Replace LifetimeRes::Anonymous by LifetimeRes::Infer.

compiler/rustc_hir/src/def.rs

@@ -738,11 +738,8 @@ pub enum LifetimeRes {
         binder: NodeId,
     },
     /// This variant is used for anonymous lifetimes that we did not resolve during
-    /// late resolution.  Shifting the work to the HIR lifetime resolver.
-    Anonymous {
-        /// Id of the introducing place. See `Param`.
-        binder: NodeId,
-    },
+    /// late resolution.  Those lifetimes will be inferred by typechecking.
+    Infer,
     /// Explicit `'static` lifetime.
     Static,
     /// Resolution failure.

compiler/rustc_hir/src/hir.rs

@@ -108,7 +108,8 @@ pub enum LifetimeName {
     Error,
 
     /// User wrote an anonymous lifetime, either `'_` or nothing.
-    Underscore,
+    /// The semantics of this lifetime should be inferred by typechecking code.
+    Infer,
 
     /// User wrote `'static`.
     Static,
@@ -118,7 +119,7 @@ impl LifetimeName {
     pub fn ident(&self) -> Ident {
         match *self {
             LifetimeName::ImplicitObjectLifetimeDefault | LifetimeName::Error => Ident::empty(),
-            LifetimeName::Underscore => Ident::with_dummy_span(kw::UnderscoreLifetime),
+            LifetimeName::Infer => Ident::with_dummy_span(kw::UnderscoreLifetime),
             LifetimeName::Static => Ident::with_dummy_span(kw::StaticLifetime),
             LifetimeName::Param(_, param_name) => param_name.ident(),
         }
@@ -127,7 +128,7 @@ impl LifetimeName {
     pub fn is_anonymous(&self) -> bool {
         match *self {
             LifetimeName::ImplicitObjectLifetimeDefault
-            | LifetimeName::Underscore
+            | LifetimeName::Infer
             | LifetimeName::Param(_, ParamName::Fresh)
             | LifetimeName::Error => true,
             LifetimeName::Static | LifetimeName::Param(..) => false,
@@ -136,7 +137,7 @@ impl LifetimeName {
 
     pub fn is_elided(&self) -> bool {
         match self {
-            LifetimeName::ImplicitObjectLifetimeDefault | LifetimeName::Underscore => true,
+            LifetimeName::ImplicitObjectLifetimeDefault | LifetimeName::Infer => 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

@@ -497,7 +497,7 @@ pub fn walk_lifetime<'v, V: Visitor<'v>>(visitor: &mut V, lifetime: &'v Lifetime
         | LifetimeName::Static
         | LifetimeName::Error
         | LifetimeName::ImplicitObjectLifetimeDefault
-        | LifetimeName::Underscore => {}
+        | LifetimeName::Infer => {}
     }
 }