1 files changed, 56 insertions, 0 deletions
diff --git a/src/test/ui/nll/issue-54556-used-vs-unused-tails.rs b/src/test/ui/nll/issue-54556-used-vs-unused-tails.rs
new file mode 100644
index 000000000..a111acca6
--- /dev/null
+++ b/src/test/ui/nll/issue-54556-used-vs-unused-tails.rs
@@ -0,0 +1,56 @@
+// This test case is exploring the space of how blocks with tail
+// expressions and statements can be composed, trying to keep each
+// case on one line so that we can compare them via a vertical scan
+// with the human eye.
+
+// Each comment on the right side of the line is summarizing the
+// expected suggestion from the diagnostic for issue #54556.
+
+fn main() {
+    {              let mut _t1 = D(Box::new("t1")); D(&_t1).end()    } ; // suggest `;`
+//~^ ERROR does not live long enough
+
+    {            { let mut _t1 = D(Box::new("t1")); D(&_t1).end() }  } ; // suggest `;`
+//~^ ERROR does not live long enough
+
+    {            { let mut _t1 = D(Box::new("t1")); D(&_t1).end() }; }   // suggest `;`
+//~^ ERROR does not live long enough
+
+    let _ =      { let mut _t1 = D(Box::new("t1")); D(&_t1).end()    } ; // suggest `;`
+//~^ ERROR does not live long enough
+
+    let _u =     { let mut _t1 = D(Box::new("t1")); D(&_t1).unit()   } ; // suggest `;`
+//~^ ERROR does not live long enough
+
+    let _x =     { let mut _t1 = D(Box::new("t1")); D(&_t1).end()    } ; // `let x = ...; x`
+//~^ ERROR does not live long enough
+    let _x =     { let mut _t1 = D(Box::new("t1")); let x = D(&_t1).end(); x } ; // no error
+
+    let mut _y;
+    _y =         { let mut _t1 = D(Box::new("t1")); D(&_t1).end() } ; // `let x = ...; x`
+//~^ ERROR does not live long enough
+    _y =         { let mut _t1 = D(Box::new("t1")); let x = D(&_t1).end(); x } ; // no error
+}
+
+fn f_param_ref(_t1: D<Box<&'static str>>) {         D(&_t1).unit()   }  // no error
+
+fn f_local_ref() { let mut _t1 = D(Box::new("t1")); D(&_t1).unit()   }  // suggest `;`
+//~^ ERROR does not live long enough
+
+fn f() -> String { let mut _t1 = D(Box::new("t1")); D(&_t1).end()   }   // `let x = ...; x`
+//~^ ERROR does not live long enough
+
+#[derive(Debug)]
+struct D<T: std::fmt::Debug>(T);
+
+impl<T: std::fmt::Debug>  Drop for D<T> {
+    fn drop(&mut self) {
+        println!("dropping {:?})", self);
+    }
+}
+
+impl<T: std::fmt::Debug> D<T> {
+    fn next<U: std::fmt::Debug>(&self, _other: U) -> D<U> { D(_other) }
+    fn end(&self) -> String { format!("End({:?})", self.0) }
+    fn unit(&self) { }
+}