wf: check foreign fn decls for well-formedness #73323

davidtwco · 2020-06-13T18:58:57Z

Fixes #73252 and fixes #73253.

This PR extends current well-formedness checking to apply to foreign function declarations, re-using the existing machinery for regular functions. In doing this, later parts of the compiler (such as the improper_ctypes lint) can rely on being operations not failing as a result of invalid code which would normally be caught earlier.

rust-highfive · 2020-06-13T18:59:00Z

r? @ecstatic-morse

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lcnr · 2020-06-14T07:22:20Z

Does this also fix #73253?

If so, this is a breaking change (which we should still land IMO) and may require a crater run 😅

Even this PR doesn't change its output, can you still add this as a test?

pub trait Unsatisfied {}

#[repr(transparent)]
pub struct Foo<T: Unsatisfied>(T);

extern "C" {
    pub fn foo() -> Foo<u32>;
}

davidtwco · 2020-06-14T12:59:13Z

Does this also fix #73253?

Even this PR doesn't change its output, can you still add this as a test?
pub trait Unsatisfied {}

#[repr(transparent)]
pub struct Foo<T: Unsatisfied>(T);

extern "C" {
    pub fn foo() -> Foo<u32>;
}

This also fixes #73253, I've added that to the test.

If so, this is a breaking change (which we should still land IMO) and may require a crater run 😅

Probably, I'll wait to see what the reviewer thinks - not entirely sure what the protocol is here.

lcnr

impl looks good 👍 requires crater run IMO

jonas-schievink · 2020-06-25T11:36:13Z

@bors try

Crater seems borked at the moment, but we can prepare a build.

bors · 2020-06-25T11:36:29Z

⌛ Trying commit 9fc57fb950edf74e880a1348a2860f41d481def1 with merge aef0c51c752d86410f02b64fbda721f083f33c39...

bors · 2020-06-25T14:01:41Z

☀️ Try build successful - checks-azure
Build commit: aef0c51c752d86410f02b64fbda721f083f33c39 (aef0c51c752d86410f02b64fbda721f083f33c39)

ecstatic-morse · 2020-06-25T17:31:15Z

Sorry. I seem to have missed this one. The implementation looks good, and it seems like something that we clearly want to do. I would be surprised if this broke real code, but I feel a bit uncomfortable approving unilaterally since the possibility exists. @rust-lang/compiler, does anyone object to this PR? Otherwise, r=me if there are no crater regressions.

estebank · 2020-06-25T19:15:19Z

Code looks good and this is a clear fix of invalid code, but having tried something similar out for types, there is a possibility of fallout in crater run. If we find that that is the case for this as well, could we phase this in as a lint then?

nikomatsakis · 2020-06-26T20:11:35Z

Definitely do a crater run. We should be able to manage a future-compatibility warning. We may want to do it anyway, but a crater run is a good first step.

davidtwco · 2020-07-08T11:52:33Z

Rebased this to make sure it was still working - will do a try build then crater run.

@bors try

bors · 2020-07-08T11:52:46Z

⌛ Trying commit 822fe7f00cc35bdaae86add5fe18de20631a2cfd with merge 85cc1486e1f000dce4bb8e1b3cfab2b654b102a8...

bors · 2020-07-08T14:34:28Z

☀️ Try build successful - checks-actions, checks-azure
Build commit: 85cc1486e1f000dce4bb8e1b3cfab2b654b102a8 (85cc1486e1f000dce4bb8e1b3cfab2b654b102a8)

davidtwco · 2020-07-08T14:35:17Z

@craterbot check

craterbot · 2020-07-08T14:35:29Z

👌 Experiment pr-73323 created and queued.
🤖 Automatically detected try build 85cc1486e1f000dce4bb8e1b3cfab2b654b102a8
🔍 You can check out the queue and this experiment's details.

