diff --git a/src/eval.rs b/src/eval.rs
index d737bfe..221ee63 100644
--- a/src/eval.rs
+++ b/src/eval.rs
@@ -11,7 +11,7 @@ use std::borrow::Cow;
 /// This represents one "frame" of evaluation context, a given EvalString may
 /// need multiple environments in order to be fully expanded.
 pub trait Env {
-    fn get_var(&self, var: &str) -> Option<EvalString<Cow<str>>>;
+    fn get_var(&self, var: &str) -> Option<EvalString<Cow<'_, str>>>;
 }
 
 /// One token within an EvalString, either literal text or a variable reference.
@@ -93,7 +93,7 @@ impl EvalString<&str> {
 }
 
 impl EvalString<String> {
-    pub fn as_cow(&self) -> EvalString<Cow<str>> {
+    pub fn as_cow(&self) -> EvalString<Cow<'_, str>> {
         EvalString(
             self.0
                 .iter()
@@ -107,7 +107,7 @@ impl EvalString<String> {
 }
 
 impl EvalString<&str> {
-    pub fn as_cow(&self) -> EvalString<Cow<str>> {
+    pub fn as_cow(&self) -> EvalString<Cow<'_, str>> {
         EvalString(
             self.0
                 .iter()
@@ -133,7 +133,7 @@ impl<'text> Vars<'text> {
     }
 }
 impl<'a> Env for Vars<'a> {
-    fn get_var(&self, var: &str) -> Option<EvalString<Cow<str>>> {
+    fn get_var(&self, var: &str) -> Option<EvalString<Cow<'_, str>>> {
         Some(EvalString::new(vec![EvalPart::Literal(
             std::borrow::Cow::Borrowed(self.get(var)?),
         )]))
@@ -141,19 +141,19 @@ impl<'a> Env for Vars<'a> {
 }
 
 impl<K: Borrow<str> + PartialEq> Env for SmallMap<K, EvalString<String>> {
-    fn get_var(&self, var: &str) -> Option<EvalString<Cow<str>>> {
+    fn get_var(&self, var: &str) -> Option<EvalString<Cow<'_, str>>> {
         Some(self.get(var)?.as_cow())
     }
 }
 
 impl<K: Borrow<str> + PartialEq> Env for SmallMap<K, EvalString<&str>> {
-    fn get_var(&self, var: &str) -> Option<EvalString<Cow<str>>> {
+    fn get_var(&self, var: &str) -> Option<EvalString<Cow<'_, str>>> {
         Some(self.get(var)?.as_cow())
     }
 }
 
 impl Env for SmallMap<&str, String> {
-    fn get_var(&self, var: &str) -> Option<EvalString<Cow<str>>> {
+    fn get_var(&self, var: &str) -> Option<EvalString<Cow<'_, str>>> {
         Some(EvalString::new(vec![EvalPart::Literal(
             std::borrow::Cow::Borrowed(self.get(var)?),
         )]))
diff --git a/src/load.rs b/src/load.rs
index 4624c51..4fc3845 100644
--- a/src/load.rs
+++ b/src/load.rs
@@ -33,7 +33,7 @@ impl<'a> BuildImplicitVars<'a> {
     }
 }
 impl<'a> eval::Env for BuildImplicitVars<'a> {
-    fn get_var(&self, var: &str) -> Option<EvalString<Cow<str>>> {
+    fn get_var(&self, var: &str) -> Option<EvalString<Cow<'_, str>>> {
         let string_to_evalstring =
             |s: String| Some(EvalString::new(vec![EvalPart::Literal(Cow::Owned(s))]));
         match var {
diff --git a/src/smallmap.rs b/src/smallmap.rs
index da8298c..0fe00a8 100644
--- a/src/smallmap.rs
+++ b/src/smallmap.rs
@@ -38,11 +38,11 @@ impl<K: PartialEq, V> SmallMap<K, V> {
         None
     }
 
-    pub fn iter(&self) -> std::slice::Iter<(K, V)> {
+    pub fn iter(&self) -> std::slice::Iter<'_, (K, V)> {
         self.0.iter()
     }
 
-    pub fn iter_mut(&mut self) -> std::slice::IterMut<(K, V)> {
+    pub fn iter_mut(&mut self) -> std::slice::IterMut<'_, (K, V)> {
         self.0.iter_mut()
     }
 
diff --git a/tests/e2e/basic.rs b/tests/e2e/basic.rs
index f652ab6..3c4ae0f 100644
--- a/tests/e2e/basic.rs
+++ b/tests/e2e/basic.rs
@@ -194,7 +194,7 @@ fn explain() -> anyhow::Result<()> {
     let out = space.run_expect(&mut n2_command(vec!["out"]))?;
     assert_output_contains(&out, "up to date");
 
-    space.write("in", "")?;
+    space.write("in", "x")?;
     let out = space.run_expect(&mut n2_command(vec!["-d", "explain", "out"]))?;
     // The main "explain" log line:
     assert_output_contains(&out, "explain: build.ninja:6: manifest changed");