Auto merge of #124330 - fmease:rollup-a98y7jf, r=fmease

Rollup of 6 pull requests

Successful merges:

 - #123316 (Test `#[unix_sigpipe = "inherit"]` with both `SIG_DFL` and `SIG_IGN`)
 - #123794 (More DefineOpaqueTypes::Yes)
 - #123881 (Bump Fuchsia versions)
 - #124281 (fix weak memory bug in TLS on Windows)
 - #124282 (windows fill_utf16_buf: explain the expected return value)
 - #124308 (Add diagnostic item for `std::iter::Enumerate`)

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

6 files changed, 320 insertions, 8 deletions

diff --git a/tests/ui/attributes/unix_sigpipe/auxiliary/assert-inherit-sig_dfl.rs b/tests/ui/attributes/unix_sigpipe/auxiliary/assert-inherit-sig_dfl.rs
new file mode 100644
index 00000000000..7f95fa7ebbe
--- /dev/null
+++ b/tests/ui/attributes/unix_sigpipe/auxiliary/assert-inherit-sig_dfl.rs
@@ -0,0 +1,8 @@
+//@ aux-crate: sigpipe_utils=sigpipe-utils.rs
+
+#![feature(unix_sigpipe)]
+
+#[unix_sigpipe = "inherit"]
+fn main() {
+    sigpipe_utils::assert_sigpipe_handler(sigpipe_utils::SignalHandler::Default);
+}
diff --git a/tests/ui/attributes/unix_sigpipe/auxiliary/assert-inherit-sig_ign.rs b/tests/ui/attributes/unix_sigpipe/auxiliary/assert-inherit-sig_ign.rs
new file mode 100644
index 00000000000..d96e8b8ef84
--- /dev/null
+++ b/tests/ui/attributes/unix_sigpipe/auxiliary/assert-inherit-sig_ign.rs
@@ -0,0 +1,8 @@
+//@ aux-crate: sigpipe_utils=sigpipe-utils.rs
+
+#![feature(unix_sigpipe)]
+
+#[unix_sigpipe = "inherit"]
+fn main() {
+    sigpipe_utils::assert_sigpipe_handler(sigpipe_utils::SignalHandler::Ignore);
+}
diff --git a/tests/ui/attributes/unix_sigpipe/unix_sigpipe-inherit.rs b/tests/ui/attributes/unix_sigpipe/unix_sigpipe-inherit.rs
index db3407a7d55..694fa460e9b 100644
--- a/tests/ui/attributes/unix_sigpipe/unix_sigpipe-inherit.rs
+++ b/tests/ui/attributes/unix_sigpipe/unix_sigpipe-inherit.rs
@@ -1,14 +1,29 @@
+//@ ignore-cross-compile because aux-bin does not yet support it
+//@ only-unix because SIGPIPE is a unix thing
+//@ aux-bin: assert-inherit-sig_dfl.rs
+//@ aux-bin: assert-inherit-sig_ign.rs
 //@ run-pass
-//@ aux-build:sigpipe-utils.rs
 
-#![feature(unix_sigpipe)]
+#![feature(rustc_private, unix_sigpipe)]
 
-#[unix_sigpipe = "inherit"]
+extern crate libc;
+
+// By default the Rust runtime resets SIGPIPE to SIG_DFL before exec:ing child
+// processes so opt-out of that with `#[unix_sigpipe = "sig_dfl"]`. See
+// https://github.com/rust-lang/rust/blob/bf4de3a874753bbee3323081c8b0c133444fed2d/library/std/src/sys/pal/unix/process/process_unix.rs#L359-L384
+#[unix_sigpipe = "sig_dfl"]
 fn main() {
-    extern crate sigpipe_utils;
+    // First expect SIG_DFL in a child process with #[unix_sigpipe = "inherit"].
+    assert_inherit_sigpipe_disposition("auxiliary/bin/assert-inherit-sig_dfl");
+
+    // With SIG_IGN we expect #[unix_sigpipe = "inherit"] to also get SIG_IGN.
+    unsafe {
+        libc::signal(libc::SIGPIPE, libc::SIG_IGN);
+    }
+    assert_inherit_sigpipe_disposition("auxiliary/bin/assert-inherit-sig_ign");
+}
 
