ditch which dependency

Author: RalfJung

miri-script/Cargo.lock

@@ -14,7 +14,6 @@ rust-version = "1.85"
 # This is needed to make this package build on stable when the parent package uses unstable cargo features.
 
 [dependencies]
-which = "7"
 walkdir = "2.3"
 itertools = "0.14"
 path_macro = "1.0"

miri-script/Cargo.toml

@@ -198,9 +198,6 @@ impl Command {
     }
 
     fn toolchain(flags: Vec<String>) -> Result<()> {
-        // Make sure rustup-toolchain-install-master is installed.
-        which::which("rustup-toolchain-install-master")
-            .context("Please install rustup-toolchain-install-master by running 'cargo install rustup-toolchain-install-master'")?;
         let sh = Shell::new()?;
         sh.change_dir(miri_dir()?);
         let new_commit = sh.read_file("rust-version")?.trim().to_owned();
@@ -227,7 +224,9 @@ impl Command {
         // Install and setup new toolchain.
         cmd!(sh, "rustup toolchain uninstall miri").run()?;
 
-        cmd!(sh, "rustup-toolchain-install-master -n miri -c cargo -c rust-src -c rustc-dev -c llvm-tools -c rustfmt -c clippy {flags...} -- {new_commit}").run()?;
+        cmd!(sh, "rustup-toolchain-install-master -n miri -c cargo -c rust-src -c rustc-dev -c llvm-tools -c rustfmt -c clippy {flags...} -- {new_commit}")
+            .run()
+            .context("Failed to run rustup-toolchain-install-master. If it is not installed, run 'cargo install rustup-toolchain-install-master'.")?;
         cmd!(sh, "rustup override set miri").run()?;
         // Cleanup.
         cmd!(sh, "cargo clean").run()?;