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LL| |//! Regression test for <https://github.com/rust-lang/rust/issues/141577>.
LL| |//!
LL| |//! The changes in <https://github.com/rust-lang/rust/pull/144298> exposed a
LL| |//! latent bug that would sometimes cause the compiler to emit a covfun record
LL| |//! for a function, but not emit a corresponding PGO symbol name entry, because
LL| |//! the function did not have any physical coverage counters. The `llvm-cov`
LL| |//! tool would then fail to resolve the covfun record's function name hash,
LL| |//! and exit with the cryptic error:
LL| |//!
LL| |//! ```text
LL| |//! malformed instrumentation profile data: function name is empty
LL| |//! ```
LL| |//!
LL| |//! The bug was then triggered in the wild by the macro-expansion of
LL| |//! `#[derive(arbitrary::Arbitrary)]`.
LL| |//!
LL| |//! This test uses a minimized form of the `Arbitrary` derive macro that was
LL| |//! found to still trigger the original bug. The bug could also be triggered
LL| |//! by a bang proc-macro or an attribute proc-macro.
LL| |
LL| |//@ edition: 2024
LL| |//@ revisions: attr bang derive
LL| |//@ proc-macro: try_in_macro_helper.rs
LL| |
LL| |trait Arbitrary {
LL| | fn try_size_hint() -> Option<usize>;
LL| |}
LL| |
LL| |// Expand via an attribute proc-macro.
LL| |#[cfg_attr(attr, try_in_macro_helper::attr)]
LL| |const _: () = ();
LL| |
LL| |// Expand via a regular bang-style proc-macro.
LL| |#[cfg(bang)]
LL| |try_in_macro_helper::bang!();
LL| |
LL| |// Expand via a derive proc-macro.
LL| |#[cfg_attr(derive, derive(try_in_macro_helper::Arbitrary))]
LL| |enum MyEnum {}
LL| |
LL| 1|fn main() {
LL| 1| MyEnum::try_size_hint();
LL| 1|}
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