Closures in enum discriminants error when they shouldn't #50689
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A-const-eval
Area: Constant evaluation (MIR interpretation)
A-typesystem
Area: The type system
P-high
High priority
regression-from-stable-to-stable
Performance or correctness regression from one stable version to another.
T-compiler
Relevant to the compiler team, which will review and decide on the PR/issue.
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estebank
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A-typesystem
nikomatsakis
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P-medium
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Doesn't seem mega urgent. Kind of a gray area for promotion. Marking as medium but nominating for discussion with @eddyb |
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The old const-eval got changed at some point to eagerly evaluate constants, but miri should be fine. |
nikomatsakis
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P-high
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Something seems wacky. Assigning to eddyb to stay on top of ;) marking as P-high for now but that might be an over-reaction. |
bors
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May 20, 2018
rustc: introduce {ast,hir}::AnonConst to consolidate so-called "embedded constants".
Previously, constants in array lengths and enum variant discriminants were "merely an expression", and had no separate ID for, e.g. type-checking or const-eval, instead reusing the expression's.
That complicated code working with bodies, because such constants were the only special case where the "owner" of the body wasn't the HIR parent, but rather the same node as the body itself.
Also, if the body happened to be a closure, we had no way to allocate a `DefId` for both the constant *and* the closure, leading to *several* bugs (mostly ICEs where type errors were expected).
This PR rectifies the situation by adding another (`{ast,hir}::AnonConst`) node around every such constant. Also, const generics are expected to rely on the new `AnonConst` nodes, as well (cc @varkor).
* fixes #48838
* fixes #50600
* fixes #50688
* fixes #50689
* obsoletes #50623
r? @nikomatsakis
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This used to work (regression from 1.14 stable) but now it doesn't:
In #50623 the error less bad and some
FIXME(#50689)are left in the code with hints, but still doesn't work. Issue #50688 seems related.The text was updated successfully, but these errors were encountered: