Auto merge of #125912 - nnethercote:rustfmt-tests-mir-opt, r=oli-obk

rustfmt `tests/mir-opt`

Continuing the work started in #125759. Details in individual commit log messages.

r? `@oli-obk`

tests/fail/intrinsics/ptr_metadata_uninit_slice_data.rs

@@ -7,10 +7,12 @@ use std::intrinsics::mir::*;
 
 #[custom_mir(dialect = "runtime")]
 pub unsafe fn deref_meta(p: *const *const [i32]) -> usize {
-    mir!({
-        RET = PtrMetadata(*p); //~ ERROR: Undefined Behavior: using uninitialized data
-        Return()
-    })
+    mir! {
+        {
+            RET = PtrMetadata(*p); //~ ERROR: Undefined Behavior: using uninitialized data
+            Return()
+        }
+    }
 }
 
 fn main() {

tests/fail/intrinsics/ptr_metadata_uninit_slice_data.stderr

@@ -1,8 +1,8 @@
 error: Undefined Behavior: using uninitialized data, but this operation requires initialized memory
   --> $DIR/ptr_metadata_uninit_slice_data.rs:LL:CC
    |
-LL |         RET = PtrMetadata(*p);
-   |         ^^^^^^^^^^^^^^^^^^^^^ using uninitialized data, but this operation requires initialized memory
+LL |             RET = PtrMetadata(*p);
+   |             ^^^^^^^^^^^^^^^^^^^^^ using uninitialized data, but this operation requires initialized memory
    |
    = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
    = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information

tests/fail/intrinsics/ptr_metadata_uninit_slice_len.rs

@@ -7,10 +7,12 @@ use std::intrinsics::mir::*;
 
 #[custom_mir(dialect = "runtime")]
 pub unsafe fn deref_meta(p: *const *const [i32]) -> usize {
-    mir!({
-        RET = PtrMetadata(*p); //~ ERROR: Undefined Behavior: using uninitialized data
-        Return()
-    })
+    mir! {
+        {
+            RET = PtrMetadata(*p); //~ ERROR: Undefined Behavior: using uninitialized data
+            Return()
+        }
+    }
 }
 
 fn main() {

tests/fail/intrinsics/ptr_metadata_uninit_slice_len.stderr

@@ -16,8 +16,8 @@ LL |         (*p.as_mut_ptr().cast::<[*const i32; 2]>())[0] = 4 as *const i32;
 error: Undefined Behavior: using uninitialized data, but this operation requires initialized memory
   --> $DIR/ptr_metadata_uninit_slice_len.rs:LL:CC
    |
-LL |         RET = PtrMetadata(*p);
-   |         ^^^^^^^^^^^^^^^^^^^^^ using uninitialized data, but this operation requires initialized memory
+LL |             RET = PtrMetadata(*p);
+   |             ^^^^^^^^^^^^^^^^^^^^^ using uninitialized data, but this operation requires initialized memory
    |
    = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
    = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information

tests/fail/intrinsics/ptr_metadata_uninit_thin.rs

@@ -7,10 +7,12 @@ use std::intrinsics::mir::*;
 
 #[custom_mir(dialect = "runtime")]
 pub unsafe fn deref_meta(p: *const *const i32) -> () {
-    mir!({
-        RET = PtrMetadata(*p); //~ ERROR: Undefined Behavior: using uninitialized data
-        Return()
-    })
+    mir! {
+        {
+            RET = PtrMetadata(*p); //~ ERROR: Undefined Behavior: using uninitialized data
+            Return()
+        }
+    }
 }
 
 fn main() {

tests/fail/intrinsics/ptr_metadata_uninit_thin.stderr

@@ -1,8 +1,8 @@
 error: Undefined Behavior: using uninitialized data, but this operation requires initialized memory
   --> $DIR/ptr_metadata_uninit_thin.rs:LL:CC
    |
-LL |         RET = PtrMetadata(*p);
-   |         ^^^^^^^^^^^^^^^^^^^^^ using uninitialized data, but this operation requires initialized memory
+LL |             RET = PtrMetadata(*p);
+   |             ^^^^^^^^^^^^^^^^^^^^^ using uninitialized data, but this operation requires initialized memory
    |
    = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
    = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information