Remove rustc_transmute's dependence on rustc_macros.

Author: nnethercote

Cargo.lock

@@ -4500,7 +4500,6 @@ dependencies = [
  "rustc_abi",
  "rustc_data_structures",
  "rustc_hir",
- "rustc_macros",
  "rustc_middle",
  "rustc_span",
  "tracing",

compiler/rustc_transmute/Cargo.toml

@@ -8,7 +8,6 @@ edition = "2024"
 rustc_abi = { path = "../rustc_abi", optional = true }
 rustc_data_structures = { path = "../rustc_data_structures" }
 rustc_hir = { path = "../rustc_hir", optional = true }
-rustc_macros = { path = "../rustc_macros", optional = true }
 rustc_middle = { path = "../rustc_middle", optional = true }
 rustc_span = { path = "../rustc_span", optional = true }
 tracing = "0.1"
@@ -18,7 +17,6 @@ tracing = "0.1"
 rustc = [
     "dep:rustc_abi",
     "dep:rustc_hir",
-    "dep:rustc_macros",
     "dep:rustc_middle",
     "dep:rustc_span",
 ]

compiler/rustc_transmute/src/lib.rs

@@ -81,14 +81,13 @@ pub enum Reason<T> {
 #[cfg(feature = "rustc")]
 mod rustc {
     use rustc_hir::lang_items::LangItem;
-    use rustc_macros::TypeVisitable;
     use rustc_middle::traits::ObligationCause;
     use rustc_middle::ty::{Const, ParamEnv, Ty, TyCtxt};
 
     use super::*;
 
     /// The source and destination types of a transmutation.
-    #[derive(TypeVisitable, Debug, Clone, Copy)]
+    #[derive(Debug, Clone, Copy)]
     pub struct Types<'tcx> {
         /// The source type.
         pub src: Ty<'tcx>,