Wrap QueryDescription into a macro.

compiler/rustc_macros/src/query.rs

@@ -344,7 +344,6 @@ fn add_query_description_impl(
     impls: &mut proc_macro2::TokenStream,
 ) {
     let name = &query.name;
-    let arg = &query.arg;
     let key = &query.key.0;
 
     // Find out if we should cache the query on disk
@@ -414,7 +413,7 @@ fn add_query_description_impl(
 
     let desc = quote! {
         #[allow(unused_variables)]
-        fn describe(tcx: QueryCtxt<'tcx>, key: #arg) -> String {
+        fn describe(tcx: QueryCtxt<'tcx>, key: Self::Key) -> String {
             let (#tcx, #key) = (*tcx, key);
             ::rustc_middle::ty::print::with_no_trimmed_paths(|| format!(#desc).into())
         }
@@ -520,7 +519,8 @@ pub fn rustc_queries(input: TokenStream) -> TokenStream {
                 $($macro)*(#cached_queries);
             }
         }
-
+        macro_rules! rustc_query_description {
-        #query_description_stream
+            () => { #query_description_stream }
+        }
     })
 }

compiler/rustc_middle/src/query/mod.rs

@@ -1,28 +1,3 @@
-use crate::dep_graph::SerializedDepNodeIndex;
-use crate::mir::interpret::{GlobalId, LitToConstInput};
-use crate::traits;
-use crate::traits::query::{
-    CanonicalPredicateGoal, CanonicalProjectionGoal, CanonicalTyGoal,
-    CanonicalTypeOpAscribeUserTypeGoal, CanonicalTypeOpEqGoal, CanonicalTypeOpNormalizeGoal,
-    CanonicalTypeOpProvePredicateGoal, CanonicalTypeOpSubtypeGoal,
-};
-use crate::ty::query::queries;
-use crate::ty::query::QueryCtxt;
-use crate::ty::subst::{GenericArg, SubstsRef};
-use crate::ty::{self, ParamEnvAnd, Ty, TyCtxt};
-use rustc_hir::def_id::{CrateNum, DefId, LocalDefId};
-use rustc_query_system::query::QueryDescription;
-
-use rustc_span::symbol::Symbol;
-
-fn describe_as_module(def_id: LocalDefId, tcx: TyCtxt<'_>) -> String {
-    if def_id.is_top_level_module() {
-        "top-level module".to_string()
-    } else {
-        format!("module `{}`", tcx.def_path_str(def_id.to_def_id()))
-    }
-}
-
 // Each of these queries corresponds to a function pointer field in the
 // `Providers` struct for requesting a value of that type, and a method
 // on `tcx: TyCtxt` (and `tcx.at(span)`) for doing that request in a way

compiler/rustc_middle/src/ty/query/plumbing.rs

@@ -3,19 +3,19 @@
 //! manage the caches, and so forth.
 
 use crate::dep_graph::{self, DepKind, DepNode, DepNodeExt, DepNodeIndex, SerializedDepNodeIndex};
-use crate::ty::query::{on_disk_cache, Queries, Query};
+use crate::ty::query::{on_disk_cache, queries, Queries, Query};
 use crate::ty::tls::{self, ImplicitCtxt};
 use crate::ty::{self, TyCtxt};
 use rustc_query_system::dep_graph::HasDepContext;
-use rustc_query_system::query::QueryContext;
 use rustc_query_system::query::{CycleError, QueryJobId, QueryJobInfo};
+use rustc_query_system::query::{QueryContext, QueryDescription};
 
 use rustc_data_structures::fx::FxHashMap;
 use rustc_data_structures::sync::Lock;
 use rustc_data_structures::thin_vec::ThinVec;
 use rustc_errors::{struct_span_err, Diagnostic, DiagnosticBuilder, Handler, Level};
 use rustc_serialize::opaque;
-use rustc_span::def_id::DefId;
+use rustc_span::def_id::{DefId, LocalDefId};
 use rustc_span::Span;
 
 #[derive(Copy, Clone)]
@@ -797,3 +797,13 @@ macro_rules! define_provider_struct {
         }
     };
 }
+
+fn describe_as_module(def_id: LocalDefId, tcx: TyCtxt<'_>) -> String {
+    if def_id.is_top_level_module() {
+        "top-level module".to_string()
+    } else {
+        format!("module `{}`", tcx.def_path_str(def_id.to_def_id()))
+    }
+}
+
+rustc_query_description! {}