Auto merge of #146418 - matthiaskrgr:rollup-za0lrux, r=matthiaskrgr

Rollup of 8 pull requests

Successful merges:

 - rust-lang/rust#145327 (std: make address resolution weirdness local to SGX)
 - rust-lang/rust#145879 (default auto traits: use default supertraits instead of `Self: Trait` bounds on associated items)
 - rust-lang/rust#146123 (Suggest examples of format specifiers in error messages)
 - rust-lang/rust#146311 (Minor symbol comment fixes.)
 - rust-lang/rust#146322 (Make Barrier RefUnwindSafe again)
 - rust-lang/rust#146327 (Add tests for deref on pin)
 - rust-lang/rust#146340 (Strip frontmatter in fewer places)
 - rust-lang/rust#146342 (Improve C-variadic error messages: part 2)

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

40 files changed, 920 insertions, 337 deletions

diff --git a/tests/ui-fulldeps/auxiliary/parser.rs b/tests/ui-fulldeps/auxiliary/parser.rs
index 6726969350d..6ee39e5130f 100644
--- a/tests/ui-fulldeps/auxiliary/parser.rs
+++ b/tests/ui-fulldeps/auxiliary/parser.rs
@@ -10,7 +10,7 @@ extern crate rustc_span;
 use rustc_ast::ast::{AttrKind, Attribute, DUMMY_NODE_ID, Expr};
 use rustc_ast::mut_visit::{self, MutVisitor};
 use rustc_ast::node_id::NodeId;
-use rustc_ast::token::{self, Token};
+use rustc_ast::token;
 use rustc_ast::tokenstream::{AttrTokenStream, AttrTokenTree, LazyAttrTokenStream};
 use rustc_errors::Diag;
 use rustc_parse::parser::Recovery;
@@ -23,6 +23,7 @@ pub fn parse_expr(psess: &ParseSess, source_code: &str) -> Option<Box<Expr>> {
         psess,
         FileName::anon_source_code(source_code),
         source_code.to_owned(),
+        rustc_parse::lexer::StripTokens::Nothing,
     ));
 
     let mut parser = parser.recovery(Recovery::Forbidden);
diff --git a/tests/ui-fulldeps/mod_dir_path_canonicalized.rs b/tests/ui-fulldeps/mod_dir_path_canonicalized.rs
index 99cb5fc5aa1..df5f29e35fe 100644
--- a/tests/ui-fulldeps/mod_dir_path_canonicalized.rs
+++ b/tests/ui-fulldeps/mod_dir_path_canonicalized.rs
@@ -16,7 +16,7 @@ extern crate rustc_span;
 #[allow(unused_extern_crates)]
 extern crate rustc_driver;
 
-use rustc_parse::{new_parser_from_file, unwrap_or_emit_fatal};
+use rustc_parse::{lexer::StripTokens, new_parser_from_file, unwrap_or_emit_fatal};
 use rustc_session::parse::ParseSess;
 use std::path::Path;
 
@@ -34,6 +34,11 @@ fn parse() {
 
     let path = Path::new(file!());
     let path = path.canonicalize().unwrap();
-    let mut parser = unwrap_or_emit_fatal(new_parser_from_file(&psess, &path, None));
+    let mut parser = unwrap_or_emit_fatal(new_parser_from_file(
+        &psess,
+        &path,
+        StripTokens::ShebangAndFrontmatter,
+        None,
+    ));
     let _ = parser.parse_crate_mod();
 }
diff --git a/tests/ui/c-variadic/issue-86053-1.rs b/tests/ui/c-variadic/issue-86053-1.rs
index 537d0263adf..58dfee55cf8 100644
--- a/tests/ui/c-variadic/issue-86053-1.rs
+++ b/tests/ui/c-variadic/issue-86053-1.rs
@@ -13,6 +13,6 @@ fn ordering4 < 'a , 'b     > ( a :            ,   self , self ,   self ,
     //~| ERROR unexpected `self` parameter in function
     //~| ERROR unexpected `self` parameter in function
     //~| ERROR `...` must be the last argument of a C-variadic function
-    //~| ERROR defining functions with C-variadic arguments is only allowed for free functions with the "C" or "C-unwind" calling convention
+    //~| ERROR `...` is not supported for non-extern functions
     //~| ERROR cannot find type `F` in this scope
 }
diff --git a/tests/ui/c-variadic/issue-86053-1.stderr b/tests/ui/c-variadic/issue-86053-1.stderr
index b58016b5a81..adbc04d3a65 100644
--- a/tests/ui/c-variadic/issue-86053-1.stderr
+++ b/tests/ui/c-variadic/issue-86053-1.stderr
@@ -46,11 +46,13 @@ error: `...` must be the last argument of a C-variadic function
 LL |     self , ... ,   self ,   self , ... ) where F : FnOnce ( & 'a & 'b usize ) {
    |            ^^^
 
-error: defining functions with C-variadic arguments is only allowed for free functions with the "C" or "C-unwind" calling convention
+error: `...` is not supported for non-extern functions
   --> $DIR/issue-86053-1.rs:11:36
    |
 LL |     self , ... ,   self ,   self , ... ) where F : FnOnce ( & 'a & 'b usize ) {
    |                                    ^^^
+   |
+   = help: only `extern "C"` and `extern "C-unwind"` functions may have a C variable argument list
 
 error[E0412]: cannot find type `F` in this scope
   --> $DIR/issue-86053-1.rs:11:48
diff --git a/tests/ui/c-variadic/not-async.rs b/tests/ui/c-variadic/not-async.rs
new file mode 100644
index 00000000000..45a7e1f8972
--- /dev/null
+++ b/tests/ui/c-variadic/not-async.rs
@@ -0,0 +1,7 @@
+//@ edition: 2021
+#![feature(c_variadic)]
+#![crate_type = "lib"]
+
+async unsafe extern "C" fn cannot_be_async(x: isize, ...) {}
+//~^ ERROR functions cannot be both `async` and C-variadic
+//~| ERROR hidden type for `impl Future<Output = ()>` captures lifetime that does not appear in bounds
diff --git a/tests/ui/c-variadic/not-async.stderr b/tests/ui/c-variadic/not-async.stderr
new file mode 100644
index 00000000000..b8caf0d8bd8
--- /dev/null
+++ b/tests/ui/c-variadic/not-async.stderr
@@ -0,0 +1,19 @@
+error: functions cannot be both `async` and C-variadic
+  --> $DIR/not-async.rs:5:1
+   |
+LL | async unsafe extern "C" fn cannot_be_async(x: isize, ...) {}
+   | ^^^^^ `async` because of this                        ^^^ C-variadic because of this
+
+error[E0700]: hidden type for `impl Future<Output = ()>` captures lifetime that does not appear in bounds
+  --> $DIR/not-async.rs:5:59
+   |
+LL | async unsafe extern "C" fn cannot_be_async(x: isize, ...) {}
+   | --------------------------------------------------------- ^^
+   | |
+   | opaque type defined here
+   |
+   = note: hidden type `{async fn body of cannot_be_async()}` captures lifetime `'_`
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0700`.
diff --git a/tests/ui/cmse-nonsecure/cmse-nonsecure-entry/generics.rs b/tests/ui/cmse-nonsecure/cmse-nonsecure-entry/generics.rs
index ad4fca8252d..eb6f4a32365 100644
--- a/tests/ui/cmse-nonsecure/cmse-nonsecure-entry/generics.rs
+++ b/tests/ui/cmse-nonsecure/cmse-nonsecure-entry/generics.rs
@@ -53,9 +53,7 @@ extern "cmse-nonsecure-entry" fn trait_object(x: &dyn Trait) -> &dyn Trait {
     x
 }
 
-extern "cmse-nonsecure-entry" fn static_trait_object(
-    x: &'static dyn Trait,
-) -> &'static dyn Trait {
+extern "cmse-nonsecure-entry" fn static_trait_object(x: &'static dyn Trait) -> &'static dyn Trait {
     //~^ ERROR return value of `"cmse-nonsecure-entry"` function too large to pass via registers [E0798]
     x
 }
@@ -63,14 +61,12 @@ extern "cmse-nonsecure-entry" fn static_trait_object(
 #[repr(transparent)]
 struct WrapperTransparent<'a>(&'a dyn Trait);
 
-extern "cmse-nonsecure-entry" fn wrapped_trait_object(
-    x: WrapperTransparent,
-) -> WrapperTransparent {
+extern "cmse-nonsecure-entry" fn wrapped_trait_object(x: WrapperTransparent) -> WrapperTransparent {
     //~^ ERROR return value of `"cmse-nonsecure-entry"` function too large to pass via registers [E0798]
     x
 }
 
-extern "cmse-nonsecure-entry" fn c_variadic(_: u32, _: ...) {
-    //~^ ERROR defining functions with C-variadic arguments is only allowed for free functions with the "C" or "C-unwind" calling convention
+unsafe extern "cmse-nonsecure-entry" fn c_variadic(_: u32, _: ...) {
+    //~^ ERROR `...` is not supported for `extern "cmse-nonsecure-entry"` functions
     //~| ERROR requires `va_list` lang_item
 }
diff --git a/tests/ui/cmse-nonsecure/cmse-nonsecure-entry/generics.stderr b/tests/ui/cmse-nonsecure/cmse-nonsecure-entry/generics.stderr
index 7aeb6969feb..8937def9428 100644
--- a/tests/ui/cmse-nonsecure/cmse-nonsecure-entry/generics.stderr
+++ b/tests/ui/cmse-nonsecure/cmse-nonsecure-entry/generics.stderr
@@ -1,8 +1,12 @@
-error: defining functions with C-variadic arguments is only allowed for free functions with the "C" or "C-unwind" calling convention
-  --> $DIR/generics.rs:73:53
+error: `...` is not supported for `extern "cmse-nonsecure-entry"` functions
+  --> $DIR/generics.rs:69:60
    |
-LL | extern "cmse-nonsecure-entry" fn c_variadic(_: u32, _: ...) {
-   |                                                     ^^^^^^
+LL | unsafe extern "cmse-nonsecure-entry" fn c_variadic(_: u32, _: ...) {
+   |        -----------------------------                       ^^^^^^
+   |        |
+   |        `extern "cmse-nonsecure-entry"` because of this
+   |
+   = help: only `extern "C"` and `extern "C-unwind"` functions may have a C variable argument list
 
 error[E0798]: functions with the `"cmse-nonsecure-entry"` ABI cannot contain generics in their type
   --> $DIR/generics.rs:30:1
@@ -50,28 +54,28 @@ LL | extern "cmse-nonsecure-entry" fn trait_object(x: &dyn Trait) -> &dyn Trait
    = note: the result must either be a (transparently wrapped) i64, u64 or f64, or be at most 4 bytes in size
 
 error[E0798]: return value of `"cmse-nonsecure-entry"` function too large to pass via registers
-  --> $DIR/generics.rs:58:6
+  --> $DIR/generics.rs:56:80
    |
-LL | ) -> &'static dyn Trait {
-   |      ^^^^^^^^^^^^^^^^^^ this type doesn't fit in the available registers
+LL | extern "cmse-nonsecure-entry" fn static_trait_object(x: &'static dyn Trait) -> &'static dyn Trait {
+   |                                                                                ^^^^^^^^^^^^^^^^^^ this type doesn't fit in the available registers
    |
    = note: functions with the `"cmse-nonsecure-entry"` ABI must pass their result via the available return registers
    = note: the result must either be a (transparently wrapped) i64, u64 or f64, or be at most 4 bytes in size
 
 error[E0798]: return value of `"cmse-nonsecure-entry"` function too large to pass via registers
-  --> $DIR/generics.rs:68:6
+  --> $DIR/generics.rs:64:81
    |
-LL | ) -> WrapperTransparent {
-   |      ^^^^^^^^^^^^^^^^^^ this type doesn't fit in the available registers
+LL | extern "cmse-nonsecure-entry" fn wrapped_trait_object(x: WrapperTransparent) -> WrapperTransparent {
+   |                                                                                 ^^^^^^^^^^^^^^^^^^ this type doesn't fit in the available registers
    |
    = note: functions with the `"cmse-nonsecure-entry"` ABI must pass their result via the available return registers
    = note: the result must either be a (transparently wrapped) i64, u64 or f64, or be at most 4 bytes in size
 
