Auto merge of #129275 - matthiaskrgr:rollup-qv64hg6, r=matthiaskrgr

Rollup of 6 pull requests

Successful merges:

 - #129194 (Fix bootstrap test `detect_src_and_out` on Windows)
 - #129217 (safe transmute: check lifetimes)
 - #129223 ( Fix wrong argument for `get_fn_decl`)
 - #129235 (Check that `#[may_dangle]` is properly applied)
 - #129245 (Fix a typo in `rustc_hir` doc comment)
 - #129271 (Prevent double panic in query system, improve diagnostics)

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

12 files changed, 483 insertions, 6 deletions

diff --git a/tests/ui/async-await/async-fn/recurse-ice-129215.rs b/tests/ui/async-await/async-fn/recurse-ice-129215.rs
new file mode 100644
index 00000000000..06a2d7be9ef
--- /dev/null
+++ b/tests/ui/async-await/async-fn/recurse-ice-129215.rs
@@ -0,0 +1,9 @@
+//@ edition: 2021
+
+async fn a() {
+    //~^ ERROR `()` is not a future
+    //~| ERROR mismatched types
+    a() //~ ERROR `()` is not a future
+}
+
+fn main() {}
diff --git a/tests/ui/async-await/async-fn/recurse-ice-129215.stderr b/tests/ui/async-await/async-fn/recurse-ice-129215.stderr
new file mode 100644
index 00000000000..98c7be2a5a3
--- /dev/null
+++ b/tests/ui/async-await/async-fn/recurse-ice-129215.stderr
@@ -0,0 +1,34 @@
+error[E0277]: `()` is not a future
+  --> $DIR/recurse-ice-129215.rs:6:5
+   |
+LL |     a()
+   |     ^^^ `()` is not a future
+   |
+   = help: the trait `Future` is not implemented for `()`
+
+error[E0277]: `()` is not a future
+  --> $DIR/recurse-ice-129215.rs:3:1
+   |
+LL | async fn a() {
+   | ^^^^^^^^^^^^ `()` is not a future
+   |
+   = help: the trait `Future` is not implemented for `()`
+
+error[E0308]: mismatched types
+  --> $DIR/recurse-ice-129215.rs:3:14
+   |
+LL |   async fn a() {
+   |  ______________^
+LL | |
+LL | |
+LL | |     a()
+LL | | }
+   | |_^ expected `()`, found `async` fn body
+   |
+   = note:    expected unit type `()`
+           found `async` fn body `{async fn body of a()}`
+
+error: aborting due to 3 previous errors
+
+Some errors have detailed explanations: E0277, E0308.
+For more information about an error, try `rustc --explain E0277`.
diff --git a/tests/ui/attributes/may_dangle.rs b/tests/ui/attributes/may_dangle.rs
new file mode 100644
index 00000000000..209ba0e88ad
--- /dev/null
+++ b/tests/ui/attributes/may_dangle.rs
@@ -0,0 +1,53 @@
+#![feature(dropck_eyepatch)]
+
+struct Implee1<'a, T, const N: usize>(&'a T);
+struct Implee2<'a, T, const N: usize>(&'a T);
+struct Implee3<'a, T, const N: usize>(&'a T);
+trait NotDrop {}
+
+unsafe impl<#[may_dangle] 'a, T, const N: usize> NotDrop for Implee1<'a, T, N> {}
+//~^ ERROR must be applied to a lifetime or type generic parameter in `Drop` impl
+
+unsafe impl<'a, #[may_dangle] T, const N: usize> NotDrop for Implee2<'a, T, N> {}
+//~^ ERROR must be applied to a lifetime or type generic parameter in `Drop` impl
+
+unsafe impl<'a, T, #[may_dangle] const N: usize> Drop for Implee1<'a, T, N> {
+    //~^ ERROR must be applied to a lifetime or type generic parameter in `Drop` impl
+    fn drop(&mut self) {}
+}
+
+// Ok, lifetime param in a `Drop` impl.
+unsafe impl<#[may_dangle] 'a, T, const N: usize> Drop for Implee2<'a, T, N> {
+    fn drop(&mut self) {}
+}
+
+// Ok, type param in a `Drop` impl.
+unsafe impl<'a, #[may_dangle] T, const N: usize> Drop for Implee3<'a, T, N> {
+    fn drop(&mut self) {}
+}
+
+// Check that this check is not textual.
+mod fake {
+    trait Drop {
+        fn drop(&mut self);
+    }
+    struct Implee<T>(T);
+
+    unsafe impl<#[may_dangle] T> Drop for Implee<T> {
+        //~^ ERROR must be applied to a lifetime or type generic parameter in `Drop` impl
+        fn drop(&mut self) {}
