From f7a8d967b02bc20c093d501746ed3de53cc7da13 Mon Sep 17 00:00:00 2001
From: Nadrieril
Date: Fri, 17 Jan 2020 10:49:02 +0000
Subject: Simplify Shift and Subst instances

---
 dhall/src/semantics/core/var.rs | 144 +---------------------------------------
 1 file changed, 1 insertion(+), 143 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 99d3125..c21e53e 100644
--- a/dhall/src/semantics/core/var.rs
+++ b/dhall/src/semantics/core/var.rs
@@ -1,6 +1,6 @@
 use std::collections::HashMap;
 
-use crate::syntax::{ExprKind, InterpolatedTextContents, Label, V};
+use crate::syntax::{Label, V};
 
 /// Stores a pair of variables: a normal one and one
 /// that corresponds to the alpha-normalized version of the first one.
@@ -143,145 +143,3 @@ impl From<Binder> for Label {
         x.name
     }
 }
-impl Shift for () {
-    fn shift(&self, _delta: isize, _var: &AlphaVar) -> Option<Self> {
-        Some(())
-    }
-}
-
-impl<A: Shift, B: Shift> Shift for (A, B) {
-    fn shift(&self, delta: isize, var: &AlphaVar) -> Option<Self> {
-        Some((self.0.shift(delta, var)?, self.1.shift(delta, var)?))
-    }
-}
-
-impl<T: Shift> Shift for Option<T> {
-    fn shift(&self, delta: isize, var: &AlphaVar) -> Option<Self> {
-        Some(match self {
-            None => None,
-            Some(x) => Some(x.shift(delta, var)?),
-        })
-    }
-}
-
-impl<T: Shift> Shift for Box<T> {
-    fn shift(&self, delta: isize, var: &AlphaVar) -> Option<Self> {
-        Some(Box::new(self.as_ref().shift(delta, var)?))
-    }
-}
-
-impl<T: Shift> Shift for std::rc::Rc<T> {
-    fn shift(&self, delta: isize, var: &AlphaVar) -> Option<Self> {
-        Some(std::rc::Rc::new(self.as_ref().shift(delta, var)?))
-    }
-}
-
-impl<T: Shift> Shift for std::cell::RefCell<T> {
-    fn shift(&self, delta: isize, var: &AlphaVar) -> Option<Self> {
-        Some(std::cell::RefCell::new(self.borrow().shift(delta, var)?))
-    }
-}
-
-impl<T: Shift, E: Clone> Shift for ExprKind<T, E> {
-    fn shift(&self, delta: isize, var: &AlphaVar) -> Option<Self> {
-        Some(self.traverse_ref_with_special_handling_of_binders(
-            |v| Ok(v.shift(delta, var)?),
-            |x, v| Ok(v.shift(delta, &var.under_binder(x))?),
-        )?)
-    }
-}
-
-impl<T: Shift> Shift for Vec<T> {
-    fn shift(&self, delta: isize, var: &AlphaVar) -> Option<Self> {
-        Some(
-            self.iter()
-                .map(|v| Ok(v.shift(delta, var)?))
-                .collect::<Result<_, _>>()?,
-        )
-    }
-}
-
-impl<K, T: Shift> Shift for HashMap<K, T>
-where
-    K: Clone + std::hash::Hash + Eq,
-{
-    fn shift(&self, delta: isize, var: &AlphaVar) -> Option<Self> {
-        Some(
-            self.iter()
-                .map(|(k, v)| Ok((k.clone(), v.shift(delta, var)?)))
-                .collect::<Result<_, _>>()?,
-        )
-    }
-}
-
-impl<T: Shift> Shift for InterpolatedTextContents<T> {
-    fn shift(&self, delta: isize, var: &AlphaVar) -> Option<Self> {
-        Some(self.traverse_ref(|x| Ok(x.shift(delta, var)?))?)
-    }
-}
-
-impl<S> Subst<S> for () {
-    fn subst_shift(&self, _var: &AlphaVar, _val: &S) -> Self {}
-}
-
-impl<S, A: Subst<S>, B: Subst<S>> Subst<S> for (A, B) {
-    fn subst_shift(&self, var: &AlphaVar, val: &S) -> Self {
-        (self.0.subst_shift(var, val), self.1.subst_shift(var, val))
-    }
-}
-
-impl<S, T: Subst<S>> Subst<S> for Option<T> {
-    fn subst_shift(&self, var: &AlphaVar, val: &S) -> Self {
-        self.as_ref().map(|x| x.subst_shift(var, val))
-    }
-}
-
-impl<S, T: Subst<S>> Subst<S> for Box<T> {
-    fn subst_shift(&self, var: &AlphaVar, val: &S) -> Self {
-        Box::new(self.as_ref().subst_shift(var, val))
-    }
-}
-
-impl<S, T: Subst<S>> Subst<S> for std::rc::Rc<T> {
-    fn subst_shift(&self, var: &AlphaVar, val: &S) -> Self {
-        std::rc::Rc::new(self.as_ref().subst_shift(var, val))
-    }
-}
-
-impl<S, T: Subst<S>> Subst<S> for std::cell::RefCell<T> {
-    fn subst_shift(&self, var: &AlphaVar, val: &S) -> Self {
-        std::cell::RefCell::new(self.borrow().subst_shift(var, val))
-    }
-}
-
-impl<S: Shift, T: Subst<S>, E: Clone> Subst<S> for ExprKind<T, E> {
-    fn subst_shift(&self, var: &AlphaVar, val: &S) -> Self {
-        self.map_ref_with_special_handling_of_binders(
-            |v| v.subst_shift(var, val),
-            |x, v| v.subst_shift(&var.under_binder(x), &val.under_binder(x)),
-        )
-    }
-}
-
-impl<S, T: Subst<S>> Subst<S> for Vec<T> {
-    fn subst_shift(&self, var: &AlphaVar, val: &S) -> Self {
-        self.iter().map(|v| v.subst_shift(var, val)).collect()
-    }
-}
-
-impl<S, T: Subst<S>> Subst<S> for InterpolatedTextContents<T> {
-    fn subst_shift(&self, var: &AlphaVar, val: &S) -> Self {
-        self.map_ref(|x| x.subst_shift(var, val))
-    }
-}
-
-impl<S, K, T: Subst<S>> Subst<S> for HashMap<K, T>
-where
-    K: Clone + std::hash::Hash + Eq,
-{
-    fn subst_shift(&self, var: &AlphaVar, val: &S) -> Self {
-        self.iter()
-            .map(|(k, v)| (k.clone(), v.subst_shift(var, val)))
-            .collect()
-    }
-}
-- 
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