 error: requires `va_list` lang_item
-  --> $DIR/generics.rs:73:53
+  --> $DIR/generics.rs:69:60
    |
-LL | extern "cmse-nonsecure-entry" fn c_variadic(_: u32, _: ...) {
-   |                                                     ^^^^^^
+LL | unsafe extern "cmse-nonsecure-entry" fn c_variadic(_: u32, _: ...) {
+   |                                                            ^^^^^^
 
 error: aborting due to 9 previous errors
 
diff --git a/tests/ui/deref/pin-deref-const.rs b/tests/ui/deref/pin-deref-const.rs
new file mode 100644
index 00000000000..6ed00177b23
--- /dev/null
+++ b/tests/ui/deref/pin-deref-const.rs
@@ -0,0 +1,79 @@
+// The purpose of this file is to track the error messages from Pin and DerefMut interacting.
+//
+// Identical to `pin-deref.rs` except for using unstable `const fn`.
+
+//@ check-fail
+
+#![feature(const_convert)]
+#![feature(const_trait_impl)]
+
+use std::ops::DerefMut;
+use std::pin::Pin;
+
+struct MyUnpinType {}
+
+impl MyUnpinType {
+    const fn at_self(&self) {}
+    const fn at_mut_self(&mut self) {}
+}
+
+struct MyPinType(core::marker::PhantomPinned);
+
+impl MyPinType {
+    const fn at_self(&self) {}
+    const fn at_mut_self(&mut self) {}
+}
+
+const fn call_mut_ref_unpin(mut r_unpin: Pin<&mut MyUnpinType>) {
+    r_unpin.at_self();
+    r_unpin.at_mut_self();
+}
+
+const fn call_ref_unpin(mut r_unpin: Pin<&MyUnpinType>) {
+    r_unpin.at_self();
+    r_unpin.at_mut_self(); //~ ERROR: cannot borrow data in dereference of `Pin<&MyUnpinType>` as mutable
+}
+
+const fn call_mut_ref_pin(mut r_pin: Pin<&mut MyPinType>) {
+    r_pin.at_self();
+    r_pin.at_mut_self(); //~ ERROR: cannot borrow data in dereference of `Pin<&mut MyPinType>` as mutable
+}
+
+const fn call_ref_pin(mut r_pin: Pin<&MyPinType>) {
+    r_pin.at_self();
+    r_pin.at_mut_self(); //~ ERROR: cannot borrow data in dereference of `Pin<&MyPinType>` as mutable
+}
+
+const fn coerce_unpin_rr<'a>(mut r_unpin: &'a mut Pin<&MyUnpinType>) -> &'a MyUnpinType {
+    r_unpin
+}
+
+const fn coerce_unpin_rm<'a>(mut r_unpin: &'a mut Pin<&MyUnpinType>) -> &'a mut MyUnpinType {
+    r_unpin //~ ERROR: cannot borrow data in dereference of `Pin<&MyUnpinType>` as mutable
+}
+
+const fn coerce_unpin_mr<'a>(mut r_unpin: &'a mut Pin<&mut MyUnpinType>) -> &'a MyUnpinType {
+    r_unpin
+}
+
+const fn coerce_unpin_mm<'a>(mut r_unpin: &'a mut Pin<&mut MyUnpinType>) -> &'a mut MyUnpinType {
+    r_unpin
+}
+
+const fn coerce_pin_rr<'a>(mut r_pin: &'a mut Pin<&MyPinType>) -> &'a MyPinType {
+    r_pin
+}
+
+const fn coerce_pin_rm<'a>(mut r_pin: &'a mut Pin<&MyPinType>) -> &'a mut MyPinType {
+    r_pin //~ ERROR: cannot borrow data in dereference of `Pin<&MyPinType>` as mutable
+}
+
+const fn coerce_pin_mr<'a>(mut r_pin: &'a mut Pin<&mut MyPinType>) -> &'a MyPinType {
+    r_pin
+}
+
+const fn coerce_pin_mm<'a>(mut r_pin: &'a mut Pin<&mut MyPinType>) -> &'a mut MyPinType {
+    r_pin //~ ERROR: cannot borrow data in dereference of `Pin<&mut MyPinType>` as mutable
+}
+
+fn main() {}
diff --git a/tests/ui/deref/pin-deref-const.stderr b/tests/ui/deref/pin-deref-const.stderr
new file mode 100644
index 00000000000..caa270e64ff
--- /dev/null
+++ b/tests/ui/deref/pin-deref-const.stderr
@@ -0,0 +1,51 @@
+error[E0596]: cannot borrow data in dereference of `Pin<&MyUnpinType>` as mutable
+  --> $DIR/pin-deref-const.rs:34:5
+   |
+LL |     r_unpin.at_mut_self();
+   |     ^^^^^^^ cannot borrow as mutable
+   |
+   = help: trait `DerefMut` is required to modify through a dereference, but it is not implemented for `Pin<&MyUnpinType>`
+
+error[E0596]: cannot borrow data in dereference of `Pin<&mut MyPinType>` as mutable
+  --> $DIR/pin-deref-const.rs:39:5
+   |
+LL |     r_pin.at_mut_self();
+   |     ^^^^^ cannot borrow as mutable
+   |
+   = help: trait `DerefMut` is required to modify through a dereference, but it is not implemented for `Pin<&mut MyPinType>`
+
+error[E0596]: cannot borrow data in dereference of `Pin<&MyPinType>` as mutable
+  --> $DIR/pin-deref-const.rs:44:5
+   |
+LL |     r_pin.at_mut_self();
+   |     ^^^^^ cannot borrow as mutable
+   |
+   = help: trait `DerefMut` is required to modify through a dereference, but it is not implemented for `Pin<&MyPinType>`
+
+error[E0596]: cannot borrow data in dereference of `Pin<&MyUnpinType>` as mutable
+  --> $DIR/pin-deref-const.rs:52:5
+   |
+LL |     r_unpin
+   |     ^^^^^^^ cannot borrow as mutable
+   |
+   = help: trait `DerefMut` is required to modify through a dereference, but it is not implemented for `Pin<&MyUnpinType>`
+
+error[E0596]: cannot borrow data in dereference of `Pin<&MyPinType>` as mutable
+  --> $DIR/pin-deref-const.rs:68:5
+   |
+LL |     r_pin
+   |     ^^^^^ cannot borrow as mutable
+   |
+   = help: trait `DerefMut` is required to modify through a dereference, but it is not implemented for `Pin<&MyPinType>`
+
+error[E0596]: cannot borrow data in dereference of `Pin<&mut MyPinType>` as mutable
+  --> $DIR/pin-deref-const.rs:76:5
+   |
+LL |     r_pin
+   |     ^^^^^ cannot borrow as mutable
+   |
+   = help: trait `DerefMut` is required to modify through a dereference, but it is not implemented for `Pin<&mut MyPinType>`
+
+error: aborting due to 6 previous errors
+
+For more information about this error, try `rustc --explain E0596`.
diff --git a/tests/ui/deref/pin-deref.rs b/tests/ui/deref/pin-deref.rs
new file mode 100644
index 00000000000..180831c9bc6
--- /dev/null
+++ b/tests/ui/deref/pin-deref.rs
@@ -0,0 +1,76 @@
+// The purpose of this file is to track the error messages from Pin and DerefMut interacting.
+//
+// Identical to `pin-deref-const.rs` except for being stable and not using `const fn`.
+
+//@ check-fail
+
+use std::ops::DerefMut;
+use std::pin::Pin;
+
+struct MyUnpinType {}
+
+impl MyUnpinType {
+    fn at_self(&self) {}
+    fn at_mut_self(&mut self) {}
+}
+
+struct MyPinType(core::marker::PhantomPinned);
+
+impl MyPinType {
+    fn at_self(&self) {}
+    fn at_mut_self(&mut self) {}
+}
+
+fn call_mut_ref_unpin(mut r_unpin: Pin<&mut MyUnpinType>) {
+    r_unpin.at_self();
+    r_unpin.at_mut_self();
+}
+
+fn call_ref_unpin(mut r_unpin: Pin<&MyUnpinType>) {
+    r_unpin.at_self();
+    r_unpin.at_mut_self(); //~ ERROR: cannot borrow data in dereference of `Pin<&MyUnpinType>` as mutable
+}
+
+fn call_mut_ref_pin(mut r_pin: Pin<&mut MyPinType>) {
+    r_pin.at_self();
+    r_pin.at_mut_self(); //~ ERROR: cannot borrow data in dereference of `Pin<&mut MyPinType>` as mutable
+}
+
+fn call_ref_pin(mut r_pin: Pin<&MyPinType>) {
+    r_pin.at_self();
+    r_pin.at_mut_self(); //~ ERROR: cannot borrow data in dereference of `Pin<&MyPinType>` as mutable
+}
+
+fn coerce_unpin_rr<'a>(mut r_unpin: &'a mut Pin<&MyUnpinType>) -> &'a MyUnpinType {
+    r_unpin
+}
+
+fn coerce_unpin_rm<'a>(mut r_unpin: &'a mut Pin<&MyUnpinType>) -> &'a mut MyUnpinType {
+    r_unpin //~ ERROR: cannot borrow data in dereference of `Pin<&MyUnpinType>` as mutable
+}
+
+fn coerce_unpin_mr<'a>(mut r_unpin: &'a mut Pin<&mut MyUnpinType>) -> &'a MyUnpinType {
+    r_unpin
+}
+
+fn coerce_unpin_mm<'a>(mut r_unpin: &'a mut Pin<&mut MyUnpinType>) -> &'a mut MyUnpinType {
+    r_unpin
+}
+
+fn coerce_pin_rr<'a>(mut r_pin: &'a mut Pin<&MyPinType>) -> &'a MyPinType {
+    r_pin
+}
+
+fn coerce_pin_rm<'a>(mut r_pin: &'a mut Pin<&MyPinType>) -> &'a mut MyPinType {
+    r_pin //~ ERROR: cannot borrow data in dereference of `Pin<&MyPinType>` as mutable
+}
+
+fn coerce_pin_mr<'a>(mut r_pin: &'a mut Pin<&mut MyPinType>) -> &'a MyPinType {
+    r_pin
+}
+
+fn coerce_pin_mm<'a>(mut r_pin: &'a mut Pin<&mut MyPinType>) -> &'a mut MyPinType {
+    r_pin //~ ERROR: cannot borrow data in dereference of `Pin<&mut MyPinType>` as mutable
+}
+
+fn main() {}
diff --git a/tests/ui/deref/pin-deref.stderr b/tests/ui/deref/pin-deref.stderr
new file mode 100644
index 00000000000..71277a10cdf
--- /dev/null
+++ b/tests/ui/deref/pin-deref.stderr
@@ -0,0 +1,51 @@
+error[E0596]: cannot borrow data in dereference of `Pin<&MyUnpinType>` as mutable
+  --> $DIR/pin-deref.rs:31:5
+   |
+LL |     r_unpin.at_mut_self();
+   |     ^^^^^^^ cannot borrow as mutable
+   |
+   = help: trait `DerefMut` is required to modify through a dereference, but it is not implemented for `Pin<&MyUnpinType>`
+
+error[E0596]: cannot borrow data in dereference of `Pin<&mut MyPinType>` as mutable
+  --> $DIR/pin-deref.rs:36:5
+   |
+LL |     r_pin.at_mut_self();
+   |     ^^^^^ cannot borrow as mutable
+   |
+   = help: trait `DerefMut` is required to modify through a dereference, but it is not implemented for `Pin<&mut MyPinType>`
+
+error[E0596]: cannot borrow data in dereference of `Pin<&MyPinType>` as mutable
+  --> $DIR/pin-deref.rs:41:5
+   |
+LL |     r_pin.at_mut_self();
+   |     ^^^^^ cannot borrow as mutable
+   |
+   = help: trait `DerefMut` is required to modify through a dereference, but it is not implemented for `Pin<&MyPinType>`
+
+error[E0596]: cannot borrow data in dereference of `Pin<&MyUnpinType>` as mutable
+  --> $DIR/pin-deref.rs:49:5
+   |
+LL |     r_unpin
+   |     ^^^^^^^ cannot borrow as mutable
+   |
+   = help: trait `DerefMut` is required to modify through a dereference, but it is not implemented for `Pin<&MyUnpinType>`
+
+error[E0596]: cannot borrow data in dereference of `Pin<&MyPinType>` as mutable
+  --> $DIR/pin-deref.rs:65:5
+   |
+LL |     r_pin
+   |     ^^^^^ cannot borrow as mutable
+   |
+   = help: trait `DerefMut` is required to modify through a dereference, but it is not implemented for `Pin<&MyPinType>`
+
+error[E0596]: cannot borrow data in dereference of `Pin<&mut MyPinType>` as mutable
+  --> $DIR/pin-deref.rs:73:5
+   |
+LL |     r_pin
+   |     ^^^^^ cannot borrow as mutable
+   |
+   = help: trait `DerefMut` is required to modify through a dereference, but it is not implemented for `Pin<&mut MyPinType>`
+
+error: aborting due to 6 previous errors
+
+For more information about this error, try `rustc --explain E0596`.
diff --git a/tests/ui/deref/pin-impl-deref.rs b/tests/ui/deref/pin-impl-deref.rs
new file mode 100644
index 00000000000..b1dc8dea3f2
--- /dev/null
+++ b/tests/ui/deref/pin-impl-deref.rs
@@ -0,0 +1,40 @@
+// The purpose of this file is to track the error messages from Pin and DerefMut interacting.
+
+//@ check-fail
+
+use std::ops::DerefMut;
+use std::pin::Pin;
+
+struct MyUnpinType {}
+
+impl MyUnpinType {
+    fn at_self(&self) {}
+    fn at_mut_self(&mut self) {}
+}
+
+struct MyPinType(core::marker::PhantomPinned);
+
+impl MyPinType {
+    fn at_self(&self) {}
+    fn at_mut_self(&mut self) {}
+}
+
+fn impl_deref_mut(_: impl DerefMut) {}
+fn unpin_impl_ref(r_unpin: Pin<&MyUnpinType>) {
+    impl_deref_mut(r_unpin)
+    //~^ ERROR: the trait bound `Pin<&MyUnpinType>: DerefMut` is not satisfied
+}
+fn unpin_impl_mut(r_unpin: Pin<&mut MyUnpinType>) {
+    impl_deref_mut(r_unpin)
+}
+fn pin_impl_ref(r_pin: Pin<&MyPinType>) {
+    impl_deref_mut(r_pin)
+    //~^ ERROR: `PhantomPinned` cannot be unpinned
+    //~| ERROR: the trait bound `Pin<&MyPinType>: DerefMut` is not satisfied
+}
+fn pin_impl_mut(r_pin: Pin<&mut MyPinType>) {
+    impl_deref_mut(r_pin)
+    //~^ ERROR: `PhantomPinned` cannot be unpinned
+}
+
+fn main() {}
diff --git a/tests/ui/deref/pin-impl-deref.stderr b/tests/ui/deref/pin-impl-deref.stderr
new file mode 100644
index 00000000000..106654641a1
--- /dev/null
+++ b/tests/ui/deref/pin-impl-deref.stderr
@@ -0,0 +1,85 @@
+error[E0277]: the trait bound `Pin<&MyUnpinType>: DerefMut` is not satisfied
+  --> $DIR/pin-impl-deref.rs:24:20
+   |
+LL |     impl_deref_mut(r_unpin)
+   |     -------------- ^^^^^^^ the trait `DerefMut` is not implemented for `Pin<&MyUnpinType>`
+   |     |
+   |     required by a bound introduced by this call
+   |
+   = note: required for `Pin<&MyUnpinType>` to implement `DerefMut`
+note: required by a bound in `impl_deref_mut`
+  --> $DIR/pin-impl-deref.rs:22:27
+   |
+LL | fn impl_deref_mut(_: impl DerefMut) {}
+   |                           ^^^^^^^^ required by this bound in `impl_deref_mut`
+help: consider mutably borrowing here
+   |
+LL |     impl_deref_mut(&mut r_unpin)
+   |                    ++++
+
+error[E0277]: the trait bound `Pin<&MyPinType>: DerefMut` is not satisfied
+  --> $DIR/pin-impl-deref.rs:31:20
+   |
+LL |     impl_deref_mut(r_pin)
+   |     -------------- ^^^^^ the trait `DerefMut` is not implemented for `Pin<&MyPinType>`
+   |     |
+   |     required by a bound introduced by this call
+   |
+   = note: required for `Pin<&MyPinType>` to implement `DerefMut`
+note: required by a bound in `impl_deref_mut`
+  --> $DIR/pin-impl-deref.rs:22:27
+   |
+LL | fn impl_deref_mut(_: impl DerefMut) {}
+   |                           ^^^^^^^^ required by this bound in `impl_deref_mut`
+help: consider mutably borrowing here
+   |
+LL |     impl_deref_mut(&mut r_pin)
+   |                    ++++
+
+error[E0277]: `PhantomPinned` cannot be unpinned
+  --> $DIR/pin-impl-deref.rs:31:20
+   |
+LL |     impl_deref_mut(r_pin)
+   |     -------------- ^^^^^ within `MyPinType`, the trait `Unpin` is not implemented for `PhantomPinned`
+   |     |
+   |     required by a bound introduced by this call
+   |
+   = note: consider using the `pin!` macro
+           consider using `Box::pin` if you need to access the pinned value outside of the current scope
+note: required because it appears within the type `MyPinType`
+  --> $DIR/pin-impl-deref.rs:15:8
+   |
+LL | struct MyPinType(core::marker::PhantomPinned);
+   |        ^^^^^^^^^
+   = note: required for `Pin<&MyPinType>` to implement `DerefMut`
+note: required by a bound in `impl_deref_mut`
+  --> $DIR/pin-impl-deref.rs:22:27
+   |
+LL | fn impl_deref_mut(_: impl DerefMut) {}
+   |                           ^^^^^^^^ required by this bound in `impl_deref_mut`
+
+error[E0277]: `PhantomPinned` cannot be unpinned
+  --> $DIR/pin-impl-deref.rs:36:20
+   |
+LL |     impl_deref_mut(r_pin)
+   |     -------------- ^^^^^ within `MyPinType`, the trait `Unpin` is not implemented for `PhantomPinned`
+   |     |
+   |     required by a bound introduced by this call
+   |
+   = note: consider using the `pin!` macro
+           consider using `Box::pin` if you need to access the pinned value outside of the current scope
+note: required because it appears within the type `MyPinType`
+  --> $DIR/pin-impl-deref.rs:15:8
+   |
+LL | struct MyPinType(core::marker::PhantomPinned);
+   |        ^^^^^^^^^
+   = note: required for `Pin<&mut MyPinType>` to implement `DerefMut`
+note: required by a bound in `impl_deref_mut`
+  --> $DIR/pin-impl-deref.rs:22:27
+   |
+LL | fn impl_deref_mut(_: impl DerefMut) {}
+   |                           ^^^^^^^^ required by this bound in `impl_deref_mut`
+
+error: aborting due to 4 previous errors
+
+For more information about this error, try `rustc --explain E0277`.
diff --git a/tests/ui/feature-gates/feature-gate-c_variadic.rs b/tests/ui/feature-gates/feature-gate-c_variadic.rs
index 45c68842093..88d91dbd081 100644
--- a/tests/ui/feature-gates/feature-gate-c_variadic.rs
+++ b/tests/ui/feature-gates/feature-gate-c_variadic.rs
@@ -1,10 +1,10 @@
-#![crate_type="lib"]
+#![crate_type = "lib"]
 
