interpret: fix overlapping aggregate initialization

12 files changed, 63 insertions, 7 deletions

diff --git a/src/tools/miri/tests/fail/both_borrows/issue-miri-1050-1.rs b/src/tools/miri/tests/fail/both_borrows/issue-miri-1050-1.rs
index dd7dae9cecf..d907c5de797 100644
--- a/src/tools/miri/tests/fail/both_borrows/issue-miri-1050-1.rs
+++ b/src/tools/miri/tests/fail/both_borrows/issue-miri-1050-1.rs
@@ -1,4 +1,6 @@
 //@revisions: stack tree
+// Ensure this even hits the aliasing model
+//@compile-flags: -Zmiri-disable-validation
 //@[tree]compile-flags: -Zmiri-tree-borrows
 //@error-in-other-file: pointer not dereferenceable
 
diff --git a/src/tools/miri/tests/fail/both_borrows/issue-miri-1050-2.rs b/src/tools/miri/tests/fail/both_borrows/issue-miri-1050-2.rs
index 5c947e64142..b54f27bb8b2 100644
--- a/src/tools/miri/tests/fail/both_borrows/issue-miri-1050-2.rs
+++ b/src/tools/miri/tests/fail/both_borrows/issue-miri-1050-2.rs
@@ -1,4 +1,6 @@
 //@revisions: stack tree
+// Ensure this even hits the aliasing model
+//@compile-flags: -Zmiri-disable-validation
 //@[tree]compile-flags: -Zmiri-tree-borrows
 //@error-in-other-file: is a dangling pointer
 use std::ptr::NonNull;
diff --git a/src/tools/miri/tests/fail/both_borrows/return_invalid_shr.stack.stderr b/src/tools/miri/tests/fail/both_borrows/return_invalid_shr.stack.stderr
index d52143500c4..7c4fe748701 100644
--- a/src/tools/miri/tests/fail/both_borrows/return_invalid_shr.stack.stderr
+++ b/src/tools/miri/tests/fail/both_borrows/return_invalid_shr.stack.stderr
@@ -11,7 +11,7 @@ help: <TAG> was created by a SharedReadOnly retag at offsets [0x4..0x8]
    |
 LL |     let ret = unsafe { &(*xraw).1 };
    |                        ^^^^^^^^^^
-help: <TAG> was later invalidated at offsets [0x0..0x8] by a write access
+help: <TAG> was later invalidated at offsets [0x4..0x8] by a write access
   --> tests/fail/both_borrows/return_invalid_shr.rs:LL:CC
    |
 LL |     unsafe { *xraw = (42, 23) }; // unfreeze
diff --git a/src/tools/miri/tests/fail/both_borrows/return_invalid_shr.tree.stderr b/src/tools/miri/tests/fail/both_borrows/return_invalid_shr.tree.stderr
index ee0f313d980..a8e3553aae2 100644
--- a/src/tools/miri/tests/fail/both_borrows/return_invalid_shr.tree.stderr
+++ b/src/tools/miri/tests/fail/both_borrows/return_invalid_shr.tree.stderr
@@ -12,7 +12,7 @@ help: the accessed tag <TAG> was created here, in the initial state Frozen
    |
 LL |     let ret = unsafe { &(*xraw).1 };
    |                        ^^^^^^^^^^
-help: the accessed tag <TAG> later transitioned to Disabled due to a foreign write access at offsets [0x0..0x8]
+help: the accessed tag <TAG> later transitioned to Disabled due to a foreign write access at offsets [0x4..0x8]
   --> tests/fail/both_borrows/return_invalid_shr.rs:LL:CC
    |
 LL |     unsafe { *xraw = (42, 23) }; // unfreeze
diff --git a/src/tools/miri/tests/fail/both_borrows/return_invalid_shr_option.stack.stderr b/src/tools/miri/tests/fail/both_borrows/return_invalid_shr_option.stack.stderr
index d66c8eeb1af..8411437ea4c 100644
--- a/src/tools/miri/tests/fail/both_borrows/return_invalid_shr_option.stack.stderr
+++ b/src/tools/miri/tests/fail/both_borrows/return_invalid_shr_option.stack.stderr
@@ -14,7 +14,7 @@ help: <TAG> was created by a SharedReadOnly retag at offsets [0x4..0x8]
    |
 LL |     let ret = Some(unsafe { &(*xraw).1 });
