Move lint expectation checking into a separate query (RFC 2383)

compiler/rustc_middle/src/query/mod.rs

@@ -157,6 +157,25 @@ rustc_queries! {
         desc { "running analysis passes on this crate" }
     }
 
+    /// This query checks the fulfillment of collected lint expectations.
+    /// All lint emitting queries have to be done before this is executed
+    /// to ensure that all expectations can be fulfilled.
+    ///
+    /// This is an extra query to enable other drivers (like rustdoc) to
+    /// only execute a small subset of the [`analysis`] query, while allowing
+    /// lints to be expected. In rustc, this query will be executed as part of
+    /// the [`analysis`] query and doesn't have to be called a second time.
+    ///
+    /// Tools can additionally pass in a tool filter. That will restrict the
+    /// expectations to only trigger for lints starting with the listed tool
+    /// name. This is useful for cases were not all linting code from rustc
+    /// was called. With the default `none` all registered lints will also
+    /// be checked for expectation fulfillment.
+    query check_expectations(key: Option<Symbol>) -> () {
+        eval_always
+        desc { "checking lint expectations (RFC 2383)" }
+    }
+
     /// Maps from the `DefId` of an item (trait/struct/enum/fn) to its
     /// associated generics.
     query generics_of(key: DefId) -> ty::Generics {