mirror of https://github.com/rust-lang/rust
20 lines
450 B
Rust
20 lines
450 B
Rust
//@ check-pass
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// Verify that variant count intrinsic can still evaluate for types like `Option<T>`.
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#![feature(variant_count)]
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pub struct GetVariantCount<T>(T);
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impl<T> GetVariantCount<T> {
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pub const VALUE: usize = std::mem::variant_count::<T>();
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}
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const fn check_variant_count<T>() -> bool {
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matches!(GetVariantCount::<Option<T>>::VALUE, GetVariantCount::<Option<()>>::VALUE)
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}
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fn main() {
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assert!(check_variant_count::<()>());
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}
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