-pub unsafe extern "C" fn test(_: i32, ap: ...) { }
+pub unsafe extern "C" fn test(_: i32, ap: ...) {}
 //~^ ERROR C-variadic functions are unstable
 
 trait Trait {
-    unsafe extern "C" fn trait_test(_: i32, ap: ...) { }
+    unsafe extern "C" fn trait_test(_: i32, ap: ...) {}
     //~^ ERROR C-variadic functions are unstable
-    //~| ERROR defining functions with C-variadic arguments is only allowed for free functions with the "C" or "C-unwind" calling convention
+    //~| ERROR associated functions cannot have a C variable argument list
 }
diff --git a/tests/ui/feature-gates/feature-gate-c_variadic.stderr b/tests/ui/feature-gates/feature-gate-c_variadic.stderr
index e30a2f1ede3..808aa20948d 100644
--- a/tests/ui/feature-gates/feature-gate-c_variadic.stderr
+++ b/tests/ui/feature-gates/feature-gate-c_variadic.stderr
@@ -1,14 +1,14 @@
-error: defining functions with C-variadic arguments is only allowed for free functions with the "C" or "C-unwind" calling convention
+error: associated functions cannot have a C variable argument list
   --> $DIR/feature-gate-c_variadic.rs:7:45
    |
-LL |     unsafe extern "C" fn trait_test(_: i32, ap: ...) { }
+LL |     unsafe extern "C" fn trait_test(_: i32, ap: ...) {}
    |                                             ^^^^^^^
 
 error[E0658]: C-variadic functions are unstable
   --> $DIR/feature-gate-c_variadic.rs:3:1
    |
-LL | pub unsafe extern "C" fn test(_: i32, ap: ...) { }
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+LL | pub unsafe extern "C" fn test(_: i32, ap: ...) {}
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = note: see issue #44930 <https://github.com/rust-lang/rust/issues/44930> for more information
    = help: add `#![feature(c_variadic)]` to the crate attributes to enable
@@ -17,8 +17,8 @@ LL | pub unsafe extern "C" fn test(_: i32, ap: ...) { }
 error[E0658]: C-variadic functions are unstable
   --> $DIR/feature-gate-c_variadic.rs:7:5
    |
-LL |     unsafe extern "C" fn trait_test(_: i32, ap: ...) { }
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+LL |     unsafe extern "C" fn trait_test(_: i32, ap: ...) {}
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = note: see issue #44930 <https://github.com/rust-lang/rust/issues/44930> for more information
    = help: add `#![feature(c_variadic)]` to the crate attributes to enable
diff --git a/tests/ui/fmt/ifmt-bad-arg.stderr b/tests/ui/fmt/ifmt-bad-arg.stderr
index 4344aee83c2..b565b836f21 100644
--- a/tests/ui/fmt/ifmt-bad-arg.stderr
+++ b/tests/ui/fmt/ifmt-bad-arg.stderr
@@ -62,6 +62,11 @@ LL |     format!("", 1, 2);
    |             |   |
    |             |   argument never used
    |             multiple missing formatting specifiers
+   |
+help: format specifiers use curly braces, consider adding 2 format specifiers
+   |
+LL |     format!("{}{}", 1, 2);
+   |              ++++
 
 error: argument never used
   --> $DIR/ifmt-bad-arg.rs:33:22
@@ -102,6 +107,11 @@ LL |     format!("", foo=2);
    |             --      ^ named argument never used
    |             |
    |             formatting specifier missing
+   |
+help: format specifiers use curly braces, consider adding a format specifier
+   |
+LL |     format!("{}", foo=2);
+   |              ++
 
 error: multiple unused formatting arguments
   --> $DIR/ifmt-bad-arg.rs:38:32
@@ -111,6 +121,8 @@ LL |     format!("{} {}", 1, 2, foo=1, bar=2);
    |             |                  |
    |             |                  named argument never used
    |             multiple missing formatting specifiers
+   |
+   = note: consider adding 2 format specifiers
 
 error: duplicate argument named `foo`
   --> $DIR/ifmt-bad-arg.rs:40:29
diff --git a/tests/ui/frontmatter/auxiliary/expr.rs b/tests/ui/frontmatter/auxiliary/expr.rs
new file mode 100644
index 00000000000..5f694110666
--- /dev/null
+++ b/tests/ui/frontmatter/auxiliary/expr.rs
@@ -0,0 +1,4 @@
+---
+-
+---
+1
diff --git a/tests/ui/frontmatter/auxiliary/makro.rs b/tests/ui/frontmatter/auxiliary/makro.rs
index 70707b27bff..1d64fa44bd3 100644
--- a/tests/ui/frontmatter/auxiliary/makro.rs
+++ b/tests/ui/frontmatter/auxiliary/makro.rs
@@ -1,8 +1,20 @@
 extern crate proc_macro;
-use proc_macro::TokenStream;
+use proc_macro::{Literal, TokenStream};
 
