Fix a bunch more Clippy lints, but disable in Circle

The unused error is causing more trouble than it's worth at this
point

17 files changed, 65 insertions, 69 deletions

diff --git a/src/description.rs b/src/description.rs
index 31f39f7578c2..48c98d76e051 100644
--- a/src/description.rs
+++ b/src/description.rs
@@ -69,12 +69,12 @@ mod tests {
     #[test]
     fn test_describe_list() {
         assert_eq!(
-            describe_list(&vec![Description("one".to_string())]),
+            describe_list(&[Description("one".to_string())]),
             "one".to_string()
         );
 
         assert_eq!(
-            describe_list(&vec![
+            describe_list(&[
                 Description("one".to_string()),
                 Description("two".to_string())
             ]),
@@ -82,7 +82,7 @@ mod tests {
         );
 
         assert_eq!(
-            describe_list(&vec![
+            describe_list(&[
                 Description("one".to_string()),
                 Description("two".to_string()),
                 Description("three".to_string())
diff --git a/src/display/color.rs b/src/display/color.rs
index 2a023f1d9564..b1e799c5ed9f 100644
--- a/src/display/color.rs
+++ b/src/display/color.rs
@@ -16,21 +16,21 @@ impl Color {
 }
 
 impl color::Color for Color {
-    fn write_fg(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn write_fg(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         self.0.write_fg(f)
     }
 
-    fn write_bg(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn write_bg(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         self.0.write_bg(f)
     }
 }
 
 impl<'a> color::Color for &'a Color {
-    fn write_fg(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn write_fg(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         self.0.write_fg(f)
     }
 
-    fn write_bg(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn write_bg(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         self.0.write_bg(f)
     }
 }
@@ -56,7 +56,7 @@ impl ColorVisitor {
 impl<'de> Visitor<'de> for ColorVisitor {
     type Value = Color;
 
-    fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
+    fn expecting(&self, formatter: &mut fmt::Formatter<'_>) -> fmt::Result {
         formatter.write_str("A color")
     }
 
diff --git a/src/display/draw_box.rs b/src/display/draw_box.rs
index 3b2b4aaf4f1d..1b3958cefca8 100644
--- a/src/display/draw_box.rs
+++ b/src/display/draw_box.rs
@@ -140,7 +140,7 @@ impl Stylable for Line {
 }
 
 impl Stylable for Neighbors<Option<BoxStyle>> {
-    fn style(&self, style: BoxStyle) -> char {
+    fn style(&self, _style: BoxStyle) -> char {
         use BoxStyle::*;
         match (self.left, self.right, self.top, self.bottom) {
             (None, None, None, None) => BOX,
diff --git a/src/display/mod.rs b/src/display/mod.rs
index 2df4277f4fa7..6e37a03d8c55 100644
--- a/src/display/mod.rs
+++ b/src/display/mod.rs
@@ -17,17 +17,17 @@ pub fn clear<T: Write>(out: &mut T) -> io::Result<()> {
 pub trait Draw: Positioned {
     /// Draw this entity, assuming the character is already at the correct
     /// position
-    fn do_draw(&self, out: &mut Write) -> io::Result<()>;
+    fn do_draw(&self, out: &mut dyn Write) -> io::Result<()>;
 }
 
 impl<T: Draw> Draw for &T {
-    fn do_draw(&self, out: &mut Write) -> io::Result<()> {
+    fn do_draw(&self, out: &mut dyn Write) -> io::Result<()> {
         (**self).do_draw(out)
     }
 }
 
