diff --git a/include/ftl/ArrayTraits.h b/include/ftl/ArrayTraits.h
new file mode 100644
index 0000000..28f717a
--- /dev/null
+++ b/include/ftl/ArrayTraits.h
@@ -0,0 +1,129 @@
+/*
+ * Copyright 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+#include <algorithm>
+#include <iterator>
+#include <new>
+
+#define FTL_ARRAY_TRAIT(T, U) using U = typename ArrayTraits<T>::U
+
+namespace android::ftl {
+
+template <typename T>
+struct ArrayTraits {
+    using value_type = T;
+    using size_type = size_t;
+    using difference_type = ptrdiff_t;
+
+    using pointer = value_type*;
+    using reference = value_type&;
+    using iterator = pointer;
+    using reverse_iterator = std::reverse_iterator<iterator>;
+
+    using const_pointer = const value_type*;
+    using const_reference = const value_type&;
+    using const_iterator = const_pointer;
+    using const_reverse_iterator = std::reverse_iterator<const_iterator>;
+
+    // TODO: Replace with std::construct_at in C++20.
+    template <typename... Args>
+    static pointer construct_at(const_iterator it, Args&&... args) {
+        void* const ptr = const_cast<void*>(static_cast<const void*>(it));
+        return new (ptr) value_type{std::forward<Args>(args)...};
+    }
+};
+
+// CRTP mixin to define iterator functions in terms of non-const Self::begin and Self::end.
+template <typename Self, typename T>
+class ArrayIterators {
+    FTL_ARRAY_TRAIT(T, size_type);
+
+    FTL_ARRAY_TRAIT(T, reference);
+    FTL_ARRAY_TRAIT(T, iterator);
+    FTL_ARRAY_TRAIT(T, reverse_iterator);
+
+    FTL_ARRAY_TRAIT(T, const_reference);
+    FTL_ARRAY_TRAIT(T, const_iterator);
+    FTL_ARRAY_TRAIT(T, const_reverse_iterator);
+
+    Self& self() const { return *const_cast<Self*>(static_cast<const Self*>(this)); }
+
+public:
+    const_iterator begin() const { return cbegin(); }
+    const_iterator cbegin() const { return self().begin(); }
+
+    const_iterator end() const { return cend(); }
+    const_iterator cend() const { return self().end(); }
+
+    reverse_iterator rbegin() { return std::make_reverse_iterator(self().end()); }
+    const_reverse_iterator rbegin() const { return crbegin(); }
+    const_reverse_iterator crbegin() const { return self().rbegin(); }
+
+    reverse_iterator rend() { return std::make_reverse_iterator(self().begin()); }
+    const_reverse_iterator rend() const { return crend(); }
+    const_reverse_iterator crend() const { return self().rend(); }
+
+    iterator last() { return self().end() - 1; }
+    const_iterator last() const { return self().last(); }
+
+    reference front() { return *self().begin(); }
+    const_reference front() const { return self().front(); }
+
+    reference back() { return *last(); }
+    const_reference back() const { return self().back(); }
+
+    reference operator[](size_type i) { return *(self().begin() + i); }
+    const_reference operator[](size_type i) const { return self()[i]; }
+};
+
+// Mixin to define comparison operators for an array-like template.
+// TODO: Replace with operator<=> in C++20.
+template <template <typename, size_t> class Array>
+struct ArrayComparators {
+    template <typename T, size_t N, size_t M>
+    friend bool operator==(const Array<T, N>& lhs, const Array<T, M>& rhs) {
+        return lhs.size() == rhs.size() && std::equal(lhs.begin(), lhs.end(), rhs.begin());
+    }
+
+    template <typename T, size_t N, size_t M>
+    friend bool operator<(const Array<T, N>& lhs, const Array<T, M>& rhs) {
+        return std::lexicographical_compare(lhs.begin(), lhs.end(), rhs.begin(), rhs.end());
+    }
+
+    template <typename T, size_t N, size_t M>
+    friend bool operator>(const Array<T, N>& lhs, const Array<T, M>& rhs) {
+        return rhs < lhs;
+    }
+
+    template <typename T, size_t N, size_t M>
+    friend bool operator!=(const Array<T, N>& lhs, const Array<T, M>& rhs) {
+        return !(lhs == rhs);
+    }
+
+    template <typename T, size_t N, size_t M>
+    friend bool operator>=(const Array<T, N>& lhs, const Array<T, M>& rhs) {
+        return !(lhs < rhs);
+    }
+
+    template <typename T, size_t N, size_t M>
+    friend bool operator<=(const Array<T, N>& lhs, const Array<T, M>& rhs) {
+        return !(lhs > rhs);
+    }
+};
+
+} // namespace android::ftl
diff --git a/include/ftl/SmallVector.h b/include/ftl/SmallVector.h