 #[proc_macro]
 pub fn check(_: TokenStream) -> TokenStream {
+    // In the following test cases, the `---` may look like the start of frontmatter but it is not!
+    // That's because it would be backward incompatible to interpret them as such in the latest
+    // stable edition. That's not only the case due to the feature gate error but also due to the
+    // fact that we "eagerly" emit errors on malformed frontmatter.
+
+    // issue: <https://github.com/rust-lang/rust/issues/145520>
+    _ = "---".parse::<TokenStream>();
+    // Just a sequence of regular Rust punctuation tokens.
     assert_eq!(6, "---\n---".parse::<TokenStream>().unwrap().into_iter().count());
+
+    // issue: <https://github.com/rust-lang/rust/issues/146132>
+    assert!("---".parse::<Literal>().is_err());
+
     Default::default()
 }
diff --git a/tests/ui/frontmatter/include-in-expr-ctxt.rs b/tests/ui/frontmatter/include-in-expr-ctxt.rs
new file mode 100644
index 00000000000..7b02c9cb8a5
--- /dev/null
+++ b/tests/ui/frontmatter/include-in-expr-ctxt.rs
@@ -0,0 +1,9 @@
+// Check that an expr-ctxt `include` doesn't try to parse frontmatter and instead
+// treats it as a regular Rust token sequence.
+//@ check-pass
+#![expect(double_negations)]
+
+fn main() {
+    // issue: <https://github.com/rust-lang/rust/issues/145945>
+    const _: () = assert!(-1 == include!("auxiliary/expr.rs"));
+}
diff --git a/tests/ui/frontmatter/include-in-item-ctxt.rs b/tests/ui/frontmatter/include-in-item-ctxt.rs
new file mode 100644
index 00000000000..c8455bc49ab
--- /dev/null
+++ b/tests/ui/frontmatter/include-in-item-ctxt.rs
@@ -0,0 +1,10 @@
+// Ensure that in item ctxts we can `include` files that contain frontmatter.
+//@ check-pass
+
+#![feature(frontmatter)]
+
+include!("auxiliary/lib.rs");
+
+fn main() {
+    foo(1);
+}
diff --git a/tests/ui/frontmatter/included-frontmatter.rs b/tests/ui/frontmatter/included-frontmatter.rs
deleted file mode 100644
index 57616cd1228..00000000000
--- a/tests/ui/frontmatter/included-frontmatter.rs
+++ /dev/null
@@ -1,12 +0,0 @@
-#![feature(frontmatter)]
-
-//@ check-pass
-
-include!("auxiliary/lib.rs");
-
-// auxiliary/lib.rs contains a frontmatter. Ensure that we can use them in an
-// `include!` macro.
-
-fn main() {
-    foo(1);
-}
diff --git a/tests/ui/frontmatter/proc-macro-observer.rs b/tests/ui/frontmatter/proc-macro-observer.rs
index b1cc1460933..6c4c8c57289 100644
--- a/tests/ui/frontmatter/proc-macro-observer.rs
+++ b/tests/ui/frontmatter/proc-macro-observer.rs
@@ -2,10 +2,9 @@
 //@ proc-macro: makro.rs
 //@ edition: 2021
 
-makro::check!();
+// Check that a proc-macro doesn't try to parse frontmatter and instead treats
+// it as a regular Rust token sequence. See `auxiliary/makro.rs` for details.
 
-// checks that a proc-macro doesn't know or parse frontmatters at all and instead treats
-// it as normal Rust code.
-// see auxiliary/makro.rs for how it is tested.
+makro::check!();
 
 fn main() {}
diff --git a/tests/ui/inference/note-and-explain-ReVar-124973.rs b/tests/ui/inference/note-and-explain-ReVar-124973.rs
index f1e24645636..aa4b909fa76 100644
--- a/tests/ui/inference/note-and-explain-ReVar-124973.rs
+++ b/tests/ui/inference/note-and-explain-ReVar-124973.rs
@@ -3,6 +3,7 @@
 #![feature(c_variadic)]
 
 async unsafe extern "C" fn multiple_named_lifetimes<'a, 'b>(_: u8, ...) {}
-//~^ ERROR hidden type for `impl Future<Output = ()>` captures lifetime that does not appear in bounds
+//~^ ERROR functions cannot be both `async` and C-variadic
+//~| ERROR hidden type for `impl Future<Output = ()>` captures lifetime that does not appear in bounds
 
 fn main() {}
diff --git a/tests/ui/inference/note-and-explain-ReVar-124973.stderr b/tests/ui/inference/note-and-explain-ReVar-124973.stderr
index 574f6508e4c..964fbc4a4fb 100644
--- a/tests/ui/inference/note-and-explain-ReVar-124973.stderr
+++ b/tests/ui/inference/note-and-explain-ReVar-124973.stderr
@@ -1,3 +1,9 @@
+error: functions cannot be both `async` and C-variadic
+  --> $DIR/note-and-explain-ReVar-124973.rs:5:1
+   |
+LL | async unsafe extern "C" fn multiple_named_lifetimes<'a, 'b>(_: u8, ...) {}
+   | ^^^^^ `async` because of this                                      ^^^ C-variadic because of this
+
 error[E0700]: hidden type for `impl Future<Output = ()>` captures lifetime that does not appear in bounds
   --> $DIR/note-and-explain-ReVar-124973.rs:5:73
    |
@@ -8,6 +14,6 @@ LL | async unsafe extern "C" fn multiple_named_lifetimes<'a, 'b>(_: u8, ...) {}
    |
    = note: hidden type `{async fn body of multiple_named_lifetimes<'a, 'b>()}` captures lifetime `'_`
 
-error: aborting due to 1 previous error
+error: aborting due to 2 previous errors
 
 For more information about this error, try `rustc --explain E0700`.
diff --git a/tests/ui/macros/format-unused-lables.stderr b/tests/ui/macros/format-unused-lables.stderr
index fad87fa2aee..90eed8dd86b 100644
--- a/tests/ui/macros/format-unused-lables.stderr
+++ b/tests/ui/macros/format-unused-lables.stderr
@@ -7,6 +7,11 @@ LL |     println!("Test", 123, 456, 789);
    |              |       |    argument never used
    |              |       argument never used
    |              multiple missing formatting specifiers
+   |
+help: format specifiers use curly braces, consider adding 3 format specifiers
+   |
+LL |     println!("Test{}{}{}", 123, 456, 789);
+   |                   ++++++
 
 error: multiple unused formatting arguments
   --> $DIR/format-unused-lables.rs:6:9
@@ -19,6 +24,11 @@ LL |         456,
    |         ^^^ argument never used
 LL |         789
    |         ^^^ argument never used
+   |
+help: format specifiers use curly braces, consider adding 3 format specifiers
+   |
+LL |     println!("Test2{}{}{}",
+   |                    ++++++
 
 error: named argument never used
   --> $DIR/format-unused-lables.rs:11:35
@@ -27,6 +37,11 @@ LL |     println!("Some stuff", UNUSED="args");
    |              ------------         ^^^^^^ named argument never used
    |              |
    |              formatting specifier missing
+   |
+help: format specifiers use curly braces, consider adding a format specifier
+   |
+LL |     println!("Some stuff{}", UNUSED="args");
+   |                         ++
 
 error: multiple unused formatting arguments
   --> $DIR/format-unused-lables.rs:14:9
diff --git a/tests/ui/mir/issue-83499-input-output-iteration-ice.rs b/tests/ui/mir/issue-83499-input-output-iteration-ice.rs
index 9277994d9b3..dc0d14bf9d6 100644
--- a/tests/ui/mir/issue-83499-input-output-iteration-ice.rs
+++ b/tests/ui/mir/issue-83499-input-output-iteration-ice.rs
@@ -4,7 +4,6 @@
 
 fn main() {}
 
-fn foo(_: Bar, ...) -> impl {}
-//~^ ERROR defining functions with C-variadic arguments is only allowed for free functions with the "C" or "C-unwind" calling convention
-//~| ERROR cannot find type `Bar` in this scope
+unsafe extern "C" fn foo(_: Bar, ...) -> impl {}
+//~^ ERROR cannot find type `Bar` in this scope
 //~| ERROR at least one trait must be specified
diff --git a/tests/ui/mir/issue-83499-input-output-iteration-ice.stderr b/tests/ui/mir/issue-83499-input-output-iteration-ice.stderr
index 4a1aa49eb6e..31a393e7367 100644
--- a/tests/ui/mir/issue-83499-input-output-iteration-ice.stderr
+++ b/tests/ui/mir/issue-83499-input-output-iteration-ice.stderr
@@ -1,21 +1,15 @@
-error: defining functions with C-variadic arguments is only allowed for free functions with the "C" or "C-unwind" calling convention
-  --> $DIR/issue-83499-input-output-iteration-ice.rs:7:16
-   |
-LL | fn foo(_: Bar, ...) -> impl {}
-   |                ^^^
-
 error: at least one trait must be specified
-  --> $DIR/issue-83499-input-output-iteration-ice.rs:7:24
+  --> $DIR/issue-83499-input-output-iteration-ice.rs:7:42
    |
-LL | fn foo(_: Bar, ...) -> impl {}
-   |                        ^^^^
+LL | unsafe extern "C" fn foo(_: Bar, ...) -> impl {}
+   |                                          ^^^^
 
 error[E0412]: cannot find type `Bar` in this scope
-  --> $DIR/issue-83499-input-output-iteration-ice.rs:7:11
+  --> $DIR/issue-83499-input-output-iteration-ice.rs:7:29
    |
-LL | fn foo(_: Bar, ...) -> impl {}
-   |           ^^^ not found in this scope
+LL | unsafe extern "C" fn foo(_: Bar, ...) -> impl {}
+   |                             ^^^ not found in this scope
 
-error: aborting due to 3 previous errors
+error: aborting due to 2 previous errors
 
 For more information about this error, try `rustc --explain E0412`.
diff --git a/tests/ui/mir/unsized-extern-static.stderr b/tests/ui/mir/unsized-extern-static.stderr
index 93aed3549d7..c0810e650ef 100644
--- a/tests/ui/mir/unsized-extern-static.stderr
+++ b/tests/ui/mir/unsized-extern-static.stderr
@@ -5,6 +5,11 @@ LL |     println!("C", unsafe { &symbol });
    |              ---  ^^^^^^^^^^^^^^^^^^ argument never used
    |              |
    |              formatting specifier missing
+   |
+help: format specifiers use curly braces, consider adding a format specifier
+   |
+LL |     println!("C{}", unsafe { &symbol });
+   |                ++
 
 error[E0277]: the size for values of type `[i8]` cannot be known at compilation time
   --> $DIR/unsized-extern-static.rs:6:5
diff --git a/tests/ui/parser/variadic-ffi-semantic-restrictions.rs b/tests/ui/parser/variadic-ffi-semantic-restrictions.rs
index 243924e6c53..4db056f15a5 100644
--- a/tests/ui/parser/variadic-ffi-semantic-restrictions.rs
+++ b/tests/ui/parser/variadic-ffi-semantic-restrictions.rs
@@ -4,25 +4,28 @@
 fn main() {}
 
 fn f1_1(x: isize, ...) {}
-//~^ ERROR defining functions with C-variadic arguments is only allowed for free functions with the "C" or "C-unwind" calling convention
+//~^ ERROR `...` is not supported for non-extern functions
 
 fn f1_2(...) {}
-//~^ ERROR defining functions with C-variadic arguments is only allowed for free functions with the "C" or "C-unwind" calling convention
+//~^ ERROR `...` is not supported for non-extern functions
+
+unsafe extern "Rust" fn f1_3(...) {}
+//~^ ERROR `...` is not supported for `extern "Rust"` functions
 
 extern "C" fn f2_1(x: isize, ...) {}
-//~^ ERROR defining functions with C-variadic arguments is only allowed for free functions with the "C" or "C-unwind" calling convention
+//~^ ERROR functions with a C variable argument list must be unsafe
 