 impl<T: Draw> Draw for Box<T> {
-    fn do_draw(&self, out: &mut Write) -> io::Result<()> {
+    fn do_draw(&self, out: &mut dyn Write) -> io::Result<()> {
         (**self).do_draw(out)
     }
 }
@@ -36,7 +36,7 @@ pub trait DrawWithNeighbors: Positioned {
     #[allow(clippy::borrowed_box)]
     fn do_draw_with_neighbors<'a, 'b>(
         &'a self,
-        out: &'b mut Write,
+        out: &'b mut dyn Write,
         neighbors: &'a Neighbors<Vec<&'a Box<dyn Entity>>>,
     ) -> io::Result<()>;
 }
@@ -44,7 +44,7 @@ pub trait DrawWithNeighbors: Positioned {
 impl<T: Draw> DrawWithNeighbors for T {
     fn do_draw_with_neighbors<'a, 'b>(
         &'a self,
-        out: &'b mut Write,
+        out: &'b mut dyn Write,
         _neighbors: &'a Neighbors<Vec<&'a Box<dyn Entity>>>,
     ) -> io::Result<()> {
         self.do_draw(out)
diff --git a/src/display/viewport.rs b/src/display/viewport.rs
index 5ff56be0a909..9d17bc87dcff 100644
--- a/src/display/viewport.rs
+++ b/src/display/viewport.rs
@@ -68,7 +68,7 @@ impl<W> Viewport<W> {
 }
 
 impl<W> Debug for Viewport<W> {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         write!(
             f,
             "Viewport {{ outer: {:?}, inner: {:?}, out: <OUT> }}",
diff --git a/src/entities/character.rs b/src/entities/character.rs
index 2b1b6efe47de..360478e8be1c 100644
--- a/src/entities/character.rs
+++ b/src/entities/character.rs
@@ -42,7 +42,7 @@ impl Character {
 }
 
 impl display::Draw for Character {
-    fn do_draw(&self, out: &mut Write) -> io::Result<()> {
+    fn do_draw(&self, out: &mut dyn Write) -> io::Result<()> {
         write!(out, "@")
     }
 }
diff --git a/src/entities/creature.rs b/src/entities/creature.rs
index 87ffda161e1c..20071c1d88eb 100644
--- a/src/entities/creature.rs
+++ b/src/entities/creature.rs
@@ -57,7 +57,7 @@ impl Describe for Creature {
 }
 
 impl display::Draw for Creature {
-    fn do_draw(&self, out: &mut Write) -> io::Result<()> {
+    fn do_draw(&self, out: &mut dyn Write) -> io::Result<()> {
         write!(out, "{}", self.typ.chr)
     }
 }
diff --git a/src/entities/entity.rs b/src/entities/entity.rs
index e43175931b68..01075d298f81 100644
--- a/src/entities/entity.rs
+++ b/src/entities/entity.rs
@@ -103,7 +103,7 @@ impl_downcast!(Entity);
 impl DrawWithNeighbors for Box<dyn Entity> {
     fn do_draw_with_neighbors<'a, 'b>(
         &'a self,
-        out: &'b mut Write,
+        out: &'b mut dyn Write,
         neighbors: &'a Neighbors<Vec<&'a Box<dyn Entity>>>,
     ) -> io::Result<()> {
         (**self).do_draw_with_neighbors(out, neighbors)
diff --git a/src/entities/entity_char.rs b/src/entities/entity_char.rs
index 2f845820021e..88ca8a55a823 100644
--- a/src/entities/entity_char.rs
+++ b/src/entities/entity_char.rs
@@ -12,7 +12,7 @@ pub struct EntityChar {
 }
 
 impl Display for EntityChar {
-    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
         write!(
             f,
             "{}{}{}",
diff --git a/src/entities/environment.rs b/src/entities/environment.rs
index 042873ec5a12..8f8a56706287 100644
--- a/src/entities/environment.rs
+++ b/src/entities/environment.rs
@@ -21,7 +21,7 @@ impl Wall {
 impl display::DrawWithNeighbors for Wall {
     fn do_draw_with_neighbors<'a, 'b>(
         &'a self,
-        out: &'b mut Write,
+        out: &'b mut dyn Write,
         neighbors: &'a Neighbors<Vec<&'a Box<dyn Entity>>>,
     ) -> io::Result<()> {
         let neighbor_styles: Neighbors<Option<BoxStyle>> =
diff --git a/src/entities/item.rs b/src/entities/item.rs
index 6e47a87f5b83..aa99fb42e2c1 100644
--- a/src/entities/item.rs
+++ b/src/entities/item.rs
@@ -44,7 +44,7 @@ impl Describe for Item {
 }
 
