From 0f4a4801ed67826dc82015d39ce8fd05e7950035 Mon Sep 17 00:00:00 2001
From: Nadrieril
Date: Fri, 17 Jan 2020 18:42:13 +0000
Subject: Replace all bulk shifting by a single shift

---
 dhall/src/semantics/core/var.rs | 20 ++++----------------
 1 file changed, 4 insertions(+), 16 deletions(-)

(limited to 'dhall/src/semantics/core/var.rs')

diff --git a/dhall/src/semantics/core/var.rs b/dhall/src/semantics/core/var.rs
index f3475e7..93776bf 100644
--- a/dhall/src/semantics/core/var.rs
+++ b/dhall/src/semantics/core/var.rs
@@ -1,5 +1,3 @@
-use std::collections::HashMap;
-
 use crate::syntax::{Label, V};
 
 /// Stores an alpha-normalized variable.
@@ -16,6 +14,9 @@ pub struct Binder {
 }
 
 impl AlphaVar {
+    pub(crate) fn default() -> Self {
+        AlphaVar { alpha: V((), 0) }
+    }
     pub(crate) fn idx(&self) -> usize {
         self.alpha.idx()
     }
@@ -35,14 +36,6 @@ impl AlphaVar {
     pub(crate) fn over_binder(&self, x: &AlphaVar) -> Option<Self> {
         self.shift(-1, x)
     }
-    pub(crate) fn under_multiple_binders(
-        &self,
-        shift_map: &HashMap<Label, usize>,
-    ) -> Self {
-        AlphaVar {
-            alpha: self.alpha.under_multiple_binders(shift_map),
-        }
-    }
 }
 
 impl Binder {
@@ -89,11 +82,6 @@ impl std::fmt::Debug for Binder {
     }
 }
 
-impl<'a> From<&'a Label> for AlphaVar {
-    fn from(x: &'a Label) -> AlphaVar {
-        AlphaVar { alpha: V((), 0) }
-    }
-}
 impl From<Binder> for AlphaVar {
     fn from(x: Binder) -> AlphaVar {
         AlphaVar { alpha: V((), 0) }
@@ -101,7 +89,7 @@ impl From<Binder> for AlphaVar {
 }
 impl<'a> From<&'a Binder> for AlphaVar {
     fn from(x: &'a Binder) -> AlphaVar {
-        x.clone().into()
+        AlphaVar { alpha: V((), 0) }
     }
 }
 
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