Add a test

Author: moatom

tests/ui/errors/issue-140578-span-format_args.rs

@@ -0,0 +1,4 @@
+fn main() {
+  println!("{:?} {a} {a:?}", [], a = 1 + 1);
+  //~^ ERROR type annotations needed
+}

tests/ui/errors/issue-140578-span-format_args.stderr

@@ -0,0 +1,11 @@
+error[E0282]: type annotations needed
+  --> $DIR/issue-140578-span-format_args.rs:2:30
+   |
+LL |   println!("{:?} {a} {a:?}", [], a = 1 + 1);
+   |                              ^^ cannot infer type
+   |
+   = note: this error originates in the macro `$crate::format_args_nl` which comes from the expansion of the macro `println` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0282`.