Auto merge of #135172 - matthiaskrgr:rollup-8fe3fxi, r=matthiaskrgr

Rollup of 7 pull requests

Successful merges:

 - #134742 (Use `PostBorrowckAnalysis` in `check_coroutine_obligations`)
 - #134771 (Report correct `SelectionError` for `ConstArgHasType` in new solver fulfill)
 - #134951 (Suppress host effect predicates if underlying trait doesn't hold)
 - #135097 (bootstrap: Consolidate coverage test suite steps into a single step)
 - #135146 (Don't enable anyhow's `backtrace` feature in opt-dist)
 - #135153 (chore: remove redundant words in comment)
 - #135157 (Move the has_errors check in rustdoc back to after TyCtxt is created)

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

Author: bors

Cargo.lock

@@ -185,9 +185,6 @@ name = "anyhow"
 version = "1.0.95"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "34ac096ce696dc2fcabef30516bb13c0a68a11d30131d3df6f04711467681b04"
-dependencies = [
- "backtrace",
-]
 
 [[package]]
 name = "ar_archive_writer"

compiler/rustc_hir_analysis/src/check/check.rs

@@ -1845,13 +1845,18 @@ pub(super) fn check_coroutine_obligations(
 
     debug!(?typeck_results.coroutine_stalled_predicates);
 
+    let mode = if tcx.next_trait_solver_globally() {
+        TypingMode::post_borrowck_analysis(tcx, def_id)
+    } else {
+        TypingMode::analysis_in_body(tcx, def_id)
+    };
+
     let infcx = tcx
         .infer_ctxt()
         // typeck writeback gives us predicates with their regions erased.
         // As borrowck already has checked lifetimes, we do not need to do it again.
         .ignoring_regions()
-        // FIXME(#132279): This should eventually use the already defined hidden types.
-        .build(TypingMode::analysis_in_body(tcx, def_id));
+        .build(mode);
 
     let ocx = ObligationCtxt::new_with_diagnostics(&infcx);
     for (predicate, cause) in &typeck_results.coroutine_stalled_predicates {
@@ -1864,12 +1869,14 @@ pub(super) fn check_coroutine_obligations(
         return Err(infcx.err_ctxt().report_fulfillment_errors(errors));
     }
 
-    // Check that any hidden types found when checking these stalled coroutine obligations
-    // are valid.
-    for (key, ty) in infcx.take_opaque_types() {
-        let hidden_type = infcx.resolve_vars_if_possible(ty.hidden_type);
-        let key = infcx.resolve_vars_if_possible(key);
-        sanity_check_found_hidden_type(tcx, key, hidden_type)?;
+    if !tcx.next_trait_solver_globally() {
+        // Check that any hidden types found when checking these stalled coroutine obligations
+        // are valid.
+        for (key, ty) in infcx.take_opaque_types() {
+            let hidden_type = infcx.resolve_vars_if_possible(ty.hidden_type);
+            let key = infcx.resolve_vars_if_possible(key);
+            sanity_check_found_hidden_type(tcx, key, hidden_type)?;
+        }
     }
 
     Ok(())

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

@@ -114,7 +114,7 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
                         //
                         // We rely on a few heuristics to identify cases where this root
                         // obligation is more important than the leaf obligation:
-                        let (main_trait_predicate, o) = if let ty::PredicateKind::Clause(
+                        let (main_trait_predicate, main_obligation) = if let ty::PredicateKind::Clause(
                             ty::ClauseKind::Trait(root_pred)
                         ) = root_obligation.predicate.kind().skip_binder()
                             && !leaf_trait_predicate.self_ty().skip_binder().has_escaping_bound_vars()
@@ -199,7 +199,7 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
                             notes,
                             parent_label,
                             append_const_msg,
-                        } = self.on_unimplemented_note(main_trait_predicate, o, &mut long_ty_file);
+                        } = self.on_unimplemented_note(main_trait_predicate, main_obligation, &mut long_ty_file);
 
