Rename HIR UnOp variants

This renames the variants in HIR UnOp from

    enum UnOp {
        UnDeref,
        UnNot,
        UnNeg,
    }

to

    enum UnOp {
        Deref,
        Not,
        Neg,
    }

Motivations:

- This is more consistent with the rest of the code base where most enum
  variants don't have a prefix.

- These variants are never used without the `UnOp` prefix so the extra
  `Un` prefix doesn't help with readability. E.g. we don't have any
  `UnDeref`s in the code, we only have `UnOp::UnDeref`.

- MIR `UnOp` type variants don't have a prefix so this is more
  consistent with MIR types.

- "un" prefix reads like "inverse" or "reverse", so as a beginner in
  rustc code base when I see "UnDeref" what comes to my mind is
  something like "&*" instead of just "*".

1 files changed, 3 insertions, 3 deletions

diff --git a/compiler/rustc_ast_lowering/src/expr.rs b/compiler/rustc_ast_lowering/src/expr.rs
index 4d6afd2fe0d..b118c0eaed4 100644
--- a/compiler/rustc_ast_lowering/src/expr.rs
+++ b/compiler/rustc_ast_lowering/src/expr.rs
@@ -260,9 +260,9 @@ impl<'hir> LoweringContext<'_, 'hir> {
 
     fn lower_unop(&mut self, u: UnOp) -> hir::UnOp {
         match u {
-            UnOp::Deref => hir::UnOp::UnDeref,
-            UnOp::Not => hir::UnOp::UnNot,
-            UnOp::Neg => hir::UnOp::UnNeg,
+            UnOp::Deref => hir::UnOp::Deref,
+            UnOp::Not => hir::UnOp::Not,
+            UnOp::Neg => hir::UnOp::Neg,
         }
     }