Clarify when handler needs to be a function

Fixes #472
dhall-lang · Apr 9, 2019 · c8f345a · c8f345a
1 parent 5a0ddc9
commit c8f345a
Showing 1 changed file with 2 additions and 1 deletion.
diff --git a/standard/semantics.md b/standard/semantics.md
@@ -4310,7 +4310,8 @@ If there is a handler without a matching alternative then that is a type error.
 
 If there is an alternative without a matching handler then that is a type error.
 
-If a handler is not a function, then that is a type error.
+If a handler is not a function and the corresponding union alternative is
+non-empty, then that is a type error.
 
 If the handler's input type does not match the corresponding alternative's type
 then that is a type error.