rustdoc: Rename SelfTy to ReceiverTy

`SelfTy` makes it sound like it is literally the `Self` type, whereas in
fact it may be `&Self` or other types. Plus, I want to use the name
`SelfTy` for a new variant of `clean::Type`. Having both causes
resolution conflicts or at least confusion.

src/librustdoc/clean/types.rs

@@ -34,7 +34,7 @@
 use {rustc_ast as ast, rustc_hir as hir};
 
 pub(crate) use self::ItemKind::*;
-pub(crate) use self::SelfTy::*;
+pub(crate) use self::ReceiverTy::*;
 pub(crate) use self::Type::{
     Array, BareFunction, BorrowedRef, DynTrait, Generic, ImplTrait, Infer, Primitive, QPath,
     RawPointer, Slice, Tuple,
@@ -1384,8 +1384,8 @@ pub(crate) struct FnDecl {
 }
 
 impl FnDecl {
-    pub(crate) fn self_type(&self) -> Option<SelfTy> {
-        self.inputs.values.get(0).and_then(|v| v.to_self())
+    pub(crate) fn receiver_type(&self) -> Option<ReceiverTy> {
+        self.inputs.values.get(0).and_then(|v| v.to_receiver())
     }
 }
 
@@ -1404,14 +1404,14 @@ pub(crate) struct Argument {
 }
 
 #[derive(Clone, PartialEq, Debug)]
-pub(crate) enum SelfTy {
+pub(crate) enum ReceiverTy {
     SelfValue,
     SelfBorrowed(Option<Lifetime>, Mutability),
     SelfExplicit(Type),
 }
 
 impl Argument {
-    pub(crate) fn to_self(&self) -> Option<SelfTy> {
+    pub(crate) fn to_receiver(&self) -> Option<ReceiverTy> {
         if self.name != kw::SelfLower {
             return None;
         }

src/librustdoc/html/format.rs

@@ -1452,7 +1452,7 @@ fn inner_full_print(
 
         let last_input_index = self.inputs.values.len().checked_sub(1);
         for (i, input) in self.inputs.values.iter().enumerate() {
-            if let Some(selfty) = input.to_self() {
+            if let Some(selfty) = input.to_receiver() {
                 match selfty {
                     clean::SelfValue => {
                         write!(f, "self")?;

src/librustdoc/html/render/mod.rs

@@ -58,7 +58,7 @@
 
 pub(crate) use self::context::*;
 pub(crate) use self::span_map::{collect_spans_and_sources, LinkFromSrc};
-use crate::clean::{self, ItemId, RenderedLink, SelfTy};
+use crate::clean::{self, ItemId, ReceiverTy, RenderedLink};
 use crate::error::Error;
 use crate::formats::cache::Cache;
 use crate::formats::item_type::ItemType;
@@ -1372,21 +1372,21 @@ fn render_deref_methods(
 
 fn should_render_item(item: &clean::Item, deref_mut_: bool, tcx: TyCtxt<'_>) -> bool {
     let self_type_opt = match *item.kind {
-        clean::MethodItem(ref method, _) => method.decl.self_type(),
-        clean::TyMethodItem(ref method) => method.decl.self_type(),
+        clean::MethodItem(ref method, _) => method.decl.receiver_type(),
+        clean::TyMethodItem(ref method) => method.decl.receiver_type(),
         _ => None,
     };
 
     if let Some(self_ty) = self_type_opt {
         let (by_mut_ref, by_box, by_value) = match self_ty {
-            SelfTy::SelfBorrowed(_, mutability)
-            | SelfTy::SelfExplicit(clean::BorrowedRef { mutability, .. }) => {
+            ReceiverTy::SelfBorrowed(_, mutability)
+            | ReceiverTy::SelfExplicit(clean::BorrowedRef { mutability, .. }) => {
                 (mutability == Mutability::Mut, false, false)
             }
-            SelfTy::SelfExplicit(clean::Type::Path { path }) => {
+            ReceiverTy::SelfExplicit(clean::Type::Path { path }) => {
                 (false, Some(path.def_id()) == tcx.lang_items().owned_box(), false)
             }
-            SelfTy::SelfValue => (false, false, true),
+            ReceiverTy::SelfValue => (false, false, true),
             _ => (false, false, false),
         };