    |               ^^^^^^^^^^^^^^^^^^^^^^^^^^^
-help: <TAG> was later invalidated at offsets [0x0..0x8] by a write access
+help: <TAG> was later invalidated at offsets [0x4..0x8] by a write access
   --> tests/fail/both_borrows/return_invalid_shr_option.rs:LL:CC
    |
 LL |     unsafe { *xraw = (42, 23) }; // unfreeze
diff --git a/src/tools/miri/tests/fail/both_borrows/return_invalid_shr_option.tree.stderr b/src/tools/miri/tests/fail/both_borrows/return_invalid_shr_option.tree.stderr
index 16110e5b062..39da45ad6db 100644
--- a/src/tools/miri/tests/fail/both_borrows/return_invalid_shr_option.tree.stderr
+++ b/src/tools/miri/tests/fail/both_borrows/return_invalid_shr_option.tree.stderr
@@ -12,7 +12,7 @@ help: the accessed tag <TAG> was created here, in the initial state Frozen
    |
 LL |     let ret = Some(unsafe { &(*xraw).1 });
    |               ^^^^^^^^^^^^^^^^^^^^^^^^^^^
-help: the accessed tag <TAG> later transitioned to Disabled due to a foreign write access at offsets [0x0..0x8]
+help: the accessed tag <TAG> later transitioned to Disabled due to a foreign write access at offsets [0x4..0x8]
   --> tests/fail/both_borrows/return_invalid_shr_option.rs:LL:CC
    |
 LL |     unsafe { *xraw = (42, 23) }; // unfreeze
diff --git a/src/tools/miri/tests/fail/both_borrows/return_invalid_shr_tuple.stack.stderr b/src/tools/miri/tests/fail/both_borrows/return_invalid_shr_tuple.stack.stderr
index 727b52ec729..a7c422aa73f 100644
--- a/src/tools/miri/tests/fail/both_borrows/return_invalid_shr_tuple.stack.stderr
+++ b/src/tools/miri/tests/fail/both_borrows/return_invalid_shr_tuple.stack.stderr
@@ -14,7 +14,7 @@ help: <TAG> was created by a SharedReadOnly retag at offsets [0x4..0x8]
    |
 LL |     let ret = (unsafe { &(*xraw).1 },);
    |               ^^^^^^^^^^^^^^^^^^^^^^^^
-help: <TAG> was later invalidated at offsets [0x0..0x8] by a write access
+help: <TAG> was later invalidated at offsets [0x4..0x8] by a write access
   --> tests/fail/both_borrows/return_invalid_shr_tuple.rs:LL:CC
    |
 LL |     unsafe { *xraw = (42, 23) }; // unfreeze
diff --git a/src/tools/miri/tests/fail/both_borrows/return_invalid_shr_tuple.tree.stderr b/src/tools/miri/tests/fail/both_borrows/return_invalid_shr_tuple.tree.stderr
index f93698f570e..66b03e57905 100644
--- a/src/tools/miri/tests/fail/both_borrows/return_invalid_shr_tuple.tree.stderr
+++ b/src/tools/miri/tests/fail/both_borrows/return_invalid_shr_tuple.tree.stderr
@@ -12,7 +12,7 @@ help: the accessed tag <TAG> was created here, in the initial state Frozen
    |
 LL |     let ret = (unsafe { &(*xraw).1 },);
    |               ^^^^^^^^^^^^^^^^^^^^^^^^
-help: the accessed tag <TAG> later transitioned to Disabled due to a foreign write access at offsets [0x0..0x8]
+help: the accessed tag <TAG> later transitioned to Disabled due to a foreign write access at offsets [0x4..0x8]
   --> tests/fail/both_borrows/return_invalid_shr_tuple.rs:LL:CC
    |
 LL |     unsafe { *xraw = (42, 23) }; // unfreeze
diff --git a/src/tools/miri/tests/fail/overlapping_assignment_aggregate.rs b/src/tools/miri/tests/fail/overlapping_assignment_aggregate.rs
new file mode 100644
index 00000000000..8d7b1946242
--- /dev/null
+++ b/src/tools/miri/tests/fail/overlapping_assignment_aggregate.rs
@@ -0,0 +1,18 @@
+//! This is like `pass/overlapping_assignment_aggregate_scalar.rs` but with a non-scalar
+//! type, and that makes it definite UB.