                         let have_alt_message = message.is_some() || label.is_some();
                         let is_try_conversion = self.is_try_conversion(span, main_trait_ref.def_id());
@@ -538,23 +538,7 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
                     }
 
                     ty::PredicateKind::Clause(ty::ClauseKind::HostEffect(predicate)) => {
-                        // FIXME(const_trait_impl): We should recompute the predicate with `~const`
-                        // if it's `const`, and if it holds, explain that this bound only
-                        // *conditionally* holds. If that fails, we should also do selection
-                        // to drill this down to an impl or built-in source, so we can
-                        // point at it and explain that while the trait *is* implemented,
-                        // that implementation is not const.
-                        let err_msg = self.get_standard_error_message(
-                            bound_predicate.rebind(ty::TraitPredicate {
-                                trait_ref: predicate.trait_ref,
-                                polarity: ty::PredicatePolarity::Positive,
-                            }),
-                            None,
-                            Some(predicate.constness),
-                            None,
-                            String::new(),
-                        );
-                        struct_span_code_err!(self.dcx(), span, E0277, "{}", err_msg)
+                        self.report_host_effect_error(bound_predicate.rebind(predicate), obligation.param_env, span)
                     }
 
                     ty::PredicateKind::Subtype(predicate) => {
@@ -763,6 +747,41 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
         applied_do_not_recommend
     }
 
+    fn report_host_effect_error(
+        &self,
+        predicate: ty::Binder<'tcx, ty::HostEffectPredicate<'tcx>>,
+        param_env: ty::ParamEnv<'tcx>,
+        span: Span,
+    ) -> Diag<'a> {
+        // FIXME(const_trait_impl): We should recompute the predicate with `~const`
+        // if it's `const`, and if it holds, explain that this bound only
+        // *conditionally* holds. If that fails, we should also do selection
+        // to drill this down to an impl or built-in source, so we can
+        // point at it and explain that while the trait *is* implemented,
+        // that implementation is not const.
+        let trait_ref = predicate.map_bound(|predicate| ty::TraitPredicate {
+            trait_ref: predicate.trait_ref,
+            polarity: ty::PredicatePolarity::Positive,
+        });
+        let err_msg = self.get_standard_error_message(
+            trait_ref,
+            None,
+            Some(predicate.constness()),
+            None,
+            String::new(),
+        );
+        let mut diag = struct_span_code_err!(self.dcx(), span, E0277, "{}", err_msg);
+        if !self.predicate_may_hold(&Obligation::new(
+            self.tcx,
+            ObligationCause::dummy(),
+            param_env,
+            trait_ref,
+        )) {
+            diag.downgrade_to_delayed_bug();
+        }
+        diag
+    }
+
     fn emit_specialized_closure_kind_error(
         &self,
         obligation: &PredicateObligation<'tcx>,

compiler/rustc_trait_selection/src/solve/fulfill.rs

@@ -10,9 +10,9 @@ use rustc_infer::traits::{
     self, FromSolverError, MismatchedProjectionTypes, Obligation, ObligationCause,
     ObligationCauseCode, PredicateObligation, PredicateObligations, SelectionError, TraitEngine,
 };
-use rustc_middle::bug;
 use rustc_middle::ty::error::{ExpectedFound, TypeError};
 use rustc_middle::ty::{self, TyCtxt};
+use rustc_middle::{bug, span_bug};
 use rustc_next_trait_solver::solve::{GenerateProofTree, HasChanged, SolverDelegateEvalExt as _};
 use tracing::{instrument, trace};
 
