[E1015] UNKNOWN EXPORT

A module's exposing (…) list names something the module does not have.

-- UNKNOWN EXPORT ------------------------- src/Api/Responses.sky:17:7 [E1015]

15 |     , uploadSkillZip
16 |     , decodeUploadedSkill
17 |     , decodeResponse
   |       ^^^^^^^^^^^^^^

module `Api.Responses` exposes `decodeResponse`, but does not define it.
Define `decodeResponse` in `Api.Responses`, or remove it from the
`exposing` list.

Added in v0.25.19.

What it covers

You wrote	It is an error when
`exposing (decode)`	the module has no top-level `decode = …`
`exposing (Foo)`	the module neither declares `Foo` nor imports it
`exposing (Foo(..))`	`Foo` is an alias declared in the module (an alias has no constructors to expose)
`exposing (Shape(Circle, Hexagon))`	`Hexagon` is not a constructor of `Shape`

A module can re-expose a type it imports (import Std.Ui.Transition exposing (Easing) then exposing (Easing)): importers reach the one original type. A module cannot re-expose a value it imports, because there is no definition in the re-exposing module to call. Write a wrapper instead:

linear : Easing
linear =
    Transition.linear

Why it is an error

Before v0.25.19 a dangling export compiled. A caller's Responses.decodeResponse body resolved to a definition that did not exist, the type checker accepted it with whatever type the call site implied, and the generated Go called a nil function. The program built and then panicked with NilDereference the first time the call ran. That breaks "if it compiles, it works", so the export itself is now rejected, and every use of the missing name is rejected too:

Responses.decodeResponse → [E1001] Undefined name, which names the dangling export as the cause;
import Responses exposing (decodeResponse) → [E1011] not exposed;
import Responses exposing (..) then decodeResponse → [E1001].

The editor (sky-lsp) reports the same diagnostics, from the same pipeline.

How to fix it

Restore the definition, or delete the name from the exposing list. If other modules still call it, they then fail with [E1001] at each call, which lists the places to update.