Warn about unknown or renamed lints

Originally I tried to do a much broader refactoring that got rid of `init_lints` altogether. My reasoning is that now the lints aren't being run anymore (after https://github.com/rust-lang/rust/pull/73566), there's no need to ignore them explicitly. But it seems there are still some lints that aren't affected by setting `lint_mod` to a no-op:

```
deny(pub_use_of_private_extern_crate)
deny(const_err)
warn(unused_imports)
```

(there are possibly more, these are just the ones that failed in the rustdoc test suite).

Some of these seem like we really should be warning about, but that's a much larger change and I don't propose to make it here. So for the time being, this just adds the `unknown_lints` and `renamed_or_removed_lints` passes to the list of lints rustdoc warns about.

3 files changed, 45 insertions, 2 deletions

diff --git a/src/librustdoc/core.rs b/src/librustdoc/core.rs
index e3086d32b5c..6952e6ed40e 100644
--- a/src/librustdoc/core.rs
+++ b/src/librustdoc/core.rs
@@ -234,7 +234,7 @@ pub fn new_handler(
 /// It returns a tuple containing:
 ///  * Vector of tuples of lints' name and their associated "max" level
 ///  * HashMap of lint id with their associated "max" level
-pub fn init_lints<F>(
+pub(crate) fn init_lints<F>(
     mut allowed_lints: Vec<String>,
     lint_opts: Vec<(String, lint::Level)>,
     filter_call: F,
@@ -257,7 +257,10 @@ where
         .filter_map(|lint| {
             // Permit feature-gated lints to avoid feature errors when trying to
             // allow all lints.
-            if lint.name == warnings_lint_name || lint.feature_gate.is_some() {
+            if lint.name == warnings_lint_name
+                || lint.feature_gate.is_some()
+                || allowed_lints.iter().any(|l| lint.name == l)
+            {
                 None
             } else {
                 filter_call(lint)
@@ -328,6 +331,8 @@ pub fn run_core(
     let private_doc_tests = rustc_lint::builtin::PRIVATE_DOC_TESTS.name;
     let no_crate_level_docs = rustc_lint::builtin::MISSING_CRATE_LEVEL_DOCS.name;
     let invalid_codeblock_attributes_name = rustc_lint::builtin::INVALID_CODEBLOCK_ATTRIBUTES.name;
+    let renamed_and_removed_lints = rustc_lint::builtin::RENAMED_AND_REMOVED_LINTS.name;
+    let unknown_lints = rustc_lint::builtin::UNKNOWN_LINTS.name;
 
     // In addition to those specific lints, we also need to allow those given through
     // command line, otherwise they'll get ignored and we don't want that.
@@ -338,6 +343,8 @@ pub fn run_core(
         private_doc_tests.to_owned(),
         no_crate_level_docs.to_owned(),
         invalid_codeblock_attributes_name.to_owned(),
+        renamed_and_removed_lints.to_owned(),
+        unknown_lints.to_owned(),
     ];
 
     let (lint_opts, lint_caps) = init_lints(lints_to_show, lint_opts, |lint| {
diff --git a/src/test/rustdoc-ui/unknown-renamed-lints.rs b/src/test/rustdoc-ui/unknown-renamed-lints.rs
new file mode 100644
index 00000000000..7faa82ea429
--- /dev/null
+++ b/src/test/rustdoc-ui/unknown-renamed-lints.rs
@@ -0,0 +1,8 @@
+#![deny(unknown_lints)]
+//~^ NOTE lint level is defined
+#![deny(renamed_and_removed_lints)]
+//~^ NOTE lint level is defined
+#![deny(x)]
+//~^ ERROR unknown lint
+#![deny(intra_doc_link_resolution_failure)]
+//~^ ERROR lint `intra_doc_link_resolution_failure` has been renamed
diff --git a/src/test/rustdoc-ui/unknown-renamed-lints.stderr b/src/test/rustdoc-ui/unknown-renamed-lints.stderr
new file mode 100644
index 00000000000..f0917f194bb
--- /dev/null
+++ b/src/test/rustdoc-ui/unknown-renamed-lints.stderr
@@ -0,0 +1,28 @@
+error: unknown lint: `x`
+  --> $DIR/unknown-renamed-lints.rs:5:9
+   |
+LL | #![deny(x)]
+   |         ^
+   |
+note: the lint level is defined here
+  --> $DIR/unknown-renamed-lints.rs:1:9
+   |
+LL | #![deny(unknown_lints)]
+   |         ^^^^^^^^^^^^^
+
+error: lint `intra_doc_link_resolution_failure` has been renamed to `broken_intra_doc_links`
+  --> $DIR/unknown-renamed-lints.rs:7:9
+   |
+LL | #![deny(intra_doc_link_resolution_failure)]
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `broken_intra_doc_links`
+   |
+note: the lint level is defined here
+  --> $DIR/unknown-renamed-lints.rs:3:9
+   |
+LL | #![deny(renamed_and_removed_lints)]
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: Compilation failed, aborting rustdoc
+
+error: aborting due to 3 previous errors
+