-    // #[unix_sigpipe = "inherit"] is active, so SIGPIPE shall NOT be ignored,
-    // instead the default handler shall be installed. (We assume that the
-    // process that runs these tests have the default handler.)
-    sigpipe_utils::assert_sigpipe_handler(sigpipe_utils::SignalHandler::Default);
+fn assert_inherit_sigpipe_disposition(aux_bin: &str) {
+    let mut cmd = std::process::Command::new(aux_bin);
+    assert!(cmd.status().unwrap().success());
 }
diff --git a/tests/ui/fn/fn_def_coercion.rs b/tests/ui/fn/fn_def_coercion.rs
new file mode 100644
index 00000000000..313be6f28cd
--- /dev/null
+++ b/tests/ui/fn/fn_def_coercion.rs
@@ -0,0 +1,58 @@
+//! Test that coercing between function items of the same function,
+//! but with different generic args succeeds in typeck, but then fails
+//! in borrowck when the lifetimes can't actually be merged.
+
+fn foo<T>(t: T) -> T {
+    t
+}
+
+fn f<'a, 'b, 'c: 'a + 'b>(a: &'a (), b: &'b (), c: &'c ()) {
+    let mut x = foo::<&'a ()>; //~ ERROR: lifetime may not live long enough
+    x = foo::<&'b ()>; //~ ERROR: lifetime may not live long enough
+    x = foo::<&'c ()>;
+    x(a);
+    x(b);
+    x(c);
+}
+
+fn g<'a, 'b, 'c: 'a + 'b>(a: &'a (), b: &'b (), c: &'c ()) {
+    let x = foo::<&'c ()>;
+    let _: &'c () = x(a); //~ ERROR lifetime may not live long enough
+}
+
+fn h<'a, 'b, 'c: 'a + 'b>(a: &'a (), b: &'b (), c: &'c ()) {
+    let x = foo::<&'a ()>;
+    let _: &'a () = x(c);
+}
+
+fn i<'a, 'b, 'c: 'a + 'b>(a: &'a (), b: &'b (), c: &'c ()) {
+    let mut x = foo::<&'c ()>;
+    x = foo::<&'b ()>; //~ ERROR lifetime may not live long enough
+    x = foo::<&'a ()>; //~ ERROR lifetime may not live long enough
+    x(a);
+    x(b);
+    x(c);
+}
+
+fn j<'a, 'b, 'c: 'a + 'b>(a: &'a (), b: &'b (), c: &'c ()) {
+    let x = match true {
+        true => foo::<&'b ()>,  //~ ERROR lifetime may not live long enough
+        false => foo::<&'a ()>, //~ ERROR lifetime may not live long enough
+    };
+    x(a);
+    x(b);
+    x(c);
+}
+
+fn k<'a, 'b, 'c: 'a + 'b>(a: &'a (), b: &'b (), c: &'c ()) {
+    let x = match true {
+        true => foo::<&'c ()>,
+        false => foo::<&'a ()>, //~ ERROR lifetime may not live long enough
+    };
+
+    x(a);
+    x(b); //~ ERROR lifetime may not live long enough
+    x(c);
+}
+
+fn main() {}
diff --git a/tests/ui/fn/fn_def_coercion.stderr b/tests/ui/fn/fn_def_coercion.stderr
new file mode 100644
index 00000000000..ec4a1bde7fd
--- /dev/null
+++ b/tests/ui/fn/fn_def_coercion.stderr
@@ -0,0 +1,154 @@
+error: lifetime may not live long enough
+  --> $DIR/fn_def_coercion.rs:10:17
+   |
+LL | fn f<'a, 'b, 'c: 'a + 'b>(a: &'a (), b: &'b (), c: &'c ()) {
+   |      --  -- lifetime `'b` defined here
+   |      |
+   |      lifetime `'a` defined here
+LL |     let mut x = foo::<&'a ()>;
+   |                 ^^^^^^^^^^^^^ assignment requires that `'a` must outlive `'b`
+   |
+   = help: consider adding the following bound: `'a: 'b`
+   = note: requirement occurs because of a function pointer to `foo`
+   = note: the function `foo` is invariant over the parameter `T`
+   = help: see <https://doc.rust-lang.org/nomicon/subtyping.html> for more information about variance
+
+error: lifetime may not live long enough
+  --> $DIR/fn_def_coercion.rs:11:5
+   |
