Fix an ICE in the vtable iteration for a trait reference in const eval when a supertrait not implemented#152287
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…l when a supertrait not implemented compiler/rustc_trait_selection/src/traits/vtable.rs@`vtable_entries`: The impossible predicates check in `vtable_entries` used `instantiate_own` which only includes the method's own where-clauses, not the parent trait's bounds. Replace it with `instantiate_and_check_impossible_predicates` which also checks the trait ref itself, so unsatisfied supertrait bounds are caught and the method is marked `Vacant` instead of ICEing.
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…enkov Fix an ICE in the vtable iteration for a trait reference in const eval when a supertrait not implemented compiler/rustc_trait_selection/src/traits/vtable.rs@`vtable_entries`: The impossible predicates check in `vtable_entries` used `instantiate_own` which only includes the method's own `where` clauses, without the parent trait's bounds. Replace it with `instantiate_and_check_impossible_predicates` which also checks the trait ref itself, so unsatisfied supertrait bounds are caught and the method is marked `Vacant` instead of ICEing. Closes rust-lang#137190. Closes rust-lang#135470.
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…enkov Fix an ICE in the vtable iteration for a trait reference in const eval when a supertrait not implemented compiler/rustc_trait_selection/src/traits/vtable.rs@`vtable_entries`: The impossible predicates check in `vtable_entries` used `instantiate_own` which only includes the method's own `where` clauses, without the parent trait's bounds. Replace it with `instantiate_and_check_impossible_predicates` which also checks the trait ref itself, so unsatisfied supertrait bounds are caught and the method is marked `Vacant` instead of ICEing. Closes rust-lang#137190. Closes rust-lang#135470.
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…enkov Fix an ICE in the vtable iteration for a trait reference in const eval when a supertrait not implemented compiler/rustc_trait_selection/src/traits/vtable.rs@`vtable_entries`: The impossible predicates check in `vtable_entries` used `instantiate_own` which only includes the method's own `where` clauses, without the parent trait's bounds. Replace it with `instantiate_and_check_impossible_predicates` which also checks the trait ref itself, so unsatisfied supertrait bounds are caught and the method is marked `Vacant` instead of ICEing. Closes rust-lang#137190. Closes rust-lang#135470.
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Rollup of 12 pull requests Successful merges: - #152388 (`rust-analyzer` subtree update) - #151613 (Align `ArrayWindows` trait impls with `Windows`) - #152134 (Set crt_static_allow_dylibs to true for Emscripten target) - #152166 (cleanup some more things in `proc_macro::bridge`) - #152236 (compiletest: `-Zunstable-options` for json targets) - #152287 (Fix an ICE in the vtable iteration for a trait reference in const eval when a supertrait not implemented) - #142957 (std: introduce path normalize methods at top of `std::path`) - #145504 (Add some conversion trait impls) - #152131 (Port rustc_no_implicit_bounds attribute to parser.) - #152315 (fix: rhs_span to rhs_span_new) - #152327 (Check stalled coroutine obligations eagerly) - #152377 (Rename the query system's `JobOwner` to `ActiveJobGuard`, and include `key_hash`)
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Rollup of 12 pull requests Successful merges: - #152388 (`rust-analyzer` subtree update) - #151613 (Align `ArrayWindows` trait impls with `Windows`) - #152134 (Set crt_static_allow_dylibs to true for Emscripten target) - #152166 (cleanup some more things in `proc_macro::bridge`) - #152236 (compiletest: `-Zunstable-options` for json targets) - #152287 (Fix an ICE in the vtable iteration for a trait reference in const eval when a supertrait not implemented) - #142957 (std: introduce path normalize methods at top of `std::path`) - #145504 (Add some conversion trait impls) - #152131 (Port rustc_no_implicit_bounds attribute to parser.) - #152315 (fix: rhs_span to rhs_span_new) - #152327 (Check stalled coroutine obligations eagerly) - #152377 (Rename the query system's `JobOwner` to `ActiveJobGuard`, and include `key_hash`)
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Rollup of 12 pull requests Successful merges: - #152388 (`rust-analyzer` subtree update) - #151613 (Align `ArrayWindows` trait impls with `Windows`) - #152134 (Set crt_static_allow_dylibs to true for Emscripten target) - #152166 (cleanup some more things in `proc_macro::bridge`) - #152236 (compiletest: `-Zunstable-options` for json targets) - #152287 (Fix an ICE in the vtable iteration for a trait reference in const eval when a supertrait not implemented) - #142957 (std: introduce path normalize methods at top of `std::path`) - #145504 (Add some conversion trait impls) - #152131 (Port rustc_no_implicit_bounds attribute to parser.) - #152315 (fix: rhs_span to rhs_span_new) - #152327 (Check stalled coroutine obligations eagerly) - #152377 (Rename the query system's `JobOwner` to `ActiveJobGuard`, and include `key_hash`)
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Rollup merge of #152287 - jakubadamw:issue-137190, r=petrochenkov Fix an ICE in the vtable iteration for a trait reference in const eval when a supertrait not implemented compiler/rustc_trait_selection/src/traits/vtable.rs@`vtable_entries`: The impossible predicates check in `vtable_entries` used `instantiate_own` which only includes the method's own `where` clauses, without the parent trait's bounds. Replace it with `instantiate_and_check_impossible_predicates` which also checks the trait ref itself, so unsatisfied supertrait bounds are caught and the method is marked `Vacant` instead of ICEing. Closes #137190. Closes #135470.
