buildRustPackage: use checkType argument

The `checkType` argument of buildRustPackage was not used anymore
since the refactoring of `buildRustPackage` into hooks. This was
an oversight that is fixed by this change.

The check type can also be passed directly to cargoCheckHook using the
`cargoCheckType` environment variable.

doc/languages-frameworks/rust.section.md

@@ -320,9 +320,10 @@ attributes can also be used:
   variable `buildAndTestSubdir` can be used to build a crate in a
   Cargo workspace. Additional maturin flags can be passed through
   `maturinBuildFlags`.
-* `cargoCheckHook`: run tests using Cargo. Additional flags can be
+* `cargoCheckHook`: run tests using Cargo. The build type for checks
-  passed to Cargo using `checkFlags` and `checkFlagsArray`. By
+  can be set using `cargoCheckType`. Additional flags can be passed to
-  default, tests are run in parallel. This can be disabled by setting
+  the tests using `checkFlags` and `checkFlagsArray`. By default,
+  tests are run in parallel. This can be disabled by setting
   `dontUseCargoParallelTests`.
 * `cargoInstallHook`: install binaries and static/shared libraries
   that were built using `cargoBuildHook`.

pkgs/build-support/rust/default.nix

@@ -103,6 +103,8 @@ stdenv.mkDerivation ((removeAttrs args ["depsExtraArgs"]) // lib.optionalAttrs u
 
   cargoBuildType = buildType;
 
+  cargoCheckType = checkType;
+
   patchRegistryDeps = ./patch-registry-deps;
 
   nativeBuildInputs = nativeBuildInputs ++ [

pkgs/build-support/rust/hooks/cargo-check-hook.sh

@@ -15,7 +15,7 @@ cargoCheckHook() {
         threads=1
     fi
 
-    argstr="--${cargoBuildType} --target @rustTargetPlatformSpec@ --frozen";
+    argstr="--${cargoCheckType} --target @rustTargetPlatformSpec@ --frozen";
 
     (
         set -x