 extern "C" fn f2_2(...) {}
-//~^ ERROR defining functions with C-variadic arguments is only allowed for free functions with the "C" or "C-unwind" calling convention
+//~^ ERROR functions with a C variable argument list must be unsafe
 
 extern "C" fn f2_3(..., x: isize) {}
 //~^ ERROR `...` must be the last argument of a C-variadic function
 
 extern "C" fn f3_1(x: isize, ...) {}
-//~^ ERROR defining functions with C-variadic arguments is only allowed for free functions with the "C" or "C-unwind" calling convention
+//~^ ERROR functions with a C variable argument list must be unsafe
 
 extern "C" fn f3_2(...) {}
-//~^ ERROR defining functions with C-variadic arguments is only allowed for free functions with the "C" or "C-unwind" calling convention
+//~^ ERROR functions with a C variable argument list must be unsafe
 
 extern "C" fn f3_3(..., x: isize) {}
 //~^ ERROR `...` must be the last argument of a C-variadic function
@@ -33,12 +36,12 @@ const unsafe extern "C" fn f4_1(x: isize, ...) {}
 
 const extern "C" fn f4_2(x: isize, ...) {}
 //~^ ERROR functions cannot be both `const` and C-variadic
-//~| ERROR defining functions with C-variadic arguments is only allowed for free functions with the "C" or "C-unwind" calling convention
+//~| ERROR functions with a C variable argument list must be unsafe
 //~| ERROR destructor of `VaListImpl<'_>` cannot be evaluated at compile-time
 
 const extern "C" fn f4_3(..., x: isize, ...) {}
 //~^ ERROR functions cannot be both `const` and C-variadic
-//~| ERROR defining functions with C-variadic arguments is only allowed for free functions with the "C" or "C-unwind" calling convention
+//~| ERROR functions with a C variable argument list must be unsafe
 //~| ERROR `...` must be the last argument of a C-variadic function
 
 extern "C" {
@@ -50,30 +53,30 @@ struct X;
 
 impl X {
     fn i_f1(x: isize, ...) {}
-    //~^ ERROR defining functions with C-variadic arguments is only allowed for free functions with the "C" or "C-unwind" calling convention
+    //~^ ERROR associated functions cannot have a C variable argument list
     fn i_f2(...) {}
-    //~^ ERROR defining functions with C-variadic arguments is only allowed for free functions with the "C" or "C-unwind" calling convention
+    //~^ ERROR associated functions cannot have a C variable argument list
     fn i_f3(..., x: isize, ...) {}
-    //~^ ERROR defining functions with C-variadic arguments is only allowed for free functions with the "C" or "C-unwind" calling convention
+    //~^ ERROR associated functions cannot have a C variable argument list
     //~| ERROR `...` must be the last argument of a C-variadic function
     fn i_f4(..., x: isize, ...) {}
-    //~^ ERROR defining functions with C-variadic arguments is only allowed for free functions with the "C" or "C-unwind" calling convention
+    //~^ ERROR associated functions cannot have a C variable argument list
     //~| ERROR `...` must be the last argument of a C-variadic function
     const fn i_f5(x: isize, ...) {}
-    //~^ ERROR defining functions with C-variadic arguments is only allowed for free functions with the "C" or "C-unwind" calling convention
+    //~^ ERROR associated functions cannot have a C variable argument list
     //~| ERROR functions cannot be both `const` and C-variadic
     //~| ERROR destructor of `VaListImpl<'_>` cannot be evaluated at compile-time
 }
 
 trait T {
     fn t_f1(x: isize, ...) {}
-    //~^ ERROR defining functions with C-variadic arguments is only allowed for free functions with the "C" or "C-unwind" calling convention
+    //~^ ERROR associated functions cannot have a C variable argument list
     fn t_f2(x: isize, ...);
-    //~^ ERROR defining functions with C-variadic arguments is only allowed for free functions with the "C" or "C-unwind" calling convention
+    //~^ ERROR associated functions cannot have a C variable argument list
     fn t_f3(...) {}
-    //~^ ERROR defining functions with C-variadic arguments is only allowed for free functions with the "C" or "C-unwind" calling convention
+    //~^ ERROR associated functions cannot have a C variable argument list
     fn t_f4(...);
-    //~^ ERROR defining functions with C-variadic arguments is only allowed for free functions with the "C" or "C-unwind" calling convention
+    //~^ ERROR associated functions cannot have a C variable argument list
     fn t_f5(..., x: isize) {}
     //~^ ERROR `...` must be the last argument of a C-variadic function
     fn t_f6(..., x: isize);
diff --git a/tests/ui/parser/variadic-ffi-semantic-restrictions.stderr b/tests/ui/parser/variadic-ffi-semantic-restrictions.stderr
index 5c55cc38b56..0cd78318de6 100644
--- a/tests/ui/parser/variadic-ffi-semantic-restrictions.stderr
+++ b/tests/ui/parser/variadic-ffi-semantic-restrictions.stderr
@@ -1,181 +1,225 @@
-error: defining functions with C-variadic arguments is only allowed for free functions with the "C" or "C-unwind" calling convention
+error: `...` is not supported for non-extern functions
   --> $DIR/variadic-ffi-semantic-restrictions.rs:6:19
    |
 LL | fn f1_1(x: isize, ...) {}
    |                   ^^^
+   |
+   = help: only `extern "C"` and `extern "C-unwind"` functions may have a C variable argument list
 
-error: defining functions with C-variadic arguments is only allowed for free functions with the "C" or "C-unwind" calling convention
+error: `...` is not supported for non-extern functions
   --> $DIR/variadic-ffi-semantic-restrictions.rs:9:9
    |
 LL | fn f1_2(...) {}
    |         ^^^
+   |
+   = help: only `extern "C"` and `extern "C-unwind"` functions may have a C variable argument list
 
-error: defining functions with C-variadic arguments is only allowed for free functions with the "C" or "C-unwind" calling convention
+error: `...` is not supported for `extern "Rust"` functions
   --> $DIR/variadic-ffi-semantic-restrictions.rs:12:30
    |
+LL | unsafe extern "Rust" fn f1_3(...) {}
+   |        -------------         ^^^
+   |        |
+   |        `extern "Rust"` because of this
+   |
+   = help: only `extern "C"` and `extern "C-unwind"` functions may have a C variable argument list
+
+error: functions with a C variable argument list must be unsafe
+  --> $DIR/variadic-ffi-semantic-restrictions.rs:15:30
+   |
 LL | extern "C" fn f2_1(x: isize, ...) {}
    |                              ^^^
+   |
+help: add the `unsafe` keyword to this definition
+   |
+LL | unsafe extern "C" fn f2_1(x: isize, ...) {}
+   | ++++++
 
-error: defining functions with C-variadic arguments is only allowed for free functions with the "C" or "C-unwind" calling convention
-  --> $DIR/variadic-ffi-semantic-restrictions.rs:15:20
+error: functions with a C variable argument list must be unsafe
+  --> $DIR/variadic-ffi-semantic-restrictions.rs:18:20
    |
 LL | extern "C" fn f2_2(...) {}
    |                    ^^^
+   |
+help: add the `unsafe` keyword to this definition
+   |
+LL | unsafe extern "C" fn f2_2(...) {}
+   | ++++++
 
 error: `...` must be the last argument of a C-variadic function
-  --> $DIR/variadic-ffi-semantic-restrictions.rs:18:20
+  --> $DIR/variadic-ffi-semantic-restrictions.rs:21:20
    |
 LL | extern "C" fn f2_3(..., x: isize) {}
    |                    ^^^
 
-error: defining functions with C-variadic arguments is only allowed for free functions with the "C" or "C-unwind" calling convention
-  --> $DIR/variadic-ffi-semantic-restrictions.rs:21:30
+error: functions with a C variable argument list must be unsafe
+  --> $DIR/variadic-ffi-semantic-restrictions.rs:24:30
    |
 LL | extern "C" fn f3_1(x: isize, ...) {}
    |                              ^^^
+   |
+help: add the `unsafe` keyword to this definition
+   |
+LL | unsafe extern "C" fn f3_1(x: isize, ...) {}
+   | ++++++
 
-error: defining functions with C-variadic arguments is only allowed for free functions with the "C" or "C-unwind" calling convention
-  --> $DIR/variadic-ffi-semantic-restrictions.rs:24:20
+error: functions with a C variable argument list must be unsafe
+  --> $DIR/variadic-ffi-semantic-restrictions.rs:27:20
    |
 LL | extern "C" fn f3_2(...) {}
    |                    ^^^
+   |
+help: add the `unsafe` keyword to this definition
+   |
+LL | unsafe extern "C" fn f3_2(...) {}
+   | ++++++
 
 error: `...` must be the last argument of a C-variadic function
-  --> $DIR/variadic-ffi-semantic-restrictions.rs:27:20
+  --> $DIR/variadic-ffi-semantic-restrictions.rs:30:20
    |
 LL | extern "C" fn f3_3(..., x: isize) {}
    |                    ^^^
 
 error: functions cannot be both `const` and C-variadic
-  --> $DIR/variadic-ffi-semantic-restrictions.rs:30:1
+  --> $DIR/variadic-ffi-semantic-restrictions.rs:33:1
    |
 LL | const unsafe extern "C" fn f4_1(x: isize, ...) {}
    | ^^^^^ `const` because of this             ^^^ C-variadic because of this
 
 error: functions cannot be both `const` and C-variadic
-  --> $DIR/variadic-ffi-semantic-restrictions.rs:34:1
+  --> $DIR/variadic-ffi-semantic-restrictions.rs:37:1
    |
 LL | const extern "C" fn f4_2(x: isize, ...) {}
    | ^^^^^ `const` because of this      ^^^ C-variadic because of this
 
-error: defining functions with C-variadic arguments is only allowed for free functions with the "C" or "C-unwind" calling convention
-  --> $DIR/variadic-ffi-semantic-restrictions.rs:34:36
+error: functions with a C variable argument list must be unsafe
+  --> $DIR/variadic-ffi-semantic-restrictions.rs:37:36
    |
 LL | const extern "C" fn f4_2(x: isize, ...) {}
    |                                    ^^^
+   |
+help: add the `unsafe` keyword to this definition
+   |
+LL | const unsafe extern "C" fn f4_2(x: isize, ...) {}
+   |       ++++++
 
 error: `...` must be the last argument of a C-variadic function
-  --> $DIR/variadic-ffi-semantic-restrictions.rs:39:26
+  --> $DIR/variadic-ffi-semantic-restrictions.rs:42:26
    |
 LL | const extern "C" fn f4_3(..., x: isize, ...) {}
    |                          ^^^
 
 error: functions cannot be both `const` and C-variadic
-  --> $DIR/variadic-ffi-semantic-restrictions.rs:39:1
+  --> $DIR/variadic-ffi-semantic-restrictions.rs:42:1
    |
 LL | const extern "C" fn f4_3(..., x: isize, ...) {}
    | ^^^^^ `const` because of this           ^^^ C-variadic because of this
 
-error: defining functions with C-variadic arguments is only allowed for free functions with the "C" or "C-unwind" calling convention
-  --> $DIR/variadic-ffi-semantic-restrictions.rs:39:41
+error: functions with a C variable argument list must be unsafe
+  --> $DIR/variadic-ffi-semantic-restrictions.rs:42:41
    |
 LL | const extern "C" fn f4_3(..., x: isize, ...) {}
    |                                         ^^^
+   |
+help: add the `unsafe` keyword to this definition
+   |
+LL | const unsafe extern "C" fn f4_3(..., x: isize, ...) {}
+   |       ++++++
 
 error: `...` must be the last argument of a C-variadic function
-  --> $DIR/variadic-ffi-semantic-restrictions.rs:45:13
+  --> $DIR/variadic-ffi-semantic-restrictions.rs:48:13
    |
 LL |     fn e_f2(..., x: isize);
    |             ^^^
 
