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1fd13fddba
After reviewing all tests with `?Sized` and discussing with lcnr, these tests seem like they could probably benefit from `#![rustc_no_implicit_bounds]`.
31 lines
1.3 KiB
Rust
31 lines
1.3 KiB
Rust
//@ compile-flags: -Znext-solver
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#![feature(rustc_attrs)]
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#![rustc_no_implicit_bounds]
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trait Tr<'a> {}
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// Fulfillment in the new solver relies on an invariant to hold: Either
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// `has_changed` is true, or computing a goal's certainty is idempotent.
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// This isn't true for `ReError`, which we used to pass through in the
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// canonicalizer even on input mode, which can cause a goal to go from
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// ambig => pass, but we don't consider `has_changed` when the response
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// only contains region constraints (since we usually uniquify regions).
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//
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// In this test:
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// Implicit negative coherence tries to prove `W<?0>: Constrain<'?1>`,
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// which will then match with the impl below. This constrains `'?1` to
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// `ReError`, but still bails w/ ambiguity bc we can't prove `?0: Sized`.
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// Then, when we recompute the goal `W<?0>: Constrain<'error>`, when
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// collecting ambiguities and overflows, we end up assembling a default
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// error candidate w/o ambiguity, which causes the goal to pass, and ICE.
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impl<'a, A> Tr<'a> for W<A> {}
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struct W<A>(A);
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impl<'a, A> Tr<'a> for A where A: Constrain<'a> {}
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//~^ ERROR conflicting implementations of trait `Tr<'_>` for type `W<_>`
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trait Constrain<'a> {}
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impl<A: Sized> Constrain<'missing> for W<A> {}
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//~^ ERROR use of undeclared lifetime name `'missing`
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fn main() {}
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