Auto merge of #124040 - GuillaumeGomez:rollup-hrrvsgh, r=GuillaumeGomez

Rollup of 7 pull requests

Successful merges:

 - #123673 (Don't ICE for kind mismatches during error rendering)
 - #123675 (Taint const qualifs if a static is referenced that didn't pass wfcheck)
 - #123975 (Port the 2 `rust-lld` run-make tests to `rmake`)
 - #124000 (Use `/* value */` as a placeholder)
 - #124013 (Box::into_raw: make Miri understand that this is a box-to-raw cast)
 - #124027 (Prefer identity equality over equating types during coercion.)
 - #124036 (Remove `default_hidden_visibility: false` from wasm targets)

r? `@ghost`
`@rustbot` modify labels: rollup

Cargo.lock

@@ -3342,6 +3342,7 @@ name = "run_make_support"
 version = "0.0.0"
 dependencies = [
  "object 0.34.0",
+ "regex",
  "wasmparser",
 ]
 

compiler/rustc_const_eval/src/transform/check_consts/check.rs

@@ -331,6 +331,11 @@ impl<'mir, 'tcx> Checker<'mir, 'tcx> {
         if self.tcx.is_thread_local_static(def_id) {
             self.tcx.dcx().span_bug(span, "tls access is checked in `Rvalue::ThreadLocalRef`");
         }
+        if let Some(def_id) = def_id.as_local()
+            && let Err(guar) = self.tcx.at(span).check_well_formed(hir::OwnerId { def_id })
+        {
+            self.error_emitted = Some(guar);
+        }
         self.check_op_spanned(ops::StaticAccess, span)
     }
 

compiler/rustc_hir_analysis/src/coherence/builtin.rs

@@ -10,8 +10,8 @@ use rustc_hir::def_id::{DefId, LocalDefId};
 use rustc_hir::lang_items::LangItem;
 use rustc_hir::ItemKind;
 use rustc_infer::infer::outlives::env::OutlivesEnvironment;
+use rustc_infer::infer::TyCtxtInferExt;
 use rustc_infer::infer::{self, RegionResolutionError};
-use rustc_infer::infer::{DefineOpaqueTypes, TyCtxtInferExt};
 use rustc_infer::traits::Obligation;
 use rustc_middle::ty::adjustment::CoerceUnsizedInfo;
 use rustc_middle::ty::{self, suggest_constraining_type_params, Ty, TyCtxt, TypeVisitableExt};
@@ -189,10 +189,7 @@ fn visit_implementation_of_dispatch_from_dyn(checker: &Checker<'_>) -> Result<()
     // even if they do not carry that attribute.
     use rustc_type_ir::TyKind::*;
     match (source.kind(), target.kind()) {
-        (&Ref(r_a, _, mutbl_a), Ref(r_b, _, mutbl_b))
-            if infcx.at(&cause, param_env).eq(DefineOpaqueTypes::No, r_a, *r_b).is_ok()
-                && mutbl_a == *mutbl_b =>
-        {
+        (&Ref(r_a, _, mutbl_a), Ref(r_b, _, mutbl_b)) if r_a == *r_b && mutbl_a == *mutbl_b => {
             Ok(())
         }
         (&RawPtr(_, a_mutbl), &RawPtr(_, b_mutbl)) if a_mutbl == b_mutbl => Ok(()),
@@ -230,18 +227,14 @@ fn visit_implementation_of_dispatch_from_dyn(checker: &Checker<'_>) -> Result<()
                         }
                     }
 
-                    if let Ok(ok) =
-                        infcx.at(&cause, param_env).eq(DefineOpaqueTypes::No, ty_a, ty_b)
-                    {
-                        if ok.obligations.is_empty() {
-                            res = Err(tcx.dcx().emit_err(errors::DispatchFromDynZST {
-                                span,
-                                name: field.name,
-                                ty: ty_a,
-                            }));
+                    if ty_a == ty_b {
+                        res = Err(tcx.dcx().emit_err(errors::DispatchFromDynZST {
+                            span,
+                            name: field.name,
+                            ty: ty_a,
+                        }));
 
