Fix opt-lambda property on opt-lambda methods

Related to PR 14726

original commit: 3905334f28a9ffdf2d963c21f159fc1ccf642632

pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/typecheck/check-class-unit.rkt

@@ -1448,6 +1448,16 @@
                         (syntax/loc stx core)
                         (attribute kw.value))])
           m))]
+    [(~and (let-values ([(meth-name:id) core]) m)
+           opt:opt-lambda^)
+     (match-define (list required optional) (attribute opt.value))
+     (quasisyntax/loc stx
+       (let-values ([(meth-name)
+                     #,(opt-lambda-property
+                        (syntax/loc stx core)
+                        (list (add1 required) ; for `this` argument
+                              optional))])
+         m))]
     [_ stx]))
 
 ;; Set<Symbol> Set<Symbol> String -> Void

pkgs/typed-racket-pkgs/typed-racket-test/tests/typed-racket/unit-tests/class-tests.rkt

@@ -1505,4 +1505,14 @@
                (super-new)
                (define/public (foo [i #f]) (void))))
            (new a%))
-         (-object #:method ([foo (t:-> -Integer -Void)]))]))
+         (-object #:method ([foo (t:-> -Integer -Void)]))]
+   [tc-e (let ()
+           (define-type-alias A%
+             (Class [foo (->* [] [Integer] Void)]))
+           (: a% A%)
+           (define a%
+             (class object%
+               (super-new)
+               (define/public (foo [i #f]) (void))))
+           (new a%))
+         (-object #:method ([foo (cl->* (t:-> -Void) (t:-> -Integer -Void))]))]))