Merge pull request #129 from dtolnay/ensure

1-argument `ensure!`
dtolnay · Dec 6, 2020 · cb57a41 · cb57a41
2 parents 0c0e41f + 6161f7d
commit cb57a41
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diff --git a/src/macros.rs b/src/macros.rs
@@ -113,6 +113,9 @@ macro_rules! bail {
 /// ```
 #[macro_export]
 macro_rules! ensure {
+    ($cond:expr $(,)?) => {
+        $crate::ensure!($cond, concat!("Condition failed: `", stringify!($cond), "`"))
+    };
     ($cond:expr, $msg:literal $(,)?) => {
         if !$cond {
             return $crate::private::Err($crate::anyhow!($msg));

diff --git a/tests/test_macros.rs b/tests/test_macros.rs
@@ -32,4 +32,13 @@ fn test_ensure() {
         Ok(())
     };
     assert!(f().is_err());
+
+    let f = || {
+        ensure!(v + v == 1);
+        Ok(())
+    };
+    assert_eq!(
+        f().unwrap_err().to_string(),
+        "Condition failed: `v + v == 1`",
+    );
 }