Skip to content

fix misleading type annotation diagonstics - #69456

Merged
bors merged 1 commit into
rust-lang:masterfrom
contrun:fix-misleading-compiler-error
Apr 25, 2020
Merged

fix misleading type annotation diagonstics#69456
bors merged 1 commit into
rust-lang:masterfrom
contrun:fix-misleading-compiler-error

Conversation

@contrun

@contruncontrun commented Feb 25, 2020

Copy link
Copy Markdown
Contributor

This solves the method call part of issue #69455

@rust-highfive

This comment has been minimized.

Sign in to view
@rust-highfiverust-highfive added the S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. label Feb 25, 2020
@LeSeulArtichaut

LeSeulArtichaut commented Feb 25, 2020

Copy link
Copy Markdown
Contributor

You may want to add a regression test for this. See the rustc book.

@rust-highfive

This comment has been minimized.

Sign in to view
@contrun
contrunforce-pushed the fix-misleading-compiler-error branch 5 times, most recently from 744fb23 to 6153629CompareFebruary 26, 2020 00:25
@rust-highfive

This comment has been minimized.

Sign in to view
@bors

This comment has been minimized.

Sign in to view
@contrun
contrunforce-pushed the fix-misleading-compiler-error branch from 6153629 to 6d7e5e2CompareMarch 14, 2020 05:49
@contruncontrun mentioned this pull request Mar 21, 2020
Closed
@JohnCSimonJohnCSimon added S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Mar 28, 2020
@JohnCSimon

JohnCSimon commented Apr 6, 2020

Copy link
Copy Markdown

Ping from triage:
@contrun any updates on this?

@contrun

contrun commented Apr 6, 2020

Copy link
Copy Markdown
ContributorAuthor

@JohnCSimon As I explained in #69455 (comment), the problem is that my PR will eliminate some relevant error message in some cases. The current error messages obviously more informative. I can push a new commit to resolve the conflict and use --bless to change the error message to accommodate my PR. But I don't know if that is desirable.

@contrun
contrunforce-pushed the fix-misleading-compiler-error branch from 6d7e5e2 to 25ec438CompareApril 6, 2020 15:28
@rust-highfive

This comment has been minimized.

Sign in to view
@cramertj

cramertj commented Apr 6, 2020

Copy link
Copy Markdown
Member

Yes, if you could --bless the output so that we can see what the changes are easily, that would be helpful!

@bors

This comment has been minimized.

Sign in to view
@contrun
contrunforce-pushed the fix-misleading-compiler-error branch from ccbb4e1 to 88c45cfCompareApril 8, 2020 02:42
@contrun
fix misleading type annotation diagonstics
3ae974f
This solves the method call part of issue
rust-lang#69455
I added a `target_span` field so as to pin down the exact location of
the error. We need a dedicated field `found_exact_method_call` to
prioritize situations like the test case `issue-69455.rs`. If we reuse
`found_method_call`, `found_local_pattern` will show up first. We can
not move `found_method_call` up, it is undesirable in various
situations.
@contrun
contrunforce-pushed the fix-misleading-compiler-error branch from 88c45cf to 3ae974fCompareApril 8, 2020 03:53
@contrun

contrun commented Apr 8, 2020

Copy link
Copy Markdown
ContributorAuthor

@cramertj It is now ready for review. I added two field in the original struct. They are needed because I can not find any way to it without affecting existing error messages.

I added a target_span field so as to pin down the exact location of
the error. We need a dedicated field found_exact_method_call to
prioritize situations like the test case #69455. If we reuse
found_method_call, found_local_pattern will show up first. This is what rustc currently shows, which is a red herring.
We can not move found_method_call up, it is undesirable in various
situations. I tried it. Many tests failed.

@joelpalmerjoelpalmer added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. and removed S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. labels Apr 16, 2020
@crlf0710

crlf0710 commented Apr 24, 2020

Copy link
Copy Markdown
Member

r? @estebank

estebank
estebank approved these changes Apr 24, 2020
View reviewed changes
Comment threadsrc/test/ui/issues/issue-69455.stderr
| ------^^^^-----------------
| | |
| | cannot infer type for type `u64`
| this method call resolves to `<Self as Test<Rhs>>::Output`

@estebankestebankApr 24, 2020

Copy link
Copy Markdown
Contributor

Choose a reason for hiding this comment

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

It would be amazing if we actually suggested <u64 as Test<u64>>::test(23u64, xs.iter().sum()), but that is beyond the scope of this PR.

@estebank

estebank commented Apr 24, 2020

Copy link
Copy Markdown
Contributor

The code looks ok to me. @contrun could you add tests for the cases you mention in your original comment would regress? I'm not sure I can see what they would be.

@contrun

contrun commented Apr 24, 2020•
edited
Loading

Copy link
Copy Markdown
ContributorAuthor

@estebank
Did you mean this one?

fn main() {
let xs: Vec<u64> = vec![1, 2, 3];
println!("{}", 23u64 + xs.iter().sum());
}

Unfortunately, my current PR does not solve that yet. This is because + is not parsed as a method call. It is parsed as a BinOp. I will submit a separate PR for that.

@estebank

estebank commented Apr 24, 2020

Copy link
Copy Markdown
Contributor

@contrun it is ok if this PR doesn't fix it, but having the test in the codebase helps us catch when an unrelated change either improves or degrades it. It also makes it easier for the reviewer to see the explicitly ignored cases.

That being said, now I see what the problem is and it shouldn't block this PR.

@bors r+

@bors

bors commented Apr 24, 2020

Copy link
Copy Markdown
Collaborator

📌 Commit 3ae974f has been approved by estebank

@borsbors 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 Apr 24, 2020
@Dylan-DPC-zzDylan-DPC-zz mentioned this pull request Apr 24, 2020
Merged
bors added a commit to rust-lang-ci/rust that referenced this pull request Apr 24, 2020
@bors
Auto merge ofrust-lang#71539- Dylan-DPC:rollup-a2vbfh9, r=Dylan-DPC
40008dc
Rollup of 8 pull requests
Successful merges:
- rust-lang#69456 (fix misleading type annotation diagonstics)
- rust-lang#71330 (Only run dataflow for const qualification if type-based check would fail)
- rust-lang#71480 (Improve PanicInfo examples readability)
- rust-lang#71485 (Add BinaryHeap::retain as suggested in rust-lang#42849)
- rust-lang#71512 (Remove useless "" args)
- rust-lang#71527 (Miscellaneous cleanup in `check_consts`)
- rust-lang#71534 (Avoid unused Option::map results)
- rust-lang#71535 (Fix typos in docs for keyword "in")
Failed merges:
r? @ghost
@bors
bors merged commit 2e2080d into rust-lang:masterApr 25, 2020
Sign up for freeto join this conversation on GitHub. Already have an account? Sign in to comment

Reviewers

@estebankestebankestebank approved these changes

Assignees

@estebankestebank

Labels

S-waiting-on-borsStatus: Waiting on bors to run and complete tests. Bors will change the label on completion.

Projects

None yet

Milestone

No milestone

Development

Successfully merging this pull request may close these issues.

9 participants

@contrun@rust-highfive@LeSeulArtichaut@bors@JohnCSimon@cramertj@crlf0710@estebank@joelpalmer