Auto merge of #136041 - matthiaskrgr:rollup-5r1k45x, r=matthiaskrgr

Rollup of 9 pull requests

Successful merges:

 - #135971 (Properly report error when object type param default references self)
 - #135977 (Fix `FormattingOptions` instantiation with `Default`)
 - #135985 (Rename test to `unresolvable-upvar-issue-87987.rs` and add some notes)
 - #135991 (Fix set_name in thread mod for NuttX)
 - #136009 (bootstrap: Handle bootstrap lockfile race condition better)
 - #136018 (Use short ty string for move errors)
 - #136027 (Skip suggestions in `derive`d code)
 - #136029 (Bootstrap: Don't move ownership of job object)
 - #136034 (fix(bootstrap): deserialize null as `f64::NAN`)

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

Author: bors

compiler/rustc_borrowck/messages.ftl

@@ -92,6 +92,9 @@ borrowck_lifetime_constraints_error =
 borrowck_limitations_implies_static =
     due to current limitations in the borrow checker, this implies a `'static` lifetime
 
+borrowck_long_type_consider_verbose = consider using `--verbose` to print the full type name to the console
+borrowck_long_type_full_path = the full type name has been written to '{$path}'
+
 borrowck_move_closure_suggestion =
     consider adding 'move' keyword before the nested closure
 

compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs

@@ -289,6 +289,8 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
                 None => "value".to_owned(),
             };
             if needs_note {
+                let mut path = None;
+                let ty = self.infcx.tcx.short_ty_string(ty, &mut path);
                 if let Some(local) = place.as_local() {
                     let span = self.body.local_decls[local].source_info.span;
                     err.subdiagnostic(crate::session_diagnostics::TypeNoCopy::Label {
@@ -304,6 +306,11 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
                         place: &note_msg,
                     });
                 };
+                if let Some(path) = path {
+                    err.subdiagnostic(crate::session_diagnostics::LongTypePath {
+                        path: path.display().to_string(),
+                    });
+                }
             }
 
             if let UseSpans::FnSelfUse {

compiler/rustc_borrowck/src/diagnostics/move_errors.rs

@@ -596,12 +596,19 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
                         self.suggest_cloning(err, place_ty, expr, None);
                     }
 
+                    let mut path = None;
+                    let ty = self.infcx.tcx.short_ty_string(place_ty, &mut path);
                     err.subdiagnostic(crate::session_diagnostics::TypeNoCopy::Label {
                         is_partial_move: false,
-                        ty: place_ty,
+                        ty,
                         place: &place_desc,
                         span,
                     });
+                    if let Some(path) = path {
+                        err.subdiagnostic(crate::session_diagnostics::LongTypePath {
+                            path: path.display().to_string(),
+                        });
+                    }
                 } else {
                     binds_to.sort();
                     binds_to.dedup();
@@ -628,12 +635,19 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
                     self.suggest_cloning(err, place_ty, expr, Some(use_spans));
                 }
 
+                let mut path = None;
+                let ty = self.infcx.tcx.short_ty_string(place_ty, &mut path);
                 err.subdiagnostic(crate::session_diagnostics::TypeNoCopy::Label {
                     is_partial_move: false,
-                    ty: place_ty,
+                    ty,
                     place: &place_desc,
                     span: use_span,
                 });
+                if let Some(path) = path {
+                    err.subdiagnostic(crate::session_diagnostics::LongTypePath {
+                        path: path.display().to_string(),
+                    });
+                }
 
                 use_spans.args_subdiag(err, |args_span| {
                     crate::session_diagnostics::CaptureArgLabel::MoveOutPlace {
@@ -831,12 +845,19 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
                     self.suggest_cloning(err, bind_to.ty, expr, None);
                 }
 