@@ -258,6 +258,23 @@ fn fulfillment_error_for_no_solution<'tcx>(
                 MismatchedProjectionTypes { err: TypeError::Mismatch },
             )
         }
+        ty::PredicateKind::Clause(ty::ClauseKind::ConstArgHasType(ct, expected_ty)) => {
+            let ct_ty = match ct.kind() {
+                ty::ConstKind::Unevaluated(uv) => {
+                    infcx.tcx.type_of(uv.def).instantiate(infcx.tcx, uv.args)
+                }
+                ty::ConstKind::Param(param_ct) => param_ct.find_ty_from_env(obligation.param_env),
+                _ => span_bug!(
+                    obligation.cause.span,
+                    "ConstArgHasWrongType failed but we don't know how to compute type"
+                ),
+            };
+            FulfillmentErrorCode::Select(SelectionError::ConstArgHasWrongType {
+                ct,
+                ct_ty,
+                expected_ty,
+            })
+        }
         ty::PredicateKind::NormalizesTo(..) => {
             FulfillmentErrorCode::Project(MismatchedProjectionTypes { err: TypeError::Mismatch })
         }

library/std/src/ffi/os_str.rs

@@ -550,7 +550,7 @@ impl OsString {
         OsStr::from_inner_mut(self.inner.leak())
     }
 
-    /// Truncate the the `OsString` to the specified length.
+    /// Truncate the `OsString` to the specified length.
     ///
     /// # Panics
     /// Panics if `len` does not lie on a valid `OsStr` boundary

library/std/src/pipe.rs

@@ -97,7 +97,7 @@ impl PipeReader {
     /// let mut jobs = vec![];
     /// let (reader, mut writer) = std::pipe::pipe()?;
     ///
-    /// // Write NUM_SLOT characters the the pipe.
+    /// // Write NUM_SLOT characters the pipe.
     /// writer.write_all(&[b'|'; NUM_SLOT as usize])?;
     ///
     /// // Spawn several processes that read a character from the pipe, do some work, then

library/std/src/sync/poison/mutex.rs

@@ -534,7 +534,7 @@ impl<T: ?Sized> Mutex<T> {
     /// # Errors
     ///
     /// If another user of this mutex panicked while holding the mutex, then
-    /// this call will return an error containing the the underlying data
+    /// this call will return an error containing the underlying data
     /// instead.
     ///
     /// # Examples

src/bootstrap/src/core/build_steps/test.rs

@@ -27,7 +27,7 @@ use crate::utils::helpers::{
     linker_args, linker_flags, t, target_supports_cranelift_backend, up_to_date,
 };
 use crate::utils::render_tests::{add_flags_and_try_run_tests, try_run_tests};
-use crate::{CLang, DocTests, GitRepo, Mode, envify};
+use crate::{CLang, DocTests, GitRepo, Mode, PathSet, envify};
 
 const ADB_TEST_DIR: &str = "/data/local/tmp/work";
 
@@ -1185,53 +1185,6 @@ macro_rules! test {
     };
 }
 
-/// Declares an alias for running the [`Coverage`] tests in only one mode.
-/// Adapted from [`test`].
-macro_rules! coverage_test_alias {
-    (
-        $( #[$attr:meta] )* // allow docstrings and attributes
-        $name:ident {
-            alias_and_mode: $alias_and_mode:expr, // &'static str
-            default: $default:expr, // bool
-            only_hosts: $only_hosts:expr // bool
-            $( , )? // optional trailing comma
-        }
-    ) => {
-        $( #[$attr] )*
-        #[derive(Debug, Clone, PartialEq, Eq, Hash)]
-        pub struct $name {
-            pub compiler: Compiler,
-            pub target: TargetSelection,
-        }
-
-        impl $name {
-            const MODE: &'static str = $alias_and_mode;
-        }
-
-        impl Step for $name {
-            type Output = ();
-            const DEFAULT: bool = $default;
-            const ONLY_HOSTS: bool = $only_hosts;
-
-            fn should_run(run: ShouldRun<'_>) -> ShouldRun<'_> {
-                // Register the mode name as a command-line alias.
-                // This allows `x test coverage-map` and `x test coverage-run`.
-                run.alias($alias_and_mode)
-            }
-
-            fn make_run(run: RunConfig<'_>) {
-                let compiler = run.builder.compiler(run.builder.top_stage, run.build_triple());
-
-                run.builder.ensure($name { compiler, target: run.target });
-            }
-
-            fn run(self, builder: &Builder<'_>) {
-                Coverage::run_coverage_tests(builder, self.compiler, self.target, Self::MODE);
-            }
-        }
-    };
-}
-
 #[derive(Debug, Copy, Clone, Hash, PartialEq, Eq, Ord, PartialOrd)]
 pub struct RunMakeSupport {
     pub compiler: Compiler,
@@ -1473,99 +1426,96 @@ impl Step for RunMake {
 
 test!(Assembly { path: "tests/assembly", mode: "assembly", suite: "assembly", default: true });
 