 impl display::Draw for Item {
-    fn do_draw(&self, out: &mut Write) -> io::Result<()> {
+    fn do_draw(&self, out: &mut dyn Write) -> io::Result<()> {
         write!(out, "{}", self.typ.chr)
     }
 }
diff --git a/src/game.rs b/src/game.rs
index add48e8bfd47..2c69061516fd 100644
--- a/src/game.rs
+++ b/src/game.rs
@@ -69,7 +69,7 @@ impl PromptResolution {
         use PromptResolution::*;
         match self {
             Cancellable(complete) => complete.cancel(),
-            Uncancellable(complete) => {}
+            Uncancellable(_complete) => {}
         }
     }
 }
@@ -200,12 +200,10 @@ impl<'a> Game<'a> {
     fn collision_at(&self, pos: Position) -> Option<Collision> {
         if !pos.within(self.viewport.inner) {
             Some(Collision::Stop)
+        } else if self.creatures_at(pos).is_empty() {
+            None
         } else {
-            if self.creatures_at(pos).is_empty() {
-                None
-            } else {
-                Some(Collision::Combat)
-            }
+            Some(Collision::Combat)
         }
     }
 
@@ -305,7 +303,7 @@ impl<'a> Game<'a> {
     }
 
     /// Step the game forward the given number of ticks
-    fn tick(&mut self, ticks: Ticks) {}
+    fn tick(&mut self, _ticks: Ticks) {}
 
     /// Get a message from the global map based on the rng in this game
     fn message<'params>(
diff --git a/src/main.rs b/src/main.rs
index 2cd0bbc08d05..8004a5739ef5 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,13 +1,7 @@
-extern crate termion;
 #[macro_use]
 extern crate log;
-extern crate config;
-extern crate log4rs;
-extern crate serde;
-extern crate toml;
 #[macro_use]
 extern crate serde_derive;
-extern crate serde_json;
 #[macro_use]
 extern crate clap;
 #[macro_use]
@@ -19,14 +13,13 @@ extern crate lazy_static;
 extern crate maplit;
 #[macro_use]
 extern crate downcast_rs;
-extern crate backtrace;
 #[macro_use]
 extern crate include_dir;
 #[macro_use]
 extern crate nom;
+#[cfg(test)]
 #[macro_use]
 extern crate matches;
-extern crate futures;
 
 #[macro_use]
 mod util;
@@ -53,6 +46,7 @@ use backtrace::Backtrace;
 use std::io::{self, StdinLock, StdoutLock};
 use std::panic;
 
+use termion;
 use termion::raw::IntoRawMode;
 use termion::raw::RawTerminal;
 
diff --git a/src/types/entity_map.rs b/src/types/entity_map.rs
index bec16cdab28a..202d8b593e15 100644
--- a/src/types/entity_map.rs
+++ b/src/types/entity_map.rs
@@ -10,7 +10,7 @@ use alga::general::{
 use std::collections::{hash_map, BTreeMap, HashMap};
 use std::iter::FromIterator;
 
-#[derive(Debug, Clone)]
+#[derive(Debug, Clone, Default)]
 pub struct EntityMap<A> {
     by_position: BTreeMap<Position, Vec<EntityID>>,
     by_id: HashMap<EntityID, A>,
@@ -24,7 +24,7 @@ impl<A: PartialEq> PartialEq for EntityMap<A> {
 }
 impl<A: Eq> Eq for EntityMap<A> {}
 
-const BY_POS_INVARIANT: &'static str =
+const BY_POS_INVARIANT: &str =
     "Invariant: All references in EntityMap.by_position should point to existent references in by_id";
 
 impl<A> EntityMap<A> {
@@ -54,26 +54,26 @@ impl<A> EntityMap<A> {
 
     /// Remove all entities at the given position
     pub fn remove_all_at(&mut self, pos: Position) {
-        self.by_position.remove(&pos).map(|eids| {
+        if let Some(eids) = self.by_position.remove(&pos) {
             for eid in eids {
                 self.by_id.remove(&eid).expect(BY_POS_INVARIANT);
             }
-        });
+        }
     }
 