+    }
+}
+
+#[may_dangle] //~ ERROR must be applied to a lifetime or type generic parameter in `Drop` impl
+struct Dangling;
+
+#[may_dangle] //~ ERROR must be applied to a lifetime or type generic parameter in `Drop` impl
+impl NotDrop for () {
+}
+
+#[may_dangle] //~ ERROR must be applied to a lifetime or type generic parameter in `Drop` impl
+fn main() {
+    #[may_dangle] //~ ERROR must be applied to a lifetime or type generic parameter in `Drop` impl
+    let () = ();
+}
diff --git a/tests/ui/attributes/may_dangle.stderr b/tests/ui/attributes/may_dangle.stderr
new file mode 100644
index 00000000000..dc24f847f71
--- /dev/null
+++ b/tests/ui/attributes/may_dangle.stderr
@@ -0,0 +1,50 @@
+error: `#[may_dangle]` must be applied to a lifetime or type generic parameter in `Drop` impl
+  --> $DIR/may_dangle.rs:8:13
+   |
+LL | unsafe impl<#[may_dangle] 'a, T, const N: usize> NotDrop for Implee1<'a, T, N> {}
+   |             ^^^^^^^^^^^^^
+
+error: `#[may_dangle]` must be applied to a lifetime or type generic parameter in `Drop` impl
+  --> $DIR/may_dangle.rs:11:17
+   |
+LL | unsafe impl<'a, #[may_dangle] T, const N: usize> NotDrop for Implee2<'a, T, N> {}
+   |                 ^^^^^^^^^^^^^
+
+error: `#[may_dangle]` must be applied to a lifetime or type generic parameter in `Drop` impl
+  --> $DIR/may_dangle.rs:14:20
+   |
+LL | unsafe impl<'a, T, #[may_dangle] const N: usize> Drop for Implee1<'a, T, N> {
+   |                    ^^^^^^^^^^^^^
+
+error: `#[may_dangle]` must be applied to a lifetime or type generic parameter in `Drop` impl
+  --> $DIR/may_dangle.rs:42:1
+   |
+LL | #[may_dangle]
+   | ^^^^^^^^^^^^^
+
+error: `#[may_dangle]` must be applied to a lifetime or type generic parameter in `Drop` impl
+  --> $DIR/may_dangle.rs:45:1
+   |
+LL | #[may_dangle]
+   | ^^^^^^^^^^^^^
+
+error: `#[may_dangle]` must be applied to a lifetime or type generic parameter in `Drop` impl
+  --> $DIR/may_dangle.rs:49:1
+   |
+LL | #[may_dangle]
+   | ^^^^^^^^^^^^^
+
+error: `#[may_dangle]` must be applied to a lifetime or type generic parameter in `Drop` impl
+  --> $DIR/may_dangle.rs:51:5
+   |
+LL |     #[may_dangle]
+   |     ^^^^^^^^^^^^^
+
+error: `#[may_dangle]` must be applied to a lifetime or type generic parameter in `Drop` impl
+  --> $DIR/may_dangle.rs:36:17
+   |
+LL |     unsafe impl<#[may_dangle] T> Drop for Implee<T> {
+   |                 ^^^^^^^^^^^^^
+
+error: aborting due to 8 previous errors
+
diff --git a/tests/ui/closures/add_semicolon_non_block_closure.rs b/tests/ui/closures/add_semicolon_non_block_closure.rs
index 3ae91be60c5..62c5e343cd3 100644
--- a/tests/ui/closures/add_semicolon_non_block_closure.rs
+++ b/tests/ui/closures/add_semicolon_non_block_closure.rs
@@ -8,4 +8,5 @@ fn main() {
     foo(|| bar())
     //~^ ERROR mismatched types [E0308]
     //~| HELP consider using a semicolon here
+    //~| HELP try adding a return type
 }
diff --git a/tests/ui/closures/add_semicolon_non_block_closure.stderr b/tests/ui/closures/add_semicolon_non_block_closure.stderr
index d095e59c7eb..7883db8f98e 100644
--- a/tests/ui/closures/add_semicolon_non_block_closure.stderr
+++ b/tests/ui/closures/add_semicolon_non_block_closure.stderr
@@ -1,8 +1,6 @@
 error[E0308]: mismatched types
   --> $DIR/add_semicolon_non_block_closure.rs:8:12
    |
-LL | fn main() {
-   |          - expected `()` because of default return type
 LL |     foo(|| bar())
    |            ^^^^^ expected `()`, found `i32`
    |
@@ -10,6 +8,10 @@ help: consider using a semicolon here
    |
 LL |     foo(|| { bar(); })
    |            +      +++
+help: try adding a return type
+   |
+LL |     foo(|| -> i32 bar())
+   |            ++++++
 