+                let mut path = None;
+                let ty = self.infcx.tcx.short_ty_string(bind_to.ty, &mut path);
                 err.subdiagnostic(crate::session_diagnostics::TypeNoCopy::Label {
                     is_partial_move: false,
-                    ty: bind_to.ty,
+                    ty,
                     place: place_desc,
                     span: binding_span,
                 });
+                if let Some(path) = path {
+                    err.subdiagnostic(crate::session_diagnostics::LongTypePath {
+                        path: path.display().to_string(),
+                    });
+                }
             }
         }
 

compiler/rustc_borrowck/src/session_diagnostics.rs

@@ -459,17 +459,24 @@ pub(crate) enum OnClosureNote<'a> {
 }
 
 #[derive(Subdiagnostic)]
-pub(crate) enum TypeNoCopy<'a, 'tcx> {
+#[note(borrowck_long_type_full_path)]
+#[note(borrowck_long_type_consider_verbose)]
+pub(crate) struct LongTypePath {
+    pub(crate) path: String,
+}
+
+#[derive(Subdiagnostic)]
+pub(crate) enum TypeNoCopy<'a> {
     #[label(borrowck_ty_no_impl_copy)]
     Label {
         is_partial_move: bool,
-        ty: Ty<'tcx>,
+        ty: String,
         place: &'a str,
         #[primary_span]
         span: Span,
     },
     #[note(borrowck_ty_no_impl_copy)]
-    Note { is_partial_move: bool, ty: Ty<'tcx>, place: &'a str },
+    Note { is_partial_move: bool, ty: String, place: &'a str },
 }
 
 #[derive(Diagnostic)]

compiler/rustc_error_codes/src/error_codes/E0393.md

@@ -3,12 +3,10 @@ A type parameter which references `Self` in its default value was not specified.
 Erroneous code example:
 
 ```compile_fail,E0393
-trait A<T=Self> {}
+trait A<T = Self> {}
 
-fn together_we_will_rule_the_galaxy(son: &A) {}
-// error: the type parameter `T` must be explicitly specified in an
-//        object type because its default value `Self` references the
-//        type `Self`
+fn together_we_will_rule_the_galaxy(son: &dyn A) {}
+// error: the type parameter `T` must be explicitly specified
 ```
 
 A trait object is defined over a single, fully-defined trait. With a regular
@@ -23,7 +21,7 @@ disallowed. Making the trait concrete by explicitly specifying the value of the
 defaulted parameter will fix this issue. Fixed example:
 
 ```
-trait A<T=Self> {}
+trait A<T = Self> {}
 
-fn together_we_will_rule_the_galaxy(son: &A<i32>) {} // Ok!
+fn together_we_will_rule_the_galaxy(son: &dyn A<i32>) {} // Ok!
 ```

compiler/rustc_hir_analysis/messages.ftl

@@ -353,7 +353,13 @@ hir_analysis_missing_type_params =
         [one] reference
         *[other] references
     } to {$parameters}
-    .note = because of the default `Self` reference, type parameters must be specified on object types
+    .note = because the parameter {$parameterCount ->
+        [one] default references
+        *[other] defaults reference
+    } `Self`, the {$parameterCount ->
+        [one] parameter
+        *[other] parameters
+    } must be specified on the object type
 
 hir_analysis_multiple_relaxed_default_bounds =
     type parameter has more than one relaxed default bound, only one is supported

compiler/rustc_hir_analysis/src/hir_ty_lowering/dyn_compatibility.rs

@@ -237,16 +237,10 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
                     // Skip `Self`
                     .skip(1)
                     .map(|(index, arg)| {
-                        if arg == dummy_self.into() {
+                        if arg.walk().any(|arg| arg == dummy_self.into()) {
                             let param = &generics.own_params[index];
                             missing_type_params.push(param.name);
                             Ty::new_misc_error(tcx).into()
-                        } else if arg.walk().any(|arg| arg == dummy_self.into()) {
-                            let guar = self.dcx().span_delayed_bug(
-                                span,
-                                "trait object trait bounds reference `Self`",
-                            );
-                            replace_dummy_self_with_error(tcx, arg, guar)
                         } else {
                             arg
                         }

compiler/rustc_hir_typeck/src/fn_ctxt/suggestions.rs

@@ -185,6 +185,9 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         rhs_ty: Ty<'tcx>,
         can_satisfy: impl FnOnce(Ty<'tcx>, Ty<'tcx>) -> bool,
     ) -> bool {
+        if lhs_expr.span.in_derive_expansion() || rhs_expr.span.in_derive_expansion() {
+            return false;
+        }
         let Some((_, lhs_output_ty, lhs_inputs)) = self.extract_callable_info(lhs_ty) else {
             return false;
         };

