Better suggestions when user tries to collect into an unsized [_] #91443
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apiraino added the T-compiler 
| Could you add a test case demonstrating the new behavior? |
compiler-errors force-pushed the bad_collect_into_slice branch from c526bb7 to aa23424 Compare 
| @Aaron1011 added a test. Still unclear what the best wording for this specific suggestion is, but demonstrating that it works. |
| ☔ The latest upstream changes (presumably #93352) made this pull request unmergeable. Please resolve the merge conflicts. |
| howdy @matthewjasper, should I reassign this PR to someone else on the high-five queue? |
| Yes please |
| reassigning per reviewer request r? rust-lang/compiler |
| @compiler-errors This looks great! My only suggestion was going to be to mention the |
compiler-errors force-pushed the bad_collect_into_slice branch from aa23424 to dea99b3 Compare 
compiler-errors force-pushed the bad_collect_into_slice branch from dea99b3 to fea0015 Compare | Alright @wesleywiser, rebased and confirmed tests still pass! |
| @bors r+ |
| 📌 Commit fea0015 has been approved by |
bors added S-waiting-on-bors 
…ice, r=wesleywiser Better suggestions when user tries to collect into an unsized `[_]` 1. Extend the predicate on `rustc_on_unimplemented` to support substitutions like note, label, etc (i.e. treat it as a `OnUnimplementedFormatString`) so we can have slightly more general `rustc_on_unimplemented` special-cases. 2. Add a `rustc_on_unimplemented` if we fail on `FromIterator<A> for [A]` which happens when we don't explicitly collect into a `vec<A>`, but then pass the return from a `.collect` call into something that takes a slice. Fixes rust-lang#91423
…askrgr Rollup of 6 pull requests Successful merges: - rust-lang#91443 (Better suggestions when user tries to collect into an unsized `[_]`) - rust-lang#91504 (`#[used(linker)]` attribute) - rust-lang#93503 (debuginfo: Fix DW_AT_containing_type vtable debuginfo regression) - rust-lang#93753 (Complete removal of #[main] attribute from compiler) - rust-lang#93799 (Fix typo in `std::fmt` docs) - rust-lang#93813 (Make a few cleanup MIR passes public) Failed merges: r? `@ghost` `@rustbot` modify labels: rollup
| What would it take to add a structured suggestion to this diagnostic? |
| @NieDzejkob, what do you mean by this? I don't think the If you're interested in that route, you probably have a good bet putting some logic to detect this case in |
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rustc_on_unimplementedto support substitutions like note, label, etc (i.e. treat it as aOnUnimplementedFormatString) so we can have slightly more generalrustc_on_unimplementedspecial-cases.rustc_on_unimplementedif we fail onFromIterator<A> for [A]which happens when we don't explicitly collect into avec<A>, but then pass the return from a.collectcall into something that takes a slice.Fixes #91423