new file mode 100644
index 0000000..b632bb2
--- /dev/null
+++ b/include/ftl/SmallVector.h
@@ -0,0 +1,381 @@
+/*
+ * Copyright 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+#include <ftl/ArrayTraits.h>
+#include <ftl/StaticVector.h>
+
+#include <algorithm>
+#include <iterator>
+#include <type_traits>
+#include <utility>
+#include <variant>
+#include <vector>
+
+namespace android::ftl {
+
+template <typename>
+struct IsSmallVector;
+
+// ftl::StaticVector that promotes to std::vector when full. SmallVector is a drop-in replacement
+// for std::vector with statically allocated storage for N elements, whose goal is to improve run
+// time by avoiding heap allocation and increasing probability of cache hits. The standard API is
+// augmented by an unstable_erase operation that does not preserve order, and a replace operation
+// that destructively emplaces.
+//
+// SmallVector<T, 0> is a specialization that thinly wraps std::vector.
+//
+// Example usage:
+//
+//     ftl::SmallVector<char, 3> vector;
+//     assert(vector.empty());
+//     assert(!vector.dynamic());
+//
+//     vector = {'a', 'b', 'c'};
+//     assert(vector.size() == 3u);
+//     assert(!vector.dynamic());
+//
+//     vector.push_back('d');
+//     assert(vector.dynamic());
+//
+//     vector.unstable_erase(vector.begin());
+//     assert(vector == (ftl::SmallVector{'d', 'b', 'c'}));
+//
+//     vector.pop_back();
+//     assert(vector.back() == 'b');
+//     assert(vector.dynamic());
+//
+//     const char array[] = "hi";
+//     vector = ftl::SmallVector(array);
+//     assert(vector == (ftl::SmallVector{'h', 'i', '\0'}));
+//     assert(!vector.dynamic());
+//
+template <typename T, size_t N>
+class SmallVector final : ArrayTraits<T>, ArrayComparators<SmallVector> {
+    using Static = StaticVector<T, N>;
+    using Dynamic = SmallVector<T, 0>;
+
+    // TODO: Replace with std::remove_cvref_t in C++20.
+    template <typename U>
+    using remove_cvref_t = std::remove_cv_t<std::remove_reference_t<U>>;
+
+public:
+    FTL_ARRAY_TRAIT(T, value_type);
+    FTL_ARRAY_TRAIT(T, size_type);
+    FTL_ARRAY_TRAIT(T, difference_type);
+
+    FTL_ARRAY_TRAIT(T, pointer);
+    FTL_ARRAY_TRAIT(T, reference);
+    FTL_ARRAY_TRAIT(T, iterator);
+    FTL_ARRAY_TRAIT(T, reverse_iterator);
+
+    FTL_ARRAY_TRAIT(T, const_pointer);
+    FTL_ARRAY_TRAIT(T, const_reference);
+    FTL_ARRAY_TRAIT(T, const_iterator);
+    FTL_ARRAY_TRAIT(T, const_reverse_iterator);
+
+    // Creates an empty vector.
+    SmallVector() = default;
+
+    // Constructs at most N elements. See StaticVector for underlying constructors.
+    template <typename Arg, typename... Args,
+              typename = std::enable_if_t<!IsSmallVector<remove_cvref_t<Arg>>{}>>
+    SmallVector(Arg&& arg, Args&&... args)
+          : mVector(std::in_place_type<Static>, std::forward<Arg>(arg),
+                    std::forward<Args>(args)...) {}
+
+    // Copies at most N elements from a smaller convertible vector.
+    template <typename U, size_t M, typename = std::enable_if_t<M <= N>>
+    SmallVector(const SmallVector<U, M>& other)
+          : SmallVector(IteratorRange, other.begin(), other.end()) {}
+
+    void swap(SmallVector& other) { mVector.swap(other.mVector); }
+
+    // Returns whether the vector is backed by static or dynamic storage.
+    bool dynamic() const { return std::holds_alternative<Dynamic>(mVector); }
+
+#define VISITOR(T, F, ...)                                               \
+    T F() __VA_ARGS__ {                                                  \
+        return std::visit([](auto&& v) -> T { return v.F(); }, mVector); \
+    }
+
+    VISITOR(size_type, max_size, const)
+    VISITOR(size_type, size, const)
+    VISITOR(bool, empty, const)
+
+    // noexcept to suppress warning about zero variadic macro arguments.
+    VISITOR(iterator, begin, noexcept)
+    VISITOR(const_iterator, begin, const)
+    VISITOR(const_iterator, cbegin, const)
+
+    VISITOR(iterator, end, noexcept)
+    VISITOR(const_iterator, end, const)
+    VISITOR(const_iterator, cend, const)
+
+    VISITOR(reverse_iterator, rbegin, noexcept)
+    VISITOR(const_reverse_iterator, rbegin, const)
+    VISITOR(const_reverse_iterator, crbegin, const)
+
+    VISITOR(reverse_iterator, rend, noexcept)
