compiler: start using rustc_ast_lowering in rustc_passes

Author: workingjubilee

Diff for: Cargo.lock

@@ -4364,6 +4364,7 @@ version = "0.0.0"
 dependencies = [
  "rustc_abi",
  "rustc_ast",
+ "rustc_ast_lowering",
  "rustc_ast_pretty",
  "rustc_attr_parsing",
  "rustc_data_structures",

Diff for: compiler/rustc_ast_lowering/src/lib.rs

@@ -83,7 +83,7 @@ mod index;
 mod item;
 mod pat;
 mod path;
-mod stability;
+pub mod stability;
 
 rustc_fluent_macro::fluent_messages! { "../messages.ftl" }
 

Diff for: compiler/rustc_ast_lowering/src/stability.rs

@@ -47,7 +47,7 @@ pub(crate) fn gate_unstable_abi(sess: &Session, features: &Features, span: Span,
     }
 }
 
-pub(crate) struct UnstableAbi {
+pub struct UnstableAbi {
     abi: ExternAbi,
     feature: Symbol,
     explain: GateReason,
@@ -74,7 +74,7 @@ impl fmt::Display for UnstableAbi {
     }
 }
 
-pub(crate) fn extern_abi_stability(abi: ExternAbi) -> Result<(), UnstableAbi> {
+pub fn extern_abi_stability(abi: ExternAbi) -> Result<(), UnstableAbi> {
     match abi {
         // stable ABIs
         ExternAbi::Rust

Diff for: compiler/rustc_passes/Cargo.toml

@@ -7,6 +7,7 @@ edition = "2021"
 # tidy-alphabetical-start
 rustc_abi = { path = "../rustc_abi" }
 rustc_ast = { path = "../rustc_ast" }
+rustc_ast_lowering = { path = "../rustc_ast_lowering" }
 rustc_ast_pretty = { path = "../rustc_ast_pretty" }
 rustc_attr_parsing = { path = "../rustc_attr_parsing" }
 rustc_data_structures = { path = "../rustc_data_structures" }

Diff for: compiler/rustc_passes/src/stability.rs

@@ -4,6 +4,7 @@
 use std::mem::replace;
 use std::num::NonZero;
 
+use rustc_ast_lowering::stability::extern_abi_stability;
 use rustc_attr_parsing::{
     self as attr, ConstStability, DeprecatedSince, Stability, StabilityLevel, StableSince,
     UnstableReason, VERSION_PLACEHOLDER,
@@ -1027,8 +1028,8 @@ impl<'tcx> Visitor<'tcx> for CheckTraitImplStable<'tcx> {
         if let TyKind::Never = t.kind {
             self.fully_stable = false;
         }
-        if let TyKind::BareFn(f) = t.kind {
-            if rustc_target::spec::abi::is_stable(f.abi.name()).is_err() {
+        if let TyKind::BareFn(function) = t.kind {
+            if extern_abi_stability(function.abi).is_err() {
                 self.fully_stable = false;
             }
         }