use 2018 edition for tests

Author: RalfJung

tests/compiletest.rs

@@ -62,6 +62,7 @@ fn compile_fail(sysroot: &Path, path: &str, target: &str, host: &str, need_fullm
     let mut flags = Vec::new();
     flags.push(format!("--sysroot {}", sysroot.display()));
     flags.push("-Dwarnings -Dunused".to_owned()); // overwrite the -Aunused in compiletest-rs
+    flags.push("--edition 2018".to_owned());
     if opt {
         // Optimizing too aggressivley makes UB detection harder, but test at least
         // the default value.
@@ -98,6 +99,7 @@ fn miri_pass(sysroot: &Path, path: &str, target: &str, host: &str, need_fullmir:
     let mut flags = Vec::new();
     flags.push(format!("--sysroot {}", sysroot.display()));
     flags.push("-Dwarnings -Dunused".to_owned()); // overwrite the -Aunused in compiletest-rs
+    flags.push("--edition 2018".to_owned());
     if opt {
         // FIXME: We use opt level 1 because MIR inlining defeats the validation
         // whitelist.

tests/run-pass/stacked-borrows.rs

@@ -68,13 +68,11 @@ fn mut_shr_raw() {
 // That should work.
 fn mut_raw_then_mut_shr() {
     let mut x = 2;
-    {
-        let xref = &mut x;
-        let xraw = &mut *xref as *mut _;
-        let xshr = &*xref;
-        assert_eq!(*xshr, 2);
-        unsafe { *xraw = 4; }
-    }
+    let xref = &mut x;
+    let xraw = &mut *xref as *mut _;
+    let xshr = &*xref;
+    assert_eq!(*xshr, 2);
+    unsafe { *xraw = 4; }
     assert_eq!(x, 4);
 }