-                            return false;
-                        }
+                        return false;
                     }
 
                     return true;
@@ -433,14 +426,12 @@ pub fn coerce_unsized_info<'tcx>(
                     // something more accepting, but we use
                     // equality because we want to be able to
                     // perform this check without computing
-                    // variance where possible. (This is because
-                    // we may have to evaluate constraint
+                    // variance or constraining opaque types' hidden types.
+                    // (This is because we may have to evaluate constraint
                     // expressions in the course of execution.)
                     // See e.g., #41936.
-                    if let Ok(ok) = infcx.at(&cause, param_env).eq(DefineOpaqueTypes::No, a, b) {
-                        if ok.obligations.is_empty() {
-                            return None;
-                        }
+                    if a == b {
+                        return None;
                     }
 
                     // Collect up all fields that were significantly changed

compiler/rustc_target/src/spec/base/wasm.rs

@@ -80,9 +80,6 @@ pub fn options() -> TargetOptions {
         // threaded model which will legalize atomics to normal operations.
         singlethread: true,
 
-        // no dynamic linking, no need for default visibility!
-        default_hidden_visibility: true,
-
         // Symbol visibility takes care of this for the WebAssembly.
         // Additionally the only known linker, LLD, doesn't support the script
         // arguments just yet

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

@@ -4545,7 +4545,7 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
             self.type_implements_trait(default_trait, [ty], param_env).must_apply_modulo_regions()
         };
 
-        Some(match ty.kind() {
+        Some(match *ty.kind() {
             ty::Never | ty::Error(_) => return None,
             ty::Bool => "false".to_string(),
             ty::Char => "\'x\'".to_string(),
@@ -4572,12 +4572,19 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
                 if let (ty::Str, hir::Mutability::Not) = (ty.kind(), mutability) {
                     "\"\"".to_string()
                 } else {
-                    let ty = self.ty_kind_suggestion(param_env, *ty)?;
+                    let ty = self.ty_kind_suggestion(param_env, ty)?;
                     format!("&{}{ty}", mutability.prefix_str())
                 }
             }
             ty::Array(ty, len) if let Some(len) = len.try_eval_target_usize(tcx, param_env) => {
-                format!("[{}; {}]", self.ty_kind_suggestion(param_env, *ty)?, len)
+                if len == 0 {
+                    "[]".to_string()
+                } else if self.type_is_copy_modulo_regions(param_env, ty) || len == 1 {
+                    // Can only suggest `[ty; 0]` if sz == 1 or copy
+                    format!("[{}; {}]", self.ty_kind_suggestion(param_env, ty)?, len)
+                } else {
+                    "/* value */".to_string()
+                }
             }
             ty::Tuple(tys) => format!(
                 "({}{})",
@@ -4587,7 +4594,7 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
                     .join(", "),
                 if tys.len() == 1 { "," } else { "" }
             ),
-            _ => "value".to_string(),
+            _ => "/* value */".to_string(),
         })
     }
 }

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

@@ -1977,6 +1977,9 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
                     for (obligation_arg, impl_arg) in
                         std::iter::zip(obligation_trait_ref.args, impl_trait_ref.args)
                     {
+                        if (obligation_arg, impl_arg).references_error() {
+                            return false;
+                        }
                         if let Err(terr) =
                             ocx.eq(&ObligationCause::dummy(), param_env, impl_arg, obligation_arg)
                         {

library/alloc/src/boxed.rs

@@ -1058,7 +1058,8 @@ impl<T: ?Sized, A: Allocator> Box<T, A> {
     #[stable(feature = "box_raw", since = "1.4.0")]
     #[inline]
     pub fn into_raw(b: Self) -> *mut T {
-        Self::into_raw_with_allocator(b).0
+        // Make sure Miri realizes that we transition from a noalias pointer to a raw pointer here.
+        unsafe { addr_of_mut!(*&mut *Self::into_raw_with_allocator(b).0) }
     }
 
