Stop NoContent appearing in BodyTypes if it appears inside Headers

Recurse through `Headers hdrs` just like any other decorator that
should be ignored.

Author: JackKelly-Bellroy

CHANGELOG.md

@@ -1,3 +1,9 @@
+Unreleased
+----------
+
+* Do not count `NoContent` as a body type if it appears in `Headers
+  hdrs NoContent`.
+
 1.1.8
 -------
 

src/Servant/OpenApi/Internal/TypeLevel/API.hs

@@ -86,7 +86,7 @@ type AddBodyType c cs a as = If (Elem c cs) (a ': as) as
 -- completely empty on responses to requests that only accept 'application/json', while
 -- setting the content-type in the response accordingly.)
 type family BodyTypes' c api :: [*] where
-  BodyTypes' c (Verb verb b cs (Headers hdrs a)) = AddBodyType c cs a '[]
+  BodyTypes' c (Verb verb b cs (Headers hdrs a)) = BodyTypes' c (Verb verb b cs a)
   BodyTypes' c (Verb verb b cs NoContent) = '[]
   BodyTypes' c (Verb verb b cs a) = AddBodyType c cs a '[]
   BodyTypes' c (ReqBody' mods cs a :> api) = AddBodyType c cs a (BodyTypes' c api)