 error: aborting due to 1 previous error
 
diff --git a/tests/ui/lint/must_not_suspend/other_items.stderr b/tests/ui/lint/must_not_suspend/other_items.stderr
index e6c36b78951..dff5210b7e4 100644
--- a/tests/ui/lint/must_not_suspend/other_items.stderr
+++ b/tests/ui/lint/must_not_suspend/other_items.stderr
@@ -1,10 +1,10 @@
-error: `must_not_suspend` attribute should be applied to a struct, enum, or trait
+error: `must_not_suspend` attribute should be applied to a struct, enum, union, or trait
   --> $DIR/other_items.rs:5:1
    |
 LL | #[must_not_suspend]
    | ^^^^^^^^^^^^^^^^^^^
 LL | mod inner {}
-   | ------------ is not a struct, enum, or trait
+   | ------------ is not a struct, enum, union, or trait
 
 error: aborting due to 1 previous error
 
diff --git a/tests/ui/lint/must_not_suspend/return.stderr b/tests/ui/lint/must_not_suspend/return.stderr
index 5a73064c787..440f8165686 100644
--- a/tests/ui/lint/must_not_suspend/return.stderr
+++ b/tests/ui/lint/must_not_suspend/return.stderr
@@ -1,4 +1,4 @@
-error: `must_not_suspend` attribute should be applied to a struct, enum, or trait
+error: `must_not_suspend` attribute should be applied to a struct, enum, union, or trait
   --> $DIR/return.rs:5:1
    |
 LL |   #[must_not_suspend]
@@ -6,7 +6,7 @@ LL |   #[must_not_suspend]
 LL | / fn foo() -> i32 {
 LL | |     0
 LL | | }
-   | |_- is not a struct, enum, or trait
+   | |_- is not a struct, enum, union, or trait
 
