bors 4f7bb9890c Auto merge of #114036 - compiler-errors:upcast-to-fewer-assocs, r=lcnr ... Rework upcasting confirmation to support upcasting to fewer projections in target bounds This PR implements a modified trait upcasting algorithm that is resilient to changes in the number of associated types in the bounds of the source and target trait objects. It does this by equating each bound of the target trait ref individually against the bounds of the source trait ref, rather than doing them all together by constructing a new trait object. #### The new way we do trait upcasting confirmation 1. Equate the target trait object's principal trait ref with one of the supertraits of the source trait object's principal. fdcab310b2/compiler/rustc_trait_selection/src/traits/select/mod.rs (L2509-L2525) 2. Make sure that every auto trait in the *target* trait object is present in the source trait ref's bounds. fdcab310b2/compiler/rustc_trait_selection/src/traits/select/mod.rs (L2559-L2562) 3. For each projection in the *target* trait object, make sure there is exactly one projection that equates with it in the source trait ref's bound. If there is more than one, bail with ambiguity. fdcab310b2/compiler/rustc_trait_selection/src/traits/select/mod.rs (L2526-L2557) * Since there may be more than one that applies, we probe first to check that there is exactly one, then we equate it outside of a probe once we know that it's unique. 4. Make sure the lifetime of the source trait object outlives the lifetime of the target. <details> <summary>Meanwhile, this is how we used to do upcasting:</summary> 1. For each supertrait of the source trait object, take that supertrait, append the source object's projection bounds, and the *target* trait object's auto trait bounds, and make this into a new object type: d12c6e947c/compiler/rustc_trait_selection/src/traits/select/confirmation.rs (L915-L929) 2. Then equate it with the target trait object: d12c6e947c/compiler/rustc_trait_selection/src/traits/select/confirmation.rs (L936) This will be a type mismatch if the target trait object has fewer projection bounds, since we compare the bounds structurally in relate: d12c6e947c/compiler/rustc_middle/src/ty/relate.rs (L696-L698) </details> Fixes #114035 Also fixes #114113, because I added a normalize call in the old solver. r? types		2023-08-04 10:55:22 +00:00
..
assembly	Auto merge of #112922 - g0djan:godjan/wasi-threads, r=wesleywiser	2023-08-02 01:01:48 +00:00
auxiliary
codegen	Auto merge of #105545 - erikdesjardins:ptrclean, r=bjorn3	2023-08-01 19:44:17 +00:00
codegen-units
debuginfo	Replace ignore-everything with only-arch	2023-07-29 15:49:07 -07:00
incremental	Forbid old-style simd_shuffleN intrinsics	2023-08-03 09:29:00 +00:00
mir-opt	bless	2023-08-03 18:42:12 +00:00
pretty
run-coverage	refactor(rustc_middle): Substs -> GenericArg	2023-07-14 13:27:35 +01:00
run-coverage-rustdoc	Re-bless the newly-migrated tests	2023-06-28 11:09:19 +10:00
run-make	Add internal_features lint	2023-08-03 14:50:50 +02:00
run-make-fulldeps	On nightly, dump ICE backtraces to disk	2023-07-19 14:10:07 +00:00
run-pass-valgrind
rustdoc	Rollup merge of #114253 - fmease:compute-variances-for-lazy-ty-aliases, r=oli-obk	2023-08-04 09:18:58 +02:00
rustdoc-gui	Rollup merge of #114404 - GuillaumeGomez:migrate-gui-test-color-26, r=notriddle	2023-08-04 07:25:47 +02:00
rustdoc-js	Auto merge of #112233 - notriddle:notriddle/search-unify, r=GuillaumeGomez	2023-06-15 03:04:46 +00:00
rustdoc-js-std	Auto merge of #108537 - GuillaumeGomez:rustdoc-search-whitespace-as-separator, r=notriddle	2023-07-02 18:49:29 +00:00
rustdoc-json	Handle inherent associated types fallout	2023-08-03 02:18:52 +02:00
rustdoc-ui	Fix windows test output.	2023-08-01 14:24:11 +02:00
ui	Auto merge of #114036 - compiler-errors:upcast-to-fewer-assocs, r=lcnr	2023-08-04 10:55:22 +00:00
ui-fulldeps	Bump syn dependency	2023-07-26 08:42:40 +00:00
COMPILER_TESTS.md