rls: tie version to rustc's

pkgs/development/compilers/rust/default.nix

@@ -66,6 +66,7 @@
         inherit CoreFoundation Security;
       };
       clippy = self.callPackage ./clippy.nix { inherit Security; };
+      rls = self.callPackage ./rls { inherit CoreFoundation Security; };
     });
   };
 }

pkgs/development/compilers/rust/rls/default.nix

@@ -0,0 +1,45 @@
+{ stdenv, fetchFromGitHub, rustPlatform
+, openssh, openssl, pkgconfig, cmake, zlib, curl, libiconv
+, CoreFoundation, Security }:
+
+rustPlatform.buildRustPackage rec {
+  pname = "rls";
+  inherit (rustPlatform.rust.rustc) src version;
+
+  # changes hash of vendor directory otherwise
+  dontUpdateAutotoolsGnuConfigScripts = true;
+
+  cargoVendorDir = "vendor";
+  preBuild = ''
+    pushd src/tools/rls
+    # client tests are flaky
+    rm tests/client.rs
+  '';
+
+  # a nightly compiler is required unless we use this cheat code.
+  RUSTC_BOOTSTRAP=1;
+
+  # rls-rustc links to rustc_private crates
+  CARGO_BUILD_RUSTFLAGS = if stdenv.isDarwin then "-C rpath" else null;
+
+  nativeBuildInputs = [ pkgconfig cmake ];
+  buildInputs = [ openssh openssl curl zlib libiconv ]
+    ++ (stdenv.lib.optionals stdenv.isDarwin [ CoreFoundation Security ]);
+
+  doCheck = true;
+
+  preInstall = "popd";
+
+  doInstallCheck = true;
+  installCheckPhase = ''
+    $out/bin/rls --version
+  '';
+
+  meta = with stdenv.lib; {
+    description = "Rust Language Server - provides information about Rust programs to IDEs and other tools";
+    homepage = https://github.com/rust-lang/rls/;
+    license = with licenses; [ asl20 /* or */ mit ];
+    maintainers = with maintainers; [ symphorien ];
+    platforms = platforms.all;
+  };
+}