Rollup merge of #112520 - chenyukang:yukang-fix-112505, r=fee1-dead

Fix the overflow issue for transmute_generic_consts

Fixes #112505

2 files changed, 19 insertions, 0 deletions

diff --git a/tests/ui/const-generics/issue-112505-overflow.rs b/tests/ui/const-generics/issue-112505-overflow.rs
new file mode 100644
index 00000000000..0dd7776d595
--- /dev/null
+++ b/tests/ui/const-generics/issue-112505-overflow.rs
@@ -0,0 +1,7 @@
+#![feature(transmute_generic_consts)]
+
+fn overflow(v: [[[u32; 8888888]; 9999999]; 777777777]) -> [[[u32; 9999999]; 777777777]; 239] {
+    unsafe { std::mem::transmute(v) } //~ ERROR cannot transmute between types of different sizes
+}
+
+fn main() { }
diff --git a/tests/ui/const-generics/issue-112505-overflow.stderr b/tests/ui/const-generics/issue-112505-overflow.stderr
new file mode 100644
index 00000000000..0432f2fa8be
--- /dev/null
+++ b/tests/ui/const-generics/issue-112505-overflow.stderr
@@ -0,0 +1,12 @@
+error[E0512]: cannot transmute between types of different sizes, or dependently-sized types
+  --> $DIR/issue-112505-overflow.rs:4:14
+   |
+LL |     unsafe { std::mem::transmute(v) }
+   |              ^^^^^^^^^^^^^^^^^^^
+   |
+   = note: source type: `[[[u32; 8888888]; 9999999]; 777777777]` (values of the type `[[[u32; 8888888]; 9999999]; 777777777]` are too big for the current architecture)
+   = note: target type: `[[[u32; 9999999]; 777777777]; 239]` (59484438436515561504 bits)
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0512`.