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Rollup of 12 pull requests Successful merges: - rust-lang/rust#152388 (`rust-analyzer` subtree update) - rust-lang/rust#151613 (Align `ArrayWindows` trait impls with `Windows`) - rust-lang/rust#152134 (Set crt_static_allow_dylibs to true for Emscripten target) - rust-lang/rust#152166 (cleanup some more things in `proc_macro::bridge`) - rust-lang/rust#152236 (compiletest: `-Zunstable-options` for json targets) - rust-lang/rust#152287 (Fix an ICE in the vtable iteration for a trait reference in const eval when a supertrait not implemented) - rust-lang/rust#142957 (std: introduce path normalize methods at top of `std::path`) - rust-lang/rust#145504 (Add some conversion trait impls) - rust-lang/rust#152131 (Port rustc_no_implicit_bounds attribute to parser.) - rust-lang/rust#152315 (fix: rhs_span to rhs_span_new) - rust-lang/rust#152327 (Check stalled coroutine obligations eagerly) - rust-lang/rust#152377 (Rename the query system's `JobOwner` to `ActiveJobGuard`, and include `key_hash`)
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When a trait impl doesn't satisfy its supertrait bounds (for example, `impl<T: Send> Bar for T` where `trait Bar: Droppable` but `T` has no `Droppable` bound), the compiler emits E0277 and then then continues compilation. If a static initialiser then upcasts through this broken impl, const evaluation builds the vtable and tries to resolve methods for the unsatisfied supertrait (for example, `<bool as Droppable>::drop`). One might think that the `impossible_predicates` guard in `vtable_entries` should catch this, but it doesn't, because it calls `predicates_of(method).instantiate_own()`, which only includes the method's own where clauses, and the parent trait's `Self: Trait` predicate lives on the trait definition, not the method, so the guard passes and we fall through to `expect_resolve_for_vtable`, which hits a `span_bug!` when resolution returns `Ok(None)`. There was a previous attempt to fix this in rust-lang#152287, which worked by switching to `instantiate_and_check_impossible_predicates`, which includes parent predicates and the trait ref. But unfortunately this is unsound and was reverted because `impossible_predicates` has a pre-existing unsoundness with coroutine witness types and opaque types (see rust-lang#153596). Let's take a different approach that avoids `impossible_predicates` entirely. Let's extract the core of `expect_resolve_for_vtable` into a fallible `try_resolve_for_vtable` that returns `Result<Instance, ErrorGuaranteed>`, and on resolution failure emit a `delayed_bug`. `vtable_entries` then can use this and return `VtblEntry::Vacant` on the error path. Fixes rust-lang#154073, rust-lang#137190, rust-lang#135470
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compiler/rustc_trait_selection/src/traits/vtable.rs@
vtable_entries:The impossible predicates check in
vtable_entriesusedinstantiate_ownwhich only includes the method's ownwhereclauses, without the parent trait's bounds. Replace it withinstantiate_and_check_impossible_predicateswhich also checks the trait ref itself, so unsatisfied supertrait bounds are caught and the method is markedVacantinstead of ICEing.Closes #137190.
Closes #135470.