rustc_layout_scalar_valid_range makes ctors unsafe

2 files changed, 27 insertions, 0 deletions

diff --git a/tests/ui/unsafe/initializing-ranged-via-ctor.rs b/tests/ui/unsafe/initializing-ranged-via-ctor.rs
new file mode 100644
index 00000000000..ca44fa7e4e7
--- /dev/null
+++ b/tests/ui/unsafe/initializing-ranged-via-ctor.rs
@@ -0,0 +1,11 @@
+#![feature(rustc_attrs)]
+#![allow(internal_features)]
+
+#[derive(Debug)]
+#[rustc_layout_scalar_valid_range_start(2)]
+struct NonZeroAndOneU8(u8);
+
+fn main() {
+    println!("{:?}", Some(1).map(NonZeroAndOneU8).unwrap());
+    //~^ ERROR found `unsafe fn(u8) -> NonZeroAndOneU8 {NonZeroAndOneU8}`
+}
diff --git a/tests/ui/unsafe/initializing-ranged-via-ctor.stderr b/tests/ui/unsafe/initializing-ranged-via-ctor.stderr
new file mode 100644
index 00000000000..d34554c6641
--- /dev/null
+++ b/tests/ui/unsafe/initializing-ranged-via-ctor.stderr
@@ -0,0 +1,16 @@
+error[E0277]: expected a `FnOnce<({integer},)>` closure, found `unsafe fn(u8) -> NonZeroAndOneU8 {NonZeroAndOneU8}`
+  --> $DIR/initializing-ranged-via-ctor.rs:9:34
+   |
+LL |     println!("{:?}", Some(1).map(NonZeroAndOneU8).unwrap());
+   |                              --- ^^^^^^^^^^^^^^^ call the function in a closure: `|| unsafe { /* code */ }`
+   |                              |
+   |                              required by a bound introduced by this call
+   |
+   = help: the trait `FnOnce<({integer},)>` is not implemented for fn item `unsafe fn(u8) -> NonZeroAndOneU8 {NonZeroAndOneU8}`
+   = note: unsafe function cannot be called generically without an unsafe block
+note: required by a bound in `Option::<T>::map`
+  --> $SRC_DIR/core/src/option.rs:LL:COL
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0277`.