This is done in two steps:
First, we make foreign functions not consider modes at all. This is because previously ++ mode was the only way to pass structs to foreign functions and so forth. We also add a lint mode warning if you use `&&` mode in a foreign function, since the semantics of that change (it used to pass a pointer to the C function, now it doesn't).
Then, we remove by value and make it equivalent to `+` mode. At the same time, we stop parsing `-` mode and convert all uses of it to `+` mode (it was already being parsed to `+` mode anyhow).
This obsoletes pull request #5298.
r? @brson
adjusting a few foreign functions that were declared with by-ref
mode. This also allows us to remove by-val mode in the near future.
With copy mode, though, we have to be careful because Rust will implicitly pass
somethings by pointer but this may not be the C ABI rules. For example, rust
will pass a struct Foo as a Foo*. So I added some code into the adapters to
fix this (though the C ABI rules may put the pointer back, oh well).
This patch also includes a lint mode for the use of by-ref mode
in foreign functions as the semantics of this have changed.
Continuing #5140
For the sake of getting this merged I've disabled debuginfo tests on mac (where running gdb needs root). Please feel free to follow up with further improvements.
r? @graydon
This removes `log` from the language. Because we can't quite implement it as a syntax extension (probably need globals at the least) it simply renames the keyword to `__log` and hides it behind macros.
After this the only way to log is with `debug!`, `info!`, etc. I figure that if there is demand for `log!` we can add it back later.
I am not sure that we ever agreed on this course of action, though I *think* there is consensus that `log` shouldn't be a statement.
These changes make const translation use adjustments (autodereference, autoreference, bare-fn-to-closure), like normal code does, replacing some ad-hoc logic that wasn't always right.
As a convenient side-effect, explicit dereference (both of pointers and of newtypes) is also supported in const expressions.
There is also a “bonus fix” for a bug in the pretty-printer exposed by one of the added tests.
Struct and enum representations have some complicatedness that's no longer needed. Now that everything's in one place and has access to anything we'd want to know about the type, flatten some of that out. Slight changes to representations in some cases.
The only thing we really lose is that C-like enums with one variant and a
non-zero discriminant now take up space, but I do not think this is a
common usage. As previously noted, that was mostly there for
transitional compatibility with the pre-adt.rs codebase.
Out goes the extra layer of struct wrapping; the destructedness flag is
added to the end of the struct. This means that, if the struct
previously had alignment padding at the end, the flag will live there
instead of increasing the struct size.
Changes the ad-hoc closure adjustment into using adjustment info instead
of being separately driven from types, and likewise for autoderef.
Also takes care of autoref (the cases we should be seeing in consts,
at least, since we can't be doing method calls which would need the
ref-to-vec mode), which didn't quite work right previously.
However, "dereference" of a newtype isn't handled yet....
