Confusing error message with type alias and incorrect list item type

[nonpop]

Trying to compile this module:

module SSCCE exposing (sscce)


type alias ListOfInts =
    List Int


sscce : ListOfInts -> ListOfInts
sscce list =
    "oops" :: list

gives the following error messages:

-- TYPE MISMATCH ------------------------------------------------- src/SSCCE.elm

Something is off with the body of the `sscce` definition:

10|     "oops" :: list
        ^^^^^^^^^^^^^^
The body is:

    List String

But the type annotation on `sscce` says it should be:

    ListOfInts

-- TYPE MISMATCH ------------------------------------------------- src/SSCCE.elm

The (::) operator can only add elements onto lists.

10|     "oops" :: list
                  ^^^^
This `list` value is a:

    ListOfInts

But (::) needs a List on the right.

• The first message is a little confusing because it seems to claim that the body type checks as List String.
• The second one is a lot confusing, because it claims that ListOfInts is not a list type. If you only see this error and not the first one you're going to have a hard time fixing it (speaking from experience; there it was not so clear that the new head was of incorrect type).