Add PartialEq and Eq implementations for Span
diff --git a/src/lib.rs b/src/lib.rs
index d49af0c..1d9f0cf 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -153,7 +153,7 @@
     pub column: usize,
 }
 
-#[derive(Copy, Clone)]
+#[derive(Copy, Clone, PartialEq, Eq)]
 pub struct Span(imp::Span);
 
 impl Span {
diff --git a/src/stable.rs b/src/stable.rs
index 5421060..cb376a9 100644
--- a/src/stable.rs
+++ b/src/stable.rs
@@ -311,7 +311,7 @@
     }
 }
 
-#[derive(Clone, Copy, Debug)]
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
 pub struct Span {
     #[cfg(procmacro2_semver_exempt)]
     lo: u32,
diff --git a/src/unstable.rs b/src/unstable.rs
index 1a25083..6f97197 100644
--- a/src/unstable.rs
+++ b/src/unstable.rs
@@ -212,7 +212,7 @@
     pub column: usize,
 }
 
-#[derive(Copy, Clone)]
+#[derive(Copy, Clone, PartialEq, Eq)]
 pub struct Span(proc_macro::Span);
 
 impl From<proc_macro::Span> for ::Span {