Lambda expressions are not supported

[will-arxed]

Against a Spanner emulator, the following command:

gcloud spanner databases create testdatabase --instance=testinstance --ddl="CREATE TABLE TestTable (
        ID INT64,
        Numbers ARRAY<INT64> NOT NULL,
        CONSTRAINT TestTableNumbersNotNullCheck CHECK (
                NOT ARRAY_INCLUDES (
                        Numbers,
                        number -> number IS NULL
                )
        ),
) PRIMARY KEY (ID);"

returns the following error:

ERROR: (gcloud.spanner.databases.create) HTTPError 400: {"code":3, "message":"Error parsing expression 'NOT ARRAY_INCLUDES (\n\t\t\tNumbers,\n\t\t\tnumber -> number IS NULL\n\t\t)' from check constraint 'TestTableNumbersNotNullCheck' in table 'TestTable': Lambda is not supported [at 3:25]\n                        number -> number IS NULL\n                        ^"}

Against a Spanner instance, the same command succeeds.

Is support planned for lambda expressions in the Spanner emulator? Thanks in advance.