-/// Coverage tests are a bit more complicated than other test suites, because
-/// we want to run the same set of test files in multiple different modes,
-/// in a way that's convenient and flexible when invoked manually.
-///
-/// This combined step runs the specified tests (or all of `tests/coverage`)
-/// in both "coverage-map" and "coverage-run" modes.
-///
-/// Used by:
-/// - `x test coverage`
-/// - `x test tests/coverage`
-/// - `x test tests/coverage/trivial.rs` (etc)
-///
-/// (Each individual mode also has its own step that will run the tests in
-/// just that mode.)
-#[derive(Debug, Clone, PartialEq, Eq, Hash)]
+/// Runs the coverage test suite at `tests/coverage` in some or all of the
+/// coverage test modes.
+#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
 pub struct Coverage {
     pub compiler: Compiler,
     pub target: TargetSelection,
+    pub mode: &'static str,
 }
 
 impl Coverage {
     const PATH: &'static str = "tests/coverage";
     const SUITE: &'static str = "coverage";
-
-    /// Runs the coverage test suite (or a user-specified subset) in one mode.
-    ///
-    /// This same function is used by the multi-mode step ([`Coverage`]) and by
-    /// the single-mode steps ([`CoverageMap`] and [`CoverageRun`]), to help
-    /// ensure that they all behave consistently with each other, regardless of
-    /// how the coverage tests have been invoked.
-    fn run_coverage_tests(
-        builder: &Builder<'_>,
-        compiler: Compiler,
-        target: TargetSelection,
-        mode: &'static str,
-    ) {
-        // Like many other test steps, we delegate to a `Compiletest` step to
-        // actually run the tests. (See `test_definitions!`.)
-        builder.ensure(Compiletest {
-            compiler,
-            target,
-            mode,
-            suite: Self::SUITE,
-            path: Self::PATH,
-            compare_mode: None,
-        });
-    }
+    const ALL_MODES: &[&str] = &["coverage-map", "coverage-run"];
 }
 
 impl Step for Coverage {
     type Output = ();
-    /// We rely on the individual CoverageMap/CoverageRun steps to run themselves.
-    const DEFAULT: bool = false;
-    /// When manually invoked, try to run as much as possible.
+    const DEFAULT: bool = true;
     /// Compiletest will automatically skip the "coverage-run" tests if necessary.
     const ONLY_HOSTS: bool = false;
 
-    fn should_run(run: ShouldRun<'_>) -> ShouldRun<'_> {
-        // Take responsibility for command-line paths within `tests/coverage`.
-        run.suite_path(Self::PATH)
+    fn should_run(mut run: ShouldRun<'_>) -> ShouldRun<'_> {
+        // Support various invocation styles, including:
+        // - `./x test coverage`
+        // - `./x test tests/coverage/trivial.rs`
+        // - `./x test coverage-map`
+        // - `./x test coverage-run -- tests/coverage/trivial.rs`
+        run = run.suite_path(Self::PATH);
+        for mode in Self::ALL_MODES {
+            run = run.alias(mode);
+        }
+        run
     }
 
