1 files changed, 45 insertions, 0 deletions
diff --git a/src/test/ui/consts/extra-const-ub/detect-extra-ub.rs b/src/test/ui/consts/extra-const-ub/detect-extra-ub.rs
new file mode 100644
index 000000000..86fbadb94
--- /dev/null
+++ b/src/test/ui/consts/extra-const-ub/detect-extra-ub.rs
@@ -0,0 +1,45 @@
+// revisions: no_flag with_flag
+// [no_flag] check-pass
+// [with_flag] compile-flags: -Zextra-const-ub-checks
+#![feature(const_ptr_read)]
+
+use std::mem::transmute;
+
+const INVALID_BOOL: () = unsafe {
+    let _x: bool = transmute(3u8);
+    //[with_flag]~^ ERROR: evaluation of constant value failed
+    //[with_flag]~| invalid value
+};
+
+const INVALID_PTR_IN_INT: () = unsafe {
+    let _x: usize = transmute(&3u8);
+    //[with_flag]~^ ERROR: any use of this value will cause an error
+    //[with_flag]~| previously accepted
+};
+
+const INVALID_SLICE_TO_USIZE_TRANSMUTE: () = unsafe {
+    let x: &[u8] = &[0; 32];
+    let _x: (usize, usize) = transmute(x);
+    //[with_flag]~^ ERROR: any use of this value will cause an error
+    //[with_flag]~| previously accepted
+};
+
+const UNALIGNED_PTR: () = unsafe {
+    let _x: &u32 = transmute(&[0u8; 4]);
+    //[with_flag]~^ ERROR: evaluation of constant value failed
+    //[with_flag]~| invalid value
+};
+
+const UNALIGNED_READ: () = {
+    INNER; //[with_flag]~ERROR any use of this value will cause an error
+    //[with_flag]~| previously accepted
+    // There is an error here but its span is in the standard library so we cannot match it...
+    // so we have this in a *nested* const, such that the *outer* const fails to use it.
+    const INNER: () = unsafe {
+        let x = &[0u8; 4];
+        let ptr = x.as_ptr().cast::<u32>();
+        ptr.read();
+    };
+};
+
+fn main() {}