     /// Consumes the `Box`, returning a wrapped raw pointer and the allocator.
@@ -1112,7 +1113,10 @@ impl<T: ?Sized, A: Allocator> Box<T, A> {
     pub fn into_raw_with_allocator(b: Self) -> (*mut T, A) {
         let mut b = mem::ManuallyDrop::new(b);
         // We carefully get the raw pointer out in a way that Miri's aliasing model understands what
-        // is happening: using the primitive "deref" of `Box`.
+        // is happening: using the primitive "deref" of `Box`. In case `A` is *not* `Global`, we
+        // want *no* aliasing requirements here!
+        // In case `A` *is* `Global`, this does not quite have the right behavior; `into_raw`
+        // works around that.
         let ptr = addr_of_mut!(**b);
         let alloc = unsafe { ptr::read(&b.1) };
         (ptr, alloc)

src/tools/compiletest/src/header.rs

@@ -265,7 +265,10 @@ impl TestProps {
             aux_bins: vec![],
             aux_crates: vec![],
             revisions: vec![],
-            rustc_env: vec![("RUSTC_ICE".to_string(), "0".to_string())],
+            rustc_env: vec![
+                ("RUSTC_ICE".to_string(), "0".to_string()),
+                ("RUST_BACKTRACE".to_string(), "short".to_string()),
+            ],
             unset_rustc_env: vec![("RUSTC_LOG_COLOR".to_string())],
             exec_env: vec![],
             unset_exec_env: vec![],
@@ -839,6 +842,7 @@ const KNOWN_DIRECTIVE_NAMES: &[&str] = &[
     "needs-profiler-support",
     "needs-relocation-model-pic",
     "needs-run-enabled",
+    "needs-rust-lld",
     "needs-rust-lldb",
     "needs-sanitizer-address",
     "needs-sanitizer-cfi",

src/tools/compiletest/src/runtest.rs

@@ -2173,8 +2173,8 @@ impl<'test> TestCx<'test> {
         let aux_dir = self.aux_output_dir();
         self.build_all_auxiliary(&self.testpaths, &aux_dir, &mut rustc);
 
-        self.props.unset_rustc_env.iter().fold(&mut rustc, Command::env_remove);
         rustc.envs(self.props.rustc_env.clone());
+        self.props.unset_rustc_env.iter().fold(&mut rustc, Command::env_remove);
         self.compose_and_run(
             rustc,
             self.config.compile_lib_path.to_str().unwrap(),
@@ -2220,10 +2220,10 @@ impl<'test> TestCx<'test> {
         );
         aux_cx.build_all_auxiliary(of, &aux_dir, &mut aux_rustc);
 
+        aux_rustc.envs(aux_props.rustc_env.clone());
         for key in &aux_props.unset_rustc_env {
             aux_rustc.env_remove(key);
         }
-        aux_rustc.envs(aux_props.rustc_env.clone());
 
         let (aux_type, crate_type) = if is_bin {
             (AuxType::Bin, Some("bin"))

src/tools/miri/tests/fail/both_borrows/newtype_pair_retagging.stack.stderr

@@ -6,7 +6,7 @@ LL |         Box(unsafe { Unique::new_unchecked(raw) }, alloc)
    |
    = help: this indicates a potential bug in the program: it performed an invalid operation, but the Stacked Borrows rules it violated are still experimental
    = help: see https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md for further information
-help: <TAG> was created by a Unique retag at offsets [0x0..0x4]
+help: <TAG> was created by a SharedReadWrite retag at offsets [0x0..0x4]
   --> $DIR/newtype_pair_retagging.rs:LL:CC
    |
 LL |     let ptr = Box::into_raw(Box::new(0i32));

src/tools/miri/tests/fail/both_borrows/newtype_retagging.stack.stderr

@@ -6,7 +6,7 @@ LL |         Box(unsafe { Unique::new_unchecked(raw) }, alloc)
    |
    = help: this indicates a potential bug in the program: it performed an invalid operation, but the Stacked Borrows rules it violated are still experimental
    = help: see https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md for further information
-help: <TAG> was created by a Unique retag at offsets [0x0..0x4]
+help: <TAG> was created by a SharedReadWrite retag at offsets [0x0..0x4]
   --> $DIR/newtype_retagging.rs:LL:CC
    |
 LL |     let ptr = Box::into_raw(Box::new(0i32));