+#![feature(custom_mir, core_intrinsics)]
+#![allow(internal_features)]
+
+use std::intrinsics::mir::*;
+
+#[custom_mir(dialect = "runtime")]
+fn main() {
+    mir! {
+        let _1: ([u8; 1],);
+        {
+            _1.0 = [0_u8; 1];
+            _1 = (_1.0, ); //~ERROR: overlapping ranges
+            Return()
+        }
+    }
+}
diff --git a/src/tools/miri/tests/fail/overlapping_assignment_aggregate.stderr b/src/tools/miri/tests/fail/overlapping_assignment_aggregate.stderr
new file mode 100644
index 00000000000..f2a6d326b71
--- /dev/null
+++ b/src/tools/miri/tests/fail/overlapping_assignment_aggregate.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: `copy_nonoverlapping` called on overlapping ranges
+  --> tests/fail/overlapping_assignment_aggregate.rs:LL:CC
+   |
+LL |             _1 = (_1.0, );
+   |             ^^^^^^^^^^^^^ Undefined Behavior occurred here
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at tests/fail/overlapping_assignment_aggregate.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to 1 previous error
+
diff --git a/src/tools/miri/tests/fail/validity/nonzero.stderr b/src/tools/miri/tests/fail/validity/nonzero.stderr
index 0c3a35d6b9f..7be3ef46639 100644
--- a/src/tools/miri/tests/fail/validity/nonzero.stderr
+++ b/src/tools/miri/tests/fail/validity/nonzero.stderr
@@ -2,7 +2,7 @@ error: Undefined Behavior: constructing invalid value: encountered 0, but expect
   --> tests/fail/validity/nonzero.rs:LL:CC
    |
 LL |     let _x = Some(unsafe { NonZero(0) });
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^ Undefined Behavior occurred here
+   |                            ^^^^^^^^^^ Undefined Behavior occurred here
    |
    = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
    = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
diff --git a/src/tools/miri/tests/pass/overlapping_assignment_aggregate_scalar.rs b/src/tools/miri/tests/pass/overlapping_assignment_aggregate_scalar.rs
new file mode 100644
index 00000000000..0cb2f764242
--- /dev/null
+++ b/src/tools/miri/tests/pass/overlapping_assignment_aggregate_scalar.rs
@@ -0,0 +1,19 @@
+#![feature(custom_mir, core_intrinsics)]
+#![allow(internal_features)]
+
+use std::intrinsics::mir::*;
+
+#[custom_mir(dialect = "runtime")]
+fn main() {
+    mir! {
+        let _1: (u8,);
+        {
+            _1.0 = 0_u8;
+            // This is a scalar type, so overlap is (for now) not UB.
+            // However, we used to treat such overlapping assignments incorrectly
+            // (see <https://github.com/rust-lang/rust/issues/146383#issuecomment-3273224645>).
+            _1 = (_1.0, );
+            Return()
+        }
+    }
+}