Auto merge of #125098 - jhpratt:rollup-2qm4gga, r=jhpratt

Rollup of 4 pull requests

Successful merges:

 - #116675 ([ptr] Document maximum allocation size)
 - #124997 (Fix ICE while casting a type with error)
 - #125072 (Add test for dynamic dispatch + Pin::new soundness)
 - #125090 (Migrate fuchsia docs from `pm` to `ffx`)

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

4 files changed, 109 insertions, 0 deletions

diff --git a/tests/ui/cast/ice-cast-type-with-error-124848.rs b/tests/ui/cast/ice-cast-type-with-error-124848.rs
new file mode 100644
index 00000000000..9b3732b02db
--- /dev/null
+++ b/tests/ui/cast/ice-cast-type-with-error-124848.rs
@@ -0,0 +1,18 @@
+// Regression test for ICE #124848
+// Tests that there is no ICE when a cast
+// involves a type with error
+
+use std::cell::Cell;
+
+struct MyType<'a>(Cell<Option<&'unpinned mut MyType<'a>>>, Pin);
+//~^ ERROR use of undeclared lifetime name `'unpinned`
+//~| ERROR cannot find type `Pin` in this scope
+
+fn main() {
+    let mut unpinned = MyType(Cell::new(None));
+    //~^ ERROR his struct takes 2 arguments but 1 argument was supplied
+    let bad_addr = &unpinned as *const Cell<Option<&'a mut MyType<'a>>> as usize;
+    //~^ ERROR use of undeclared lifetime name `'a`
+    //~| ERROR use of undeclared lifetime name `'a`
+    //~| ERROR casting `&MyType<'_>` as `*const Cell<Option<&mut MyType<'_>>>` is invalid
+}
diff --git a/tests/ui/cast/ice-cast-type-with-error-124848.stderr b/tests/ui/cast/ice-cast-type-with-error-124848.stderr
new file mode 100644
index 00000000000..2d86bf76d11
--- /dev/null
+++ b/tests/ui/cast/ice-cast-type-with-error-124848.stderr
@@ -0,0 +1,63 @@
+error[E0261]: use of undeclared lifetime name `'unpinned`
+  --> $DIR/ice-cast-type-with-error-124848.rs:7:32
+   |
+LL | struct MyType<'a>(Cell<Option<&'unpinned mut MyType<'a>>>, Pin);
+   |               -                ^^^^^^^^^ undeclared lifetime
+   |               |
+   |               help: consider introducing lifetime `'unpinned` here: `'unpinned,`
+
+error[E0261]: use of undeclared lifetime name `'a`
+  --> $DIR/ice-cast-type-with-error-124848.rs:14:53
+   |
+LL | fn main() {
+   |        - help: consider introducing lifetime `'a` here: `<'a>`
+...
+LL |     let bad_addr = &unpinned as *const Cell<Option<&'a mut MyType<'a>>> as usize;
+   |                                                     ^^ undeclared lifetime
+
+error[E0261]: use of undeclared lifetime name `'a`
+  --> $DIR/ice-cast-type-with-error-124848.rs:14:67
+   |
+LL | fn main() {
+   |        - help: consider introducing lifetime `'a` here: `<'a>`
+...
+LL |     let bad_addr = &unpinned as *const Cell<Option<&'a mut MyType<'a>>> as usize;
+   |                                                                   ^^ undeclared lifetime
+
+error[E0412]: cannot find type `Pin` in this scope
+  --> $DIR/ice-cast-type-with-error-124848.rs:7:60
+   |
+LL | struct MyType<'a>(Cell<Option<&'unpinned mut MyType<'a>>>, Pin);
+   |                                                            ^^^ not found in this scope
+   |
+help: consider importing this struct
+   |
+LL + use std::pin::Pin;
+   |
+
+error[E0061]: this struct takes 2 arguments but 1 argument was supplied
+  --> $DIR/ice-cast-type-with-error-124848.rs:12:24
+   |
+LL |     let mut unpinned = MyType(Cell::new(None));
+   |                        ^^^^^^----------------- an argument is missing
+   |
+note: tuple struct defined here
+  --> $DIR/ice-cast-type-with-error-124848.rs:7:8
+   |
+LL | struct MyType<'a>(Cell<Option<&'unpinned mut MyType<'a>>>, Pin);
+   |        ^^^^^^
+help: provide the argument
+   |
+LL |     let mut unpinned = MyType(Cell::new(None), /* value */);
+   |                              ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+error[E0606]: casting `&MyType<'_>` as `*const Cell<Option<&mut MyType<'_>>>` is invalid
+  --> $DIR/ice-cast-type-with-error-124848.rs:14:20
+   |
+LL |     let bad_addr = &unpinned as *const Cell<Option<&'a mut MyType<'a>>> as usize;
+   |                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: aborting due to 6 previous errors
+
+Some errors have detailed explanations: E0061, E0261, E0412, E0606.
+For more information about an error, try `rustc --explain E0061`.
diff --git a/tests/ui/coercion/pin-dyn-dispatch-sound.rs b/tests/ui/coercion/pin-dyn-dispatch-sound.rs
new file mode 100644
index 00000000000..b9d43ebac8b
--- /dev/null
+++ b/tests/ui/coercion/pin-dyn-dispatch-sound.rs
@@ -0,0 +1,19 @@
+use std::marker::PhantomPinned;
+use std::pin::Pin;
+
+trait MyUnpinTrait {
+    fn into_pinned_type(self: Pin<&mut Self>) -> Pin<&mut PhantomPinned>;
+}
+impl MyUnpinTrait for PhantomPinned {
+    fn into_pinned_type(self: Pin<&mut Self>) -> Pin<&mut PhantomPinned> {
+        self
+    }
+}
+impl Unpin for dyn MyUnpinTrait {} //~ ERROR E0321
+
+// It would be unsound for this function to compile.
+fn pin_it(not_yet_pinned: &mut PhantomPinned) -> Pin<&mut PhantomPinned> {
+    Pin::new(not_yet_pinned as &mut dyn MyUnpinTrait).into_pinned_type()
+}
+
+fn main() {}
diff --git a/tests/ui/coercion/pin-dyn-dispatch-sound.stderr b/tests/ui/coercion/pin-dyn-dispatch-sound.stderr
new file mode 100644
index 00000000000..45860bfcfc7
--- /dev/null
+++ b/tests/ui/coercion/pin-dyn-dispatch-sound.stderr
@@ -0,0 +1,9 @@
+error[E0321]: cross-crate traits with a default impl, like `Unpin`, can only be implemented for a struct/enum type, not `(dyn MyUnpinTrait + 'static)`
+  --> $DIR/pin-dyn-dispatch-sound.rs:12:1
+   |
+LL | impl Unpin for dyn MyUnpinTrait {}
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ can't implement cross-crate trait with a default impl for non-struct/enum type
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0321`.