src/tools/miri/tests/pass/issues/issue-miri-3473.rs

@@ -0,0 +1,28 @@
+//@revisions: stack tree
+//@[tree]compile-flags: -Zmiri-tree-borrows
+use std::cell::UnsafeCell;
+
+#[repr(C)]
+#[derive(Default)]
+struct Node {
+    _meta: UnsafeCell<usize>,
+    value: usize,
+}
+
+impl Node {
+    fn value(&self) -> &usize {
+        &self.value
+    }
+}
+
+/// This used to cause Stacked Borrows errors because of trouble around conversion
+/// from Box to raw pointer.
+fn main() {
+    unsafe {
+        let a = Box::into_raw(Box::new(Node::default()));
+        let ptr = &*a;
+        *UnsafeCell::raw_get(a.cast::<UnsafeCell<usize>>()) = 2;
+        assert_eq!(*ptr.value(), 0);
+        drop(Box::from_raw(a));
+    }
+}

src/tools/miri/tests/pass/stacked-borrows/stacked-borrows.rs

@@ -20,6 +20,7 @@ fn main() {
     wide_raw_ptr_in_tuple();
     not_unpin_not_protected();
     write_does_not_invalidate_all_aliases();
+    box_into_raw_allows_interior_mutable_alias();
 }
 
 // Make sure that reading from an `&mut` does, like reborrowing to `&`,
@@ -263,3 +264,14 @@ fn write_does_not_invalidate_all_aliases() {
     other::lib2();
     assert_eq!(*x, 1337); // oops, the value changed! I guess not all pointers were invalidated
 }
+
+fn box_into_raw_allows_interior_mutable_alias() { unsafe {
+    let b = Box::new(std::cell::Cell::new(42));
+    let raw = Box::into_raw(b);
+    let c = &*raw;
+    let d = raw.cast::<i32>(); // bypassing `Cell` -- only okay in Miri tests
+    // `c` and `d` should permit arbitrary aliasing with each other now.
+    *d = 1;
+    c.set(2);
+    drop(Box::from_raw(raw));
+} }

src/tools/run-make-support/Cargo.toml

@@ -6,3 +6,4 @@ edition = "2021"
 [dependencies]
 object = "0.34.0"
 wasmparser = "0.118.2"
+regex = "1.8" # 1.8 to avoid memchr 2.6.0, as 2.5.0 is pinned in the workspace

src/tools/run-make-support/src/lib.rs

@@ -13,6 +13,7 @@ use std::path::{Path, PathBuf};
 use std::process::{Command, Output};
 
 pub use object;
+pub use regex;
 pub use wasmparser;
 
 pub use cc::{cc, extra_c_flags, extra_cxx_flags, Cc};

src/tools/run-make-support/src/rustc.rs

@@ -128,9 +128,8 @@ impl Rustc {
         self
     }
 
-    /// Specify target triple.
+    /// Specify the target triple, or a path to a custom target json spec file.
     pub fn target(&mut self, target: &str) -> &mut Self {
-        assert!(!target.contains(char::is_whitespace), "target triple cannot contain spaces");
         self.cmd.arg(format!("--target={target}"));
         self
     }
@@ -149,6 +148,12 @@ impl Rustc {
         self
     }
 
+    /// Add an extra argument to the linker invocation, via `-Clink-arg`.
+    pub fn link_arg(&mut self, link_arg: &str) -> &mut Self {
+        self.cmd.arg(format!("-Clink-arg={link_arg}"));
+        self
+    }
+
     #[track_caller]
     pub fn run_fail_assert_exit_code(&mut self, code: i32) -> Output {
         let caller_location = std::panic::Location::caller();

src/tools/tidy/src/allowed_run_make_makefiles.txt

@@ -249,8 +249,6 @@ run-make/rlib-format-packed-bundled-libs-2/Makefile
 run-make/rlib-format-packed-bundled-libs-3/Makefile
 run-make/rlib-format-packed-bundled-libs/Makefile
 run-make/rmeta-preferred/Makefile
-run-make/rust-lld-custom-target/Makefile
-run-make/rust-lld/Makefile
 run-make/rustc-macro-dep-files/Makefile
 run-make/rustdoc-determinism/Makefile
 run-make/rustdoc-error-lines/Makefile