 error: aborting due to 1 previous error
 
diff --git a/tests/ui/transmutability/references/accept_assume_lifetime_extension.rs b/tests/ui/transmutability/references/accept_assume_lifetime_extension.rs
new file mode 100644
index 00000000000..3bdd7256791
--- /dev/null
+++ b/tests/ui/transmutability/references/accept_assume_lifetime_extension.rs
@@ -0,0 +1,91 @@
+//@ check-pass
+
+//! Accept lifetime extensions with `Assume::LIFETIMES`.
+
+#![feature(transmutability, core_intrinsics)]
+
+use std::mem::{Assume, BikeshedIntrinsicFrom};
+
+unsafe fn transmute<Src, Dst>(src: Src) -> Dst
+where
+    Dst: BikeshedIntrinsicFrom<Src, { Assume::SAFETY.and(Assume::LIFETIMES) }>,
+{
+    core::intrinsics::transmute_unchecked(src)
+}
+
+mod bare {
+    use super::*;
+
+    fn extend_bare<'a>(src: &'a u8) -> &'static u8 {
+        unsafe { transmute(src) }
+    }
+}
+
+mod nested {
+    use super::*;
+
+    fn extend_nested<'a>(src: &'a &'a u8) -> &'a &'static u8 {
+        unsafe { transmute(src) }
+    }
+}
+
+mod tuple {
+    use super::*;
+
+    fn extend_unit<'a>(src: (&'a u8,)) -> (&'static u8,) {
+        unsafe { transmute(src) }
+    }
+
+    fn extend_pair<'a>(src: (&'a u8, u8)) -> (&'static u8, u8) {
+        unsafe { transmute(src) }
+    }
+}
+
+mod r#struct {
+    use super::*;
+
+    struct Struct<'a>(&'a u8);
+
+    fn extend_struct<'a>(src: Struct<'a>) -> Struct<'static> {
+        unsafe { transmute(src) }
+    }
+}
+
+mod r#enum {
+    use super::*;
+
+    enum Single<'a> {
+        A(&'a u8),
+    }
+
+    fn extend_single<'a>(src: Single<'a>) -> Single<'static> {
+        unsafe { transmute(src) }
+    }
+
+    enum Multi<'a> {
+        A(&'a u8),
+        B,
+        C,
+    }
+
+    fn extend_multi<'a>(src: Multi<'a>) -> Multi<'static> {
+        unsafe { transmute(src) }
+    }
+}
+
+mod hrtb {
+    use super::*;
+
+    fn call_extend_hrtb<'a>(src: &'a u8) -> &'static u8 {
+        unsafe { extend_hrtb(src) }
+    }
+
+    unsafe fn extend_hrtb<'a>(src: &'a u8) -> &'static u8
+    where
+        for<'b> &'b u8: BikeshedIntrinsicFrom<&'a u8, { Assume::LIFETIMES }>,
+    {
+        core::intrinsics::transmute_unchecked(src)
+    }
+}
+
+fn main() {}
diff --git a/tests/ui/transmutability/references/accept_unexercised_lifetime_extension.rs b/tests/ui/transmutability/references/accept_unexercised_lifetime_extension.rs
new file mode 100644
index 00000000000..559ee23a446
--- /dev/null
+++ b/tests/ui/transmutability/references/accept_unexercised_lifetime_extension.rs
@@ -0,0 +1,68 @@
+//@ check-pass
+
+//! Accept lifetime extensions of un-exercised lifetimes.
+
+#![feature(transmutability, core_intrinsics)]
+
+use std::mem::{Assume, BikeshedIntrinsicFrom};
+
+unsafe fn transmute<Src, Dst>(src: Src) -> Dst
+where
+    Dst: BikeshedIntrinsicFrom<Src, { Assume::SAFETY }>,
+{
+    core::intrinsics::transmute_unchecked(src)
+}
+
+enum Void {}
+
+mod phantom {
+    use super::*;
+    use std::marker::PhantomData;
+
+    fn extend_bare<'a>(src: PhantomData<&'a u8>) -> PhantomData<&'static u8> {
+        unsafe { transmute(src) }
+    }
+}
+
+
+mod tuple {
+    use super::*;
+
+    fn extend_pair<'a>(src: (&'a u8, Void)) -> (&'static u8, Void) {
+        unsafe { transmute(src) }
+    }
+}
+
+mod r#struct {
+    use super::*;
+
+    struct Struct<'a>(&'a u8, Void);
+
+    fn extend_struct<'a>(src: Struct<'a>) -> Struct<'static> {