-error: defining functions with C-variadic arguments is only allowed for free functions with the "C" or "C-unwind" calling convention
-  --> $DIR/variadic-ffi-semantic-restrictions.rs:52:23
+error: associated functions cannot have a C variable argument list
+  --> $DIR/variadic-ffi-semantic-restrictions.rs:55:23
    |
 LL |     fn i_f1(x: isize, ...) {}
    |                       ^^^
 
-error: defining functions with C-variadic arguments is only allowed for free functions with the "C" or "C-unwind" calling convention
-  --> $DIR/variadic-ffi-semantic-restrictions.rs:54:13
+error: associated functions cannot have a C variable argument list
+  --> $DIR/variadic-ffi-semantic-restrictions.rs:57:13
    |
 LL |     fn i_f2(...) {}
    |             ^^^
 
 error: `...` must be the last argument of a C-variadic function
-  --> $DIR/variadic-ffi-semantic-restrictions.rs:56:13
+  --> $DIR/variadic-ffi-semantic-restrictions.rs:59:13
    |
 LL |     fn i_f3(..., x: isize, ...) {}
    |             ^^^
 
-error: defining functions with C-variadic arguments is only allowed for free functions with the "C" or "C-unwind" calling convention
-  --> $DIR/variadic-ffi-semantic-restrictions.rs:56:28
+error: associated functions cannot have a C variable argument list
+  --> $DIR/variadic-ffi-semantic-restrictions.rs:59:28
    |
 LL |     fn i_f3(..., x: isize, ...) {}
    |                            ^^^
 
 error: `...` must be the last argument of a C-variadic function
-  --> $DIR/variadic-ffi-semantic-restrictions.rs:59:13
+  --> $DIR/variadic-ffi-semantic-restrictions.rs:62:13
    |
 LL |     fn i_f4(..., x: isize, ...) {}
    |             ^^^
 
-error: defining functions with C-variadic arguments is only allowed for free functions with the "C" or "C-unwind" calling convention
-  --> $DIR/variadic-ffi-semantic-restrictions.rs:59:28
+error: associated functions cannot have a C variable argument list
+  --> $DIR/variadic-ffi-semantic-restrictions.rs:62:28
    |
 LL |     fn i_f4(..., x: isize, ...) {}
    |                            ^^^
 
 error: functions cannot be both `const` and C-variadic
-  --> $DIR/variadic-ffi-semantic-restrictions.rs:62:5
+  --> $DIR/variadic-ffi-semantic-restrictions.rs:65:5
    |
 LL |     const fn i_f5(x: isize, ...) {}
    |     ^^^^^                   ^^^ C-variadic because of this
    |     |
    |     `const` because of this
 
-error: defining functions with C-variadic arguments is only allowed for free functions with the "C" or "C-unwind" calling convention
-  --> $DIR/variadic-ffi-semantic-restrictions.rs:62:29
+error: associated functions cannot have a C variable argument list
+  --> $DIR/variadic-ffi-semantic-restrictions.rs:65:29
    |
 LL |     const fn i_f5(x: isize, ...) {}
    |                             ^^^
 
-error: defining functions with C-variadic arguments is only allowed for free functions with the "C" or "C-unwind" calling convention
-  --> $DIR/variadic-ffi-semantic-restrictions.rs:69:23
+error: associated functions cannot have a C variable argument list
+  --> $DIR/variadic-ffi-semantic-restrictions.rs:72:23
    |
 LL |     fn t_f1(x: isize, ...) {}
    |                       ^^^
 
-error: defining functions with C-variadic arguments is only allowed for free functions with the "C" or "C-unwind" calling convention
-  --> $DIR/variadic-ffi-semantic-restrictions.rs:71:23
+error: associated functions cannot have a C variable argument list
+  --> $DIR/variadic-ffi-semantic-restrictions.rs:74:23
    |
 LL |     fn t_f2(x: isize, ...);
    |                       ^^^
 
-error: defining functions with C-variadic arguments is only allowed for free functions with the "C" or "C-unwind" calling convention
-  --> $DIR/variadic-ffi-semantic-restrictions.rs:73:13
+error: associated functions cannot have a C variable argument list
+  --> $DIR/variadic-ffi-semantic-restrictions.rs:76:13
    |
 LL |     fn t_f3(...) {}
    |             ^^^
 
-error: defining functions with C-variadic arguments is only allowed for free functions with the "C" or "C-unwind" calling convention
-  --> $DIR/variadic-ffi-semantic-restrictions.rs:75:13
+error: associated functions cannot have a C variable argument list
+  --> $DIR/variadic-ffi-semantic-restrictions.rs:78:13
    |
 LL |     fn t_f4(...);
    |             ^^^
 
 error: `...` must be the last argument of a C-variadic function
-  --> $DIR/variadic-ffi-semantic-restrictions.rs:77:13
+  --> $DIR/variadic-ffi-semantic-restrictions.rs:80:13
    |
 LL |     fn t_f5(..., x: isize) {}
    |             ^^^
 
 error: `...` must be the last argument of a C-variadic function
-  --> $DIR/variadic-ffi-semantic-restrictions.rs:79:13
+  --> $DIR/variadic-ffi-semantic-restrictions.rs:82:13
    |
 LL |     fn t_f6(..., x: isize);
    |             ^^^
 
 error[E0493]: destructor of `VaListImpl<'_>` cannot be evaluated at compile-time
-  --> $DIR/variadic-ffi-semantic-restrictions.rs:30:43
+  --> $DIR/variadic-ffi-semantic-restrictions.rs:33:43
    |
 LL | const unsafe extern "C" fn f4_1(x: isize, ...) {}
    |                                           ^^^   - value is dropped here
@@ -183,7 +227,7 @@ LL | const unsafe extern "C" fn f4_1(x: isize, ...) {}
    |                                           the destructor for this type cannot be evaluated in constant functions
 
 error[E0493]: destructor of `VaListImpl<'_>` cannot be evaluated at compile-time
-  --> $DIR/variadic-ffi-semantic-restrictions.rs:34:36
+  --> $DIR/variadic-ffi-semantic-restrictions.rs:37:36
    |
 LL | const extern "C" fn f4_2(x: isize, ...) {}
    |                                    ^^^   - value is dropped here
@@ -191,13 +235,13 @@ LL | const extern "C" fn f4_2(x: isize, ...) {}
    |                                    the destructor for this type cannot be evaluated in constant functions
 
 error[E0493]: destructor of `VaListImpl<'_>` cannot be evaluated at compile-time
-  --> $DIR/variadic-ffi-semantic-restrictions.rs:62:29
+  --> $DIR/variadic-ffi-semantic-restrictions.rs:65:29
    |
 LL |     const fn i_f5(x: isize, ...) {}
    |                             ^^^   - value is dropped here
    |                             |
    |                             the destructor for this type cannot be evaluated in constant functions
 
-error: aborting due to 32 previous errors
+error: aborting due to 33 previous errors
 
 For more information about this error, try `rustc --explain E0493`.
diff --git a/tests/ui/suggestions/missing-format-specifiers-issue-68293.rs b/tests/ui/suggestions/missing-format-specifiers-issue-68293.rs
new file mode 100644
index 00000000000..29799624d78
--- /dev/null
+++ b/tests/ui/suggestions/missing-format-specifiers-issue-68293.rs
@@ -0,0 +1,35 @@
+fn no_format_specifier_two_unused_args() {
+    println!("Hello", "World");
+    //~^ ERROR argument never used
+    //~| NOTE formatting specifier missing
+    //~| NOTE argument never used
+    //~| HELP format specifiers use curly braces, consider adding a format specifier
+}
+
+fn no_format_specifier_multiple_unused_args() {
+    println!("list: ", 1, 2, 3);
+    //~^ ERROR multiple unused formatting arguments
+    //~| NOTE multiple missing formatting specifiers
+    //~| NOTE argument never used
+    //~| NOTE argument never used
+    //~| NOTE argument never used
+    //~| HELP format specifiers use curly braces, consider adding 3 format specifiers
+}
+
+fn missing_format_specifiers_one_unused_arg() {
+    println!("list: {}, {}", 1, 2, 3);
+    //~^ ERROR argument never used
+    //~| NOTE formatting specifier missing
+    //~| NOTE argument never used
+}
+
+fn missing_format_specifiers_multiple_unused_args() {
+    println!("list: {}", 1, 2, 3);
+    //~^ ERROR multiple unused formatting arguments
+    //~| NOTE multiple missing formatting specifiers
+    //~| NOTE argument never used
+    //~| NOTE argument never used
+    //~| NOTE consider adding 2 format specifiers
+}
+
+fn main() { }
diff --git a/tests/ui/suggestions/missing-format-specifiers-issue-68293.stderr b/tests/ui/suggestions/missing-format-specifiers-issue-68293.stderr
new file mode 100644
index 00000000000..081409789f5
--- /dev/null
+++ b/tests/ui/suggestions/missing-format-specifiers-issue-68293.stderr
@@ -0,0 +1,49 @@
+error: argument never used
+  --> $DIR/missing-format-specifiers-issue-68293.rs:2:23
+   |
+LL |     println!("Hello", "World");
+   |              -------  ^^^^^^^ argument never used
+   |              |
+   |              formatting specifier missing
+   |
+help: format specifiers use curly braces, consider adding a format specifier
+   |
+LL |     println!("Hello{}", "World");
+   |                    ++
+
+error: multiple unused formatting arguments
+  --> $DIR/missing-format-specifiers-issue-68293.rs:10:24
+   |
+LL |     println!("list: ", 1, 2, 3);
+   |              --------  ^  ^  ^ argument never used
+   |              |         |  |
+   |              |         |  argument never used
+   |              |         argument never used
+   |              multiple missing formatting specifiers
+   |
+help: format specifiers use curly braces, consider adding 3 format specifiers
+   |
+LL |     println!("list: {}{}{}", 1, 2, 3);
+   |                     ++++++
+
+error: argument never used
+  --> $DIR/missing-format-specifiers-issue-68293.rs:20:36
+   |
+LL |     println!("list: {}, {}", 1, 2, 3);
+   |              --------------        ^ argument never used
+   |              |
+   |              formatting specifier missing
+
+error: multiple unused formatting arguments
+  --> $DIR/missing-format-specifiers-issue-68293.rs:27:29
+   |
+LL |     println!("list: {}", 1, 2, 3);
+   |              ----------     ^  ^ argument never used
+   |              |              |
+   |              |              argument never used
+   |              multiple missing formatting specifiers
+   |
+   = note: consider adding 2 format specifiers
+
+error: aborting due to 4 previous errors
+
diff --git a/tests/ui/trait-bounds/more_maybe_bounds.rs b/tests/ui/trait-bounds/more_maybe_bounds.rs
index d367dd5b299..ddd4313bd5e 100644
--- a/tests/ui/trait-bounds/more_maybe_bounds.rs
+++ b/tests/ui/trait-bounds/more_maybe_bounds.rs
@@ -21,6 +21,20 @@ fn bar<T: ?Sized + ?Trait2 + ?Trait1 + ?Trait4>(_: &T) {}
 
