Rollup merge of #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.

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/lib.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/mod.rs

@@ -1,2 +0,0 @@
-pub mod check_consts;
-pub mod validate;

compiler/rustc_mir_transform/Cargo.toml

@@ -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" }

compiler/rustc_mir_transform/src/inline.rs

@@ -1,7 +1,6 @@
 //! Inlining pass for MIR functions
 use crate::deref_separator::deref_finder;
 use rustc_attr::InlineAttr;
-use rustc_const_eval::transform::validate::validate_types;
 use rustc_hir::def::DefKind;
 use rustc_hir::def_id::DefId;
 use rustc_index::bit_set::BitSet;
@@ -21,6 +20,7 @@
 use crate::cost_checker::CostChecker;
 use crate::simplify::simplify_cfg;
 use crate::util;
+use crate::validate::validate_types;
 use std::iter;
 use std::ops::{Range, RangeFrom};
 

compiler/rustc_mir_transform/src/lib.rs

@@ -109,9 +109,9 @@
 mod sroa;
 mod unreachable_enum_branching;
 mod unreachable_prop;
+mod validate;
 
-use rustc_const_eval::transform::check_consts::{self, ConstCx};
-use rustc_const_eval::transform::validate;
+use rustc_const_eval::check_consts::{self, ConstCx};
 use rustc_mir_dataflow::rustc_peek;
 
 rustc_fluent_macro::fluent_messages! { "../messages.ftl" }

compiler/rustc_mir_transform/src/promote_consts.rs

@@ -30,7 +30,7 @@
 use std::cell::Cell;
 use std::{cmp, iter, mem};
 
-use rustc_const_eval::transform::check_consts::{qualifs, ConstCx};
+use rustc_const_eval::check_consts::{qualifs, ConstCx};
 
 /// A `MirPass` for promotion.
 ///

src/tools/clippy/clippy_utils/src/qualify_min_const_fn.rs

@@ -6,7 +6,7 @@
 use clippy_config::msrvs::{self, Msrv};
 use hir::LangItem;
 use rustc_attr::StableSince;
-use rustc_const_eval::transform::check_consts::ConstCx;
+use rustc_const_eval::check_consts::ConstCx;
 use rustc_hir as hir;
 use rustc_hir::def_id::DefId;
 use rustc_infer::infer::TyCtxtInferExt;

src/tools/miri/tests/panic/mir-validation.stderr

@@ -1,4 +1,4 @@
-thread 'rustc' panicked at compiler/rustc_const_eval/src/transform/validate.rs:LL:CC:
+thread 'rustc' panicked at compiler/rustc_mir_transform/src/validate.rs:LL:CC:
 broken MIR in Item(DefId) (after phase change to runtime-optimized) at bb0[1]:
 (*(_2.0: *mut i32)), has deref at the wrong place
 stack backtrace: