Provide better type hints when a type doesn't support a binary operator #110877
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Provide better type hints when a type doesn't support a binary operator For example, when checking whether `vec![A] == vec![A]` holds, we first evaluate the LHS's ty, then probe for any `PartialEq` implementations for that. If none is found, we report an error by evaluating `Vec<A>: PartialEq<?0>` for fulfillment errors, but the RHS is not yet evaluated and remains an inference variable `?0`! To fix this, we evaluate the RHS and equate it to that RHS infer var `?0`, so that we are able to provide more detailed fulfillment errors for why `Vec<A>: PartialEq<Vec<A>>` doesn't hold (namely, the nested obligation `A: PartialEq<A>` doesn't hold). Fixes rust-lang#95285 Fixes rust-lang#110867
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…iaskrgr Rollup of 8 pull requests Successful merges: - rust-lang#110877 (Provide better type hints when a type doesn't support a binary operator) - rust-lang#110917 (only error combining +whole-archive and +bundle for rlibs) - rust-lang#110921 (Use `NonNull::new_unchecked` and `NonNull::len` in `rustc_arena`.) - rust-lang#110927 (Encoder/decoder cleanups) - rust-lang#110944 (share BinOp::Offset between CTFE and Miri) - rust-lang#110948 (run-make test: using single quotes to not trigger the shell) - rust-lang#110957 (Fix an ICE in conflict error diagnostics) - rust-lang#110960 (fix false negative for `unused_mut`) Failed merges: r? `@ghost` `@rustbot` modify labels: rollup
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…h726 Don't use `can_eq` in `derive(..)` suggestion for missing method Unsatisfied predicates returned from method probe may reference inference vars from that probe, so drop this extra check I added in rust-lang#110877 for more accurate derive suggestions... Fixes rust-lang#111500
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For example, when checking whether
vec![A] == vec![A]holds, we first evaluate the LHS's ty, then probe for anyPartialEqimplementations for that. If none is found, we report an error by evaluatingVec<A>: PartialEq<?0>for fulfillment errors, but the RHS is not yet evaluated and remains an inference variable?0!To fix this, we evaluate the RHS and equate it to that RHS infer var
?0, so that we are able to provide more detailed fulfillment errors for whyVec<A>: PartialEq<Vec<A>>doesn't hold (namely, the nested obligationA: PartialEq<A>doesn't hold).Fixes #95285
Fixes #110867