Avoid empty identifiers for delegate params and args.

Instead use `argN`. The empty identifiers could flow to
`Liveness::should_warn`, where they would trigger a bounds error.

Fixes #139512.

1 files changed, 2 insertions, 2 deletions

diff --git a/tests/pretty/hir-delegation.pp b/tests/pretty/hir-delegation.pp
index 1dc83ed635c..872a6a45aed 100644
--- a/tests/pretty/hir-delegation.pp
+++ b/tests/pretty/hir-delegation.pp
@@ -11,13 +11,13 @@ extern crate std;
 fn b<C>(e: C) { }
 
 trait G {
-    fn b(: _) -> _ { b({ }) }
+    fn b(arg0: _) -> _ { b({ }) }
 }
 
 mod m {
     fn add(a: u32, b: u32) -> u32 { a + b }
 }
 
-fn add(: _, : _) -> _ { m::add(, ) }
+fn add(arg0: _, arg1: _) -> _ { m::add(arg0, arg1) }
 
 fn main() { { let _ = add(1, 2); }; }