let case be the head of an application too

tests/Tests/Parser.idr

@@ -400,7 +400,15 @@ tests = "parser" :- [
       `(Case (PQ Any _) (V "n" {}) (Unused _, NAT _)
         (CaseNat (Nat 0 _) (Unused _, PQ One _, PV "ih" _, V "ih" {}) _) _),
     parseFails term "caseω n return A of { zero ⇒ a }",
-    parseFails term "caseω n return ℕ of { succ ⇒ 5 }"
+    parseFails term "caseω n return ℕ of { succ ⇒ 5 }",
+    parseMatch term
+      "case1 f s return x ⇒ A x of { (l, r) ⇒ r l } x"
+      `(App
+        (Case (PQ One _) (App (V "f" {}) (V "s" {}) _)
+          (PV "x" _, App (V "A" {}) (V "x" {}) _)
+          (CasePair (PV "l" _, PV "r" _)
+                    (App (V "r" {}) (V "l" {}) _) _) _)
+        (V "x" {}) _)
   ],
 
   "definitions" :-