Rollup of 9 pull requests #72778
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Rollup of 9 pull requests #72778
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Co-authored-by: Oliver Scherer <github35764891676564198441@oli-obk.de>
This commit adjusts the condition used in the recursion limit check of the monomorphization collector, from `>` to `>=`. In rust-lang#67552, the test case had infinite indirect recursion, repeating a handful of functions (from the perspective of the monomorphization collector): `rec` -> `identity` -> `Iterator::count` -> `Iterator::fold` -> `Iterator::next` -> `rec`. During this process, `resolve_associated_item` was invoked for `Iterator::fold` (during the construction of an `Instance`), and ICE'd due to substitutions needing inference. However, previous iterations of this recursion would have called this function for `Iterator::fold` - and did! - and succeeded in doing so (trivially checkable from debug logging, `()` is present where `_` is in the substs of the failing execution). The expected outcome of this test case would be a recursion limit error (which is present when the `identity` fn indirection is removed), and the recursion depth of `rec` is increasing (other functions finish collecting their neighbours and thus have their recursion depths reset). When the ICE occurs, the recursion depth of `rec` is 256 (which matches the recursion limit), which suggests perhaps that a different part of the compiler is using a `>=` comparison and returning a different result on this recursion rather than what it returned in every previous recursion, thus stopping the monomorphization collector from reporting an error on the next recursion, where `recursion_depth_of_rec > 256` would have been true. With grep and some educated guesses, we can determine that the recursion limit check at line 818 in `src/librustc_trait_selection/traits/project.rs` is the other check that is using a different comparison. Modifying either comparison to be `>` or `>=` respectively will fix the error, but changing the monomorphization collector produces the nicer error. Signed-off-by: David Wood <david@davidtw.co>
This commit introduces a `Limit` type which is used to ensure that all comparisons against limits within the compiler are consistent (which can result in ICEs if they aren't). Signed-off-by: David Wood <david@davidtw.co>
more `LocalDefId`s
Resolve overflow behavior for RangeFrom This specifies a documented unspecified implementation detail of `RangeFrom` and makes it consistently implement the specified behavior. Specifically, `(u8::MAX).next()` is defined to cause an overflow, and resolve that overflow in the same manner as the `Step::forward` implementation. The inconsistency that has existed is `<RangeFrom as Iterator>::nth`. The existing behavior should be plain to see after rust-lang#69659: the skipping part previously always panicked if it caused an overflow, but the final step (to set up the state for further iteration) has always been debug-checked. The inconsistency, then, is that `RangeFrom::nth` does not implement the same behavior as the naive (and default) implementation of just calling `next` multiple times. This PR aligns `RangeFrom::nth` to have identical behavior to the naive implementation. It also lines up with the standard behavior of primitive math in Rust everywhere else in the language: debug checked overflow. cc @Amanieu --- Followup to rust-lang#69659. Closes rust-lang#25708 (by documenting the panic as intended). The documentation wording is preliminary and can probably be improved. This will probably need an FCP, as it changes observable stable behavior.
…nikomatsakis Fix ICE with explicit late-bound lifetimes Rather than returning an explicit late-bound lifetime as a generic argument count mismatch (which is not necessarily true), this PR propagates the presence of explicit late-bound lifetimes. This avoids an ICE that can occur due to the presence of explicit late-bound lifetimes when building generic substitutions by explicitly ignoring them. r? @varkor cc @davidtwco (this removes a check you introduced in rust-lang#60892) Resolves rust-lang#72278
Override Box::<[T]>::clone_from Avoid dropping and reallocating when cloning to an existing box if the lengths are the same. It would be nice if this could also be specialized for `Copy` but I don't know how that works since it's not on stable. Will gladly look into it if it's deemed as a good idea. This is my first PR with code, hope I did everything right 😄
Properly handle InlineAsmOperand::SymFn when collecting monomorphized items Fixes rust-lang#72484
…r-comparison, r=varkor mir: adjust conditional in recursion limit check Fixes rust-lang#67552. This PR adjusts the condition used in the recursion limit check of the monomorphization collector, from `>` to `>=`. In rust-lang#67552, the test case had infinite indirect recursion, repeating a handful of functions (from the perspective of the monomorphization collector): `rec` -> `identity` -> `Iterator::count` -> `Iterator::fold` -> `Iterator::next` -> `rec`. During this process, `resolve_associated_item` was invoked for `Iterator::fold` (during the construction of an `Instance`), and ICE'd due to substitutions needing inference. However, previous iterations of this recursion would have called this function for `Iterator::fold` - and did! - and succeeded in doing so (trivially checkable from debug logging, `()` is present where `_` is in the substs of the failing execution). The expected outcome of this test case would be a recursion limit error (which is present when the `identity` fn indirection is removed), and the recursion depth of `rec` is increasing (other functions finish collecting their neighbours and thus have their recursion depths reset). When the ICE occurs, the recursion depth of `rec` is 256 (which matches the recursion limit), which suggests perhaps that a different part of the compiler is using a `>=` comparison and returning a different result on this recursion rather than what it returned in every previous recursion, thus stopping the monomorphization collector from reporting an error on the next recursion, where `recursion_depth_of_rec > 256` would have been true. With grep and some educated guesses, we can determine that the recursion limit check at line 818 in `src/librustc_trait_selection/traits/project.rs` is the other check that is using a different comparison. Modifying either comparison to be `>` or `>=` respectively will fix the error, but changing the monomorphization collector produces the nicer error.
multiple Return terminators are possible @ecstatic-morse mentioned in rust-lang#72515 that multiple `Return` terminators are possible. Update the docs accordingly. Cc @rust-lang/wg-mir-opt
…r=petrochenkov Only capture tokens for items with outer attributes Suggested by @petrochenkov in rust-lang#43081 (comment)
Eagerly lower asm sub-expressions to HIR even if there is an error Fixes rust-lang#72570 r? @oli-obk
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📌 Commit 69310de has been approved by |
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☀️ Test successful - checks-azure |
This was referenced May 30, 2020
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One of these PRs gave a small perf win on |
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Successful merges:
LocalDefIds #72299 (moreLocalDefIds)Failed merges:
r? @ghost