Rollup merge of #107972 - saethlin:fix-test-ub, r=michaelwoerister

Fix unintentional UB in ui tests

``@matthiaskrgr`` found UB in a bunch of the ui tests. This PR fixes a batch of miscellaneous tests I didn't think needed reviewers from a particular part of the project.

Author: matthiaskrgr

tests/ui/closures/2229_closure_analysis/migrations/auto_traits.fixed

@@ -26,7 +26,7 @@ fn test_send_trait() {
         //~| HELP: add a dummy let to cause `fptr` to be fully captured
         *fptr.0 = 20;
         //~^ NOTE: in Rust 2018, this closure captures all of `fptr`, but in Rust 2021, it will only capture `fptr.0`
-    } });
+    } }).join().unwrap();
 }
 
 /* Test Sync Trait Migration */
@@ -47,7 +47,7 @@ fn test_sync_trait() {
         //~| HELP: add a dummy let to cause `fptr` to be fully captured
         *fptr.0.0 = 20;
         //~^ NOTE: in Rust 2018, this closure captures all of `fptr`, but in Rust 2021, it will only capture `fptr.0.0`
-    } });
+    } }).join().unwrap();
 }
 
 /* Test Clone Trait Migration */

tests/ui/closures/2229_closure_analysis/migrations/auto_traits.rs

@@ -26,7 +26,7 @@ fn test_send_trait() {
         //~| HELP: add a dummy let to cause `fptr` to be fully captured
         *fptr.0 = 20;
         //~^ NOTE: in Rust 2018, this closure captures all of `fptr`, but in Rust 2021, it will only capture `fptr.0`
-    });
+    }).join().unwrap();
 }
 
 /* Test Sync Trait Migration */
@@ -47,7 +47,7 @@ fn test_sync_trait() {
         //~| HELP: add a dummy let to cause `fptr` to be fully captured
         *fptr.0.0 = 20;
         //~^ NOTE: in Rust 2018, this closure captures all of `fptr`, but in Rust 2021, it will only capture `fptr.0.0`
-    });
+    }).join().unwrap();
 }
 
 /* Test Clone Trait Migration */

tests/ui/closures/2229_closure_analysis/migrations/auto_traits.stderr

@@ -19,7 +19,7 @@ LL ~     thread::spawn(move || { let _ = &fptr; unsafe {
 LL |
  ...
 LL |
-LL ~     } });
+LL ~     } }).join().unwrap();
    |
 
 error: changes to closure capture in Rust 2021 will affect which traits the closure implements
@@ -41,7 +41,7 @@ LL ~     thread::spawn(move || { let _ = &fptr; unsafe {
 LL |
  ...
 LL |
-LL ~     } });
+LL ~     } }).join().unwrap();
    |
 
 error: changes to closure capture in Rust 2021 will affect drop order and which traits the closure implements

tests/ui/closures/2229_closure_analysis/migrations/multi_diagnostics.fixed

@@ -145,7 +145,7 @@ fn test_multi_traits_issues() {
         //~^ NOTE: in Rust 2018, this closure captures all of `fptr1`, but in Rust 2021, it will only capture `fptr1.0.0`
         *fptr2.0 = 20;
         //~^ NOTE: in Rust 2018, this closure captures all of `fptr2`, but in Rust 2021, it will only capture `fptr2.0`
-    } });
+    } }).join().unwrap();
 }
 
 fn main() {

tests/ui/closures/2229_closure_analysis/migrations/multi_diagnostics.rs

@@ -141,7 +141,7 @@ fn test_multi_traits_issues() {
         //~^ NOTE: in Rust 2018, this closure captures all of `fptr1`, but in Rust 2021, it will only capture `fptr1.0.0`
         *fptr2.0 = 20;
         //~^ NOTE: in Rust 2018, this closure captures all of `fptr2`, but in Rust 2021, it will only capture `fptr2.0`
-    });
+    }).join().unwrap();
 }
 
 fn main() {

tests/ui/closures/2229_closure_analysis/migrations/multi_diagnostics.stderr

@@ -111,7 +111,7 @@ LL ~     thread::spawn(move || { let _ = (&fptr1, &fptr2); unsafe {
 LL |
  ...
 LL |
-LL ~     } });
+LL ~     } }).join().unwrap();
    |
 
 error: aborting due to 5 previous errors

tests/ui/consts/const-eval/issue-91827-extern-types.rs

@@ -28,7 +28,10 @@ pub struct ListImpl<T, const N: usize> {
 
 impl<T> List<T> {
     const fn as_slice(&self) -> &[T] {
-        unsafe { std::slice::from_raw_parts(self.data.as_ptr(), self.len) }
+        unsafe {
+            let ptr = (self as *const List<T>).cast::<usize>().add(1).cast::<T>();
+            std::slice::from_raw_parts(ptr, self.len)
+        }
     }
 }
 

tests/ui/unsized/unsized3-rpass.rs

@@ -59,7 +59,7 @@ pub fn main() {
         }
 
         let data: Box<Foo_<i32>> = Box::new(Foo_ { f: [1, 2, 3] });
-        let x: &Foo<i32> = mem::transmute(slice::from_raw_parts(&*data, 3));
+        let x: &Foo<i32> = mem::transmute(ptr::slice_from_raw_parts(&*data, 3));
         assert_eq!(x.f.len(), 3);
         assert_eq!(x.f[0], 1);
 
@@ -70,7 +70,7 @@ pub fn main() {
 
         let data: Box<_> =
             Box::new(Baz_ { f1: 42, f2: ['a' as u8, 'b' as u8, 'c' as u8, 'd' as u8, 'e' as u8] });
-        let x: &Baz = mem::transmute(slice::from_raw_parts(&*data, 5));
+        let x: &Baz = mem::transmute(ptr::slice_from_raw_parts(&*data, 5));
         assert_eq!(x.f1, 42);
         let chs: Vec<char> = x.f2.chars().collect();
         assert_eq!(chs.len(), 5);