add test for external arity

CHANGELOG.md

@@ -1,6 +1,6 @@
 merlin 3.3.2
 ============
-Tue Jul  9 17:34:42 CEST 2019
+Mon Jul 15 11:10:35 CEST 2019
 
  + backend
  - `**` globbing in .merlin won't look into hidden directories
@@ -15,6 +15,8 @@ Tue Jul 9 17:34:42 CEST 2019
  from a cmi), this fixes "jump to definition" on mutually recursive
  bindings (#984)
  - when completing an infix operator in a sub-module, wrap with () (#992)
+ - disable arity checks on externals (for Bucklescript compatibility)
+ - remove parser preprocessing (simplify compilation for OCaml < 4.08) (#997)
  + editor modes
  - emacs
  + fix position computation in presence of tabs or multi-byte characters (#981)

tests/misc/dune

@@ -0,0 +1,8 @@
+(alias
+ (name runtest)
+ (deps external-arity.t)
+ (action
+ (progn
+ (setenv MERLIN %{dep:../merlin-wrapper}
+ (run %{bin:mdx} test --syntax=cram %{deps}))
+ (diff? %{deps} %{deps}.corrected))))

tests/misc/external-arity.t

@@ -0,0 +1,12 @@
+Bucklescript allow externals to have a non-arrow type. We relax this
+restriction in Merlin too as it ease some peoples life and is not really
+problematic for normal OCaml users.
+
+ $ $MERLIN single errors -filename external_arity.ml -w +A <<EOF \
+ > external foo : unit list = "foo" \
+ > EOF
+ {
+ "class": "return",
+ "value": [],
+ "notifications": []
+ }