Remove deprecated lang items

They have been deprecated for years and there is no trace left of them
in the compiler.

Author: leoyvens

src/librustc/middle/lang_items.rs

@@ -327,14 +327,6 @@ language_item_table! {
 
     PhantomDataItem,                 "phantom_data",            phantom_data;
 
-    // Deprecated:
-    CovariantTypeItem,               "covariant_type",          covariant_type;
-    ContravariantTypeItem,           "contravariant_type",      contravariant_type;
-    InvariantTypeItem,               "invariant_type",          invariant_type;
-    CovariantLifetimeItem,           "covariant_lifetime",      covariant_lifetime;
-    ContravariantLifetimeItem,       "contravariant_lifetime",  contravariant_lifetime;
-    InvariantLifetimeItem,           "invariant_lifetime",      invariant_lifetime;
-
     NonZeroItem,                     "non_zero",                non_zero;
 
     DebugTraitLangItem,              "debug_trait",             debug_trait;

src/librustc_typeck/variance/terms.rs

@@ -98,15 +98,6 @@ fn lang_items(tcx: TyCtxt) -> Vec<(ast::NodeId, Vec<ty::Variance>)> {
     let all = vec![
         (lang_items.phantom_data(), vec![ty::Covariant]),
         (lang_items.unsafe_cell_type(), vec![ty::Invariant]),
-
-        // Deprecated:
-        (lang_items.covariant_type(), vec![ty::Covariant]),
-        (lang_items.contravariant_type(), vec![ty::Contravariant]),
-        (lang_items.invariant_type(), vec![ty::Invariant]),
-        (lang_items.covariant_lifetime(), vec![ty::Covariant]),
-        (lang_items.contravariant_lifetime(), vec![ty::Contravariant]),
-        (lang_items.invariant_lifetime(), vec![ty::Invariant]),
-
         ];
 
     all.into_iter() // iterating over (Option<DefId>, Variance)