diff --git a/rust-version b/rust-version
index 16a773193d14..835708a42baa 100644
--- a/rust-version
+++ b/rust-version
@@ -1 +1 @@
-a6008fac97f81a3fc51668b0c7fa0e2e6f2a599b
+78a089487b5f6d5e4205ac4500410b442857bced
diff --git a/tests/compile-fail/alloc/deallocate-bad-alignment.rs b/tests/compile-fail/alloc/deallocate-bad-alignment.rs
index 621c05344b4a..852a0660217e 100644
--- a/tests/compile-fail/alloc/deallocate-bad-alignment.rs
+++ b/tests/compile-fail/alloc/deallocate-bad-alignment.rs
@@ -1,6 +1,6 @@
 use std::alloc::{alloc, dealloc, Layout};
 
-// error-pattern: allocation has size 1 and alignment 1, but gave size 1 and alignment 2
+// error-pattern: has size 1 and alignment 1, but gave size 1 and alignment 2
 
 fn main() {
     unsafe {
diff --git a/tests/compile-fail/alloc/deallocate-bad-size.rs b/tests/compile-fail/alloc/deallocate-bad-size.rs
index 386bb56b9091..167cc015c2da 100644
--- a/tests/compile-fail/alloc/deallocate-bad-size.rs
+++ b/tests/compile-fail/alloc/deallocate-bad-size.rs
@@ -1,6 +1,6 @@
 use std::alloc::{alloc, dealloc, Layout};
 
-// error-pattern: allocation has size 1 and alignment 1, but gave size 2 and alignment 1
+// error-pattern: has size 1 and alignment 1, but gave size 2 and alignment 1
 
 fn main() {
     unsafe {
diff --git a/tests/compile-fail/alloc/reallocate-bad-size.rs b/tests/compile-fail/alloc/reallocate-bad-size.rs
index 7826f26f9b8c..80239015dc1d 100644
--- a/tests/compile-fail/alloc/reallocate-bad-size.rs
+++ b/tests/compile-fail/alloc/reallocate-bad-size.rs
@@ -1,6 +1,6 @@
 use std::alloc::{alloc, realloc, Layout};
 
-// error-pattern: allocation has size 1 and alignment 1, but gave size 2 and alignment 1
+// error-pattern: has size 1 and alignment 1, but gave size 2 and alignment 1
 
 fn main() {
     unsafe {
diff --git a/tests/compile-fail/alloc/stack_free.rs b/tests/compile-fail/alloc/stack_free.rs
index 50a590e448a6..d854fa993a79 100644
--- a/tests/compile-fail/alloc/stack_free.rs
+++ b/tests/compile-fail/alloc/stack_free.rs
@@ -1,7 +1,7 @@
 // Validation/SB changes why we fail
 // compile-flags: -Zmiri-disable-validation -Zmiri-disable-stacked-borrows
 
-// error-pattern: deallocating stack variable memory using Rust heap deallocation operation
+// error-pattern: which is stack variable memory, using Rust heap deallocation operation
 
 fn main() {
     let x = 42;
diff --git a/tests/run-pass/heap_allocator.rs b/tests/run-pass/heap_allocator.rs
index cf9a2f4b6925..5d89243b86a9 100644
--- a/tests/run-pass/heap_allocator.rs
+++ b/tests/run-pass/heap_allocator.rs
@@ -4,7 +4,7 @@ use std::ptr::NonNull;
 use std::alloc::{Global, AllocRef, Layout, System};
 use std::slice;
 
-fn check_alloc<T: AllocRef>(mut allocator: T) { unsafe {
+fn check_alloc<T: AllocRef>(allocator: T) { unsafe {
     for &align in &[4, 8, 16, 32] {
         let layout_20 = Layout::from_size_align(20, align).unwrap();
         let layout_40 = Layout::from_size_align(40, 4*align).unwrap();
@@ -42,7 +42,7 @@ fn check_alloc<T: AllocRef>(mut allocator: T) { unsafe {
     }
 } }
 
-fn check_align_requests<T: AllocRef>(mut allocator: T) {
+fn check_align_requests<T: AllocRef>(allocator: T) {
     for &size in &[2, 8, 64] { // size less than and bigger than alignment
         for &align in &[4, 8, 16, 32] { // Be sure to cover less than and bigger than `MIN_ALIGN` for all architectures
             let iterations = 32;