diff --git a/pkgs/development/compilers/rust/rustfmt.nix b/pkgs/development/compilers/rust/rustfmt.nix
index 66a18f40ad4..eb8560ada84 100644
--- a/pkgs/development/compilers/rust/rustfmt.nix
+++ b/pkgs/development/compilers/rust/rustfmt.nix
@@ -16,6 +16,11 @@ rustPlatform.buildRustPackage rec {
   # As of 1.0.0 and rustc 1.30 rustfmt requires a nightly compiler
   RUSTC_BOOTSTRAP = 1;
 
+  # As of rustc 1.45.0, these env vars are required to build rustfmt (due to
+  # https://github.com/rust-lang/rust/pull/72001)
+  CFG_RELEASE = "${rustPlatform.rust.rustc.version}-nightly";
+  CFG_RELEASE_CHANNEL = "nightly";
+
   meta = with stdenv.lib; {
     description = "A tool for formatting Rust code according to style guidelines";
     homepage = "https://github.com/rust-lang-nursery/rustfmt";