+LL | fn f<'a, 'b, 'c: 'a + 'b>(a: &'a (), b: &'b (), c: &'c ()) {
+   |      --  -- lifetime `'b` defined here
+   |      |
+   |      lifetime `'a` defined here
+LL |     let mut x = foo::<&'a ()>;
+LL |     x = foo::<&'b ()>;
+   |     ^^^^^^^^^^^^^^^^^ assignment requires that `'b` must outlive `'a`
+   |
+   = help: consider adding the following bound: `'b: 'a`
+   = note: requirement occurs because of a function pointer to `foo`
+   = note: the function `foo` is invariant over the parameter `T`
+   = help: see <https://doc.rust-lang.org/nomicon/subtyping.html> for more information about variance
+
+help: `'a` and `'b` must be the same: replace one with the other
+
+error: lifetime may not live long enough
+  --> $DIR/fn_def_coercion.rs:20:12
+   |
+LL | fn g<'a, 'b, 'c: 'a + 'b>(a: &'a (), b: &'b (), c: &'c ()) {
+   |      --      -- lifetime `'c` defined here
+   |      |
+   |      lifetime `'a` defined here
+LL |     let x = foo::<&'c ()>;
+LL |     let _: &'c () = x(a);
+   |            ^^^^^^ type annotation requires that `'a` must outlive `'c`
+   |
+   = help: consider adding the following bound: `'a: 'c`
+
+error: lifetime may not live long enough
+  --> $DIR/fn_def_coercion.rs:30:5
+   |
+LL | fn i<'a, 'b, 'c: 'a + 'b>(a: &'a (), b: &'b (), c: &'c ()) {
+   |      --  -- lifetime `'b` defined here
+   |      |
+   |      lifetime `'a` defined here
+LL |     let mut x = foo::<&'c ()>;
+LL |     x = foo::<&'b ()>;
+   |     ^^^^^^^^^^^^^^^^^ assignment requires that `'b` must outlive `'a`
+   |
+   = help: consider adding the following bound: `'b: 'a`
+   = note: requirement occurs because of a function pointer to `foo`
+   = note: the function `foo` is invariant over the parameter `T`
+   = help: see <https://doc.rust-lang.org/nomicon/subtyping.html> for more information about variance
+
+error: lifetime may not live long enough
+  --> $DIR/fn_def_coercion.rs:31:5
+   |
+LL | fn i<'a, 'b, 'c: 'a + 'b>(a: &'a (), b: &'b (), c: &'c ()) {
+   |      --  -- lifetime `'b` defined here
+   |      |
+   |      lifetime `'a` defined here
+...
+LL |     x = foo::<&'a ()>;
+   |     ^^^^^^^^^^^^^^^^^ assignment requires that `'a` must outlive `'b`
+   |
+   = help: consider adding the following bound: `'a: 'b`
+   = note: requirement occurs because of a function pointer to `foo`
+   = note: the function `foo` is invariant over the parameter `T`
+   = help: see <https://doc.rust-lang.org/nomicon/subtyping.html> for more information about variance
+
+help: `'a` and `'b` must be the same: replace one with the other
+   |
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
+
+error: lifetime may not live long enough
+  --> $DIR/fn_def_coercion.rs:39:17
+   |
+LL | fn j<'a, 'b, 'c: 'a + 'b>(a: &'a (), b: &'b (), c: &'c ()) {
+   |      --  -- lifetime `'b` defined here
+   |      |
+   |      lifetime `'a` defined here
+LL |     let x = match true {
+LL |         true => foo::<&'b ()>,
+   |                 ^^^^^^^^^^^^^ assignment requires that `'b` must outlive `'a`
+   |
+   = help: consider adding the following bound: `'b: 'a`
+   = note: requirement occurs because of a function pointer to `foo`
+   = note: the function `foo` is invariant over the parameter `T`
+   = help: see <https://doc.rust-lang.org/nomicon/subtyping.html> for more information about variance
+
