);
 
-        // Declare a symbol `foo` with the desired linkage.
-        let g1 = cx.declare_global(sym, cx.type_i8());
+        // Declare a symbol `foo`. If `foo` is an extern_weak symbol, we declare
+        // an extern_weak function, otherwise a global with the desired linkage.
+        let g1 = if matches!(attrs.import_linkage, Some(Linkage::ExternalWeak)) {
+            // An `extern_weak` function is represented as an `Option<unsafe extern ...>`,
+            // we extract the function signature and declare it as an extern_weak function
+            // instead of an extern_weak i8.
+            let instance = Instance::mono(cx.tcx, def_id);
+            if let ty::Adt(struct_def, args) = instance.ty(cx.tcx, cx.typing_env()).kind()
+                && cx.tcx.is_lang_item(struct_def.did(), LangItem::Option)
+                && let ty::FnPtr(sig, header) = args.type_at(0).kind()
+            {
+                let fn_sig = sig.with(*header);
+
+                let fn_abi = cx.fn_abi_of_fn_ptr(fn_sig, ty::List::empty());
+                cx.declare_fn(sym, &fn_abi, None)
+            } else {
+                cx.declare_global(sym, cx.type_i8())
+            }
+        } else {
+            cx.declare_global(sym, cx.type_i8())
+        };
         llvm::set_linkage(g1, base::linkage_to_llvm(linkage));
 
         // Declare an internal global `extern_with_linkage_foo` which

compiler/rustc_hir_pretty/src/lib.rs

@@ -2148,9 +2148,11 @@ impl<'a> State<'a> {
                 s.print_implicit_self(&decl.implicit_self);
             } else {
                 if let Some(arg_name) = arg_names.get(i) {
-                    s.word(arg_name.to_string());
-                    s.word(":");
-                    s.space();
+                    if arg_name.name != kw::Empty {
+                        s.word(arg_name.to_string());
+                        s.word(":");
+                        s.space();
+                    }
                 } else if let Some(body_id) = body_id {
                     s.ann.nested(s, Nested::BodyParamPat(body_id, i));
                     s.word(":");

compiler/rustc_hir_typeck/src/expr.rs

@@ -2060,7 +2060,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 // struct-like enums (yet...), but it's definitely not
                 // a bug to have constructed one.
                 if adt_kind != AdtKind::Enum {
-                    tcx.check_stability(v_field.did, Some(expr.hir_id), field.span, None);
+                    tcx.check_stability(v_field.did, Some(field.hir_id), field.span, None);
                 }
 
                 self.field_ty(field.span, v_field, args)

compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs

@@ -19,7 +19,7 @@ use rustc_middle::ty::visit::TypeVisitableExt;
 use rustc_middle::ty::{self, IsSuggestable, Ty, TyCtxt};
 use rustc_middle::{bug, span_bug};
 use rustc_session::Session;
-use rustc_span::{DUMMY_SP, Ident, Span, Symbol, kw, sym};
+use rustc_span::{DUMMY_SP, Ident, Span, kw, sym};
 use rustc_trait_selection::error_reporting::infer::{FailureCode, ObligationCauseExt};
 use rustc_trait_selection::infer::InferCtxtExt;
 use rustc_trait_selection::traits::{self, ObligationCauseCode, ObligationCtxt, SelectionContext};
@@ -2679,7 +2679,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                     params.get(is_method as usize..params.len() - sig.decl.c_variadic as usize)?;
                 debug_assert_eq!(params.len(), fn_inputs.len());
                 Some((
-                    fn_inputs.zip(params.iter().map(|param| FnParam::Name(param))).collect(),
+                    fn_inputs.zip(params.iter().map(|&param| FnParam::Name(param))).collect(),
                     generics,
                 ))
             }
@@ -2710,32 +2710,38 @@ impl<'tcx> Visitor<'tcx> for FindClosureArg<'tcx> {
 #[derive(Clone, Copy)]
 enum FnParam<'hir> {
     Param(&'hir hir::Param<'hir>),
-    Name(&'hir Ident),
+    Name(Ident),
 }
+
 impl FnParam<'_> {
     fn span(&self) -> Span {
         match self {
-            Self::Param(x) => x.span,
-            Self::Name(x) => x.span,
-        }
-    }
-
-    fn name(&self) -> Option<Symbol> {
-        match self {
-            Self::Param(x) if let hir::PatKind::Binding(_, _, ident, _) = x.pat.kind => {
-                Some(ident.name)
-            }
-            Self::Name(x) if x.name != kw::Empty => Some(x.name),
-            _ => None,
+            Self::Param(param) => param.span,
+            Self::Name(ident) => ident.span,
         }
     }
 