-    pub fn get<'a>(&'a self, id: EntityID) -> Option<&'a A> {
+    pub fn get(&self, id: EntityID) -> Option<&A> {
         self.by_id.get(&id)
     }
 
-    pub fn get_mut<'a>(&'a mut self, id: EntityID) -> Option<&'a mut A> {
+    pub fn get_mut(&mut self, id: EntityID) -> Option<&mut A> {
         self.by_id.get_mut(&id)
     }
 
-    pub fn entities<'a>(&'a self) -> impl Iterator<Item = &'a A> {
+    pub fn entities(&self) -> impl Iterator<Item = &A> {
         self.by_id.values()
     }
 
-    pub fn entities_mut<'a>(&'a mut self) -> impl Iterator<Item = &'a mut A> {
+    pub fn entities_mut(&mut self) -> impl Iterator<Item = &mut A> {
         self.by_id.values_mut()
     }
 
@@ -81,8 +81,8 @@ impl<A> EntityMap<A> {
         self.by_id.keys()
     }
 
-    pub fn drain<'a>(&'a mut self) -> Drain<'a, A> {
-        let ids = self.ids().map(|e| *e).collect::<Vec<_>>();
+    pub fn drain(&mut self) -> Drain<'_, A> {
+        let ids = self.ids().copied().collect::<Vec<_>>();
         Drain {
             map: self,
             ids_iter: Box::new(ids.into_iter()),
@@ -103,7 +103,7 @@ impl<A: Positioned + Identified<EntityID>> EntityMap<A> {
         self.by_id.entry(entity_id).or_insert(entity);
         self.by_position
             .entry(pos)
-            .or_insert(Vec::new())
+            .or_insert_with(Vec::new)
             .push(entity_id);
         entity_id
     }
@@ -113,12 +113,14 @@ impl<A: Positioned + Identified<EntityID>> EntityMap<A> {
         self.by_id.remove(&id).map(|e| {
             let mut empty = false;
             let position = e.position();
-            self.by_position.get_mut(&position).map(|es| {
+
+            if let Some(es) = self.by_position.get_mut(&position) {
                 es.retain(|e| *e != id);
-                if es.len() == 0 {
+                if es.is_empty() {
                     empty = true;
                 }
-            });
+            }
+
             if empty {
                 self.by_position.remove(&position);
             }
@@ -172,7 +174,7 @@ impl<'a, A: Positioned + Identified<EntityID>> IntoIterator
     type Item = (&'a EntityID, &'a A);
     type IntoIter = std::collections::hash_map::Iter<'a, EntityID, A>;
     fn into_iter(self) -> Self::IntoIter {
-        (&self.by_id).into_iter()
+        (&self.by_id).iter()
     }
 }
 
@@ -246,20 +248,21 @@ impl<A: PositionedMut> EntityMap<A> {
             old_pos = Some(entity.position());
             entity.set_position(new_position);
         }
-        old_pos.map(|p| {
-            self.by_position
-                .get_mut(&p)
-                .map(|es| es.retain(|e| *e != entity_id));
+
+        if let Some(p) = old_pos {
+            if let Some(es) = self.by_position.get_mut(&p) {
+                es.retain(|e| *e != entity_id);
+            }
 
             self.by_position
                 .entry(new_position)
-                .or_insert(Vec::new())
+                .or_insert_with(Vec::new)
                 .push(entity_id);
-        });
+        }
     }
 }
 