compiler/rustc_mir_build/messages.ftl

@@ -25,6 +25,8 @@ mir_build_borrow_of_moved_value = borrow of moved value
     .occurs_because_label = move occurs because `{$name}` has type `{$ty}`, which does not implement the `Copy` trait
     .value_borrowed_label = value borrowed here after move
     .suggestion = borrow this binding in the pattern to avoid moving the value
+    .full_type_name = the full type name has been written to '{$path}'
+    .consider_verbose = consider using `--verbose` to print the full type name to the console
 
 mir_build_call_to_deprecated_safe_fn_requires_unsafe =
     call to deprecated safe function `{$function}` is unsafe and requires unsafe block

compiler/rustc_mir_build/src/errors.rs

@@ -790,17 +790,21 @@ pub(crate) struct IrrefutableLetPatternsWhileLet {
 
 #[derive(Diagnostic)]
 #[diag(mir_build_borrow_of_moved_value)]
-pub(crate) struct BorrowOfMovedValue<'tcx> {
+pub(crate) struct BorrowOfMovedValue {
     #[primary_span]
     #[label]
     #[label(mir_build_occurs_because_label)]
     pub(crate) binding_span: Span,
     #[label(mir_build_value_borrowed_label)]
     pub(crate) conflicts_ref: Vec<Span>,
     pub(crate) name: Symbol,
-    pub(crate) ty: Ty<'tcx>,
+    pub(crate) ty: String,
     #[suggestion(code = "ref ", applicability = "machine-applicable")]
     pub(crate) suggest_borrowing: Option<Span>,
+    #[note(mir_build_full_type_name)]
+    #[note(mir_build_consider_verbose)]
+    pub(crate) has_path: bool,
+    pub(crate) path: String,
 }
 
 #[derive(Diagnostic)]

compiler/rustc_mir_build/src/thir/pattern/check_match.rs

@@ -795,12 +795,16 @@ fn check_borrow_conflicts_in_at_patterns<'tcx>(cx: &MatchVisitor<'_, 'tcx>, pat:
                 }
             });
             if !conflicts_ref.is_empty() {
+                let mut path = None;
+                let ty = cx.tcx.short_ty_string(ty, &mut path);
                 sess.dcx().emit_err(BorrowOfMovedValue {
                     binding_span: pat.span,
                     conflicts_ref,
                     name,
                     ty,
                     suggest_borrowing: Some(pat.span.shrink_to_lo()),
+                    has_path: path.is_some(),
+                    path: path.map(|p| p.display().to_string()).unwrap_or_default(),
                 });
             }
             return;

library/core/src/fmt/mod.rs

@@ -288,7 +288,7 @@ pub enum DebugAsHex {
 ///
 /// `FormattingOptions` is a [`Formatter`] without an attached [`Write`] trait.
 /// It is mainly used to construct `Formatter` instances.
-#[derive(Copy, Clone, Debug, PartialEq, Eq, Default)]
+#[derive(Copy, Clone, Debug, PartialEq, Eq)]
 #[unstable(feature = "formatting_options", issue = "118117")]
 pub struct FormattingOptions {
     flags: u32,
@@ -508,6 +508,15 @@ impl FormattingOptions {
     }
 }
 
+#[unstable(feature = "formatting_options", issue = "118117")]
+impl Default for FormattingOptions {
+    /// Same as [`FormattingOptions::new()`].
+    fn default() -> Self {
+        // The `#[derive(Default)]` implementation would set `fill` to `\0` instead of space.
+        Self::new()
+    }
+}
+
 /// Configuration for formatting.
 ///
 /// A `Formatter` represents various options related to formatting. Users do not

library/core/tests/fmt/mod.rs

@@ -51,6 +51,12 @@ fn test_maybe_uninit_short() {
     assert_eq!(format!("{x:?}"), "MaybeUninit<u32>");
 }
 