 // FIXME: `?Trait1` should be rejected, `Trait1` isn't marked `#[lang = "default_traitN"]`.
 fn baz<T>() where T: Iterator<Item: ?Trait1> {}
+//~^ ERROR this relaxed bound is not permitted here
+
+struct S1<T>(T);
+
+impl<T> S1<T> {
+    fn f() where T: ?Trait1 {}
+    //~^ ERROR this relaxed bound is not permitted here
+}
+
+trait Trait5<'a> {}
+
+struct S2<T>(T) where for<'a> T: ?Trait5<'a>;
+//~^ ERROR this relaxed bound is not permitted here
+//~| ERROR bound modifier `?` can only be applied to default traits like `Sized`
 
 struct S;
 impl !Trait2 for S {}
diff --git a/tests/ui/trait-bounds/more_maybe_bounds.stderr b/tests/ui/trait-bounds/more_maybe_bounds.stderr
index 8dd83fc7728..0d78cfd5820 100644
--- a/tests/ui/trait-bounds/more_maybe_bounds.stderr
+++ b/tests/ui/trait-bounds/more_maybe_bounds.stderr
@@ -1,3 +1,27 @@
+error: this relaxed bound is not permitted here
+  --> $DIR/more_maybe_bounds.rs:23:37
+   |
+LL | fn baz<T>() where T: Iterator<Item: ?Trait1> {}
+   |                                     ^^^^^^^
+   |
+   = note: in this context, relaxed bounds are only allowed on type parameters defined by the closest item
+
+error: this relaxed bound is not permitted here
+  --> $DIR/more_maybe_bounds.rs:29:21
+   |
+LL |     fn f() where T: ?Trait1 {}
+   |                     ^^^^^^^
+   |
+   = note: in this context, relaxed bounds are only allowed on type parameters defined by the closest item
+
+error: this relaxed bound is not permitted here
+  --> $DIR/more_maybe_bounds.rs:35:34
+   |
+LL | struct S2<T>(T) where for<'a> T: ?Trait5<'a>;
+   |                                  ^^^^^^^^^^^
+   |
+   = note: in this context, relaxed bounds are only allowed on type parameters defined by the closest item
+
 error: bound modifier `?` can only be applied to default traits like `Sized`
   --> $DIR/more_maybe_bounds.rs:17:20
    |
@@ -16,5 +40,11 @@ error: bound modifier `?` can only be applied to default traits like `Sized`
 LL | fn bar<T: ?Sized + ?Trait2 + ?Trait1 + ?Trait4>(_: &T) {}
    |                                        ^^^^^^^
 
-error: aborting due to 3 previous errors
+error: bound modifier `?` can only be applied to default traits like `Sized`
+  --> $DIR/more_maybe_bounds.rs:35:34
+   |
+LL | struct S2<T>(T) where for<'a> T: ?Trait5<'a>;
+   |                                  ^^^^^^^^^^^
+
+error: aborting due to 7 previous errors
 
diff --git a/tests/ui/traits/default_auto_traits/backward-compatible-lazy-bounds-pass.rs b/tests/ui/traits/default_auto_traits/backward-compatible-lazy-bounds-pass.rs
deleted file mode 100644
index 745b6ee9bc5..00000000000
--- a/tests/ui/traits/default_auto_traits/backward-compatible-lazy-bounds-pass.rs
+++ /dev/null
@@ -1,31 +0,0 @@
-//@ check-pass
-//@ compile-flags: -Zexperimental-default-bounds
-
-#![feature(auto_traits, lang_items, no_core, rustc_attrs, trait_alias)]
-#![no_std]
-#![no_core]
-
-#[lang = "pointee_sized"]
-trait PointeeSized {}
-
-#[lang = "meta_sized"]
-trait MetaSized: PointeeSized {}
-
-#[lang = "sized"]
-trait Sized: MetaSized {}
-
-#[lang = "default_trait1"]
-auto trait DefaultTrait1 {}
-
-#[lang = "default_trait2"]
-auto trait DefaultTrait2 {}
-
-trait Trait<Rhs: ?Sized = Self> {}
-trait Trait1 : Trait {}
-
-trait Trait2 {
-    type Type;
-}
-trait Trait3<T> = Trait2<Type = T>;
-
-fn main() {}
diff --git a/tests/ui/traits/default_auto_traits/maybe-bounds-in-dyn-traits.rs b/tests/ui/traits/default_auto_traits/maybe-bounds-in-dyn-traits.rs
index e7cca41a47e..2e1a5d2424b 100644
--- a/tests/ui/traits/default_auto_traits/maybe-bounds-in-dyn-traits.rs
+++ b/tests/ui/traits/default_auto_traits/maybe-bounds-in-dyn-traits.rs
@@ -13,32 +13,37 @@
 #![no_core]
 
 #[lang = "pointee_sized"]
-trait PointeeSized {}
+trait PointeeSized: ?Leak {}
 
 #[lang = "meta_sized"]
-trait MetaSized: PointeeSized {}
+trait MetaSized: PointeeSized + ?Leak {}
 
 #[lang = "sized"]
-trait Sized: MetaSized {}
+trait Sized: MetaSized + ?Leak {}
 
 #[lang = "copy"]
-pub trait Copy {}
+pub trait Copy: ?Leak {}
 impl<'a, T: ?Sized> Copy for &'a T {}
 
 #[lang = "legacy_receiver"]
-trait Receiver {}
+trait Receiver: ?Leak {}
 impl<T: ?Sized + ?Leak> Receiver for &T {}
+impl<T: ?Sized + ?Leak> Receiver for &mut T {}
 
 #[lang = "unsize"]
-trait Unsize<T: ?Sized + ?Leak> {}
+trait Unsize<T: ?Sized + ?Leak>: ?Leak {}
 
 #[lang = "coerce_unsized"]
-trait CoerceUnsized<T: ?Leak + ?Sized> {}
+trait CoerceUnsized<T: ?Leak + ?Sized>: ?Leak {}
 impl<'a, 'b: 'a, T: ?Sized + ?Leak + Unsize<U>, U: ?Sized + ?Leak> CoerceUnsized<&'a U> for &'b T {}
+// Omit `T: ?Leak` and `U: ?Leak`.
+impl<'a, 'b: 'a, T: ?Sized + Unsize<U>, U: ?Sized> CoerceUnsized<&'a mut U> for &'b mut T {}
 
 #[lang = "dispatch_from_dyn"]
-trait DispatchFromDyn<T: ?Leak> {}
+trait DispatchFromDyn<T: ?Leak>: ?Leak {}
 impl<'a, T: ?Sized + ?Leak + Unsize<U>, U: ?Sized + ?Leak> DispatchFromDyn<&'a U> for &'a T {}
+// Omit `T: ?Leak` and `U: ?Leak`.
+impl<'a, T: ?Sized + Unsize<U>, U: ?Sized> DispatchFromDyn<&'a mut U> for &'a mut T {}
 
 #[lang = "default_trait1"]
 auto trait Leak {}
@@ -47,25 +52,52 @@ struct NonLeakS;
 impl !Leak for NonLeakS {}
 struct LeakS;
 
-trait Trait {
-    fn leak_foo(&self) {}
-    fn maybe_leak_foo(&self) where Self: ?Leak {}
+fn bounds_check() {
+    trait LeakTr {}
+
+    trait MaybeLeakTr: ?Leak {}
+
+    impl MaybeLeakTr for NonLeakS {}
+
+    impl LeakTr for LeakS {}
+    impl MaybeLeakTr for LeakS {}
+
+    let _: &dyn LeakTr = &NonLeakS;
+    //~^ ERROR  the trait bound `NonLeakS: bounds_check::LeakTr` is not satisfied
+    let _: &dyn LeakTr = &LeakS;
+
+    let _: &(dyn LeakTr + ?Leak) = &NonLeakS;
+    let _: &(dyn LeakTr + ?Leak) = &LeakS;
+
+    let _: &dyn MaybeLeakTr = &NonLeakS;
+    let _: &dyn MaybeLeakTr = &LeakS;
 }
 
-impl Trait for NonLeakS {}
-impl Trait for LeakS {}
-
-fn main() {
-    let _: &dyn Trait = &NonLeakS;
-    //~^ ERROR the trait bound `NonLeakS: Leak` is not satisfied
-    let _: &dyn Trait = &LeakS;
-    let _: &(dyn Trait + ?Leak) = &LeakS;
-    let x: &(dyn Trait + ?Leak) = &NonLeakS;
-    x.leak_foo();
-    //~^ ERROR the trait bound `dyn Trait: Leak` is not satisfied
-    x.maybe_leak_foo();
+fn dyn_compat_check() {
+    trait DynCompatCheck1: ?Leak {
+        fn foo(&self) {}
+    }
+
+    trait DynCompatCheck2: ?Leak {
+        fn mut_foo(&mut self) {}
+    }
+
+    impl DynCompatCheck1 for NonLeakS {}
+    impl DynCompatCheck2 for NonLeakS {}
+
+    let _: &(dyn DynCompatCheck1 + ?Leak) = &NonLeakS;
+    // There is no `?Leak` bound on corresponding `DispatchFromDyn` impl.
+    let _: &dyn DynCompatCheck2 = &NonLeakS;
+    //~^ ERROR the trait `DynCompatCheck2` is not dyn compatible
+}
+
+fn args_check() {
+    trait LeakTr {}
+
     // Ensure that we validate the generic args of relaxed bounds in trait object types.
-    let _: dyn Trait + ?Leak<(), Undefined = ()>;
+    let _: dyn LeakTr + ?Leak<(), Undefined = ()>;
     //~^ ERROR trait takes 0 generic arguments but 1 generic argument was supplied
     //~| ERROR associated type `Undefined` not found for `Leak`
 }
+
+fn main() {}
diff --git a/tests/ui/traits/default_auto_traits/maybe-bounds-in-dyn-traits.stderr b/tests/ui/traits/default_auto_traits/maybe-bounds-in-dyn-traits.stderr
index b19c082a1b8..b96a2915c33 100644
--- a/tests/ui/traits/default_auto_traits/maybe-bounds-in-dyn-traits.stderr
+++ b/tests/ui/traits/default_auto_traits/maybe-bounds-in-dyn-traits.stderr
@@ -1,49 +1,57 @@
-error[E0277]: the trait bound `NonLeakS: Leak` is not satisfied
-  --> $DIR/maybe-bounds-in-dyn-traits.rs:59:25
+error[E0277]: the trait bound `NonLeakS: bounds_check::LeakTr` is not satisfied
+  --> $DIR/maybe-bounds-in-dyn-traits.rs:65:26
    |
-LL |     let _: &dyn Trait = &NonLeakS;
-   |                         ^^^^^^^^^ unsatisfied trait bound
+LL |     let _: &dyn LeakTr = &NonLeakS;
+   |                          ^^^^^^^^^ unsatisfied trait bound
    |
-help: the trait `Leak` is not implemented for `NonLeakS`
-  --> $DIR/maybe-bounds-in-dyn-traits.rs:46:1
+help: the trait `bounds_check::LeakTr` is not implemented for `NonLeakS`
+  --> $DIR/maybe-bounds-in-dyn-traits.rs:51:1
    |
 LL | struct NonLeakS;
    | ^^^^^^^^^^^^^^^
-   = note: required for the cast from `&NonLeakS` to `&dyn Trait + Leak`
+   = help: the trait `bounds_check::LeakTr` is implemented for `LeakS`
+   = note: required for the cast from `&NonLeakS` to `&dyn bounds_check::LeakTr + Leak`
 
-error[E0277]: the trait bound `dyn Trait: Leak` is not satisfied
-  --> $DIR/maybe-bounds-in-dyn-traits.rs:64:7
-   |
-LL |     x.leak_foo();
-   |       ^^^^^^^^ the trait `Leak` is not implemented for `dyn Trait`
-   |
-note: required by a bound in `Trait::leak_foo`
-  --> $DIR/maybe-bounds-in-dyn-traits.rs:51:5
-   |
-LL |     fn leak_foo(&self) {}
-   |     ^^^^^^^^^^^^^^^^^^^^^ required by this bound in `Trait::leak_foo`
+error[E0038]: the trait `DynCompatCheck2` is not dyn compatible
+  --> $DIR/maybe-bounds-in-dyn-traits.rs:90:17
+   |
+LL |         fn mut_foo(&mut self) {}
+   |                    --------- help: consider changing method `mut_foo`'s `self` parameter to be `&self`: `&Self`
+...
+LL |     let _: &dyn DynCompatCheck2 = &NonLeakS;
+   |                 ^^^^^^^^^^^^^^^ `DynCompatCheck2` is not dyn compatible
+   |
+note: for a trait to be dyn compatible it needs to allow building a vtable
+      for more information, visit <https://doc.rust-lang.org/reference/items/traits.html#dyn-compatibility>
+  --> $DIR/maybe-bounds-in-dyn-traits.rs:82:20
+   |
+LL |     trait DynCompatCheck2: ?Leak {
+   |           --------------- this trait is not dyn compatible...
+LL |         fn mut_foo(&mut self) {}
+   |                    ^^^^^^^^^ ...because method `mut_foo`'s `self` parameter cannot be dispatched on
+   = help: only type `NonLeakS` implements `DynCompatCheck2`; consider using it directly instead.
 