+    VISITOR(const_reverse_iterator, rend, const)
+    VISITOR(const_reverse_iterator, crend, const)
+
+    VISITOR(iterator, last, noexcept)
+    VISITOR(const_iterator, last, const)
+
+    VISITOR(reference, front, noexcept)
+    VISITOR(const_reference, front, const)
+
+    VISITOR(reference, back, noexcept)
+    VISITOR(const_reference, back, const)
+
+#undef VISITOR
+
+    reference operator[](size_type i) {
+        return std::visit([i](auto& v) -> reference { return v[i]; }, mVector);
+    }
+
+    const_reference operator[](size_type i) const {
+        return std::visit([i](const auto& v) -> const_reference { return v[i]; }, mVector);
+    }
+
+    // Replaces an element, and returns a reference to it. The iterator must be dereferenceable, so
+    // replacing at end() is erroneous.
+    //
+    // The element is emplaced via move constructor, so type T does not need to define copy/move
+    // assignment, e.g. its data members may be const.
+    //
+    // The arguments may directly or indirectly refer to the element being replaced.
+    //
+    // Iterators to the replaced element point to its replacement, and others remain valid.
+    //
+    template <typename... Args>
+    reference replace(const_iterator it, Args&&... args) {
+        return std::
+                visit([it, &args...](auto& v)
+                              -> reference { return v.replace(it, std::forward<Args>(args)...); },
+                      mVector);
+    }
+
+    // Appends an element, and returns a reference to it.
+    //
+    // If the vector reaches its static or dynamic capacity, then all iterators are invalidated.
+    // Otherwise, only the end() iterator is invalidated.
+    //
+    template <typename... Args>
+    reference emplace_back(Args&&... args) {
+        constexpr auto insertStatic = &Static::template emplace_back<Args...>;
+        constexpr auto insertDynamic = &Dynamic::template emplace_back<Args...>;
+        return *insert<insertStatic, insertDynamic>(std::forward<Args>(args)...);
+    }
+
+    // Appends an element.
+    //
+    // If the vector reaches its static or dynamic capacity, then all iterators are invalidated.
+    // Otherwise, only the end() iterator is invalidated.
+    //
+    void push_back(const value_type& v) {
+        constexpr auto insertStatic =
+                static_cast<bool (Static::*)(const value_type&)>(&Static::push_back);
+        constexpr auto insertDynamic =
+                static_cast<bool (Dynamic::*)(const value_type&)>(&Dynamic::push_back);
+        insert<insertStatic, insertDynamic>(v);
+    }
+
+    void push_back(value_type&& v) {
+        constexpr auto insertStatic =
+                static_cast<bool (Static::*)(value_type&&)>(&Static::push_back);
+        constexpr auto insertDynamic =
+                static_cast<bool (Dynamic::*)(value_type&&)>(&Dynamic::push_back);
+        insert<insertStatic, insertDynamic>(std::move(v));
+    }
+
+    // Removes the last element. The vector must not be empty, or the call is erroneous.
+    //
+    // The last() and end() iterators are invalidated.
+    //
+    void pop_back() {
+        std::visit([](auto& v) { v.pop_back(); }, mVector);
+    }
+
+    // Erases an element, but does not preserve order. Rather than shifting subsequent elements,
+    // this moves the last element to the slot of the erased element.
+    //
+    // The last() and end() iterators, as well as those to the erased element, are invalidated.
+    //
+    void unstable_erase(iterator it) {
+        std::visit([it](auto& v) { v.unstable_erase(it); }, mVector);
+    }
+
+private:
+    template <typename... Vs>
+    struct Visitor : Vs... {};
+
+    // TODO: Remove this deduction guide in C++20.
+    template <typename... Vs>
+    Visitor(Vs...) -> Visitor<Vs...>;
+
+    template <auto insertStatic, auto insertDynamic, typename... Args>
+    auto insert(Args&&... args) {
+        return std::visit(Visitor{[this, &args...](Static& vector) {
+                                      if (vector.full()) {
+                                          return (promote(vector).*
+                                                  insertDynamic)(std::forward<Args>(args)...);
+                                      }
+
+                                      return (vector.*insertStatic)(std::forward<Args>(args)...);
