Add `rustfmt` cfg to well known cfgs list

1 files changed, 5 insertions, 3 deletions

diff --git a/compiler/rustc_session/src/config/cfg.rs b/compiler/rustc_session/src/config/cfg.rs
index 31badbd8692..2fa04bbe345 100644
--- a/compiler/rustc_session/src/config/cfg.rs
+++ b/compiler/rustc_session/src/config/cfg.rs
@@ -262,13 +262,15 @@ impl CheckCfg {
 
         ins!(sym::debug_assertions, no_values);
 
-        // These four are never set by rustc, but we set them anyway: they
-        // should not trigger a lint because `cargo clippy`, `cargo doc`,
-        // `cargo test` and `cargo miri run` (respectively) can set them.
+        // These four are never set by rustc, but we set them anyway; they
+        // should not trigger the lint because `cargo clippy`, `cargo doc`,
+        // `cargo test`, `cargo miri run` and `cargo fmt` (respectively)
+        // can set them.
         ins!(sym::clippy, no_values);
         ins!(sym::doc, no_values);
         ins!(sym::doctest, no_values);
         ins!(sym::miri, no_values);
+        ins!(sym::rustfmt, no_values);
 
         ins!(sym::overflow_checks, no_values);