Rollup merge of #133746 - oli-obk:push-xwyrylxmrtvq, r=jieyouxu

Change `AttrArgs::Eq` to a struct variant

Cleanups for simplifying https://github.com/rust-lang/rust/pull/131808

Basically changes `AttrArgs::Eq` to a struct variant and then avoids several matches on `AttrArgsEq` in favor of methods on it. This will make future refactorings simpler, as they can either keep methods or switch to field accesses without having to restructure code

compiler/rustc_ast_lowering/src/lib.rs

@@ -889,7 +889,8 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
             // This is an inert key-value attribute - it will never be visible to macros
             // after it gets lowered to HIR. Therefore, we can extract literals to handle
             // nonterminals in `#[doc]` (e.g. `#[doc = $e]`).
-            AttrArgs::Eq(eq_span, AttrArgsEq::Ast(expr)) => {
+            &AttrArgs::Eq { eq_span, ref value } => {
+                let expr = value.unwrap_ast();
                 // In valid code the value always ends up as a single literal. Otherwise, a dummy
                 // literal suffices because the error is handled elsewhere.
                 let lit = if let ExprKind::Lit(token_lit) = expr.kind
@@ -905,10 +906,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
                         span: DUMMY_SP,
                     }
                 };
-                AttrArgs::Eq(*eq_span, AttrArgsEq::Hir(lit))
-            }
-            AttrArgs::Eq(_, AttrArgsEq::Hir(lit)) => {
-                unreachable!("in literal form when lowering mac args eq: {:?}", lit)
+                AttrArgs::Eq { eq_span, value: AttrArgsEq::Hir(lit) }
             }
         }
     }