diff --git a/compiler/rustc_codegen_ssa/src/back/symbol_export.rs b/compiler/rustc_codegen_ssa/src/back/symbol_export.rs
index 7cae637a49d3..1a5afefbb2bc 100644
--- a/compiler/rustc_codegen_ssa/src/back/symbol_export.rs
+++ b/compiler/rustc_codegen_ssa/src/back/symbol_export.rs
@@ -133,8 +133,8 @@ fn reachable_non_generics_provider(tcx: TyCtxt<'_>, cnum: CrateNum) -> DefIdMap<
         })
         .collect();
 
-    if let Some(id) = tcx.proc_macro_decls_static(LOCAL_CRATE) {
-        reachable_non_generics.insert(id, SymbolExportLevel::C);
+    if let Some(id) = tcx.proc_macro_decls_static(()) {
+        reachable_non_generics.insert(id.to_def_id(), SymbolExportLevel::C);
     }
 
     if let Some(id) = tcx.plugin_registrar_fn(()) {
diff --git a/compiler/rustc_interface/src/passes.rs b/compiler/rustc_interface/src/passes.rs
index 948aad966faf..803efb303e47 100644
--- a/compiler/rustc_interface/src/passes.rs
+++ b/compiler/rustc_interface/src/passes.rs
@@ -824,7 +824,9 @@ fn analysis(tcx: TyCtxt<'_>, cnum: CrateNum) -> Result<()> {
 
                 sess.time("looking_for_plugin_registrar", || tcx.ensure().plugin_registrar_fn(()));
 
-                sess.time("looking_for_derive_registrar", || proc_macro_decls::find(tcx));
+                sess.time("looking_for_derive_registrar", || {
+                    tcx.ensure().proc_macro_decls_static(())
+                });
 
                 let cstore = tcx
                     .cstore_as_any()
diff --git a/compiler/rustc_interface/src/proc_macro_decls.rs b/compiler/rustc_interface/src/proc_macro_decls.rs
index 4637055a82de..88cf6275ebbd 100644
--- a/compiler/rustc_interface/src/proc_macro_decls.rs
+++ b/compiler/rustc_interface/src/proc_macro_decls.rs
@@ -1,21 +1,15 @@
 use rustc_hir as hir;
-use rustc_hir::def_id::{CrateNum, DefId, LOCAL_CRATE};
+use rustc_hir::def_id::LocalDefId;
 use rustc_hir::itemlikevisit::ItemLikeVisitor;
 use rustc_middle::ty::query::Providers;
 use rustc_middle::ty::TyCtxt;
 use rustc_span::symbol::sym;
 
-pub fn find(tcx: TyCtxt<'_>) -> Option<DefId> {
-    tcx.proc_macro_decls_static(LOCAL_CRATE)
-}
-
-fn proc_macro_decls_static(tcx: TyCtxt<'_>, cnum: CrateNum) -> Option<DefId> {
-    assert_eq!(cnum, LOCAL_CRATE);
-
+fn proc_macro_decls_static(tcx: TyCtxt<'_>, (): ()) -> Option<LocalDefId> {
     let mut finder = Finder { tcx, decls: None };
     tcx.hir().krate().visit_all_item_likes(&mut finder);
 
-    finder.decls.map(|id| tcx.hir().local_def_id(id).to_def_id())
+    finder.decls.map(|id| tcx.hir().local_def_id(id))
 }
 
 struct Finder<'tcx> {
diff --git a/compiler/rustc_metadata/src/rmeta/decoder/cstore_impl.rs b/compiler/rustc_metadata/src/rmeta/decoder/cstore_impl.rs
index 6975ecef1c26..3a28154f72c7 100644
--- a/compiler/rustc_metadata/src/rmeta/decoder/cstore_impl.rs
+++ b/compiler/rustc_metadata/src/rmeta/decoder/cstore_impl.rs
@@ -185,14 +185,6 @@ provide! { <'tcx> tcx, def_id, other, cdata,
     }
     native_libraries => { Lrc::new(cdata.get_native_libraries(tcx.sess)) }
     foreign_modules => { cdata.get_foreign_modules(tcx) }
-    proc_macro_decls_static => {
-        cdata.root.proc_macro_data.as_ref().map(|data| {
-            DefId {
-                krate: def_id.krate,
-                index: data.proc_macro_decls_static,
-            }
-        })
-    }
     crate_disambiguator => { cdata.root.disambiguator }
     crate_hash => { cdata.root.hash }
     crate_host_hash => { cdata.host_hash }
diff --git a/compiler/rustc_metadata/src/rmeta/encoder.rs b/compiler/rustc_metadata/src/rmeta/encoder.rs
index 55b6672afb9f..1c2dcdba3c16 100644
--- a/compiler/rustc_metadata/src/rmeta/encoder.rs
+++ b/compiler/rustc_metadata/src/rmeta/encoder.rs
@@ -1575,7 +1575,7 @@ impl EncodeContext<'a, 'tcx> {
             let tcx = self.tcx;
             let hir = tcx.hir();
 
-            let proc_macro_decls_static = tcx.proc_macro_decls_static(LOCAL_CRATE).unwrap().index;
+            let proc_macro_decls_static = tcx.proc_macro_decls_static(()).unwrap().local_def_index;
             let stability = tcx.lookup_stability(DefId::local(CRATE_DEF_INDEX)).copied();
             let macros = self.lazy(hir.krate().proc_macros.iter().map(|p| p.owner.local_def_index));
             let spans = self.tcx.sess.parse_sess.proc_macro_quoted_spans();
diff --git a/compiler/rustc_middle/src/query/mod.rs b/compiler/rustc_middle/src/query/mod.rs
index e1d56311ae18..28e37c215aa2 100644
--- a/compiler/rustc_middle/src/query/mod.rs
+++ b/compiler/rustc_middle/src/query/mod.rs
@@ -1207,7 +1207,7 @@ rustc_queries! {
     query plugin_registrar_fn(_: ()) -> Option<LocalDefId> {
         desc { "looking up the plugin registrar for a crate" }
     }
-    query proc_macro_decls_static(_: CrateNum) -> Option<DefId> {
+    query proc_macro_decls_static(_: ()) -> Option<LocalDefId> {
         desc { "looking up the derive registrar for a crate" }
     }
     query crate_disambiguator(_: CrateNum) -> CrateDisambiguator {
diff --git a/compiler/rustc_symbol_mangling/src/lib.rs b/compiler/rustc_symbol_mangling/src/lib.rs
index afb83d08e620..7fb24ad1ed8e 100644
--- a/compiler/rustc_symbol_mangling/src/lib.rs
+++ b/compiler/rustc_symbol_mangling/src/lib.rs
@@ -169,7 +169,7 @@ fn compute_symbol_name(
             let disambiguator = tcx.sess.local_crate_disambiguator();
             return tcx.sess.generate_plugin_registrar_symbol(disambiguator);
         }
-        if tcx.proc_macro_decls_static(LOCAL_CRATE) == Some(def_id.to_def_id()) {
+        if tcx.proc_macro_decls_static(()) == Some(def_id) {
             let disambiguator = tcx.sess.local_crate_disambiguator();
             return tcx.sess.generate_proc_macro_decls_symbol(disambiguator);
         }