Remove the distinction between LifetimeName::Implicit and LifetimeName::Underscore.

compiler/rustc_hir/src/def.rs

@@ -742,8 +742,6 @@ pub enum LifetimeRes {
     Anonymous {
         /// Id of the introducing place. See `Param`.
         binder: NodeId,
-        /// Whether this lifetime was spelled or elided.
-        elided: bool,
     },
     /// Explicit `'static` lifetime.
     Static,

compiler/rustc_hir/src/hir.rs

@@ -90,9 +90,6 @@ pub enum LifetimeName {
     /// User-given names or fresh (synthetic) names.
     Param(LocalDefId, ParamName),
 
-    /// User wrote nothing (e.g., the lifetime in `&u32`).
-    Implicit,
-
     /// Implicit lifetime in a context like `dyn Foo`. This is
     /// distinguished from implicit lifetimes elsewhere because the
     /// lifetime that they default to must appear elsewhere within the
@@ -110,7 +107,7 @@ pub enum LifetimeName {
     /// that was already reported.
     Error,
 
-    /// User wrote specifies `'_`.
+    /// User wrote an anonymous lifetime, either `'_` or nothing.
     Underscore,
 
     /// User wrote `'static`.
@@ -120,9 +117,7 @@ pub enum LifetimeName {
 impl LifetimeName {
     pub fn ident(&self) -> Ident {
         match *self {
-            LifetimeName::ImplicitObjectLifetimeDefault
-            | LifetimeName::Implicit
-            | LifetimeName::Error => Ident::empty(),
+            LifetimeName::ImplicitObjectLifetimeDefault | LifetimeName::Error => Ident::empty(),
             LifetimeName::Underscore => Ident::with_dummy_span(kw::UnderscoreLifetime),
             LifetimeName::Static => Ident::with_dummy_span(kw::StaticLifetime),
             LifetimeName::Param(_, param_name) => param_name.ident(),
@@ -132,7 +127,6 @@ impl LifetimeName {
     pub fn is_anonymous(&self) -> bool {
         match *self {
             LifetimeName::ImplicitObjectLifetimeDefault
-            | LifetimeName::Implicit
             | LifetimeName::Underscore
             | LifetimeName::Param(_, ParamName::Fresh)
             | LifetimeName::Error => true,
@@ -142,9 +136,7 @@ impl LifetimeName {
 
     pub fn is_elided(&self) -> bool {
         match self {
-            LifetimeName::ImplicitObjectLifetimeDefault
-            | LifetimeName::Implicit
-            | LifetimeName::Underscore => true,
+            LifetimeName::ImplicitObjectLifetimeDefault | LifetimeName::Underscore => true,
 
             // It might seem surprising that `Fresh` counts as
             // *not* elided -- but this is because, as far as the code

compiler/rustc_hir/src/intravisit.rs

@@ -496,7 +496,6 @@ pub fn walk_lifetime<'v, V: Visitor<'v>>(visitor: &mut V, lifetime: &'v Lifetime
         | LifetimeName::Param(_, ParamName::Error)
         | LifetimeName::Static
         | LifetimeName::Error
-        | LifetimeName::Implicit
         | LifetimeName::ImplicitObjectLifetimeDefault
         | LifetimeName::Underscore => {}
     }