Update (doc) comments

Several (doc) comments were super outdated or didn't provide enough context.

Some doc comments shoved everything in a single paragraph without respecting
the fact that the first paragraph should be a single sentence because rustdoc
treats these as item descriptions / synopses on module pages.

book/src/development/type_checking.md

@@ -118,10 +118,10 @@ Here the HIR sees the types without "thinking" about them, it knows that the fun
 an `u32`. As far as `hir::Ty` is concerned those might be different types. But at the `ty::Ty` level the compiler
 understands that they're the same type, in-depth lifetimes, etc...
 
-To get from a `hir::Ty` to a `ty::Ty`, you can use the [`hir_ty_to_ty`][hir_ty_to_ty] function outside of bodies or
+To get from a `hir::Ty` to a `ty::Ty`, you can use the [`lower_ty`][lower_ty] function outside of bodies or
 the [`TypeckResults::node_type()`][node_type] method inside of bodies.
 
-> **Warning**: Don't use `hir_ty_to_ty` inside of bodies, because this can cause ICEs.
+> **Warning**: Don't use `lower_ty` inside of bodies, because this can cause ICEs.
 
 ## Creating Types programmatically
 
@@ -162,6 +162,6 @@ in this chapter:
 [Ty]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_middle/ty/struct.Ty.html
 [TyKind]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_type_ir/ty_kind/enum.TyKind.html
 [TypeckResults]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_middle/ty/struct.TypeckResults.html
-[middle_ty]: https://doc.rust-lang.org/beta/nightly-rustc/rustc_middle/ty/struct.Ty.html
-[hir_ty]: https://doc.rust-lang.org/beta/nightly-rustc/rustc_hir/struct.Ty.html
-[hir_ty_to_ty]: https://doc.rust-lang.org/beta/nightly-rustc/rustc_hir_analysis/fn.hir_ty_to_ty.html
+[middle_ty]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_middle/ty/struct.Ty.html
+[hir_ty]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_hir/struct.Ty.html
+[lower_ty]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_hir_analysis/fn.lower_ty.html

clippy_lints/src/types/redundant_allocation.rs

@@ -56,7 +56,7 @@ pub(super) fn check<'tcx>(cx: &LateContext<'tcx>, hir_ty: &hir::Ty<'tcx>, qpath:
     };
     let inner_span = match qpath_generic_tys(inner_qpath).next() {
         Some(hir_ty) => {
-            // Reallocation of a fat pointer causes it to become thin. `hir_ty_to_ty` is safe to use
+            // Reallocation of a fat pointer causes it to become thin. `lower_ty` is safe to use
             // here because `mod.rs` guarantees this lint is only run on types outside of bodies and
             // is not run on locals.
             let ty = lower_ty(cx.tcx, hir_ty);

clippy_lints/src/use_self.rs

@@ -193,7 +193,7 @@ impl<'tcx> LateLintPass<'tcx> for UseSelf {
     }
 
     fn check_body(&mut self, _: &LateContext<'_>, _: &hir::Body<'_>) {
-        // `hir_ty_to_ty` cannot be called in `Body`s or it will panic (sometimes). But in bodies
+        // `lower_ty` cannot be called in `Body`s or it will panic (sometimes). But in bodies
         // we can use `cx.typeck_results.node_type(..)` to get the `ty::Ty` from a `hir::Ty`.
         // However the `node_type()` method can *only* be called in bodies.
         if let Some(&mut StackItem::Check { ref mut in_body, .. }) = self.stack.last_mut() {

tests/ui/crashes/ice-6179.rs

@@ -1,5 +1,5 @@
 //! This is a minimal reproducer for the ICE in https://github.com/rust-lang/rust-clippy/pull/6179.
-//! The ICE is mainly caused by using `hir_ty_to_ty`. See the discussion in the PR for details.
+//! The ICE is mainly caused by using `lower_ty`. See the discussion in the PR for details.
 
 #![warn(clippy::use_self)]
 #![allow(dead_code, clippy::let_with_type_underscore)]