racket/unit: fix signature handling of define-values/invoke-unit/infer

Closes PR 14453

pkgs/racket-pkgs/racket-test/tests/units/test-unit.rkt

@@ -1855,4 +1855,36 @@
 
 ;; ----------------------------------------
 
+(module check-define-values-invoke-unit-spec racket/base
+  (require racket/unit)
+
+  (define-signature a^ (foo))
+  (define-signature b^ (bar))
+
+  (define-unit works@
+    (import) (export a^) (define foo 'foo))
+  (define-values/invoke-unit/infer
+    (export (rename a^ [qux foo]))
+    works@)
+
+  (define-unit doesnt@
+    (import) (export b^) (define bar 0))
+  (define-unit work@
+    (import b^) (export a^) (define foo bar))
+  ;; No rename on export
+  (define-values/invoke-unit/infer
+    (export a^)
+    (link doesnt@ work@))
+  ;; Rename on export
+  (define-values/invoke-unit/infer
+    (export (rename a^ [baz foo]))
+    (link doesnt@ work@))
+
+  (provide results)
+  (define results (list foo baz)))
+
+(test '(0 0) (dynamic-require ''check-define-values-invoke-unit-spec 'results))
+
+;; ----------------------------------------
+
 (displayln "tests passed")

racket/collects/racket/private/unit-syntax.rkt

@@ -56,8 +56,8 @@
 
 (define check-tagged-id (check-tagged check-id))
 
-;; check-spec-syntax : syntax-object boolean (syntax-object -> boolean) ->
-;; ensures that s matches spec.
+;; check-spec-syntax : syntax-object boolean (syntax-object -> boolean) -> prim-spec?
+;; ensures that s matches spec, returns the core prim-spec (which is usually an identifier)
 ;; tag-spec ::= spec
 ;;            | (tag symbol spec)
 ;; spec ::= prim-spec
@@ -69,7 +69,9 @@
   ((check-tagged (λ (s) (check-spec-syntax s import? prim-spec?))) s))
 
 (define (check-spec-syntax s import? prim-spec?)
-  (unless (prim-spec? s)
+  (cond
+   [(prim-spec? s) s]
+   [else
     (let ((ie (if import? 'import 'export)))
       (unless (stx-pair? s)
         (raise-stx-err (format "bad ~a spec" ie) s))
@@ -124,7 +126,7 @@
             (syntax->list #'(clause ...)))
            (check-spec-syntax #'sub-s import? prim-spec?)))
         ((k . x)
-         (raise-stx-err (format "bad ~a-spec keyword" ie) #'k))))))
+         (raise-stx-err (format "bad ~a-spec keyword" ie) #'k))))]))
 
 ;; check-unit-syntax : syntax-object -> syntax-object
 ;; ensures that stx matches ((import i ...) (export e ...) b ...)

racket/collects/racket/unit.rkt

@@ -2101,7 +2101,7 @@
              [exports
               (map 
                (lambda (e)
-                 (define tid (check-tagged-id e))
+                 (define tid (check-tagged-spec-syntax e #f identifier?))
                  (define lookup (bound-identifier-mapping-get 
                                  lnk-table
                                  (cdr tid)