+        unsafe { transmute(src) }
+    }
+}
+
+mod r#enum {
+    use super::*;
+
+    enum Single<'a> {
+        A(&'a u8, Void),
+    }
+
+    fn extend_single<'a>(src: Single<'a>) -> Single<'static> {
+        unsafe { transmute(src) }
+    }
+
+    enum Multi<'a> {
+        A(&'a u8, Void),
+        B,
+        C,
+    }
+
+    fn extend_multi<'a>(src: Multi<'a>) -> Multi<'static> {
+        unsafe { transmute(src) }
+    }
+}
+
+fn main() {}
diff --git a/tests/ui/transmutability/references/reject_lifetime_extension.rs b/tests/ui/transmutability/references/reject_lifetime_extension.rs
new file mode 100644
index 00000000000..79bb4e1e556
--- /dev/null
+++ b/tests/ui/transmutability/references/reject_lifetime_extension.rs
@@ -0,0 +1,91 @@
+//@ check-fail
+
+//! Reject lifetime extensions.
+
+#![feature(transmutability, core_intrinsics)]
+
+use std::mem::{Assume, BikeshedIntrinsicFrom};
+
+unsafe fn transmute<Src, Dst>(src: Src) -> Dst
+where
+    Dst: BikeshedIntrinsicFrom<Src, { Assume::SAFETY }>,
+{
+    core::intrinsics::transmute_unchecked(src)
+}
+
+mod bare {
+    use super::*;
+
+    fn extend_bare<'a>(src: &'a u8) -> &'static u8 {
+        unsafe { transmute(src) } //~ ERROR lifetime may not live long enough
+    }
+}
+
+mod nested {
+    use super::*;
+
+    fn extend_nested<'a>(src: &'a &'a u8) -> &'a &'static u8 {
+        unsafe { transmute(src) } //~ ERROR lifetime may not live long enough
+    }
+}
+
+mod tuple {
+    use super::*;
+
+    fn extend_unit<'a>(src: (&'a u8,)) -> (&'static u8,) {
+        unsafe { transmute(src) } //~ ERROR lifetime may not live long enough
+    }
+
+    fn extend_pair<'a>(src: (&'a u8, u8)) -> (&'static u8, u8) {
+        unsafe { transmute(src) } //~ ERROR lifetime may not live long enough
+    }
+}
+
+mod r#struct {
+    use super::*;
+
+    struct Struct<'a>(&'a u8);
+
+    fn extend_struct<'a>(src: Struct<'a>) -> Struct<'static> {
+        unsafe { transmute(src) } //~ ERROR lifetime may not live long enough
+    }
+}
+
+mod r#enum {
+    use super::*;
+
+    enum Single<'a> {
+        A(&'a u8),
+    }
+
+    fn extend_single<'a>(src: Single<'a>) -> Single<'static> {
+        unsafe { transmute(src) } //~ ERROR lifetime may not live long enough
+    }
+
+    enum Multi<'a> {
+        A(&'a u8),
+        B,
+        C,
+    }
+
+    fn extend_multi<'a>(src: Multi<'a>) -> Multi<'static> {
+        unsafe { transmute(src) } //~ ERROR lifetime may not live long enough
+    }
+}
+
+mod hrtb {
+    use super::*;
+
+    fn call_extend_hrtb<'a>(src: &'a u8) -> &'static u8 {
+        unsafe { extend_hrtb(src) } //~ ERROR borrowed data escapes outside of function
+    }
+
+    unsafe fn extend_hrtb<'a>(src: &'a u8) -> &'static u8
+    where
+        for<'b> &'b u8: BikeshedIntrinsicFrom<&'a u8>,
+    {
+        core::intrinsics::transmute_unchecked(src)
+    }
+}
+
+fn main() {}
diff --git a/tests/ui/transmutability/references/reject_lifetime_extension.stderr b/tests/ui/transmutability/references/reject_lifetime_extension.stderr
new file mode 100644
index 00000000000..df1b81f26d2
--- /dev/null
+++ b/tests/ui/transmutability/references/reject_lifetime_extension.stderr
@@ -0,0 +1,78 @@
+error: lifetime may not live long enough
+  --> $DIR/reject_lifetime_extension.rs:20:18
+   |
+LL |     fn extend_bare<'a>(src: &'a u8) -> &'static u8 {
