Rollup merge of #104559 - nnethercote:split-MacArgs, r=petrochenkov

Split `MacArgs` in two.

`MacArgs` is an enum with three variants: `Empty`, `Delimited`, and `Eq`. It's used in two ways:
- For representing attribute macro arguments (e.g. in `AttrItem`), where all three variants are used.
- For representing function-like macros (e.g. in `MacCall` and `MacroDef`), where only the `Delimited` variant is used.

In other words, `MacArgs` is used in two quite different places due to them having partial overlap. I find this makes the code hard to read. It also leads to various unreachable code paths, and allows invalid values (such as accidentally using `MacArgs::Empty` in a `MacCall`).

This commit splits `MacArgs` in two:
- `DelimArgs` is a new struct just for the "delimited arguments" case. It is now used in `MacCall` and `MacroDef`.
- `AttrArgs` is a renaming of the old `MacArgs` enum for the attribute macro case. Its `Delimited` variant now contains a `DelimArgs`.

Various other related things are renamed as well.

These changes make the code clearer, avoids several unreachable paths, and disallows the invalid values.

r? `@petrochenkov`

1 files changed, 1 insertions, 1 deletions

diff --git a/compiler/rustc_middle/src/ty/parameterized.rs b/compiler/rustc_middle/src/ty/parameterized.rs
index e1e705a922f..d6025248081 100644
--- a/compiler/rustc_middle/src/ty/parameterized.rs
+++ b/compiler/rustc_middle/src/ty/parameterized.rs
@@ -70,7 +70,7 @@ trivially_parameterized_over_tcx! {
     ty::adjustment::CoerceUnsizedInfo,
     ty::fast_reject::SimplifiedTypeGen<DefId>,
     rustc_ast::Attribute,
-    rustc_ast::MacArgs,
+    rustc_ast::DelimArgs,
     rustc_attr::ConstStability,
     rustc_attr::DefaultBodyStability,
     rustc_attr::Deprecation,