std: Remove generics from Option::expect

This commit removes the <M: Any + Send> type parameter from Option::expect in
favor of just taking a hard-coded `&str` argument. This allows this function to
move into libcore.

Previous code using strings with `expect` will continue to work, but code using
this implicitly to transmit task failure will need to unwrap manually with a
`match` statement.

[breaking-change]
Closes #14008

1 files changed, 1 insertions, 1 deletions

diff --git a/src/libstd/vec.rs b/src/libstd/vec.rs
index 916ba083b3e..cdcee9464de 100644
--- a/src/libstd/vec.rs
+++ b/src/libstd/vec.rs
@@ -21,7 +21,7 @@ use mem;
 use num::{CheckedMul, CheckedAdd};
 use num;
 use ops::{Add, Drop};
-use option::{None, Option, Some, Expect};
+use option::{None, Option, Some};
 use ptr::RawPtr;
 use ptr;
 use raw::Slice;