From 509743469035582d916e6a2f331fd5018c81447e Mon Sep 17 00:00:00 2001
From: Nadrieril
Date: Fri, 16 Aug 2019 11:11:28 +0200
Subject: Use `!` type instead of custom empty type

---
 dhall_syntax/src/core/expr.rs    | 14 ++------------
 dhall_syntax/src/core/visitor.rs |  2 +-
 2 files changed, 3 insertions(+), 13 deletions(-)

(limited to 'dhall_syntax/src/core')

diff --git a/dhall_syntax/src/core/expr.rs b/dhall_syntax/src/core/expr.rs
index 30ac4eb..efbcee2 100644
--- a/dhall_syntax/src/core/expr.rs
+++ b/dhall_syntax/src/core/expr.rs
@@ -8,20 +8,10 @@ pub type Integer = isize;
 pub type Natural = usize;
 pub type Double = NaiveDouble;
 
-/// An empty type
-#[derive(Debug, Copy, Clone, PartialEq, Eq)]
-pub enum Void {}
-
-impl std::fmt::Display for Void {
-    fn fmt(&self, _f: &mut std::fmt::Formatter) -> Result<(), std::fmt::Error> {
-        match *self {}
-    }
-}
-
-pub fn trivial_result<T>(x: Result<T, Void>) -> T {
+pub fn trivial_result<T>(x: Result<T, !>) -> T {
     match x {
         Ok(x) => x,
-        Err(e) => match e {},
+        Err(e) => e,
     }
 }
 
diff --git a/dhall_syntax/src/core/visitor.rs b/dhall_syntax/src/core/visitor.rs
index 7b4ed4b..5a5fcc9 100644
--- a/dhall_syntax/src/core/visitor.rs
+++ b/dhall_syntax/src/core/visitor.rs
@@ -176,7 +176,7 @@ impl<'a, T, SE1, SE2, E1, E2> ExprFFallibleVisitor<'a, SE1, SE2, E1, E2>
 where
     T: ExprFInFallibleVisitor<'a, SE1, SE2, E1, E2>,
 {
-    type Error = Void;
+    type Error = !;
 
     fn visit_subexpr(&mut self, subexpr: &'a SE1) -> Result<SE2, Self::Error> {
         Ok(self.0.visit_subexpr(subexpr))
-- 
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