From 4de0d85abf050536ca844b879d341c014d47e9a9 Mon Sep 17 00:00:00 2001
From: Daira Hopwood <daira@jacaranda.org>
Date: Sat, 3 Sep 2022 16:41:30 +0100
Subject: [PATCH] The std::expected proposal has unnecessary instances of
 undefined behaviour for operator->, operator*, and error(). Make these into
 assertion failures (this still conforms to the proposal).

Signed-off-by: Daira Hopwood <daira@jacaranda.org>
---
 contrib/debian/copyright                      |  2 +-
 depends/packages/tl_expected.mk               |  5 ++
 .../remove-undefined-behaviour.diff           | 78 +++++++++++++++++++
 3 files changed, 84 insertions(+), 1 deletion(-)
 create mode 100644 depends/patches/tl_expected/remove-undefined-behaviour.diff

diff --git a/contrib/debian/copyright b/contrib/debian/copyright
index 9592b10e9..b82cf4330 100644
--- a/contrib/debian/copyright
+++ b/contrib/debian/copyright
@@ -161,7 +161,7 @@ Copyright: 2006 Nemanja Trifunovic
 License: Boost-Software-License-1.0
 
 Files: depends/sources/tl-expected-*.tar.gz
-Copyright: 2017-2021 Sy Brand <simonrbrand@gmail.com> (@TartanLlama)
+Copyright: 2017-2021 Sy Brand <simonrbrand@gmail.com> (@TartanLlama), 2022 The Zcash developers
 License: CC0-1.0
 Comment: Other contributors are Simon Truscott (@bobbleclank), Kévin Alexandre Boissonneault (@KABoissonneault),
  and Björn Fahller (@rollbear).
diff --git a/depends/packages/tl_expected.mk b/depends/packages/tl_expected.mk
index 700e1d108..9e378026c 100644
--- a/depends/packages/tl_expected.mk
+++ b/depends/packages/tl_expected.mk
@@ -4,6 +4,11 @@ $(package)_download_path=https://github.com/TartanLlama/expected/archive
 $(package)_download_file=96d547c03d2feab8db64c53c3744a9b4a7c8f2c5.tar.gz
 $(package)_file_name=tl-expected-1.0.1.tar.gz
 $(package)_sha256_hash=64901df1de9a5a3737b331d3e1de146fa6ffb997017368b322c08f45c51b90a7
+$(package)_patches=remove-undefined-behaviour.diff
+
+define $(package)_preprocess_cmds
+  patch -p1 < $($(package)_patch_dir)/remove-undefined-behaviour.diff
+endef
 
 define $(package)_stage_cmds
   mkdir $($(package)_staging_dir)$(host_prefix)/include && \
diff --git a/depends/patches/tl_expected/remove-undefined-behaviour.diff b/depends/patches/tl_expected/remove-undefined-behaviour.diff
new file mode 100644
index 000000000..84b60e0c5
--- /dev/null
+++ b/depends/patches/tl_expected/remove-undefined-behaviour.diff
@@ -0,0 +1,78 @@
+diff --recursive --unified tl-expected-1.0.1-orig/include/tl/expected.hpp tl-expected-1.0.1/include/tl/expected.hpp
+--- tl-expected-1.0.1-orig/include/tl/expected.hpp	2022-08-30 20:10:13.269489852 +0100
++++ tl-expected-1.0.1/include/tl/expected.hpp	2022-08-30 20:17:35.744258828 +0100
+@@ -24,6 +24,7 @@
+ #include <functional>
+ #include <type_traits>
+ #include <utility>
++#include <cassert>
+ 
+ #if defined(__EXCEPTIONS) || defined(_CPPUNWIND)
+ #define TL_EXPECTED_EXCEPTIONS_ENABLED
+@@ -1862,27 +1863,37 @@
+     }
+   }
+ 
+-  constexpr const T *operator->() const { return valptr(); }
+-  TL_EXPECTED_11_CONSTEXPR T *operator->() { return valptr(); }
++  constexpr const T *operator->() const {
++    assert(has_value());
++    return valptr();
++  }
++  TL_EXPECTED_11_CONSTEXPR T *operator->() {
++    assert(has_value());
++    return valptr();
++  }
+ 
+   template <class U = T,
+             detail::enable_if_t<!std::is_void<U>::value> * = nullptr>
+   constexpr const U &operator*() const & {
++    assert(has_value());
+     return val();
+   }
+   template <class U = T,
+             detail::enable_if_t<!std::is_void<U>::value> * = nullptr>
+   TL_EXPECTED_11_CONSTEXPR U &operator*() & {
++    assert(has_value());
+     return val();
+   }
+   template <class U = T,
+             detail::enable_if_t<!std::is_void<U>::value> * = nullptr>
+   constexpr const U &&operator*() const && {
++    assert(has_value());
+     return std::move(val());
+   }
+   template <class U = T,
+             detail::enable_if_t<!std::is_void<U>::value> * = nullptr>
+   TL_EXPECTED_11_CONSTEXPR U &&operator*() && {
++    assert(has_value());
+     return std::move(val());
+   }
+ 
+@@ -1918,10 +1929,22 @@
+     return std::move(val());
+   }
+ 
+-  constexpr const E &error() const & { return err().value(); }
+-  TL_EXPECTED_11_CONSTEXPR E &error() & { return err().value(); }
+-  constexpr const E &&error() const && { return std::move(err().value()); }
+-  TL_EXPECTED_11_CONSTEXPR E &&error() && { return std::move(err().value()); }
++  constexpr const E &error() const & {
++    assert(!has_value());
++    return err().value();
++  }
++  TL_EXPECTED_11_CONSTEXPR E &error() & {
++    assert(!has_value());
++    return err().value();
++  }
++  constexpr const E &&error() const && {
++    assert(!has_value());
++    return std::move(err().value());
++  }
++  TL_EXPECTED_11_CONSTEXPR E &&error() && {
++    assert(!has_value());
++    return std::move(err().value());
++  }
+ 
+   template <class U> constexpr T value_or(U &&v) const & {
+     static_assert(std::is_copy_constructible<T>::value &&