+error: lifetime may not live long enough
+  --> $DIR/fn_def_coercion.rs:40:18
+   |
+LL | fn j<'a, 'b, 'c: 'a + 'b>(a: &'a (), b: &'b (), c: &'c ()) {
+   |      --  -- lifetime `'b` defined here
+   |      |
+   |      lifetime `'a` defined here
+...
+LL |         false => foo::<&'a ()>,
+   |                  ^^^^^^^^^^^^^ assignment requires that `'a` must outlive `'b`
+   |
+   = help: consider adding the following bound: `'a: 'b`
+   = note: requirement occurs because of a function pointer to `foo`
+   = note: the function `foo` is invariant over the parameter `T`
+   = help: see <https://doc.rust-lang.org/nomicon/subtyping.html> for more information about variance
+
+help: `'a` and `'b` must be the same: replace one with the other
+   |
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
+
+error: lifetime may not live long enough
+  --> $DIR/fn_def_coercion.rs:50:18
+   |
+LL | fn k<'a, 'b, 'c: 'a + 'b>(a: &'a (), b: &'b (), c: &'c ()) {
+   |      --      -- lifetime `'c` defined here
+   |      |
+   |      lifetime `'a` defined here
+...
+LL |         false => foo::<&'a ()>,
+   |                  ^^^^^^^^^^^^^ assignment requires that `'a` must outlive `'c`
+   |
+   = help: consider adding the following bound: `'a: 'c`
+   = note: requirement occurs because of a function pointer to `foo`
+   = note: the function `foo` is invariant over the parameter `T`
+   = help: see <https://doc.rust-lang.org/nomicon/subtyping.html> for more information about variance
+
+error: lifetime may not live long enough
+  --> $DIR/fn_def_coercion.rs:54:5
+   |
+LL | fn k<'a, 'b, 'c: 'a + 'b>(a: &'a (), b: &'b (), c: &'c ()) {
+   |      --  -- lifetime `'b` defined here
+   |      |
+   |      lifetime `'a` defined here
+...
+LL |     x(b);
+   |     ^^^^ argument requires that `'b` must outlive `'a`
+   |
+   = help: consider adding the following bound: `'b: 'a`
+
+help: the following changes may resolve your lifetime errors
+   |
+   = help: add bound `'a: 'c`
+   = help: add bound `'b: 'a`
+
+error: aborting due to 9 previous errors
+
diff --git a/tests/ui/fn/fn_def_opaque_coercion.rs b/tests/ui/fn/fn_def_opaque_coercion.rs
new file mode 100644
index 00000000000..0a8810cf4f8
--- /dev/null
+++ b/tests/ui/fn/fn_def_opaque_coercion.rs
@@ -0,0 +1,69 @@
+//! Test that coercing between function items of the same function,
+//! but with different generic args works.
+
+//@check-pass
+
+#![feature(type_alias_impl_trait)]
+
+fn foo<T>(t: T) -> T {
+    t
+}
+
+type F = impl Sized;
+
+fn f(a: F) {
+    let mut x = foo::<F>;
+    x = foo::<()>;
+    x(a);
+    x(());
+}
+
+type G = impl Sized;
+
+fn g(a: G) {
+    let x = foo::<()>;
+    let _: () = x(a);
+}
+
+type H = impl Sized;
+
+fn h(a: H) {
+    let x = foo::<H>;
+    let _: H = x(());
+}
+
+type I = impl Sized;
+
+fn i(a: I) {
+    let mut x = foo::<()>;
+    x = foo::<I>;
+    x(a);
+    x(());
+}
+
+type J = impl Sized;
+
+fn j(a: J) {
+    let x = match true {
+        true => foo::<J>,
+        false => foo::<()>,
+    };
+    x(a);
+    x(());
+}
+
+fn k() -> impl Sized {
+    fn bind<T, F: FnOnce(T) -> T>(_: T, f: F) -> F {
+        f
+    }
+    let x = match true {
+        true => {
+            let f = foo;
+            bind(k(), f)
+        }
+        false => foo::<()>,
+    };
+    todo!()
+}
+
+fn main() {}