+#[test]
+fn formatting_options_ctor() {
+    use core::fmt::FormattingOptions;
+    assert_eq!(FormattingOptions::new(), FormattingOptions::default());
+}
+
 #[test]
 fn formatting_options_flags() {
     use core::fmt::*;

library/std/src/sys/pal/unix/thread.rs

@@ -130,7 +130,12 @@ impl Thread {
         }
     }
 
-    #[cfg(any(target_os = "linux", target_os = "freebsd", target_os = "dragonfly"))]
+    #[cfg(any(
+        target_os = "linux",
+        target_os = "freebsd",
+        target_os = "dragonfly",
+        target_os = "nuttx"
+    ))]
     pub fn set_name(name: &CStr) {
         unsafe {
             cfg_if::cfg_if! {
@@ -139,7 +144,7 @@ impl Thread {
                     const TASK_COMM_LEN: usize = 16;
                     let name = truncate_cstr::<{ TASK_COMM_LEN }>(name);
                 } else {
-                    // FreeBSD and DragonFly BSD do not enforce length limits.
+                    // FreeBSD, DragonFly, FreeBSD and NuttX do not enforce length limits.
                 }
             };
             // Available since glibc 2.12, musl 1.1.16, and uClibc 1.0.20 for Linux,
@@ -150,7 +155,7 @@ impl Thread {
         }
     }
 
-    #[cfg(any(target_os = "openbsd", target_os = "nuttx"))]
+    #[cfg(target_os = "openbsd")]
     pub fn set_name(name: &CStr) {
         unsafe {
             libc::pthread_set_name_np(libc::pthread_self(), name.as_ptr());

src/bootstrap/bootstrap.py

@@ -1310,9 +1310,6 @@ def bootstrap(args):
     args = [build.bootstrap_binary()]
     args.extend(sys.argv[1:])
     env = os.environ.copy()
-    # The Python process ID is used when creating a Windows job object
-    # (see src\bootstrap\src\utils\job.rs)
-    env["BOOTSTRAP_PARENT_ID"] = str(os.getpid())
     env["BOOTSTRAP_PYTHON"] = sys.executable
     run(args, env=env, verbose=build.verbose, is_bootstrap=True)
 

src/bootstrap/src/bin/main.rs

@@ -57,7 +57,9 @@ fn main() {
             }
             err => {
                 drop(err);
-                if let Ok(pid) = pid {
+                // #135972: We can reach this point when the lock has been taken,
+                // but the locker has not yet written its PID to the file
+                if let Some(pid) = pid.ok().filter(|pid| !pid.is_empty()) {
                     println!("WARNING: build directory locked by process {pid}, waiting for lock");
                 } else {
                     println!("WARNING: build directory locked, waiting for lock");

src/bootstrap/src/utils/job.rs

@@ -42,9 +42,9 @@ pub unsafe fn setup(build: &mut crate::Build) {
 #[cfg(windows)]
 mod for_windows {
     use std::ffi::c_void;
-    use std::{env, io, mem};
+    use std::{io, mem};
 
-    use windows::Win32::Foundation::{CloseHandle, DUPLICATE_SAME_ACCESS, DuplicateHandle, HANDLE};
+    use windows::Win32::Foundation::CloseHandle;
     use windows::Win32::System::Diagnostics::Debug::{
         SEM_NOGPFAULTERRORBOX, SetErrorMode, THREAD_ERROR_MODE,
     };
@@ -53,9 +53,7 @@ mod for_windows {
         JOB_OBJECT_LIMIT_PRIORITY_CLASS, JOBOBJECT_EXTENDED_LIMIT_INFORMATION,
         JobObjectExtendedLimitInformation, SetInformationJobObject,
     };
-    use windows::Win32::System::Threading::{
-        BELOW_NORMAL_PRIORITY_CLASS, GetCurrentProcess, OpenProcess, PROCESS_DUP_HANDLE,
-    };
+    use windows::Win32::System::Threading::{BELOW_NORMAL_PRIORITY_CLASS, GetCurrentProcess};
     use windows::core::PCWSTR;
 
     use crate::Build;
@@ -95,49 +93,8 @@ mod for_windows {
             return;
         }
 
