From bc3599b815c6f9cad2f4efd30c009cbe8f765ca1 Mon Sep 17 00:00:00 2001
From: Nadrieril
Date: Fri, 27 Dec 2019 17:03:43 +0000
Subject: Assign a unique id to each binder

---
 dhall/src/semantics/core/var.rs | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 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 add0500..28ddadd 100644
--- a/dhall/src/semantics/core/var.rs
+++ b/dhall/src/semantics/core/var.rs
@@ -11,11 +11,17 @@ pub struct AlphaVar {
     alpha: V<()>,
 }
 
+type BinderUID = u64;
+
 // Exactly like a Label, but equality returns always true.
 // This is so that ValueKind equality is exactly alpha-equivalence.
 #[derive(Clone, Eq)]
 pub struct Binder {
     name: Label,
+    /// Id of the binder, unique across the current expression. Used to distinguish bindersinstead
+    /// of their name. The id won't actually be unique when there are imports around, but
+    /// typechecking ensures this can't cause a conflict.
+    uid: BinderUID,
 }
 
 pub(crate) trait Shift: Sized {
@@ -67,8 +73,8 @@ impl AlphaVar {
 }
 
 impl Binder {
-    pub(crate) fn new(name: Label) -> Self {
-        Binder { name }
+    pub(crate) fn new(name: Label, uid: BinderUID) -> Self {
+        Binder { name, uid }
     }
     pub(crate) fn to_label_maybe_alpha(&self, alpha: bool) -> Label {
         if alpha {
-- 
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