diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/libstd/macros.rs | 13 | ||||
| -rw-r--r-- | src/test/ui/rfc-2361-dbg-macro/dbg-macro-expected-behavior.rs | 22 |
2 files changed, 34 insertions, 1 deletions
diff --git a/src/libstd/macros.rs b/src/libstd/macros.rs index e245a048955..9eba76cc04a 100644 --- a/src/libstd/macros.rs +++ b/src/libstd/macros.rs @@ -321,6 +321,15 @@ macro_rules! eprintln { /// assert_eq!(dbg!(1usize, 2u32), (1, 2)); /// ``` /// +/// However, a single argument with a trailing comma will still not be treated +/// as a tuple, following the convention of ignoring trailing commas in macro +/// invocations. You can use a 1-tuple directly if you need one: +/// +/// ``` +/// assert_eq!(1, dbg!(1u32,)); // trailing comma ignored +/// assert_eq!((1,), dbg!((1u32,))); // 1-tuple +/// ``` +/// /// [stderr]: https://en.wikipedia.org/wiki/Standard_streams#Standard_error_(stderr) /// [`debug!`]: https://docs.rs/log/*/log/macro.debug.html /// [`log`]: https://crates.io/crates/log @@ -341,9 +350,11 @@ macro_rules! dbg { } } }; + // Trailing comma with single argument is ignored + ($val:expr,) => { dbg!($val) }; ($($val:expr),+ $(,)?) => { ($(dbg!($val)),+,) - } + }; } /// Awaits the completion of an async call. diff --git a/src/test/ui/rfc-2361-dbg-macro/dbg-macro-expected-behavior.rs b/src/test/ui/rfc-2361-dbg-macro/dbg-macro-expected-behavior.rs index f1b73ee115d..e2a7ac349ec 100644 --- a/src/test/ui/rfc-2361-dbg-macro/dbg-macro-expected-behavior.rs +++ b/src/test/ui/rfc-2361-dbg-macro/dbg-macro-expected-behavior.rs @@ -54,6 +54,17 @@ fn test() { 7331 })); assert_eq!(foo, 42); + + // Test trailing comma: + assert_eq!(("Yeah",), dbg!(("Yeah",))); + + // Test multiple arguments: + assert_eq!((1u8, 2u32), dbg!(1, + 2)); + + // Test multiple arguments + trailing comma: + assert_eq!((1u8, 2u32, "Yeah"), dbg!(1u8, 2u32, + "Yeah",)); } fn validate_stderr(stderr: Vec<String>) { @@ -85,6 +96,17 @@ fn validate_stderr(stderr: Vec<String>) { "before", ":51] { foo += 1; eprintln!(\"before\"); 7331 } = 7331", + + ":59] (\"Yeah\",) = (", + " \"Yeah\",", + ")", + + ":62] 1 = 1", + ":62] 2 = 2", + + ":66] 1u8 = 1", + ":66] 2u32 = 2", + ":66] \"Yeah\" = \"Yeah\"", ]); } |