-        // If we've got a parent process (e.g., the python script that called us)
-        // then move ownership of this job object up to them. That way if the python
-        // script is killed (e.g., via ctrl-c) then we'll all be torn down.
-        //
-        // If we don't have a parent (e.g., this was run directly) then we
-        // intentionally leak the job object handle. When our process exits
+        // Note: we intentionally leak the job object handle. When our process exits
         // (normally or abnormally) it will close the handle implicitly, causing all
         // processes in the job to be cleaned up.
-        let pid = match env::var("BOOTSTRAP_PARENT_ID") {
-            Ok(s) => s,
-            Err(..) => return,
-        };
-
-        let parent = match OpenProcess(PROCESS_DUP_HANDLE, false, pid.parse().unwrap()).ok() {
-            Some(parent) => parent,
-            _ => {
-                // If we get a null parent pointer here, it is possible that either
-                // we have an invalid pid or the parent process has been closed.
-                // Since the first case rarely happens
-                // (only when wrongly setting the environmental variable),
-                // it might be better to improve the experience of the second case
-                // when users have interrupted the parent process and we haven't finish
-                // duplicating the handle yet.
-                return;
-            }
-        };
-
-        let mut parent_handle = HANDLE::default();
-        // If this fails, well at least we tried! An example of DuplicateHandle
-        // failing in the past has been when the wrong python2 package spawned this
-        // build system (e.g., the `python2` package in MSYS instead of
-        // `mingw-w64-x86_64-python2`). Not sure why it failed, but the "failure
-        // mode" here is that we only clean everything up when the build system
-        // dies, not when the python parent does, so not too bad.
-        let _ = DuplicateHandle(
-            GetCurrentProcess(),
-            job,
-            parent,
-            &mut parent_handle,
-            0,
-            false,
-            DUPLICATE_SAME_ACCESS,
-        );
-        CloseHandle(parent).ok();
     }
 }

src/build_helper/src/metrics.rs

@@ -16,6 +16,7 @@ pub struct JsonInvocation {
     //
     // This is necessary to easily correlate this invocation with logs or other data.
     pub start_time: u64,
+    #[serde(deserialize_with = "null_as_f64_nan")]
     pub duration_including_children_sec: f64,
     pub children: Vec<JsonNode>,
 }
@@ -28,6 +29,7 @@ pub enum JsonNode {
         type_: String,
         debug_repr: String,
 
+        #[serde(deserialize_with = "null_as_f64_nan")]
         duration_excluding_children_sec: f64,
         system_stats: JsonStepSystemStats,
 
@@ -88,5 +90,11 @@ pub struct JsonInvocationSystemStats {
 #[derive(Serialize, Deserialize)]
 #[serde(rename_all = "snake_case")]
 pub struct JsonStepSystemStats {
+    #[serde(deserialize_with = "null_as_f64_nan")]
     pub cpu_utilization_percent: f64,
 }
+
+fn null_as_f64_nan<'de, D: serde::Deserializer<'de>>(d: D) -> Result<f64, D::Error> {
+    use serde::Deserialize as _;
+    Option::<f64>::deserialize(d).map(|f| f.unwrap_or(f64::NAN))
+}

src/tools/tidy/src/issues.txt

@@ -409,7 +409,6 @@ ui/closure_context/issue-26046-fn-once.rs
 ui/closure_context/issue-42065.rs
 ui/closures/2229_closure_analysis/issue-118144.rs
 ui/closures/2229_closure_analysis/issue-87378.rs
-ui/closures/2229_closure_analysis/issue-87987.rs
 ui/closures/2229_closure_analysis/issue-88118-2.rs
 ui/closures/2229_closure_analysis/issue-88476.rs
 ui/closures/2229_closure_analysis/issue-89606.rs

