Rollup merge of rust-lang#125483 - workingjubilee:move-transform-validate-to-mir-transform, r=oli-obk

compiler: validate.rs belongs next to what it validates

It's hard to find code that is deeply nested and far away from its callsites, so let's move `rustc_const_eval::transform::validate` into `rustc_mir_transform`, where all of its callers are. As `rustc_mir_transform` already depends on `rustc_const_eval`, the added visible dependency edge doesn't mean the dependency tree got any worse.

This also lets us unnest the `check_consts` module.

I did look into moving everything inside `rustc_const_eval::transform` into `rustc_mir_transform`. It turned out to be a much more complex operation, with more concerns and real edges into the `const_eval` crate, whereas this was both faster and more obvious.

Author: matthiaskrgr

Cargo.lock

@@ -4252,6 +4252,7 @@ dependencies = [
  "rustc_fluent_macro",
  "rustc_hir",
  "rustc_index",
+ "rustc_infer",
  "rustc_macros",
  "rustc_middle",
  "rustc_mir_build",

compiler/rustc_const_eval/src/transform/check_consts/check.rs renamed to compiler/rustc_const_eval/src/check_consts/check.rs

@@ -14,10 +14,10 @@
 #![feature(yeet_expr)]
 #![feature(if_let_guard)]
 
+pub mod check_consts;
 pub mod const_eval;
 mod errors;
 pub mod interpret;
-pub mod transform;
 pub mod util;
 
 use std::sync::atomic::AtomicBool;

compiler/rustc_const_eval/src/transform/check_consts/mod.rs renamed to compiler/rustc_const_eval/src/check_consts/mod.rs

@@ -16,6 +16,7 @@ rustc_errors = { path = "../rustc_errors" }
 rustc_fluent_macro = { path = "../rustc_fluent_macro" }
 rustc_hir = { path = "../rustc_hir" }
 rustc_index = { path = "../rustc_index" }
+rustc_infer = { path = "../rustc_infer" }
 rustc_macros = { path = "../rustc_macros" }
 rustc_middle = { path = "../rustc_middle" }
 rustc_mir_build = { path = "../rustc_mir_build" }