build-support/rust: remove assertMsg usage

pkgs/build-support/rust/build-rust-crate/test/rcgen-crates.nix

@@ -4669,7 +4669,7 @@ rec {
                   # Not rate-limited, CDN URL.
                   url = "https://static.crates.io/crates/${crateConfig.crateName}/${crateConfig.crateName}-${crateConfig.version}.crate";
                   sha256 =
-                    assert (lib.assertMsg (crateConfig ? sha256) "Missing sha256 for ${name}");
+                    assert crateConfig ? sha256 || throw "Missing sha256 for ${name}";
                     crateConfig.sha256;
                 });
               extraRustcOpts =

pkgs/build-support/rust/build-rust-package/default.nix

@@ -78,8 +78,9 @@ lib.extendMkDerivation {
       ...
     }@args:
 
-    assert lib.assertMsg useFetchCargoVendor
-      "buildRustPackage: `useFetchCargoVendor` is non‐optional and enabled by default as of 25.05, remove it";
+    assert
+      useFetchCargoVendor
+      || throw "buildRustPackage: `useFetchCargoVendor` is non‐optional and enabled by default as of 25.05, remove it";
 
     assert lib.warnIf (args ? useFetchCargoVendor)
       "buildRustPackage: `useFetchCargoVendor` is non‐optional and enabled by default as of 25.05, remove it"

pkgs/build-support/rust/import-cargo-lock.nix

@@ -120,9 +120,11 @@ let
       checksum =
         pkg.checksum or parsedLockFile.metadata."checksum ${pkg.name} ${pkg.version} (${pkg.source})";
     in
-    assert lib.assertMsg (checksum != null) ''
-      Package ${pkg.name} does not have a checksum.
-    '';
+    assert
+      checksum != null
+      || throw ''
+        Package ${pkg.name} does not have a checksum.
+      '';
     fetchurl {
       name = "crate-${pkg.name}-${pkg.version}.tar.gz";
       url = "${downloadUrl}/${pkg.name}/${pkg.version}/download";