Rollup merge of #68111 - varkor:const-generics-type_name, r=oli-obk

Print constants in `type_name` for const generics

Fixes https://github.com/rust-lang/rust/issues/65372.

r? @oli-obk as there may have been a deliberate decision not to in 5b9848912a (diff-4ed1a72c0bfdf17be769ed520932cd02R80).

src/test/ui/const-generics/const-generic-type_name.rs

@@ -0,0 +1,11 @@
+// run-pass
+
+#![feature(const_generics)]
+//~^ WARN the feature `const_generics` is incomplete and may cause the compiler to crash
+
+#[derive(Debug)]
+struct S<const N: usize>;
+
+fn main() {
+    assert_eq!(std::any::type_name::<S<3>>(), "const_generic_type_name::S<3usize>");
+}

src/test/ui/const-generics/const-generic-type_name.stderr

@@ -0,0 +1,8 @@
+warning: the feature `const_generics` is incomplete and may cause the compiler to crash
+  --> $DIR/const-generic-type_name.rs:3:12
+   |
+LL | #![feature(const_generics)]
+   |            ^^^^^^^^^^^^^^
+   |
+   = note: `#[warn(incomplete_features)]` on by default
+