Parsing bug in :map schema

[yuhan0]

Using registry references to "composite" schemas in :map schemas and wrapping them in a vector without additional arguments causes an unexpected error.

(def reg
  {::foo [:tuple :int :int]
   ::bar :int})

(malli/schema
  [:map {:registry reg}
   [::foo]])
;; => Execution error (ExceptionInfo) at malli.impl.util/-fail! (util.cljc:16).
;;    :malli.core/invalid-schema {:schema [:tuple :int :int]}

Additional context:

It parses correctly if the reference is not wrapped in a vector, or if a map argument is included.

[:map {:registry reg}
 ::foo]

[:map {:registry reg}
 [::foo {}]]

Additionally, this only happens with "composite" schemas that take arguments like :tuple, :map-of, :<= etc.

The failing syntax from before works if the reference is a plain type-schema like :any, :string, :int etc.

[:map {:registry reg}
 [::bar]]