+   |                    -- lifetime `'a` defined here
+LL |         unsafe { transmute(src) }
+   |                  ^^^^^^^^^^^^^^ returning this value requires that `'a` must outlive `'static`
+
+error: lifetime may not live long enough
+  --> $DIR/reject_lifetime_extension.rs:28:18
+   |
+LL |     fn extend_nested<'a>(src: &'a &'a u8) -> &'a &'static u8 {
+   |                      -- lifetime `'a` defined here
+LL |         unsafe { transmute(src) }
+   |                  ^^^^^^^^^^^^^^ returning this value requires that `'a` must outlive `'static`
+
+error: lifetime may not live long enough
+  --> $DIR/reject_lifetime_extension.rs:36:18
+   |
+LL |     fn extend_unit<'a>(src: (&'a u8,)) -> (&'static u8,) {
+   |                    -- lifetime `'a` defined here
+LL |         unsafe { transmute(src) }
+   |                  ^^^^^^^^^^^^^^ returning this value requires that `'a` must outlive `'static`
+
+error: lifetime may not live long enough
+  --> $DIR/reject_lifetime_extension.rs:40:18
+   |
+LL |     fn extend_pair<'a>(src: (&'a u8, u8)) -> (&'static u8, u8) {
+   |                    -- lifetime `'a` defined here
+LL |         unsafe { transmute(src) }
+   |                  ^^^^^^^^^^^^^^ returning this value requires that `'a` must outlive `'static`
+
+error: lifetime may not live long enough
+  --> $DIR/reject_lifetime_extension.rs:50:18
+   |
+LL |     fn extend_struct<'a>(src: Struct<'a>) -> Struct<'static> {
+   |                      -- lifetime `'a` defined here
+LL |         unsafe { transmute(src) }
+   |                  ^^^^^^^^^^^^^^ returning this value requires that `'a` must outlive `'static`
+
+error: lifetime may not live long enough
+  --> $DIR/reject_lifetime_extension.rs:62:18
+   |
+LL |     fn extend_single<'a>(src: Single<'a>) -> Single<'static> {
+   |                      -- lifetime `'a` defined here
+LL |         unsafe { transmute(src) }
+   |                  ^^^^^^^^^^^^^^ returning this value requires that `'a` must outlive `'static`
+
+error: lifetime may not live long enough
+  --> $DIR/reject_lifetime_extension.rs:72:18
+   |
+LL |     fn extend_multi<'a>(src: Multi<'a>) -> Multi<'static> {
+   |                     -- lifetime `'a` defined here
+LL |         unsafe { transmute(src) }
+   |                  ^^^^^^^^^^^^^^ returning this value requires that `'a` must outlive `'static`
+
+error[E0521]: borrowed data escapes outside of function
+  --> $DIR/reject_lifetime_extension.rs:80:18
+   |
+LL |     fn call_extend_hrtb<'a>(src: &'a u8) -> &'static u8 {
+   |                         --  --- `src` is a reference that is only valid in the function body
+   |                         |
+   |                         lifetime `'a` defined here
+LL |         unsafe { extend_hrtb(src) }
+   |                  ^^^^^^^^^^^^^^^^
+   |                  |
+   |                  `src` escapes the function body here
+   |                  argument requires that `'a` must outlive `'static`
+   |
+note: due to current limitations in the borrow checker, this implies a `'static` lifetime
+  --> $DIR/reject_lifetime_extension.rs:85:25
+   |
+LL |         for<'b> &'b u8: BikeshedIntrinsicFrom<&'a u8>,
+   |                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: aborting due to 8 previous errors
+
+For more information about this error, try `rustc --explain E0521`.