Simplify for loop desugar

compiler/rustc_span/src/hygiene.rs

@@ -1099,18 +1099,11 @@ pub enum DesugaringKind {
     OpaqueTy,
     Async,
     Await,
-    ForLoop(ForLoopLoc),
+    ForLoop,
     LetElse,
     WhileLoop,
 }
 
-/// A location in the desugaring of a `for` loop
-#[derive(Clone, Copy, PartialEq, Debug, Encodable, Decodable, HashStable_Generic)]
-pub enum ForLoopLoc {
-    Head,
-    IntoIter,
-}
-
 impl DesugaringKind {
     /// The description wording should combine well with "desugaring of {}".
     pub fn descr(self) -> &'static str {
@@ -1121,7 +1114,7 @@ impl DesugaringKind {
             DesugaringKind::QuestionMark => "operator `?`",
             DesugaringKind::TryBlock => "`try` block",
             DesugaringKind::OpaqueTy => "`impl Trait`",
-            DesugaringKind::ForLoop(_) => "`for` loop",
+            DesugaringKind::ForLoop => "`for` loop",
             DesugaringKind::LetElse => "`let...else`",
             DesugaringKind::WhileLoop => "`while` loop",
         }

compiler/rustc_span/src/lib.rs

@@ -41,7 +41,7 @@ pub mod edition;
 use edition::Edition;
 pub mod hygiene;
 use hygiene::Transparency;
-pub use hygiene::{DesugaringKind, ExpnKind, ForLoopLoc, MacroKind};
+pub use hygiene::{DesugaringKind, ExpnKind, MacroKind};
 pub use hygiene::{ExpnData, ExpnHash, ExpnId, LocalExpnId, SyntaxContext};
 pub mod def_id;
 use def_id::{CrateNum, DefId, DefPathHash, LocalDefId, LOCAL_CRATE};

compiler/rustc_span/src/symbol.rs

@@ -269,7 +269,6 @@ symbols! {
         __D,
         __H,
         __S,
-        __next,
         __try_var,
         _args,
         _d,