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

arbitrary_self_types: add support for raw pointer self types #46664

Merged
merged 14 commits into from
Dec 19, 2017
Merged

arbitrary_self_types: add support for raw pointer self types #46664

Changes from 1 commit
Commits
Show all changes
14 commits
Select commit Hold shift + click to select a range
361b3db
implement raw-pointer `self`. Works for traits, including trait objec…
mikeyhew Nov 9, 2017
083635e
changed some stuff in probe.rs and it broke libstd
mikeyhew Nov 10, 2017
e7d1542
don't emit a type error if autoderef ends in an inference variable, a…
mikeyhew Nov 10, 2017
bff74fb
shorten lines for tidy
mikeyhew Dec 11, 2017
cb9f552
Add a feature_gate test for raw pointer self
mikeyhew Dec 11, 2017
8aac984
Fix ICE in probe::confirm::extract_existential_trait_ref with raw poi…
mikeyhew Dec 11, 2017
c5fc7c5
update error message in test/compile-fail/issue-26194.rs
mikeyhew Dec 11, 2017
428b025
remove test for issue #26194 because it is now redundant
mikeyhew Dec 11, 2017
bc0439b
Warn about inference variables behind raw pointers in method lookup
mikeyhew Dec 14, 2017
4cae2c0
Add tests with *const Rc<Self> and similar self types
mikeyhew Dec 14, 2017
0cc573a
better variable names in tests
mikeyhew Dec 14, 2017
63ce99c
add a ui test for the inference variable warning
mikeyhew Dec 14, 2017
23555b9
fix ui test
mikeyhew Dec 15, 2017
5c656f0
update ui/arbitrary-self-types-not-object-safe with shorter error mes…
mikeyhew Dec 17, 2017
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
Prev Previous commit
Next Next commit
don't emit a type error if autoderef ends in an inference variable, a… 
…s long as we went through a raw pointer

This avoids a break in backward compatibility in the following case:

```
let ptr = std::ptr::null();
let _ = &data as *const *const ();
if data.null() {}
```
  • Loading branch information
@mikeyhew
mikeyhew committed Dec 17, 2017
commit e7d1542a52dd04b58058d5d170a7a9b09f528f8c
10 changes: 7 additions & 3 deletions src/librustc_typeck/check/method/probe.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -321,9 +321,13 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
// a real method lookup, this is a hard error (it's an
// ambiguity and we can't make progress).
if !is_suggestion.0 {
let t = self.structurally_resolved_type(span, final_ty);
assert_eq!(t, self.tcx.types.err);
return None
// don't report a type error if we dereferenced a raw pointer,
Copy link
Contributor

@arielb1 arielb1 Dec 12, 2017 •
edited
Loading

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Is that really a problem in practice?

If then, I think we might want a warning cycle here. This looks like a sort of expected inference breakage, so it should remain an error.

Copy link
Contributor Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

It broke something in libstd:

rust/src/libstd/sys_common/gnu/libbacktrace.rs

Line 76 in 707d070

let mut data = ptr::null();

Here's a minimal reproduction:

fn main() {
    let data = std::ptr::null();
    let _ = &data as *const *const ();
    if data.is_null() {}
}

Copy link
Contributor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

I get that. I think we should probably make this a future-compat warning, or an error with the arbitrary_self_types feature flag set.

// because that would break backwards compatibility in certain cases
if !reached_raw_pointer {
let t = self.structurally_resolved_type(span, final_ty);
assert_eq!(t, self.tcx.types.err);
return None
}
} else {
// If we're just looking for suggestions,
// though, ambiguity is no big thing, we can
Expand Down