     fn display(&self, idx: usize) -> impl '_ + fmt::Display {
         struct D<'a>(FnParam<'a>, usize);
         impl fmt::Display for D<'_> {
             fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-                if let Some(name) = self.0.name() {
-                    write!(f, "`{name}`")
+                // A "unique" param name is one that (a) exists, and (b) is guaranteed to be unique
+                // among the parameters, i.e. `_` does not count.
+                let unique_name = match self.0 {
+                    FnParam::Param(param)
+                        if let hir::PatKind::Binding(_, _, ident, _) = param.pat.kind =>
+                    {
+                        Some(ident.name)
+                    }
+                    FnParam::Name(ident)
+                        if ident.name != kw::Empty && ident.name != kw::Underscore =>
+                    {
+                        Some(ident.name)
+                    }
+                    _ => None,
+                };
+                if let Some(unique_name) = unique_name {
+                    write!(f, "`{unique_name}`")
                 } else {
                     write!(f, "parameter #{}", self.1 + 1)
                 }

compiler/rustc_hir_typeck/src/pat.rs

@@ -1422,7 +1422,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
 
                 self.tcx.check_stability(
                     variant.fields[FieldIdx::from_usize(i)].did,
-                    Some(pat.hir_id),
+                    Some(subpat.hir_id),
                     subpat.span,
                     None,
                 );
@@ -1686,7 +1686,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                         .get(&ident)
                         .map(|(i, f)| {
                             self.write_field_index(field.hir_id, *i);
-                            self.tcx.check_stability(f.did, Some(pat.hir_id), span, None);
+                            self.tcx.check_stability(f.did, Some(field.hir_id), span, None);
                             self.field_ty(span, f, args)
                         })
                         .unwrap_or_else(|| {

compiler/rustc_middle/src/hir/map.rs

@@ -281,8 +281,9 @@ impl<'tcx> TyCtxt<'tcx> {
     }
 
     pub fn hir_body_param_names(self, id: BodyId) -> impl Iterator<Item = Ident> {
-        self.hir_body(id).params.iter().map(|arg| match arg.pat.kind {
+        self.hir_body(id).params.iter().map(|param| match param.pat.kind {
             PatKind::Binding(_, _, ident, _) => ident,
+            PatKind::Wild => Ident::new(kw::Underscore, param.pat.span),
             _ => Ident::empty(),
         })
     }

compiler/rustc_parse/src/parser/expr.rs

@@ -2588,7 +2588,8 @@ impl<'a> Parser<'a> {
     }
 
     /// Parses the condition of a `if` or `while` expression.
-    fn parse_expr_cond(&mut self) -> PResult<'a, P<Expr>> {
+    // Public because it is used in rustfmt forks such as https://github.com/tucant/rustfmt/blob/30c83df9e1db10007bdd16dafce8a86b404329b2/src/parse/macros/html.rs#L57 for custom if expressions.
+    pub fn parse_expr_cond(&mut self) -> PResult<'a, P<Expr>> {
         let attrs = self.parse_outer_attributes()?;
         let (mut cond, _) =
             self.parse_expr_res(Restrictions::NO_STRUCT_LITERAL | Restrictions::ALLOW_LET, attrs)?;

compiler/rustc_target/src/target_features.rs

@@ -603,13 +603,18 @@ static CSKY_FEATURES: &[(&str, Stability, ImpliedFeatures)] = &[
 static LOONGARCH_FEATURES: &[(&str, Stability, ImpliedFeatures)] = &[
     // tidy-alphabetical-start
     ("d", Unstable(sym::loongarch_target_feature), &["f"]),
+    ("div32", Unstable(sym::loongarch_target_feature), &[]),
     ("f", Unstable(sym::loongarch_target_feature), &[]),
     ("frecipe", Unstable(sym::loongarch_target_feature), &[]),
+    ("lam-bh", Unstable(sym::loongarch_target_feature), &[]),
+    ("lamcas", Unstable(sym::loongarch_target_feature), &[]),
     ("lasx", Unstable(sym::loongarch_target_feature), &["lsx"]),
     ("lbt", Unstable(sym::loongarch_target_feature), &[]),
+    ("ld-seq-sa", Unstable(sym::loongarch_target_feature), &[]),
     ("lsx", Unstable(sym::loongarch_target_feature), &["d"]),
     ("lvz", Unstable(sym::loongarch_target_feature), &[]),
     ("relax", Unstable(sym::loongarch_target_feature), &[]),
+    ("scq", Unstable(sym::loongarch_target_feature), &[]),
     ("ual", Unstable(sym::loongarch_target_feature), &[]),
     // tidy-alphabetical-end
 ];

compiler/rustc_trait_selection/src/error_reporting/traits/suggestions.rs

@@ -1998,7 +1998,10 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
                 .iter()
                 .enumerate()
                 .map(|(i, ident)| {
-                    if ident.name.is_empty() || ident.name == kw::SelfLower {
+                    if ident.name.is_empty()
+                        || ident.name == kw::Underscore
+                        || ident.name == kw::SelfLower
+                    {
                         format!("arg{i}")
                     } else {
                         format!("{ident}")

