From 280b3174476ef8fe5a98f3614f4fe253fa243d8c Mon Sep 17 00:00:00 2001
From: Nadrieril
Date: Wed, 29 Jan 2020 21:35:28 +0000
Subject: Finally get rid of all of the shift/subst_shift !

---
 dhall/src/syntax/ast/expr.rs | 22 ----------------------
 1 file changed, 22 deletions(-)

(limited to 'dhall/src/syntax')

diff --git a/dhall/src/syntax/ast/expr.rs b/dhall/src/syntax/ast/expr.rs
index 0da617b..424ac34 100644
--- a/dhall/src/syntax/ast/expr.rs
+++ b/dhall/src/syntax/ast/expr.rs
@@ -320,18 +320,6 @@ impl<E> Expr<E> {
     }
 }
 
-impl<Label: PartialEq + Clone> V<Label> {
-    pub(crate) fn shift(&self, delta: isize, var: &V<Label>) -> Option<Self> {
-        let V(x, n) = var;
-        let V(y, m) = self;
-        Some(if x == y && n <= m {
-            V(y.clone(), add_ui(*m, delta)?)
-        } else {
-            V(y.clone(), *m)
-        })
-    }
-}
-
 pub fn trivial_result<T>(x: Result<T, !>) -> T {
     match x {
         Ok(x) => x,
@@ -339,16 +327,6 @@ pub fn trivial_result<T>(x: Result<T, !>) -> T {
     }
 }
 
-/// Add an isize to an usize
-/// Returns `None` on over/underflow
-fn add_ui(u: usize, i: isize) -> Option<usize> {
-    Some(if i < 0 {
-        u.checked_sub(i.checked_neg()? as usize)?
-    } else {
-        u.checked_add(i as usize)?
-    })
-}
-
 impl PartialEq for NaiveDouble {
     fn eq(&self, other: &Self) -> bool {
         self.0.to_bits() == other.0.to_bits()
-- 
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