From 67faae44b46715c482fc45fa4e3ee655da3e2a64 Mon Sep 17 00:00:00 2001 From: David Tolnay Date: Mon, 4 Nov 2024 14:29:25 -0500 Subject: [PATCH] Add regression test for issue 345 error[E0599]: `test_no_bound_on_named_fmt::Error` doesn't implement `std::fmt::Display` --> tests/test_generics.rs:173:22 | 168 | struct Error { | --------------- method `to_string` not found for this struct because it doesn't satisfy `_: Display` or `_: ToString` ... 173 | assert_eq!(error.to_string(), "..."); | ^^^^^^^^^ `test_no_bound_on_named_fmt::Error` cannot be formatted with the default formatter | = note: the following trait bounds were not satisfied: `test_no_bound_on_named_fmt::Error: std::fmt::Display` which is required by `test_no_bound_on_named_fmt::Error: ToString` = note: in format strings you may be able to use `{:?}` (or {:#?} for pretty-print) instead note: the trait `std::fmt::Display` must be implemented --> $RUSTUP_HOME/toolchains/nightly-aarch64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/fmt/mod.rs:727:1 | 727 | pub trait Display { | ^^^^^^^^^^^^^^^^^ = help: items from traits can only be used if the trait is implemented and in scope = note: the following trait defines an item `to_string`, perhaps you need to implement it: candidate #1: `ToString` --- tests/test_generics.rs | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/tests/test_generics.rs b/tests/test_generics.rs index d7790e2..4d49edf 100644 --- a/tests/test_generics.rs +++ b/tests/test_generics.rs @@ -159,3 +159,16 @@ pub struct StructFromGeneric { #[derive(Error, Debug)] #[error(transparent)] pub struct StructTransparentGeneric(pub E); + +// Regression test for https://github.com/dtolnay/thiserror/issues/345 +#[test] +fn test_no_bound_on_named_fmt() { + #[derive(Error, Debug)] + #[error("{thing}", thing = "...")] + struct Error { + thing: T, + } + + let error = Error { thing: DebugOnly }; + assert_eq!(error.to_string(), "..."); +}