diff options
| author | Clar Fon <them@lightdark.xyz> | 2019-01-22 17:51:33 -0500 |
|---|---|---|
| committer | Clar Fon <them@lightdark.xyz> | 2019-01-22 17:52:03 -0500 |
| commit | 6fb5b73cf4dcf69e72ae414e83c53fe5eb8f0ffe (patch) | |
| tree | 8365616e9a426bcb92c2e61beba368911a565b5a /src/libstd | |
| parent | 96909179d9ec80db286605876ce67659dd16fd4b (diff) | |
| download | rust-6fb5b73cf4dcf69e72ae414e83c53fe5eb8f0ffe.tar.gz rust-6fb5b73cf4dcf69e72ae414e83c53fe5eb8f0ffe.zip | |
dbg!() without parameters.
Diffstat (limited to 'src/libstd')
| -rw-r--r-- | src/libstd/macros.rs | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/src/libstd/macros.rs b/src/libstd/macros.rs index b87257188df..cfb8336e540 100644 --- a/src/libstd/macros.rs +++ b/src/libstd/macros.rs @@ -305,10 +305,16 @@ macro_rules! eprintln { /// let _ = dbg!(a); // <-- `a` is moved again; error! /// ``` /// +/// You can also use `dbg!()` without a value to just print the +/// file and line whenever it's reached. +/// /// [stderr]: https://en.wikipedia.org/wiki/Standard_streams#Standard_error_(stderr) #[macro_export] #[stable(feature = "dbg_macro", since = "1.32.0")] macro_rules! dbg { + () => { + eprintln!("[{}:{}]", file!(), line!()); + }; ($val:expr) => { // Use of `match` here is intentional because it affects the lifetimes // of temporaries - https://stackoverflow.com/a/48732525/1063961 |