From: Ian Jackson <ijackson@chiark.greenend.org.uk>
Date: Mon, 15 Feb 2021 00:03:21 +0000 (+0000)
Subject: Use Void and abolish our Impossible
X-Git-Tag: otter-0.4.0~452
X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?a=commitdiff_plain;h=0cd1a9359f1d30457ce64b5389e6f1c96d521896;p=otter.git

Use Void and abolish our Impossible

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>
---

diff --git a/daemon/api.rs b/daemon/api.rs
index 98a3c6e1..413dc996 100644
--- a/daemon/api.rs
+++ b/daemon/api.rs
@@ -401,7 +401,7 @@ api_route!{
     '_normal_global_ops__not_loop: loop {
       let pc = gs.pieces.byid_mut(piece)?;
       let gpl = gs.players.byid_mut(player)?;
-      let _: Impossible = match (self.opname.as_str(), self.wrc) {
+      let _: Void = match (self.opname.as_str(), self.wrc) {
 
         ("flip", wrc@ WRC::UpdateSvg) => {
           let nfaces = p.nfaces();
@@ -421,7 +421,7 @@ api_route!{
     }
 
     '_abnormal_global_ops__notloop: loop {
-      let _: Impossible = match self {
+      let _: Void = match self {
 
         _ => break,
       };
diff --git a/src/global.rs b/src/global.rs
index 373da0df..60faeba7 100644
--- a/src/global.rs
+++ b/src/global.rs
@@ -1397,8 +1397,8 @@ fn client_expire_old_clients() {
     #[derive(Debug)]
     struct Now(HashSet<ClientId>);
     impl ClientIterator for Now {
-      type Ret = Impossible;
-      fn old(&mut self, client: ClientId) -> Option<Impossible> {
+      type Ret = Void;
+      fn old(&mut self, client: ClientId) -> Option<Void> {
         self.0.insert(client);
         None
       }
diff --git a/src/prelude.rs b/src/prelude.rs
index dc9d269f..d20a432e 100644
--- a/src/prelude.rs
+++ b/src/prelude.rs
@@ -84,6 +84,7 @@ pub use strum::EnumString;
 pub use thiserror::Error;
 pub use url::Url;
 pub use vecdeque_stableix::Deque as StableIndexVecDeque;
+pub use void::Void;
 
 pub use otter_base::zcoord::{self, ZCoord};
 pub use otter_base::misc as base_misc;
@@ -121,10 +122,6 @@ pub type SecondarySlotMap<K,V> = slotmap::secondary::SecondaryMap<K,V>;
 pub type SvgData = Vec<u8>;
 pub type Colour = Html;
 
-#[derive(Debug,Copy,Clone)]
-pub enum Impossible { }
-display_as_debug!(Impossible);
-
 // ---------- type abbreviations ----------
 
 pub type AE = anyhow::Error;
diff --git a/src/spec.rs b/src/spec.rs
index 0e2d121a..1d6ee23e 100644
--- a/src/spec.rs
+++ b/src/spec.rs
@@ -376,7 +376,7 @@ pub mod implementation {
     pub fn account_glob(&self) -> String {
       fn scope_glob(scope: AccountScope) -> String {
         let mut out = "".to_string();
-        scope.display_name(&["*"], |s| Ok::<_,Impossible>(out += s)).unwrap();
+        scope.display_name(&["*"], |s| Ok::<_,Void>(out += s)).unwrap();
         out
       }
       match self {
diff --git a/src/tz.rs b/src/tz.rs
index 002a94af..91d95d11 100644
--- a/src/tz.rs
+++ b/src/tz.rs
@@ -68,8 +68,8 @@ type MemoTable = Option<HashMap<String, Timezone>>;
 static MEMO: RwLock<MemoTable> = const_rwlock(None);
 
 impl FromStr for Timezone {
-  type Err = Impossible;
-  #[throws(Impossible)]
+  type Err = Void;
+  #[throws(Void)]
   fn from_str(name: &str) -> Self {
     if name.is_empty() { return default() }