Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Improve compile error from using Gen constructor incorrectly #170

Open
wants to merge 1 commit into
base: master
Choose a base branch
from
+12 −1
Open

Improve compile error from using Gen constructor incorrectly #170

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
13 changes: 12 additions & 1 deletion include/rapidcheck/Gen.hpp
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -1,5 +1,6 @@
#pragma once

#include <type_traits>
#include <cassert>

#include "rapidcheck/detail/Any.h"
Expand All @@ -17,6 +18,13 @@ Gen<Decay<typename std::result_of<Mapper(T)>::type>> map(Gen<T> gen,

} // namespace gen

// Concept check for types that have method
// `Shrinkable<T> G::operator()(const Random &, int) const`
template<typename T, typename G>
using MakesShrinkable = std::is_convertible<
decltype(std::declval<const G>()(std::declval<Random>(), 0)),
Shrinkable<T>>;

template <typename T>
class Gen<T>::IGenImpl {
public:
Expand Down Expand Up @@ -55,7 +63,10 @@ class Gen<T>::GenImpl : public IGenImpl {
template <typename T>
template <typename Impl, typename>
Gen<T>::Gen(Impl &&impl)
: m_impl(new GenImpl<Decay<Impl>>(std::forward<Impl>(impl))) {}
: m_impl(new GenImpl<Decay<Impl>>(std::forward<Impl>(impl))) {
static_assert(MakesShrinkable<T, Decay<Impl>>::value,
"Generator implementation must have a method Shrinkable<T> operator()(const Random &, int) const");
}

template <typename T>
std::string Gen<T>::name() const {
Expand Down