Add warn(unreachable_pub) to rustc_type_ir.

Author: nnethercote

compiler/rustc_type_ir/src/fold.rs

@@ -354,7 +354,7 @@ struct Shifter<I: Interner> {
 }
 
 impl<I: Interner> Shifter<I> {
-    pub fn new(cx: I, amount: u32) -> Self {
+    fn new(cx: I, amount: u32) -> Self {
         Shifter { cx, current_index: ty::INNERMOST, amount }
     }
 }

compiler/rustc_type_ir/src/lib.rs

@@ -5,6 +5,7 @@
     feature(associated_type_defaults, never_type, rustc_attrs, negative_impls)
 )]
 #![cfg_attr(feature = "nightly", allow(internal_features))]
+#![warn(unreachable_pub)]
 // tidy-alphabetical-end
 
 extern crate self as rustc_type_ir;