ℹ️ Crater is a tool to run experiments across parts of the Rust ecosystem. Learn more

craterbot · 2020-07-14T21:17:04Z

🚧 Experiment pr-73323 is now running

ℹ️ Crater is a tool to run experiments across parts of the Rust ecosystem. Learn more

craterbot · 2020-07-19T00:45:09Z

🎉 Experiment pr-73323 is completed!
📊 7 regressed and 10 fixed (112019 total)
📰 Open the full report.

⚠️ If you notice any spurious failure please add them to the blacklist!
ℹ️ Crater is a tool to run experiments across parts of the Rust ecosystem. Learn more

lcnr · 2020-07-19T07:37:32Z

It looks like all regressions are spurious to me.

This commit extends current well-formedness checking to apply to foreign function declarations, re-using the existing machinery for regular functions. In doing this, later parts of the compiler (such as the `improper_ctypes` lint) can rely on being operations not failing as a result of invalid code which would normally be caught earlier. Signed-off-by: David Wood <david@davidtw.co>

davidtwco · 2020-07-20T09:54:16Z

Rebased this PR; I agree with @lcnr that the crater report looks good, so I'll r=ecstatic-morse after CI passes.

davidtwco · 2020-07-20T11:56:39Z

@bors r=ecstatic-morse

bors · 2020-07-20T11:56:41Z

📌 Commit ceac273 has been approved by ecstatic-morse

@ghost

…arth Rollup of 13 pull requests Successful merges: - rust-lang#72714 (Fix debug assertion in typeck) - rust-lang#73197 (Impl Default for ranges) - rust-lang#73323 (wf: check foreign fn decls for well-formedness) - rust-lang#74051 (disallow non-static lifetimes in const generics) - rust-lang#74376 (test caching opt_const_param_of on disc) - rust-lang#74501 (Ayu theme: Use different background color for Run button) - rust-lang#74505 (Fix search input focus in ayu theme) - rust-lang#74522 (Update sanitizer docs) - rust-lang#74546 (Fix duplicate maybe_uninit_extra attribute) - rust-lang#74552 (Stabilize TAU constant.) - rust-lang#74555 (Improve "important traits" popup display on mobile) - rust-lang#74557 (Fix an ICE on an invalid `binding @ ...` in a tuple struct pattern) - rust-lang#74561 (update backtrace-rs) Failed merges: r? @ghost

rust-highfive assigned ecstatic-morse Jun 13, 2020

rust-highfive added the S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. label Jun 13, 2020

davidtwco force-pushed the issue-73252-wfcheck-foreign-fn-decl branch from c83d10f to 9fc57fb Compare June 14, 2020 12:57

lcnr approved these changes Jun 25, 2020

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davidtwco force-pushed the issue-73252-wfcheck-foreign-fn-decl branch from 9fc57fb to 822fe7f Compare July 8, 2020 11:52

craterbot added S-waiting-on-crater Status: Waiting on a crater run to be completed. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Jul 8, 2020

craterbot added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. and removed S-waiting-on-crater Status: Waiting on a crater run to be completed. labels Jul 19, 2020

davidtwco force-pushed the issue-73252-wfcheck-foreign-fn-decl branch from 822fe7f to ceac273 Compare July 20, 2020 09:53

bors added S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Jul 20, 2020

Manishearth mentioned this pull request Jul 20, 2020

Rollup of 13 pull requests #74569

Merged

bors merged commit 0897bc2 into rust-lang:master Jul 21, 2020

davidtwco deleted the issue-73252-wfcheck-foreign-fn-decl branch July 21, 2020 09:21

dtolnay mentioned this pull request Dec 29, 2020

ICE in rustc_infer error reporting on elided lifetime in extern signature #80468

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cuviper added this to the 1.47.0 milestone May 2, 2024

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wf: check foreign fn decls for well-formedness #73323

wf: check foreign fn decls for well-formedness #73323

davidtwco commented Jun 13, 2020 •

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wf: check foreign fn decls for well-formedness #73323

wf: check foreign fn decls for well-formedness #73323

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