maint: Clean up compatibility layer.

* modules/rosenthal/packages/rust-crates.scm (crate-name->package-name)
(define-cargo-inputs, crate-source): Remove, as they are available in
(guix build-system cargo).
* modules/rosenthal/utils/cargo.scm (rosenthal-cargo-inputs): Define using
cargo-inputs.
* modules/rosenthal/utils/download.scm (go-mod-vendor): Stop accessing nss-certs
from (gnu packages certs) module.

modules/rosenthal/packages/rust-crates.scm

@@ -15,37 +15,6 @@
 ;;; This file is managed by ‘guix import’.  DO NOT add definitions manually.
 ;;;
 
-(define* (crate-name->package-name name)
-  (downstream-package-name "rust-" name))
-
-(define* (crate-source name version hash #:key (patches '()) (snippet #f))
-  (origin
-    (method url-fetch)
-    (uri (crate-uri name version))
-    (file-name
-     (string-append (crate-name->package-name name) "-" version ".tar.gz"))
-    (sha256 (base32 hash))
-    (modules '((guix build utils)))
-    (patches patches)
-    (snippet snippet)))
-
-(define-syntax define-cargo-inputs
-  (syntax-rules (=>)
-    ((_ lookup inputs ...)
-     (define lookup
-       (let ((table (make-hash-table)))
-         (letrec-syntax ((record
-                          (syntax-rules (=>)
-                            ((_) #t)
-                            ((_ (name => lst) rest (... ...))
-                             (begin
-                               (hashq-set! table 'name (filter identity lst))
-                               (record rest (... ...)))))))
-           (record inputs ...)
-           (lambda (name)
-             "Return the inputs for NAME."
-             (hashq-ref table name))))))))
-
 ;;;
 ;;; Rust dependencies fetched from crates.io and non-workspace development
 ;;; snapshots.

modules/rosenthal/utils/cargo.scm

@@ -3,15 +3,9 @@
 ;;; SPDX-License-Identifier: GPL-3.0-or-later
 
 (define-module (rosenthal utils cargo)
-  #:use-module (guix diagnostics)
-  #:use-module (guix i18n)
+  #:use-module (srfi srfi-26)
+  #:use-module (guix build-system cargo)
   #:export (rosenthal-cargo-inputs))
 
-(define* (rosenthal-cargo-inputs name #:key (module '(rosenthal packages rust-crates)))
-  "Lookup Cargo inputs for NAME defined in MODULE, return an empty list if
-unavailable."
-  (let ((lookup (module-ref (resolve-interface module) 'lookup-cargo-inputs)))
-    (or (lookup name)
-        (begin
-          (warning (G_ "no Cargo inputs available for '~a'~%") name)
-          '()))))
+(define rosenthal-cargo-inputs
+  (cut cargo-inputs <> #:module '(rosenthal packages rust-crates)))

modules/rosenthal/utils/download.scm

@@ -15,10 +15,7 @@
 (define* (go-mod-vendor #:key go)
   (lambda* (src hash-algo hash #:optional name #:key (system (%current-system)))
     (define nss-certs
-      (or (false-if-exception
-           (module-ref (resolve-interface '(gnu packages nss)) 'nss-certs))
-          (false-if-exception
-           (module-ref (resolve-interface '(gnu packages certs)) 'nss-certs))))
+      (module-ref (resolve-interface '(gnu packages nss)) 'nss-certs))
 
     (gexp->derivation
      (or name "vendored-go-dependencies")