     fn make_run(run: RunConfig<'_>) {
         let compiler = run.builder.compiler(run.builder.top_stage, run.build_triple());
+        let target = run.target;
+
+        // List of (coverage) test modes that the coverage test suite will be
+        // run in. It's OK for this to contain duplicates, because the call to
+        // `Builder::ensure` below will take care of deduplication.
+        let mut modes = vec![];
+
+        // From the pathsets that were selected on the command-line (or by default),
+        // determine which modes to run in.
+        for path in &run.paths {
+            match path {
+                PathSet::Set(_) => {
+                    for mode in Self::ALL_MODES {
+                        if path.assert_single_path().path == Path::new(mode) {
+                            modes.push(mode);
+                            break;
+                        }
+                    }
+                }
+                PathSet::Suite(_) => {
+                    modes.extend(Self::ALL_MODES);
+                    break;
+                }
+            }
+        }
+
+        // Skip any modes that were explicitly skipped/excluded on the command-line.
+        // FIXME(Zalathar): Integrate this into central skip handling somehow?
+        modes.retain(|mode| !run.builder.config.skip.iter().any(|skip| skip == Path::new(mode)));
+
+        // FIXME(Zalathar): Make these commands skip all coverage tests, as expected:
+        // - `./x test --skip=tests`
+        // - `./x test --skip=tests/coverage`
+        // - `./x test --skip=coverage`
+        // Skip handling currently doesn't have a way to know that skipping the coverage
+        // suite should also skip the `coverage-map` and `coverage-run` aliases.
 
-        run.builder.ensure(Coverage { compiler, target: run.target });
+        for mode in modes {
+            run.builder.ensure(Coverage { compiler, target, mode });
+        }
     }
 
     fn run(self, builder: &Builder<'_>) {
-        // Run the specified coverage tests (possibly all of them) in both modes.
-        Self::run_coverage_tests(builder, self.compiler, self.target, CoverageMap::MODE);
-        Self::run_coverage_tests(builder, self.compiler, self.target, CoverageRun::MODE);
-    }
-}
-
-coverage_test_alias! {
-    /// Runs the `tests/coverage` test suite in "coverage-map" mode only.
-    /// Used by `x test` and `x test coverage-map`.
-    CoverageMap {
-        alias_and_mode: "coverage-map",
-        default: true,
-        only_hosts: false,
-    }
-}
-coverage_test_alias! {
-    /// Runs the `tests/coverage` test suite in "coverage-run" mode only.
-    /// Used by `x test` and `x test coverage-run`.
-    CoverageRun {
-        alias_and_mode: "coverage-run",
-        default: true,
-        // Compiletest knows how to automatically skip these tests when cross-compiling,
-        // but skipping the whole step here makes it clearer that they haven't run at all.
-        only_hosts: true,
+        let Self { compiler, target, mode } = self;
+        // Like other compiletest suite test steps, delegate to an internal
+        // compiletest task to actually run the tests.
+        builder.ensure(Compiletest {
+            compiler,
+            target,
+            mode,
+            suite: Self::SUITE,
+            path: Self::PATH,
+            compare_mode: None,
+        });
     }
 }
 

src/bootstrap/src/core/builder/mod.rs

@@ -944,8 +944,6 @@ impl<'a> Builder<'a> {
                 test::Ui,
                 test::Crashes,
                 test::Coverage,
-                test::CoverageMap,
-                test::CoverageRun,
                 test::MirOpt,
                 test::Codegen,
                 test::CodegenUnits,

