mirror of https://github.com/rust-lang/rust.git
25 lines
1.2 KiB
Rust
25 lines
1.2 KiB
Rust
// Given a const argument `a`: `{ N }` and some const argument `b` which references the
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// first anon const like so: `{ [1; a] }`. The `b` anon const should not be allowed to use
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// any generic parameters as:
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// - The anon const is not a simple bare parameter, e.g. `N`
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// - The anon const is not the *length* of an array repeat expression, e.g. the `N` in `[1; N]`.
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//
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// On the other hand `a` *is* a const argument for the length of a repeat expression and
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// so it *should* inherit the generics declared on its parent definition. (This hack is
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// introduced for backwards compatibility and is tracked in #76200)
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//
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// In this specific case `a`'s parent should be `b` which does not have any generics.
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// This means that even though `a` inherits generics from `b`, it still winds up not having
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// access to any generic parameters. If `a` were to inherit its generics from the surrounding
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// function `foo` then the reference to `a` from `b` would contain generic parameters not usable
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// by `b` which would cause us to ICE.
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fn bar<const N: usize>() {}
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fn foo<const N: usize>() {
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bar::<{ [1; N] }>();
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//~^ ERROR: generic parameters may not be used in const operations
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}
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fn main() {}
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