Run buffered lints attached to anon consts

Fixes #84195

compiler/rustc_lint/src/early.rs

@@ -109,6 +109,7 @@ impl<'a, T: EarlyLintPass> ast_visit::Visitor<'a> for EarlyContextAndPass<'a, T>
 
     fn visit_anon_const(&mut self, c: &'a ast::AnonConst) {
         run_early_pass!(self, check_anon_const, c);
+        self.check_id(c.id);
         ast_visit::walk_anon_const(self, c);
     }
 

src/test/ui/macros/issue-84195-lint-anon-const.rs

@@ -0,0 +1,14 @@
+// Regression test for issue #84195
+// Checks that we properly fire lints that occur inside
+// anon consts.
+
+#![deny(semicolon_in_expressions_from_macros)]
+
+macro_rules! len {
+    () => { 0; }; //~  ERROR trailing semicolon
+                  //~| WARN this was previously accepted
+}
+
+fn main() {
+    let val: [u8; len!()] = [];
+}

src/test/ui/macros/issue-84195-lint-anon-const.stderr

@@ -0,0 +1,20 @@
+error: trailing semicolon in macro used in expression position
+  --> $DIR/issue-84195-lint-anon-const.rs:8:14
+   |
+LL |     () => { 0; };
+   |              ^
+...
+LL |     let val: [u8; len!()] = [];
+   |                   ------ in this macro invocation
+   |
+note: the lint level is defined here
+  --> $DIR/issue-84195-lint-anon-const.rs:5:9
+   |
+LL | #![deny(semicolon_in_expressions_from_macros)]
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #79813 <https://github.com/rust-lang/rust/issues/79813>
+   = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: aborting due to previous error
+