-pub struct Drain<'a, A: 'a> {
+pub struct Drain<'a, A> {
     map: &'a mut EntityMap<A>,
     ids_iter: Box<dyn Iterator<Item = EntityID> + 'a>,
 }
@@ -313,9 +316,7 @@ mod tests {
     fn gen_entity_map() -> BoxedStrategy<EntityMap<TestEntity>> {
         any::<Vec<TestEntity>>()
             .prop_map(|ents| {
-                ents.iter()
-                    .map(|e| e.clone())
-                    .collect::<EntityMap<TestEntity>>()
+                ents.iter().cloned().collect::<EntityMap<TestEntity>>()
             })
             .boxed()
     }
diff --git a/src/types/mod.rs b/src/types/mod.rs
index 21748bac9015..31d2ecd29770 100644
--- a/src/types/mod.rs
+++ b/src/types/mod.rs
@@ -427,6 +427,7 @@ impl<A> Neighbors<Vec<A>> {
 
 #[cfg(test)]
 mod tests {
+    #![allow(clippy::unnecessary_operation)]
     use super::*;
     use proptest::prelude::*;
 
diff --git a/src/util/promise.rs b/src/util/promise.rs
index 63fbca1ddc18..22f1e8b47f58 100644
--- a/src/util/promise.rs
+++ b/src/util/promise.rs
@@ -3,9 +3,11 @@ use std::pin::Pin;
 use std::sync::{Arc, RwLock};
 use std::task::{Context, Poll, Waker};
 
+type Waiter<Env, T> = Box<dyn Fn(&mut Env, &T)>;
+
 pub struct Promise<Env, T> {
     inner: Arc<RwLock<Inner<T>>>,
-    waiters: Arc<RwLock<Vec<Box<dyn Fn(&mut Env, &T)>>>>,
+    waiters: Arc<RwLock<Vec<Waiter<Env, T>>>>,
 }
 
 pub struct Complete<T> {
@@ -29,7 +31,7 @@ pub fn promise<Env, T>() -> (Complete<T>, Promise<Env, T>) {
         inner: inner.clone(),
         waiters: Arc::new(RwLock::new(Vec::new())),
     };
-    let complete = Complete { inner: inner };
+    let complete = Complete { inner };
     (complete, promise)
 }
 
@@ -127,7 +129,7 @@ impl<Env, P: Give<Env>> Give<Env> for &P {
 
 impl<Env, T> Future for Promise<Env, T> {
     type Output = Arc<T>;
-    fn poll(self: Pin<&mut Self>, cx: &mut Context) -> Poll<Self::Output> {
+    fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
         let mut inner = self.inner.write().unwrap();
         match inner.value {
             Some(ref v) => Poll::Ready(v.clone()),
diff --git a/src/util/template.rs b/src/util/template.rs
index a3faadc31c91..bb77f9b4d610 100644
--- a/src/util/template.rs
+++ b/src/util/template.rs
@@ -18,7 +18,7 @@ impl<'a> Path<'a> {
 }
 
 impl<'a> Display for Path<'a> {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         write!(f, "{}", self.head)?;
         for part in &self.tail {
             write!(f, ".{}", part)?;
@@ -96,7 +96,7 @@ impl<'a> TemplateVisitor<'a> {
 impl<'a> serde::de::Visitor<'a> for TemplateVisitor<'a> {
     type Value = Template<'a>;
 
-    fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
+    fn expecting(&self, formatter: &mut fmt::Formatter<'_>) -> fmt::Result {
         formatter.write_str("a valid template string")
     }
 
@@ -126,7 +126,7 @@ impl<'a> Template<'a> {
         input: &'a str,
     ) -> Result<Template<'a>, Err<(&'a str, ErrorKind)>> {
         let (remaining, res) = template(input)?;
-        if remaining.len() > 0 {
+        if !remaining.is_empty() {
             unreachable!();
         }
         Ok(res)
@@ -157,7 +157,7 @@ pub enum TemplateError<'a> {
 }
 
 impl<'a> Display for TemplateError<'a> {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         use TemplateError::*;
         match self {
             MissingParam(path) => {
@@ -179,7 +179,7 @@ impl<'a> TemplateParams<'a> {
         match self {
             Direct(_) => None,
             Nested(m) => m.get(path.head).and_then(|next| {
-                if path.tail.len() == 0 {
+                if path.tail.is_empty() {
                     match next {
                         Direct(s) => Some(*s),
                         _ => None,