1 files changed, 51 insertions, 0 deletions
diff --git a/tests/ui/macros/issue-98466.rs b/tests/ui/macros/issue-98466.rs
new file mode 100644
index 00000000000..2c3b099afde
--- /dev/null
+++ b/tests/ui/macros/issue-98466.rs
@@ -0,0 +1,51 @@
+// check-pass
+// run-rustfix
+
+fn main() {
+    let mut _x: usize;
+    _x = 1;
+    println!("_x is {}", _x = 5);
+    //~^ WARNING named argument `_x` is not used by name [named_arguments_used_positionally]
+    //~| HELP use the named argument by name to avoid ambiguity
+    println!("_x is {}", y = _x);
+    //~^ WARNING named argument `y` is not used by name [named_arguments_used_positionally]
+    //~| HELP use the named argument by name to avoid ambiguity
+    println!("first positional arg {}, second positional arg {}, _x is {}", 1, 2, y = _x);
+    //~^ WARNING named argument `y` is not used by name [named_arguments_used_positionally]
+    //~| HELP use the named argument by name to avoid ambiguity
+
+    let mut _x: usize;
+    _x = 1;
+    let _f = format!("_x is {}", _x = 5);
+    //~^ WARNING named argument `_x` is not used by name [named_arguments_used_positionally]
+    //~| HELP use the named argument by name to avoid ambiguity
+    let _f = format!("_x is {}", y = _x);
+    //~^ WARNING named argument `y` is not used by name [named_arguments_used_positionally]
+    //~| HELP use the named argument by name to avoid ambiguity
+    let _f = format!("first positional arg {}, second positional arg {}, _x is {}", 1, 2, y = _x);
+    //~^ WARNING named argument `y` is not used by name [named_arguments_used_positionally]
+    //~| HELP use the named argument by name to avoid ambiguity
+
+    let s = "0.009";
+    // Confirm that named arguments used in formatting are correctly considered.
+    println!(".{:0<width$}", s, width = _x);
+
+    let region = "abc";
+    let width = 8;
+    let ls = "abcde";
+    let full = "abcde";
+    // Confirm that named arguments used in formatting are correctly considered.
+    println!(
+        "| {r:rw$?} | {ui:4?} | {v}",
+        r = region,
+        rw = width,
+        ui = ls,
+        v = full,
+    );
+
+    // Confirm that named arguments used in formatting are correctly considered.
+    println!("{:.a$}", "aaaaaaaaaaaaaaaaaa", a = 4);
+
+    // Confirm that named arguments used in formatting are correctly considered.
+    println!("{:._a$}", "aaaaaaaaaaaaaaaaaa", _a = 4);
+}