Cannot declare and define an integer array using the colon operator

Summary:

It is a parser error to declare and define a one-dimensional integer array using the colon operator.

Description:

It is a parser error to declare and define a one-dimensional integer array using the colon operator.

Reproducible Steps:

Try to parse the following Stan program

data {
  int<lower=1> K;
}
transformed data {
  int arr[K] = 1:K;
}

Current Output:

SYNTAX ERROR, MESSAGE(S) FROM PARSER:

variable definition dimensions mismatch, definition specifies 1, declaration specifies 0  error in 'model_int_array' at line 5, column 17
  -------------------------------------------------
     3: }
     4: transformed data {
     5:   int arr[K] = 1:K;
                        ^
     6: }
  -------------------------------------------------

Error in stanc(model_code = paste(program, collapse = "\n"), model_name = model_cppname,  : 
  failed to parse Stan model 'int_array' due to the above error.

Expected Output:

Nothing. It should assign the integers from 1 to K to arr

Additional Information:

Current Version:

v2.17.0

Start by parsing the provided Stan program in stanc3 and confirm the reported dimension-mismatch error for int arr[K] = 1:K. Trace the parser or type-checking path that handles the colon expression in this declaration. Done means the program parses successfully and assigns the integers from 1 through K to arr.