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

@@ -2481,7 +2481,7 @@ impl Step for Gcc {
     fn run(self, builder: &Builder<'_>) -> Self::Output {
         let tarball = Tarball::new(builder, "gcc", &self.target.triple);
         let output = builder.ensure(super::gcc::Gcc { target: self.target });
-        tarball.add_file(output.libgccjit, ".", 0o644);
+        tarball.add_file(output.libgccjit, "lib", 0o644);
         tarball.generate()
     }
 }

src/bootstrap/src/core/build_steps/gcc.rs

@@ -63,18 +63,23 @@ impl Step for Gcc {
         }
 
         build_gcc(&metadata, builder, target);
-
-        let lib_alias = metadata.install_dir.join("lib/libgccjit.so.0");
-        if !lib_alias.exists() {
-            t!(builder.symlink_file(&libgccjit_path, lib_alias));
-        }
+        create_lib_alias(builder, &libgccjit_path);
 
         t!(metadata.stamp.write());
 
         GccOutput { libgccjit: libgccjit_path }
     }
 }
 
+/// Creates a libgccjit.so.0 alias next to libgccjit.so if it does not
+/// already exist
+fn create_lib_alias(builder: &Builder<'_>, libgccjit: &PathBuf) {
+    let lib_alias = libgccjit.parent().unwrap().join("libgccjit.so.0");
+    if !lib_alias.exists() {
+        t!(builder.symlink_file(libgccjit, lib_alias));
+    }
+}
+
 pub struct Meta {
     stamp: BuildStamp,
     out_dir: PathBuf,
@@ -109,8 +114,10 @@ fn try_download_gcc(builder: &Builder<'_>, target: TargetSelection) -> Option<Pa
         builder.config.download_ci_gcc(&sha, &root);
         t!(gcc_stamp.write());
     }
-    // FIXME: put libgccjit.so into a lib directory in dist::Gcc
-    Some(root.join("libgccjit.so"))
+
+    let libgccjit = root.join("lib").join("libgccjit.so");
+    create_lib_alias(builder, &libgccjit);
+    Some(libgccjit)
 }
 
 #[cfg(test)]
@@ -177,6 +184,14 @@ fn libgccjit_built_path(install_dir: &Path) -> PathBuf {
 }
 
 fn build_gcc(metadata: &Meta, builder: &Builder<'_>, target: TargetSelection) {
+    if builder.build.cc_tool(target).is_like_clang()
+        || builder.build.cxx_tool(target).is_like_clang()
+    {
+        panic!(
+            "Attempting to build GCC using Clang, which is known to misbehave. Please use GCC as the host C/C++ compiler. "
+        );
+    }
+
     let Meta { stamp: _, out_dir, install_dir, root } = metadata;
 
     t!(fs::create_dir_all(out_dir));
@@ -203,18 +218,13 @@ fn build_gcc(metadata: &Meta, builder: &Builder<'_>, target: TargetSelection) {
     let mut configure_cmd = command(src_dir.join("configure"));
     configure_cmd
         .current_dir(out_dir)
-        // On CI, we compile GCC with Clang.
-        // The -Wno-everything flag is needed to make GCC compile with Clang 19.
-        // `-g -O2` are the default flags that are otherwise used by Make.
-        // FIXME(kobzol): change the flags once we have [gcc] configuration in config.toml.
-        .env("CXXFLAGS", "-Wno-everything -g -O2")
-        .env("CFLAGS", "-Wno-everything -g -O2")
         .arg("--enable-host-shared")
-        .arg("--enable-languages=jit")
+        .arg("--enable-languages=c,jit,lto")
         .arg("--enable-checking=release")
         .arg("--disable-bootstrap")
         .arg("--disable-multilib")
         .arg(format!("--prefix={}", install_dir.display()));
+
     let cc = builder.build.cc(target).display().to_string();
     let cc = builder
         .build

src/bootstrap/src/lib.rs

@@ -27,6 +27,7 @@ use std::{env, fs, io, str};
 
 use build_helper::ci::gha;
 use build_helper::exit;
+use cc::Tool;
 use termcolor::{ColorChoice, StandardStream, WriteColor};
 use utils::build_stamp::BuildStamp;
 use utils::channel::GitInfo;
@@ -1218,6 +1219,16 @@ Executed at: {executed_at}"#,
         self.cc.borrow()[&target].path().into()
     }
 
+    /// Returns the internal `cc::Tool` for the C compiler.
+    fn cc_tool(&self, target: TargetSelection) -> Tool {
+        self.cc.borrow()[&target].clone()
+    }
+
+    /// Returns the internal `cc::Tool` for the C++ compiler.
+    fn cxx_tool(&self, target: TargetSelection) -> Tool {
+        self.cxx.borrow()[&target].clone()
+    }
+
     /// Returns C flags that `cc-rs` thinks should be enabled for the
     /// specified target by default.
     fn cc_handled_clags(&self, target: TargetSelection, c: CLang) -> Vec<String> {