Rollup merge of #100003 - nnethercote:improve-size-assertions, r=lqd

Improve size assertions.

- For any file with four or more size assertions, move them into a
  separate module (as is already done for `hir.rs`).
- Add some more for AST nodes and THIR nodes.
- Put the `hir.rs` ones in alphabetical order.

r? `@lqd`

compiler/rustc_middle/src/thir.rs

@@ -190,10 +190,6 @@ pub enum StmtKind<'tcx> {
     },
 }
 
-// `Expr` is used a lot. Make sure it doesn't unintentionally get bigger.
-#[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))]
-rustc_data_structures::static_assert_size!(Expr<'_>, 104);
-
 #[derive(Clone, Debug, Copy, PartialEq, Eq, Hash, HashStable, TyEncodable, TyDecodable)]
 #[derive(TypeFoldable, TypeVisitable)]
 pub struct LocalVarId(pub hir::HirId);
@@ -812,3 +808,14 @@ impl<'tcx> fmt::Display for Pat<'tcx> {
         }
     }
 }
+
+// Some nodes are used a lot. Make sure they don't unintentionally get bigger.
+#[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))]
+mod size_asserts {
+    use super::*;
+    // These are in alphabetical order, which is easy to maintain.
+    rustc_data_structures::static_assert_size!(Block, 56);
+    rustc_data_structures::static_assert_size!(Expr<'_>, 104);
+    rustc_data_structures::static_assert_size!(Pat<'_>, 24);
+    rustc_data_structures::static_assert_size!(Stmt<'_>, 120);
+}