+                                  },
+                                  [&args...](Dynamic& vector) {
+                                      return (vector.*insertDynamic)(std::forward<Args>(args)...);
+                                  }},
+                          mVector);
+    }
+
+    Dynamic& promote(Static& staticVector) {
+        assert(staticVector.full());
+
+        // Allocate double capacity to reduce probability of reallocation.
+        Dynamic vector;
+        vector.reserve(Static::max_size() * 2);
+        std::move(staticVector.begin(), staticVector.end(), std::back_inserter(vector));
+
+        return mVector.template emplace<Dynamic>(std::move(vector));
+    }
+
+    std::variant<Static, Dynamic> mVector;
+};
+
+// Partial specialization without static storage.
+template <typename T>
+class SmallVector<T, 0> final : ArrayTraits<T>,
+                                ArrayIterators<SmallVector<T, 0>, T>,
+                                std::vector<T> {
+    using ArrayTraits<T>::construct_at;
+
+    using Iter = ArrayIterators<SmallVector, T>;
+    using Impl = std::vector<T>;
+
+    friend Iter;
+
+public:
+    FTL_ARRAY_TRAIT(T, value_type);
+    FTL_ARRAY_TRAIT(T, size_type);
+    FTL_ARRAY_TRAIT(T, difference_type);
+
+    FTL_ARRAY_TRAIT(T, pointer);
+    FTL_ARRAY_TRAIT(T, reference);
+    FTL_ARRAY_TRAIT(T, iterator);
+    FTL_ARRAY_TRAIT(T, reverse_iterator);
+
+    FTL_ARRAY_TRAIT(T, const_pointer);
+    FTL_ARRAY_TRAIT(T, const_reference);
+    FTL_ARRAY_TRAIT(T, const_iterator);
+    FTL_ARRAY_TRAIT(T, const_reverse_iterator);
+
+    using Impl::Impl;
+
+    using Impl::empty;
+    using Impl::max_size;
+    using Impl::size;
+
+    using Impl::reserve;
+
+    // std::vector iterators are not necessarily raw pointers.
+    iterator begin() { return Impl::data(); }
+    iterator end() { return Impl::data() + size(); }
+
+    using Iter::begin;
+    using Iter::end;
+
+    using Iter::cbegin;
+    using Iter::cend;
+
+    using Iter::rbegin;
+    using Iter::rend;
+
+    using Iter::crbegin;
+    using Iter::crend;
+
+    using Iter::last;
+
+    using Iter::back;
+    using Iter::front;
+
+    using Iter::operator[];
+
+    template <typename... Args>
+    reference replace(const_iterator it, Args&&... args) {
+        value_type element{std::forward<Args>(args)...};
+        std::destroy_at(it);
+        // This is only safe because exceptions are disabled.
+        return *construct_at(it, std::move(element));
+    }
+
+    template <typename... Args>
+    iterator emplace_back(Args&&... args) {
+        return &Impl::emplace_back(std::forward<Args>(args)...);
+    }
+
+    bool push_back(const value_type& v) {
+        Impl::push_back(v);
+        return true;
+    }
+
+    bool push_back(value_type&& v) {
+        Impl::push_back(std::move(v));
+        return true;
+    }
+
+    using Impl::pop_back;
+
+    void unstable_erase(iterator it) {
+        if (it != last()) std::iter_swap(it, last());
+        pop_back();
+    }
+
+    void swap(SmallVector& other) { Impl::swap(other); }
+};
+
+template <typename>
+struct IsSmallVector : std::false_type {};
+
+template <typename T, size_t N>
+struct IsSmallVector<SmallVector<T, N>> : std::true_type {};
+
+// Deduction guide for array constructor.
+template <typename T, size_t N>
+SmallVector(T (&)[N]) -> SmallVector<std::remove_cv_t<T>, N>;
+
+// Deduction guide for variadic constructor.
+template <typename T, typename... Us, typename V = std::decay_t<T>,
+          typename = std::enable_if_t<(std::is_constructible_v<V, Us> && ...)>>
+SmallVector(T&&, Us&&...) -> SmallVector<V, 1 + sizeof...(Us)>;
+
+// Deduction guide for in-place constructor.
+template <typename T, typename... Us>
+SmallVector(std::in_place_type_t<T>, Us&&...) -> SmallVector<T, sizeof...(Us)>;
+
+// Deduction guide for StaticVector conversion.
+template <typename T, size_t N>
+SmallVector(StaticVector<T, N>&&) -> SmallVector<T, N>;
+
+template <typename T, size_t N>
+inline void swap(SmallVector<T, N>& lhs, SmallVector<T, N>& rhs) {
+    lhs.swap(rhs);
+}
+
+} // namespace android::ftl
diff --git a/include/ftl/StaticVector.h b/include/ftl/StaticVector.h
index c0cdd11..457095d 100644
--- a/include/ftl/StaticVector.h
+++ b/include/ftl/StaticVector.h
@@ -16,11 +16,12 @@
 
