Remove `kw::Empty` uses from `rustc_middle`.

There are several places in `rustc_middle` that check for an empty
lifetime name. These checks appear to be totally unnecessary, because
empty lifetime names aren't produced here. (Empty lifetime names *are*
possible in `hir::Lifetime`. Perhaps there was some confusion between
it and the `rustc_middle` types?)

This commit removes the `kw::Empty` checks.

1 files changed, 1 insertions, 3 deletions

diff --git a/compiler/rustc_middle/src/ty/generics.rs b/compiler/rustc_middle/src/ty/generics.rs
index 85d9db7ee74..d4cc562e70c 100644
--- a/compiler/rustc_middle/src/ty/generics.rs
+++ b/compiler/rustc_middle/src/ty/generics.rs
@@ -73,9 +73,7 @@ impl GenericParamDef {
 
     pub fn is_anonymous_lifetime(&self) -> bool {
         match self.kind {
-            GenericParamDefKind::Lifetime => {
-                self.name == kw::UnderscoreLifetime || self.name == kw::Empty
-            }
+            GenericParamDefKind::Lifetime => self.name == kw::UnderscoreLifetime,
             _ => false,
         }
     }