diff --git a/crates/rust-analyzer/tests/slow-tests/tidy.rs b/crates/rust-analyzer/tests/slow-tests/tidy.rs
index 18f95925d9..58099a58de 100644
--- a/crates/rust-analyzer/tests/slow-tests/tidy.rs
+++ b/crates/rust-analyzer/tests/slow-tests/tidy.rs
@@ -13,9 +13,8 @@ use xshell::cmd;
 fn check_code_formatting() {
     let sh = &Shell::new().unwrap();
     sh.change_dir(sourcegen::project_root());
-    sh.set_var("RUSTUP_TOOLCHAIN", "stable");
 
-    let out = cmd!(sh, "rustfmt --version").read().unwrap();
+    let out = cmd!(sh, "rustup run stable rustfmt --version").read().unwrap();
     if !out.contains("stable") {
         panic!(
             "Failed to run rustfmt from toolchain 'stable'. \
@@ -23,9 +22,9 @@ fn check_code_formatting() {
         )
     }
 
-    let res = cmd!(sh, "cargo fmt -- --check").run();
+    let res = cmd!(sh, "rustup run stable cargo fmt -- --check").run();
     if res.is_err() {
-        let _ = cmd!(sh, "cargo fmt").run();
+        let _ = cmd!(sh, "rustup run stable cargo fmt").run();
     }
     res.unwrap()
 }
diff --git a/crates/sourcegen/src/lib.rs b/crates/sourcegen/src/lib.rs
index ce0224ec74..4e0ee63f32 100644
--- a/crates/sourcegen/src/lib.rs
+++ b/crates/sourcegen/src/lib.rs
@@ -136,7 +136,7 @@ impl fmt::Display for Location {
 }
 
 fn ensure_rustfmt(sh: &Shell) {
-    let version = cmd!(sh, "rustfmt --version").read().unwrap_or_default();
+    let version = cmd!(sh, "rustup run stable rustfmt --version").read().unwrap_or_default();
     if !version.contains("stable") {
         panic!(
             "Failed to run rustfmt from toolchain 'stable'. \
@@ -147,13 +147,15 @@ fn ensure_rustfmt(sh: &Shell) {
 
 pub fn reformat(text: String) -> String {
     let sh = Shell::new().unwrap();
-    sh.set_var("RUSTUP_TOOLCHAIN", "stable");
     ensure_rustfmt(&sh);
     let rustfmt_toml = project_root().join("rustfmt.toml");
-    let mut stdout = cmd!(sh, "rustfmt --config-path {rustfmt_toml} --config fn_single_line=true")
-        .stdin(text)
-        .read()
-        .unwrap();
+    let mut stdout = cmd!(
+        sh,
+        "rustup run stable rustfmt --config-path {rustfmt_toml} --config fn_single_line=true"
+    )
+    .stdin(text)
+    .read()
+    .unwrap();
     if !stdout.ends_with('\n') {
         stdout.push('\n');
     }