 error[E0107]: trait takes 0 generic arguments but 1 generic argument was supplied
-  --> $DIR/maybe-bounds-in-dyn-traits.rs:68:25
+  --> $DIR/maybe-bounds-in-dyn-traits.rs:98:26
    |
-LL |     let _: dyn Trait + ?Leak<(), Undefined = ()>;
-   |                         ^^^^-------------------- help: remove the unnecessary generics
-   |                         |
-   |                         expected 0 generic arguments
+LL |     let _: dyn LeakTr + ?Leak<(), Undefined = ()>;
+   |                          ^^^^-------------------- help: remove the unnecessary generics
+   |                          |
+   |                          expected 0 generic arguments
    |
 note: trait defined here, with 0 generic parameters
-  --> $DIR/maybe-bounds-in-dyn-traits.rs:44:12
+  --> $DIR/maybe-bounds-in-dyn-traits.rs:49:12
    |
 LL | auto trait Leak {}
    |            ^^^^
 
 error[E0220]: associated type `Undefined` not found for `Leak`
-  --> $DIR/maybe-bounds-in-dyn-traits.rs:68:34
+  --> $DIR/maybe-bounds-in-dyn-traits.rs:98:35
    |
-LL |     let _: dyn Trait + ?Leak<(), Undefined = ()>;
-   |                                  ^^^^^^^^^ associated type `Undefined` not found
+LL |     let _: dyn LeakTr + ?Leak<(), Undefined = ()>;
+   |                                   ^^^^^^^^^ associated type `Undefined` not found
 
 error: aborting due to 4 previous errors
 
-Some errors have detailed explanations: E0107, E0220, E0277.
-For more information about an error, try `rustc --explain E0107`.
+Some errors have detailed explanations: E0038, E0107, E0220, E0277.
+For more information about an error, try `rustc --explain E0038`.
diff --git a/tests/ui/traits/default_auto_traits/maybe-bounds-in-traits.rs b/tests/ui/traits/default_auto_traits/maybe-bounds-in-traits.rs
index b3801baaf70..ac4c4aca2ef 100644
--- a/tests/ui/traits/default_auto_traits/maybe-bounds-in-traits.rs
+++ b/tests/ui/traits/default_auto_traits/maybe-bounds-in-traits.rs
@@ -14,18 +14,22 @@
 #![no_std]
 #![no_core]
 
+#[lang = "copy"]
+pub trait Copy: ?Leak {}
+
 #[lang = "pointee_sized"]
-trait PointeeSized {}
+trait PointeeSized: ?Leak {}
 
 #[lang = "meta_sized"]
-trait MetaSized: PointeeSized {}
+trait MetaSized: PointeeSized + ?Leak {}
 
 #[lang = "sized"]
-trait Sized: MetaSized {}
+trait Sized: MetaSized + ?Leak {}
 
 #[lang = "legacy_receiver"]
-trait LegacyReceiver {}
+trait LegacyReceiver: ?Leak {}
 impl<T: ?Sized + ?Leak> LegacyReceiver for &T {}
+// Omit `T: ?Leak`.
 impl<T: ?Sized> LegacyReceiver for &mut T {}
 
 #[lang = "default_trait1"]
@@ -38,83 +42,40 @@ struct LeakS;
 mod supertraits {
     use crate::*;
 
-    trait MaybeLeakT1: ?Leak {}
-    trait MaybeLeakT2 where Self: ?Leak {}
+    trait MaybeLeak: ?Leak {}
+    impl MaybeLeak for NonLeakS {}
 
-    impl MaybeLeakT1 for NonLeakS {}
-    impl MaybeLeakT2 for NonLeakS {}
+    trait LeakT {}
+    impl LeakT for NonLeakS {}
+    //~^ ERROR the trait bound `NonLeakS: Leak` is not satisfied
 }
 
-mod maybe_self_assoc_type {
+mod assoc_type_maybe_bounds {
     use crate::*;
 
-    trait TestBase1<T: ?Sized> {}
-    trait TestBase2<T: ?Leak + ?Sized> {}
-
-    trait Test1<T> {
-        type MaybeLeakSelf: TestBase1<Self> where Self: ?Leak;
-        //~^ ERROR the trait bound `Self: Leak` is not satisfied
-        type LeakSelf: TestBase1<Self>;
-    }
-
-    trait Test2<T> {
-        type MaybeLeakSelf: TestBase2<Self> where Self: ?Leak;
-        type LeakSelf: TestBase2<Self>;
-    }
-
-    trait Test3 {
+    trait Test1 {
         type Leak1 = LeakS;
         type Leak2 = NonLeakS;
         //~^ ERROR the trait bound `NonLeakS: Leak` is not satisfied
     }
 
-    trait Test4 {
+    trait Test2 {
         type MaybeLeak1: ?Leak = LeakS;
         type MaybeLeak2: ?Leak = NonLeakS;
     }
-
-    trait Test5: ?Leak {
-        // ok, because assoc types have implicit where Self: Leak
-        type MaybeLeakSelf1: TestBase1<Self>;
-        type MaybeLeakSelf2: TestBase2<Self>;
-    }
-}
-
-mod maybe_self_assoc_const {
-    use crate::*;
-
-    const fn size_of<T: ?Sized>() -> usize {
-        0
-    }
-
-    trait Trait {
-        const CLeak: usize = size_of::<Self>();
-        const CNonLeak: usize = size_of::<Self>() where Self: ?Leak;
-        //~^ ERROR the trait bound `Self: Leak` is not satisfied
-    }
 }
 
 mod methods {
     use crate::*;
 
-    trait Trait {
-        fn leak_foo(&self) {}
-        fn maybe_leak_foo(&self) where Self: ?Leak {}
-        fn mut_leak_foo(&mut self) {}
-        // there is no relax bound on corresponding Receiver impl
-        fn mut_maybe_leak_foo(&mut self) where Self: ?Leak {}
-        //~^ ERROR `&mut Self` cannot be used as the type of `self` without the `arbitrary_self_types`
+    trait ReceiveCheck1: ?Leak {
+        fn foo(&self) {}
     }
 
-    impl Trait for NonLeakS {}
-    impl Trait for LeakS {}
-
-    fn foo() {
-        LeakS.leak_foo();
-        LeakS.maybe_leak_foo();
-        NonLeakS.leak_foo();
-        //~^ ERROR the trait bound `NonLeakS: Leak` is not satisfied
-        NonLeakS.maybe_leak_foo();
+    trait ReceiveCheck2: ?Leak {
+        // There is no `?Leak` bound on corresponding `LegacyReceiver` impl.
+        fn mut_foo(&mut self) {}
+        //~^ ERROR `&mut Self` cannot be used as the type of `self` without the `arbitrary_self_types`
     }
 }
 
diff --git a/tests/ui/traits/default_auto_traits/maybe-bounds-in-traits.stderr b/tests/ui/traits/default_auto_traits/maybe-bounds-in-traits.stderr
index 372bf817600..ab62ab81b21 100644
--- a/tests/ui/traits/default_auto_traits/maybe-bounds-in-traits.stderr
+++ b/tests/ui/traits/default_auto_traits/maybe-bounds-in-traits.stderr
@@ -1,81 +1,49 @@
 error[E0277]: the trait bound `NonLeakS: Leak` is not satisfied
-  --> $DIR/maybe-bounds-in-traits.rs:67:22
+  --> $DIR/maybe-bounds-in-traits.rs:49:20
    |
-LL |         type Leak2 = NonLeakS;
-   |                      ^^^^^^^^ unsatisfied trait bound
+LL |     impl LeakT for NonLeakS {}
+   |                    ^^^^^^^^ unsatisfied trait bound
    |
 help: the trait `Leak` is not implemented for `NonLeakS`
-  --> $DIR/maybe-bounds-in-traits.rs:34:1
+  --> $DIR/maybe-bounds-in-traits.rs:38:1
    |
 LL | struct NonLeakS;
    | ^^^^^^^^^^^^^^^
-note: required by a bound in `Test3::Leak2`
-  --> $DIR/maybe-bounds-in-traits.rs:67:9
+note: required by a bound in `LeakT`
+  --> $DIR/maybe-bounds-in-traits.rs:48:5
    |
-LL |         type Leak2 = NonLeakS;
-   |         ^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `Test3::Leak2`
+LL |     trait LeakT {}
+   |     ^^^^^^^^^^^^^^ required by this bound in `LeakT`
 
-error[E0277]: the trait bound `Self: Leak` is not satisfied
-  --> $DIR/maybe-bounds-in-traits.rs:55:29
+error[E0277]: the trait bound `NonLeakS: Leak` is not satisfied
+  --> $DIR/maybe-bounds-in-traits.rs:58:22
    |
-LL |         type MaybeLeakSelf: TestBase1<Self> where Self: ?Leak;
-   |                             ^^^^^^^^^^^^^^^ the trait `Leak` is not implemented for `Self`
+LL |         type Leak2 = NonLeakS;
+   |                      ^^^^^^^^ unsatisfied trait bound
    |
-note: required by a bound in `TestBase1`
-  --> $DIR/maybe-bounds-in-traits.rs:51:21
+help: the trait `Leak` is not implemented for `NonLeakS`
+  --> $DIR/maybe-bounds-in-traits.rs:38:1
    |
-LL |     trait TestBase1<T: ?Sized> {}
-   |                     ^ required by this bound in `TestBase1`
-help: consider further restricting `Self`
+LL | struct NonLeakS;
+   | ^^^^^^^^^^^^^^^
+note: required by a bound in `Test1::Leak2`
+  --> $DIR/maybe-bounds-in-traits.rs:58:9
    |
-LL |     trait Test1<T>: Leak {
-   |                   ++++++
+LL |         type Leak2 = NonLeakS;
+   |         ^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `Test1::Leak2`
 
 error[E0658]: `&mut Self` cannot be used as the type of `self` without the `arbitrary_self_types` feature
-  --> $DIR/maybe-bounds-in-traits.rs:105:31
+  --> $DIR/maybe-bounds-in-traits.rs:77:20
    |
-LL |         fn mut_maybe_leak_foo(&mut self) where Self: ?Leak {}
-   |                               ^^^^^^^^^
+LL |         fn mut_foo(&mut self) {}
+   |                    ^^^^^^^^^
    |
    = note: see issue #44874 <https://github.com/rust-lang/rust/issues/44874> for more information
    = help: add `#![feature(arbitrary_self_types)]` to the crate attributes to enable
    = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
    = help: consider changing to `self`, `&self`, `&mut self`, or a type implementing `Receiver` such as `self: Box<Self>`, `self: Rc<Self>`, or `self: Arc<Self>`
 
-error[E0277]: the trait bound `Self: Leak` is not satisfied
-  --> $DIR/maybe-bounds-in-traits.rs:92:43
-   |
-LL |         const CNonLeak: usize = size_of::<Self>() where Self: ?Leak;
-   |                                           ^^^^ the trait `Leak` is not implemented for `Self`
-   |
-note: required by a bound in `size_of`
-  --> $DIR/maybe-bounds-in-traits.rs:86:22
-   |
-LL |     const fn size_of<T: ?Sized>() -> usize {
-   |                      ^ required by this bound in `size_of`
-help: consider further restricting `Self`
-   |
-LL |     trait Trait: Leak {
-   |                ++++++
-
-error[E0277]: the trait bound `NonLeakS: Leak` is not satisfied
-  --> $DIR/maybe-bounds-in-traits.rs:115:18
-   |
-LL |         NonLeakS.leak_foo();
-   |                  ^^^^^^^^ unsatisfied trait bound
-   |
-help: the trait `Leak` is not implemented for `NonLeakS`
-  --> $DIR/maybe-bounds-in-traits.rs:34:1
-   |
-LL | struct NonLeakS;
-   | ^^^^^^^^^^^^^^^
-note: required by a bound in `methods::Trait::leak_foo`
-  --> $DIR/maybe-bounds-in-traits.rs:101:9
-   |
-LL |         fn leak_foo(&self) {}
-   |         ^^^^^^^^^^^^^^^^^^^^^ required by this bound in `Trait::leak_foo`
-
-error: aborting due to 5 previous errors
+error: aborting due to 3 previous errors
 
 Some errors have detailed explanations: E0277, E0658.
 For more information about an error, try `rustc --explain E0277`.