tests/ui/closures/2229_closure_analysis/issue-87987.rs

@@ -0,0 +1,46 @@
+//! When a closure syntactically captures a place, but doesn't actually capture
+//! it, make sure MIR building doesn't ICE when handling that place.
+//!
+//! Under the Rust 2021 disjoint capture rules, this sort of non-capture can
+//! occur when a place is only inspected by infallible non-binding patterns.
+
+// FIXME(#135985): On its own, this test should probably just be check-pass.
+// But there are few/no other tests that use non-binding array patterns and
+// invoke the later parts of the compiler, so building/running has some value.
+
+//@ run-pass
+//@ edition:2021
+
+#[expect(dead_code)]
+struct Props {
+    field_1: u32,
+    field_2: u32,
+}
+
+fn main() {
+    // Test 1
+    let props_2 = Props { field_1: 1, field_2: 1 };
+
+    let _ = || {
+        let _: Props = props_2;
+    };
+
+    // Test 2
+    let mut arr = [1, 3, 4, 5];
+
+    let mref = &mut arr;
+
+    // These array patterns don't need to inspect the array, so the array
+    // isn't captured.
+    let _c = || match arr {
+        [_, _, _, _] => println!("C"),
+    };
+    let _d = || match arr {
+        [_, .., _] => println!("D"),
+    };
+    let _e = || match arr {
+        [_, ..] => println!("E"),
+    };
+
+    println!("{:#?}", mref);
+}

tests/ui/closures/2229_closure_analysis/issue-87987.stderr

@@ -0,0 +1,8 @@
+use std::rc::Rc;
+
+#[derive(PartialEq)] //~ NOTE in this expansion
+pub struct Function {
+    callback: Rc<dyn Fn()>, //~ ERROR binary operation `==` cannot be applied to type `Rc<dyn Fn()>`
+}
+
+fn main() {}

tests/ui/closures/2229_closure_analysis/unresolvable-upvar-issue-87987.rs

@@ -0,0 +1,14 @@
+error[E0369]: binary operation `==` cannot be applied to type `Rc<dyn Fn()>`
+  --> $DIR/do-not-suggest-calling-fn-in-derive-macro.rs:5:5
+   |
+LL | #[derive(PartialEq)]
+   |          --------- in this derive macro expansion
+LL | pub struct Function {
+LL |     callback: Rc<dyn Fn()>,
+   |     ^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: this error originates in the derive macro `PartialEq` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0369`.

tests/ui/deriving/do-not-suggest-calling-fn-in-derive-macro.rs

@@ -0,0 +1,17 @@
+//@ compile-flags: --diagnostic-width=60 -Zwrite-long-types-to-disk=yes
+//@ normalize-stderr: "long-type-\d+" -> "long-type-hash"
+type A = (String, String, String, String);
+type B = (A, A, A, A);
+type C = (B, B, B, B);
+type D = (C, C, C, C);
+
+trait Trait {}
+
+fn require_trait<T: Trait>() {}
+
+fn foo(x: D) {
+    let _a = x;
+    let _b = x; //~ ERROR use of moved value
+}
+
+fn main() {}

tests/ui/deriving/do-not-suggest-calling-fn-in-derive-macro.stderr

@@ -0,0 +1,20 @@
+error[E0382]: use of moved value: `x`
+  --> $DIR/non-copy-type-moved.rs:14:14
+   |
+LL | fn foo(x: D) {
+   |        - move occurs because `x` has type `((..., ..., ..., ...), ..., ..., ...)`, which does not implement the `Copy` trait
+LL |     let _a = x;
+   |              - value moved here
+LL |     let _b = x;
+   |              ^ value used here after move
+   |
+   = note: the full type name has been written to '$TEST_BUILD_DIR/diagnostic-width/non-copy-type-moved/non-copy-type-moved.long-type-hash.txt'
+   = note: consider using `--verbose` to print the full type name to the console
+help: consider cloning the value if the performance cost is acceptable
+   |
+LL |     let _a = x.clone();
+   |               ++++++++
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0382`.

tests/ui/diagnostic-width/non-copy-type-moved.rs

@@ -0,0 +1,17 @@
+trait A<C = <Self as D>::E> {}
+
+trait D {
+    type E;
+}
+
+impl A<()> for () {}
+impl D for () {
+    type E = ();
+}
+
+fn f() {
+    let B: &dyn A = &();
+    //~^ ERROR the type parameter `C` must be explicitly specified
+}
+
+fn main() {}

tests/ui/diagnostic-width/non-copy-type-moved.stderr

@@ -0,0 +1,18 @@
+error[E0393]: the type parameter `C` must be explicitly specified
+  --> $DIR/default-param-self-projection.rs:13:17
+   |
+LL | trait A<C = <Self as D>::E> {}
+   | --------------------------- type parameter `C` must be specified for this
+...
+LL |     let B: &dyn A = &();
+   |                 ^
+   |
+   = note: because the parameter default references `Self`, the parameter must be specified on the object type
+help: set the type parameter to the desired type
+   |
+LL |     let B: &dyn A<C> = &();
+   |                  +++
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0393`.

