diff --git a/src/cancellable.h b/src/cancellable.h
deleted file mode 100644
index 5cd03f510..000000000
--- a/src/cancellable.h
+++ /dev/null
@@ -1,53 +0,0 @@
-#ifndef FISH_CANCELLABLE_H
-#define FISH_CANCELLABLE_H
-
-#include "maybe.h"
-
-/// A simple value type representing cancellation via a signal.
-struct cancellation_t {
-    int signal;
-
-    explicit cancellation_t(int sig) : signal(sig) {}
-};
-
-/// A cancellable_t<T> is a wrapper around T which may be cancelled, for example by a signal.
-template <typename T>
-class cancellable_t : private maybe_t<T> {
-    using super = maybe_t<T>;
-
-   public:
-    /// Construct from a T.
-    /* implicit */ cancellable_t(T &&v) : super(v) {}
-    /* implicit */ cancellable_t(const T &v) : super(v) {}
-
-    /// Construct from a cancellation.
-    /* implicit */ cancellable_t(cancellation_t c) : super(none()), signal_(c.signal) {}
-
-    cancellable_t(const cancellable_t &) = default;
-    cancellable_t(cancellable_t &&) = default;
-
-    /// Access the cancellation signal, if this was cancelled.
-    int signal() const {
-        assert(!has_value() && "Not cancelled");
-        return signal_;
-    }
-
-    /// \return whether this was cancelled.
-    bool is_cancelled() const { return !has_value(); }
-
-    // Expose maybe_t<T>::value and dereferencing.
-    using super::has_value;
-    using super::value;
-    using super::operator->;
-    using super::operator*;
-
-    /// Notice we don't compare signals when checking for equality.
-    bool operator==(const cancellable_t &rhs) const { super::operator==(rhs); }
-    bool operator!=(const cancellable_t &rhs) const { super::operator!=(rhs); }
-
-   private:
-    // The cancellation signal.
-    int signal_{0};
-};
-
-#endif