rollup merge of #23863: pnkfelix/arith-oflo-const-eval

const_eval : add overflow-checking for {`+`, `-`, `*`, `/`, `<<`, `>>`}.

One tricky detail here: There is some duplication of labor between `rustc::middle::const_eval` and `rustc_trans::trans::consts`. It might be good to explore ways to try to factor out the common structure to the two passes (by abstracting over the particular value-representation used in the compile-time interpreter).

----

Update: Rebased atop #23841

Fix #22531

Fix #23030

Fix #23221

Fix #23235

1 files changed, 2 insertions, 1 deletions

diff --git a/src/libstd/old_io/extensions.rs b/src/libstd/old_io/extensions.rs
index 0e5dd3aa4aa..aec794af759 100644
--- a/src/libstd/old_io/extensions.rs
+++ b/src/libstd/old_io/extensions.rs
@@ -519,7 +519,8 @@ mod bench {
         ({
             use super::u64_from_be_bytes;
 
-            let data = (0..$stride*100+$start_index).collect::<Vec<_>>();
+            let len = $stride.wrapping_mul(100).wrapping_add($start_index);
+            let data = (0..len).collect::<Vec<_>>();
             let mut sum = 0;
             $b.iter(|| {
                 let mut i = $start_index;