SessionDiagnostic for QueryOverflow error

compiler/rustc_error_messages/locales/en-US/query_system.ftl

@@ -21,3 +21,5 @@ query_system_cycle_recursive_ty_alias_help2 = see <https://doc.rust-lang.org/ref
 query_system_cycle_recursive_trait_alias = trait aliases cannot be recursive
 
 query_system_cycle_which_requires = ...which requires {$desc}...
+
+query_system_query_overflow = queries overflow the depth limit!

compiler/rustc_error_messages/src/lib.rs

@@ -48,11 +48,11 @@
     passes => "../locales/en-US/passes.ftl",
     plugin_impl => "../locales/en-US/plugin_impl.ftl",
     privacy => "../locales/en-US/privacy.ftl",
+    query_system => "../locales/en-US/query_system.ftl",
     save_analysis => "../locales/en-US/save_analysis.ftl",
     ty_utils => "../locales/en-US/ty_utils.ftl",
     typeck => "../locales/en-US/typeck.ftl",
     mir_dataflow => "../locales/en-US/mir_dataflow.ftl",
-    query_system => "../locales/en-US/query_system.ftl",
 }
 
 pub use fluent_generated::{self as fluent, DEFAULT_LOCALE_RESOURCES};

compiler/rustc_query_system/src/error.rs

@@ -67,3 +67,7 @@ pub struct IncrementCompilation {
     pub run_cmd: String,
     pub dep_node: String,
 }
+
+#[derive(SessionDiagnostic)]
+#[diag(query_system::query_overflow)]
+pub struct QueryOverflow;

compiler/rustc_query_system/src/query/mod.rs

@@ -125,6 +125,6 @@ fn start_query<R>(
     ) -> R;
 
     fn depth_limit_error(&self) {
-        self.dep_context().sess().fatal("queries overflow the depth limit!");
+        self.dep_context().sess().emit_fatal(crate::error::QueryOverflow);
     }
 }