tests/ui/dyn-compatibility/default-param-self-projection.rs

@@ -7,7 +7,7 @@ LL |
 LL | fn together_we_will_rule_the_galaxy(son: &dyn A) {}
    |                                               ^
    |
-   = note: because of the default `Self` reference, type parameters must be specified on object types
+   = note: because the parameter default references `Self`, the parameter must be specified on the object type
 help: set the type parameter to the desired type
    |
 LL | fn together_we_will_rule_the_galaxy(son: &dyn A<T>) {}

tests/ui/dyn-compatibility/default-param-self-projection.stderr

@@ -7,7 +7,7 @@ LL |
 LL | fn f(a: &dyn A) {}
    |              ^
    |
-   = note: because of the default `Self` reference, type parameters must be specified on object types
+   = note: because the parameter default references `Self`, the parameter must be specified on the object type
 help: set the type parameter to the desired type
    |
 LL | fn f(a: &dyn A<T>) {}

tests/ui/error-codes/E0393.stderr

@@ -10,6 +10,7 @@ fn w<'a, T: 'a, F: Fn(&'a T)>() {
     let b: &dyn FromResidual = &();
     //~^ ERROR: the trait `FromResidual` is not dyn compatible
     //~| ERROR: the trait `FromResidual` is not dyn compatible
+    //~| ERROR the type parameter `R` must be explicitly specified
 }
 
 fn main() {}

tests/ui/issues/issue-22370.stderr

@@ -1,3 +1,18 @@
+error[E0393]: the type parameter `R` must be explicitly specified
+  --> $DIR/canonicalize-fresh-infer-vars-issue-103626.rs:10:17
+   |
+LL | trait FromResidual<R = <Self as Try>::Residual> {
+   | ----------------------------------------------- type parameter `R` must be specified for this
+...
+LL |     let b: &dyn FromResidual = &();
+   |                 ^^^^^^^^^^^^
+   |
+   = note: because the parameter default references `Self`, the parameter must be specified on the object type
+help: set the type parameter to the desired type
+   |
+LL |     let b: &dyn FromResidual<R> = &();
+   |                             +++
+
 error[E0038]: the trait `FromResidual` is not dyn compatible
   --> $DIR/canonicalize-fresh-infer-vars-issue-103626.rs:10:32
    |
@@ -45,6 +60,7 @@ help: alternatively, consider constraining `from_residual` so it does not apply
 LL |     fn from_residual(residual: R) -> Self where Self: Sized;
    |                                           +++++++++++++++++
 
-error: aborting due to 2 previous errors
+error: aborting due to 3 previous errors
 
-For more information about this error, try `rustc --explain E0038`.
+Some errors have detailed explanations: E0038, E0393.
+For more information about an error, try `rustc --explain E0038`.

tests/ui/traits/object/canonicalize-fresh-infer-vars-issue-103626.rs

@@ -97,7 +97,7 @@ LL | pub trait Bar<X=usize, A=Self> {
 LL |     let e = Bar::<usize>::lol();
    |             ^^^^^^^^^^^^ missing reference to `A`
    |
-   = note: because of the default `Self` reference, type parameters must be specified on object types
+   = note: because the parameter default references `Self`, the parameter must be specified on the object type
 
 error: aborting due to 5 previous errors; 5 warnings emitted
 

tests/ui/traits/object/canonicalize-fresh-infer-vars-issue-103626.stderr

@@ -7,7 +7,7 @@ LL | trait Foo<T=Self> {
 LL | fn foo(x: &dyn Foo) { }
    |                ^^^
    |
-   = note: because of the default `Self` reference, type parameters must be specified on object types
+   = note: because the parameter default references `Self`, the parameter must be specified on the object type
 help: set the type parameter to the desired type
    |
 LL | fn foo(x: &dyn Foo<T>) { }