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| author | Mazdak Farrokhzad <twingoow@gmail.com> | 2019-03-19 15:16:46 +0100 |
|---|---|---|
| committer | GitHub <noreply@github.com> | 2019-03-19 15:16:46 +0100 |
| commit | d4ef74b2daab3119e34e2dbed6bb2ab40b49cae9 (patch) | |
| tree | b82f9d1975bfffa209df981ced4e12cc02360a87 /src/libstd | |
| parent | c1975dbd34a69565cd0a66770377ed9bfc85fa35 (diff) | |
| parent | ea9e2c4ef5cf2d1867b284bd4f84b5417d8df45b (diff) | |
| download | rust-d4ef74b2daab3119e34e2dbed6bb2ab40b49cae9.tar.gz rust-d4ef74b2daab3119e34e2dbed6bb2ab40b49cae9.zip | |
Rollup merge of #57847 - clarcharr:dbg_no_params, r=Centril
dbg!() without parameters Fixes #57845.
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 9d0eb2e6b1c..d5dc5f7c4f0 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 |