Map literals: improve type inference and error messages

The struct has type File for member some_file, and task some_task has an output member some_file that has type File, so why is miniwdl check failing?

(test.wdl Ln 14 Col 26) Expected Array[File] instead of File
                "some_file": some_task.some_file,
                             ^^^^^^^^^^^^^^^^^^^
* Hint: for compatibility with older existing WDL code, try setting --no-quant-check to relax quantifier validation rules.

version 1.0
struct FooStruct {
    Array[File] list_of_files
    File some_file
}

workflow some_workflow {
    input {
        String file_name
    }
    output {
        FooStruct out = {
            "list_of_files": some_task.list_of_files,
            "some_file": some_task.some_file,
        }
    }
    call some_task  {
        input:
            file_name=file_name
    }
}

task some_task {
    input {
        String file_name
    }
    output {
      Array[File] list_of_files = glob("~{file_name}*.txt")
      File some_file = "~{file_name}.txt"
    }
    command <<<
        echo Hi > ~{file_name}.txt
    >>>
}

[nh13]

I’ll use the object literal constructor going forward but I’ll leave it open in case someone wants to implement it.

[mlin]

@ynedelec I think the confusion between Map and object literals is inherent in WDL but I’m not sure exactly how Cromwell handles all these cases. The key fact relevant here is that a Map has homogeneous value types (and may have non-string keys).

WDL 1.1 has a new struct initialization syntax, but it’s essentially the same old object initializer except you replace object with the name of the struct.