 #pragma once
 
+#include <ftl/ArrayTraits.h>
+
 #include <algorithm>
 #include <cassert>
 #include <iterator>
 #include <memory>
-#include <new>
 #include <type_traits>
 #include <utility>
 
@@ -63,9 +64,16 @@
 //     assert(vector == (ftl::StaticVector{'h', 'i', '\0'}));
 //
 template <typename T, size_t N>
-class StaticVector final {
+class StaticVector final : ArrayTraits<T>,
+                           ArrayIterators<StaticVector<T, N>, T>,
+                           ArrayComparators<StaticVector> {
     static_assert(N > 0);
 
+    using ArrayTraits<T>::construct_at;
+
+    using Iter = ArrayIterators<StaticVector, T>;
+    friend Iter;
+
     // There is ambiguity when constructing from two iterator-like elements like pointers:
     // they could be an iterator range, or arguments for in-place construction. Assume the
     // latter unless they are input iterators and cannot be used to construct elements. If
@@ -76,19 +84,19 @@
             std::negation<std::is_constructible<T, I>>>;
 
 public:
-    using value_type = T;
-    using size_type = size_t;
-    using difference_type = ptrdiff_t;
+    FTL_ARRAY_TRAIT(T, value_type);
+    FTL_ARRAY_TRAIT(T, size_type);
+    FTL_ARRAY_TRAIT(T, difference_type);
 
-    using pointer = value_type*;
-    using reference = value_type&;
-    using iterator = pointer;
-    using reverse_iterator = std::reverse_iterator<iterator>;
+    FTL_ARRAY_TRAIT(T, pointer);
+    FTL_ARRAY_TRAIT(T, reference);
+    FTL_ARRAY_TRAIT(T, iterator);
+    FTL_ARRAY_TRAIT(T, reverse_iterator);
 
-    using const_pointer = const value_type*;
-    using const_reference = const value_type&;
-    using const_iterator = const_pointer;
-    using const_reverse_iterator = std::reverse_iterator<const_iterator>;
+    FTL_ARRAY_TRAIT(T, const_pointer);
+    FTL_ARRAY_TRAIT(T, const_reference);
+    FTL_ARRAY_TRAIT(T, const_iterator);
+    FTL_ARRAY_TRAIT(T, const_reverse_iterator);
 
     // Creates an empty vector.
     StaticVector() = default;
@@ -180,32 +188,26 @@
     bool full() const { return size() == max_size(); }
 
     iterator begin() { return std::launder(reinterpret_cast<pointer>(mData)); }
-    const_iterator begin() const { return cbegin(); }
-    const_iterator cbegin() const { return mut().begin(); }
-
     iterator end() { return begin() + size(); }
-    const_iterator end() const { return cend(); }
-    const_iterator cend() const { return mut().end(); }
 
