tidy + move logic to fn

Author: BoxyUwU

compiler/rustc_error_messages/locales/en-US/hir_analysis.ftl

@@ -147,6 +147,6 @@ hir_analysis_const_impl_for_non_const_trait =
 hir_analysis_const_bound_for_non_const_trait =
     ~const can only be applied to `#[const_trait]` traits
 
-hir_analysis_self_in_impl_self = 
+hir_analysis_self_in_impl_self =
     `Self` is not valid in the self type of an impl block
-    .note = replace `Self` with a different type
+    .note = replace `Self` with a different type

compiler/rustc_hir/src/hir.rs

@@ -2418,6 +2418,30 @@ impl<'hir> Ty<'hir> {
         }
         final_ty
     }
+
+    pub fn find_self_aliases(&self) -> Vec<Span> {
+        use crate::intravisit::Visitor;
+        struct MyVisitor(Vec<Span>);
+        impl<'v> Visitor<'v> for MyVisitor {
+            fn visit_ty(&mut self, t: &'v Ty<'v>) {
+                if matches!(
+                    &t.kind,
+                    TyKind::Path(QPath::Resolved(
+                        _,
+                        Path { res: crate::def::Res::SelfTyAlias { .. }, .. },
+                    ))
+                ) {
+                    self.0.push(t.span);
+                    return;
+                }
+                crate::intravisit::walk_ty(self, t);
+            }
+        }
+
+        let mut my_visitor = MyVisitor(vec![]);
+        my_visitor.visit_ty(self);
+        my_visitor.0
+    }
 }
 
 /// Not represented directly in the AST; referred to by name through a `ty_path`.

compiler/rustc_hir_analysis/src/collect/type_of.rs

@@ -319,36 +319,11 @@ pub(super) fn type_of(tcx: TyCtxt<'_>, def_id: DefId) -> Ty<'_> {
                     }
                 }
                 ItemKind::TyAlias(self_ty, _) => icx.to_ty(self_ty),
-                ItemKind::Impl(
-                    hir::Impl { self_ty, .. }
-                ) => {
-                    struct MyVisitor(Vec<Span>);
-                    impl<'v> hir::intravisit::Visitor<'v> for MyVisitor {
-                        fn visit_ty(&mut self, t: &'v Ty<'v>) {
-                            if matches!(
-                                &t.kind,
-                                TyKind::Path(hir::QPath::Resolved(
-                                    _,
-                                    Path {
-                                        res: hir::def::Res::SelfTyAlias { .. },
-                                        ..
-                                    },
-                                ))
-                            ) {
-                                self.0.push(t.span);
-                                return;
-                            }
-                            hir::intravisit::walk_ty(self, t);
-                        }
-                    }
-
-                    let mut my_visitor = MyVisitor(vec![]);
-                    my_visitor.visit_ty(self_ty);
-
-                    match my_visitor.0 {
-                        spans if spans.len() > 0 => { 
+                ItemKind::Impl(hir::Impl { self_ty, .. }) => {
+                    match self_ty.find_self_aliases() {
+                        spans if spans.len() > 0 => {
                             tcx.sess.emit_err(crate::errors::SelfInImplSelf { span: spans.into(), note: (), });
-                            tcx.ty_error() 
+                            tcx.ty_error()
                         },
                         _ => icx.to_ty(*self_ty),
                     }