Naming class member variables the same as constructor arguments is a very
slippery slope because of how member variable names get resolved. Compiler
is not very helpful here and we need static analysis to forbid this kind of
stuff.
The following example illustrates the cause quite well:
```cpp
struct B {
B(int) {}
};
struct A {
A(int b): b([&](){
return b;
static_assert(std::is_same_v<decltype(b), int>);
}()) {
static_assert(std::is_same_v<decltype(b), int>);
}
void member() {
static_assert(std::is_same_v<decltype(b), B>);
}
B b;
};
int main() {
A(1).member();
}
```
From N4861 6.5.1 Unqualified name lookup:
> In all the cases listed in [basic.lookup.unqual], the scopes are searched
> for a declaration in the order listed in each of the respective categories;
> name lookup ends as soon as a declaration is found for the name.
> If no declaration is found, the program is ill-formed.
In the affected code there was a use-after-move for all accesses in the constructor
body, but this UB wasn't triggered.
These types of errors are trivial to catch via clang-tidy's [clang-analyzer-cplusplus.Move].
This was broken since a03bb4455c because
Nix 2.18 does not support broken $SHELL settings. So don't try a
broken $SHELL on old Nix versions. (It's a mystery though why
tests.remoteBuilds_local_nix_2_13 and tests.remoteBuilds_local_nix_2_3
didn't fail...)
https://hydra.nixos.org/build/277366807
This may occur when stderr is a tty but stdin is empty.
E.g.
$ nix build </dev/null
error: unexpected EOF reading a line
These stdio handles are how some non-interactive sandboxes behave,
including the Nix build sandbox and Hercules CI Effects.
Unfortunately `StringSource` class is very easy was very easy to misuse
because the ctor took a plain `std::string_view` which has a bad habit
of being implicitly convertible from an rvalue `std::string`. This lead
to unintentional use-after-free bugs.
This patch makes `StringSource` much harder to misuse by disabling the ctor
from a `std::string &&` (but `const std::string &` is ok).
Fix affected tests from libstore-tests.
Reformat those tests with clangd's range formatting since the diff is tiny
and it seems appropriate.
It had gotten rather big. Hopefully we'll eventually have some generic
infra for a "multi-package dev shell" and not need so much code for
this, but until then it's better in a separate file.