-    reverse_iterator rbegin() { return std::make_reverse_iterator(end()); }
-    const_reverse_iterator rbegin() const { return crbegin(); }
-    const_reverse_iterator crbegin() const { return mut().rbegin(); }
+    using Iter::begin;
+    using Iter::end;
 
-    reverse_iterator rend() { return std::make_reverse_iterator(begin()); }
-    const_reverse_iterator rend() const { return crend(); }
-    const_reverse_iterator crend() const { return mut().rend(); }
+    using Iter::cbegin;
+    using Iter::cend;
 
-    iterator last() { return end() - 1; }
-    const_iterator last() const { return mut().last(); }
+    using Iter::rbegin;
+    using Iter::rend;
 
-    reference front() { return *begin(); }
-    const_reference front() const { return mut().front(); }
+    using Iter::crbegin;
+    using Iter::crend;
 
-    reference back() { return *last(); }
-    const_reference back() const { return mut().back(); }
+    using Iter::last;
 
-    reference operator[](size_type i) { return *(begin() + i); }
-    const_reference operator[](size_type i) const { return mut()[i]; }
+    using Iter::back;
+    using Iter::front;
+
+    using Iter::operator[];
 
     // Replaces an element, and returns a reference to it. The iterator must be dereferenceable, so
     // replacing at end() is erroneous.
@@ -242,7 +244,13 @@
     //
     // On success, the end() iterator is invalidated.
     //
-    bool push_back(value_type v) {
+    bool push_back(const value_type& v) {
+        // Two statements for sequence point.
+        const iterator it = emplace_back(v);
+        return it != end();
+    }
+
+    bool push_back(value_type&& v) {
         // Two statements for sequence point.
         const iterator it = emplace_back(std::move(v));
         return it != end();
@@ -273,8 +281,6 @@
 private:
     struct Empty {};
 
-    StaticVector& mut() const { return *const_cast<StaticVector*>(this); }
-
     // Recursion for variadic constructor.
     template <size_t I, typename E, typename... Es>
     StaticVector(std::index_sequence<I>, E&& element, Es&&... elements)
@@ -286,13 +292,6 @@
     template <size_t I>
     explicit StaticVector(std::index_sequence<I>) : mSize(I) {}
 
-    // TODO: Replace with std::construct_at in C++20.
-    template <typename... Args>
-    static pointer construct_at(const_iterator it, Args&&... args) {
-        void* const ptr = const_cast<void*>(static_cast<const void*>(it));
-        return new (ptr) value_type{std::forward<Args>(args)...};
-    }
-
     size_type mSize = 0;
     std::aligned_storage_t<sizeof(value_type), alignof(value_type)> mData[N];
 };
@@ -348,35 +347,4 @@
     lhs.swap(rhs);
 }
 
-// TODO: Replace with operator<=> in C++20.
-template <typename T, size_t N, size_t M>
-inline bool operator==(const StaticVector<T, N>& lhs, const StaticVector<T, M>& rhs) {
-    return lhs.size() == rhs.size() && std::equal(lhs.begin(), lhs.end(), rhs.begin());
-}
-
-template <typename T, size_t N, size_t M>
-inline bool operator<(const StaticVector<T, N>& lhs, const StaticVector<T, M>& rhs) {
-    return std::lexicographical_compare(lhs.begin(), lhs.end(), rhs.begin(), rhs.end());
-}
-
-template <typename T, size_t N, size_t M>
-inline bool operator>(const StaticVector<T, N>& lhs, const StaticVector<T, M>& rhs) {
-    return rhs < lhs;
-}
-
-template <typename T, size_t N, size_t M>
-inline bool operator!=(const StaticVector<T, N>& lhs, const StaticVector<T, M>& rhs) {
-    return !(lhs == rhs);
-}
-
-template <typename T, size_t N, size_t M>
-inline bool operator>=(const StaticVector<T, N>& lhs, const StaticVector<T, M>& rhs) {
-    return !(lhs < rhs);
-}
-
-template <typename T, size_t N, size_t M>
-inline bool operator<=(const StaticVector<T, N>& lhs, const StaticVector<T, M>& rhs) {
-    return !(rhs < lhs);
-}
-
 } // namespace android::ftl