src/bootstrap/src/core/builder/tests.rs

@@ -828,3 +828,36 @@ fn test_test_compiler() {
 
     assert_eq!((compiler, cranelift, gcc), (true, false, false));
 }
+
+#[test]
+fn test_test_coverage() {
+    struct Case {
+        cmd: &'static [&'static str],
+        expected: &'static [&'static str],
+    }
+    let cases = &[
+        Case { cmd: &["test"], expected: &["coverage-map", "coverage-run"] },
+        Case { cmd: &["test", "coverage"], expected: &["coverage-map", "coverage-run"] },
+        Case { cmd: &["test", "coverage-map"], expected: &["coverage-map"] },
+        Case { cmd: &["test", "coverage-run"], expected: &["coverage-run"] },
+        Case { cmd: &["test", "coverage", "--skip=coverage"], expected: &[] },
+        Case { cmd: &["test", "coverage", "--skip=tests/coverage"], expected: &[] },
+        Case { cmd: &["test", "coverage", "--skip=coverage-map"], expected: &["coverage-run"] },
+        Case { cmd: &["test", "coverage", "--skip=coverage-run"], expected: &["coverage-map"] },
+        Case { cmd: &["test", "--skip=coverage-map", "--skip=coverage-run"], expected: &[] },
+        Case { cmd: &["test", "coverage", "--skip=tests"], expected: &[] },
+    ];
+
+    for &Case { cmd, expected } in cases {
+        // Print each test case so that if one fails, the most recently printed
+        // case is the one that failed.
+        println!("Testing case: {cmd:?}");
+        let cmd = cmd.iter().copied().map(str::to_owned).collect::<Vec<_>>();
+        let config = configure_with_args(&cmd, &[TEST_TRIPLE_1], &[TEST_TRIPLE_1]);
+        let mut cache = run_build(&config.paths.clone(), config);
+
+        let modes =
+            cache.all::<test::Coverage>().iter().map(|(step, ())| step.mode).collect::<Vec<_>>();
+        assert_eq!(modes, expected);
+    }
+}

src/ci/docker/host-x86_64/dist-riscv64-linux/patches/gcc/8.5.0/0002-hidden-jump-target.patch

@@ -10,7 +10,7 @@ https://sourceware.org/bugzilla/show_bug.cgi?id=28509
 And this is the first version of the proposed binutils patch,
 https://sourceware.org/pipermail/binutils/2021-November/118398.html
 
-After applying the binutils patch, I get the the unexpected error when
+After applying the binutils patch, I get the unexpected error when
 building libgcc,
 
 /scratch/nelsonc/riscv-gnu-toolchain/riscv-gcc/libgcc/config/riscv/div.S:42:

src/librustdoc/lib.rs

@@ -865,11 +865,11 @@ fn main_args(
         }
 
         let krate = rustc_interface::passes::parse(sess);
-        if sess.dcx().has_errors().is_some() {
-            sess.dcx().fatal("Compilation failed, aborting rustdoc");
-        }
-
         rustc_interface::create_and_enter_global_ctxt(compiler, krate, |tcx| {
+            if sess.dcx().has_errors().is_some() {
+                sess.dcx().fatal("Compilation failed, aborting rustdoc");
+            }
+
             let (krate, render_opts, mut cache) = sess.time("run_global_ctxt", || {
                 core::run_global_ctxt(tcx, show_coverage, render_options, output_format)
             });

src/tools/opt-dist/Cargo.toml

@@ -7,7 +7,7 @@ edition = "2021"
 build_helper = { path = "../../build_helper" }
 env_logger = "0.11"
 log = "0.4"
-anyhow = { version = "1", features = ["backtrace"] }
+anyhow = "1"
 humantime = "2"
 humansize = "2"
 sysinfo = { version = "0.31.2", default-features = false, features = ["disk"] }

tests/ui/coroutine/issue-52304.rs

@@ -1,4 +1,6 @@
 //@ check-pass
+//@ revisions: current next
+//@ ignore-compare-mode-next-solver (explicit revisions)
 
 #![feature(coroutines, coroutine_trait)]
 

tests/ui/duplicate/multiple-types-with-same-name-and-derive.rs

@@ -1,5 +1,5 @@
 // Here, there are two types with the same name. One of these has a `derive` annotation, but in the
-// expansion these `impl`s are associated to the the *other* type. There is a suggestion to remove
+// expansion these `impl`s are associated to the *other* type. There is a suggestion to remove
 // unneeded type parameters, but because we're now point at a type with no type parameters, the
 // suggestion would suggest removing code from an empty span, which would ICE in nightly.
 //

tests/ui/traits/const-traits/double-error-for-unimplemented-trait.rs

@@ -0,0 +1,22 @@
+// Make sure we don't issue *two* error messages for the trait predicate *and* host predicate.
+
+#![feature(const_trait_impl)]
+
+#[const_trait]
+trait Trait {
+  type Out;
+}
+
+const fn needs_const<T: ~const Trait>(_: &T) {}
+
+const IN_CONST: () = {
+  needs_const(&());
+  //~^ ERROR the trait bound `(): Trait` is not satisfied
+};
+
+const fn conditionally_const() {
+  needs_const(&());
+  //~^ ERROR the trait bound `(): Trait` is not satisfied
+}
+
+fn main() {}

