Silence clippy on FIXME'd code and fix the new lints otherwise

src/tools/miri/cargo-miri/src/util.rs

@@ -82,7 +82,7 @@ pub enum MiriCommand {
 pub fn escape_for_toml(s: &str) -> String {
     // We want to surround this string in quotes `"`. So we first escape all quotes,
     // and also all backslashes (that are used to escape quotes).
-    let s = s.replace('\\', r#"\\"#).replace('"', r#"\""#);
+    let s = s.replace('\\', r"\\").replace('"', r#"\""#);
     format!("\"{s}\"")
 }
 
@@ -130,7 +130,7 @@ pub fn exec(mut cmd: Command) -> ! {
     {
         use std::os::unix::process::CommandExt;
         let error = cmd.exec();
-        Err(error).expect("failed to run command")
+        panic!("failed to run command: {error}")
     }
 }
 

src/tools/miri/src/lib.rs

@@ -9,6 +9,7 @@
 #![feature(local_key_cell_methods)]
 #![feature(round_ties_even)]
 #![feature(os_str_bytes)]
+#![feature(lint_reasons)]
 // Configure clippy and other lints
 #![allow(
     clippy::collapsible_else_if,

src/tools/miri/src/shims/unix/linux/fd.rs

@@ -181,6 +181,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
     /// `EFD_SEMAPHORE` - miri does not support semaphore-like semantics.
     ///
     /// <https://linux.die.net/man/2/eventfd>
+    #[expect(clippy::needless_if)]
     fn eventfd(
         &mut self,
         val: &OpTy<'tcx, Provenance>,