tests/ui/traits/const-traits/double-error-for-unimplemented-trait.stderr

@@ -0,0 +1,41 @@
+error[E0277]: the trait bound `(): Trait` is not satisfied
+  --> $DIR/double-error-for-unimplemented-trait.rs:13:15
+   |
+LL |   needs_const(&());
+   |   ----------- ^^^ the trait `Trait` is not implemented for `()`
+   |   |
+   |   required by a bound introduced by this call
+   |
+help: this trait has no implementations, consider adding one
+  --> $DIR/double-error-for-unimplemented-trait.rs:6:1
+   |
+LL | trait Trait {
+   | ^^^^^^^^^^^
+note: required by a bound in `needs_const`
+  --> $DIR/double-error-for-unimplemented-trait.rs:10:25
+   |
+LL | const fn needs_const<T: ~const Trait>(_: &T) {}
+   |                         ^^^^^^^^^^^^ required by this bound in `needs_const`
+
+error[E0277]: the trait bound `(): Trait` is not satisfied
+  --> $DIR/double-error-for-unimplemented-trait.rs:18:15
+   |
+LL |   needs_const(&());
+   |   ----------- ^^^ the trait `Trait` is not implemented for `()`
+   |   |
+   |   required by a bound introduced by this call
+   |
+help: this trait has no implementations, consider adding one
+  --> $DIR/double-error-for-unimplemented-trait.rs:6:1
+   |
+LL | trait Trait {
+   | ^^^^^^^^^^^
+note: required by a bound in `needs_const`
+  --> $DIR/double-error-for-unimplemented-trait.rs:10:25
+   |
+LL | const fn needs_const<T: ~const Trait>(_: &T) {}
+   |                         ^^^^^^^^^^^^ required by this bound in `needs_const`
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0277`.

tests/ui/typeck/issue-114918/const-in-impl-fn-return-type.stderr renamed to tests/ui/typeck/issue-114918/const-in-impl-fn-return-type.current.stderr

@@ -1,11 +1,11 @@
 error[E0308]: mismatched types
-  --> $DIR/const-in-impl-fn-return-type.rs:15:39
+  --> $DIR/const-in-impl-fn-return-type.rs:20:39
    |
 LL |     fn func<const N: u32>() -> [(); { () }] {
    |                                       ^^ expected `usize`, found `()`
 
 error: the constant `N` is not of type `usize`
-  --> $DIR/const-in-impl-fn-return-type.rs:7:32
+  --> $DIR/const-in-impl-fn-return-type.rs:12:32
    |
 LL |     fn func<const N: u32>() -> [(); N];
    |                                ^^^^^^^ expected `usize`, found `u32`

tests/ui/typeck/issue-114918/const-in-impl-fn-return-type.next.stderr

@@ -0,0 +1,15 @@
+error[E0308]: mismatched types
+  --> $DIR/const-in-impl-fn-return-type.rs:20:39
+   |
+LL |     fn func<const N: u32>() -> [(); { () }] {
+   |                                       ^^ expected `usize`, found `()`
+
+error: the constant `N` is not of type `usize`
+  --> $DIR/const-in-impl-fn-return-type.rs:12:32
+   |
+LL |     fn func<const N: u32>() -> [(); N];
+   |                                ^^^^^^^ expected `usize`, found `u32`
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0308`.

tests/ui/typeck/issue-114918/const-in-impl-fn-return-type.rs

@@ -1,4 +1,9 @@
+//@ revisions: current next
+//@[next] compile-flags: -Znext-solver
+//@ ignore-compare-mode-next-solver (explicit revisions)
+
 // Regression test for #114918
+
 // Test that a const generic enclosed in a block within the return type
 // of an impl fn produces a type mismatch error instead of triggering
 // a const eval cycle