4 files changed, 38 insertions, 15 deletions

diff --git a/crates/hir_def/src/body/lower.rs b/crates/hir_def/src/body/lower.rs
index e4bf5603c..23e2fd764 100644
--- a/crates/hir_def/src/body/lower.rs
+++ b/crates/hir_def/src/body/lower.rs
@@ -803,7 +803,7 @@ impl ExprCollector<'_> {
                 }
                 Either::Right(e) => {
                     let mac = MacroDefId {
-                        krate: Some(self.expander.module.krate),
+                        krate: self.expander.module.krate,
                         ast_id: Some(self.expander.ast_id(&e)),
                         kind: MacroDefKind::Declarative,
                         local_inner: false,
diff --git a/crates/hir_def/src/item_scope.rs b/crates/hir_def/src/item_scope.rs
index a8b3fe844..62ab3b2bd 100644
--- a/crates/hir_def/src/item_scope.rs
+++ b/crates/hir_def/src/item_scope.rs
@@ -363,7 +363,7 @@ impl ItemInNs {
                 ModuleDefId::TypeAliasId(id) => id.lookup(db).module(db).krate,
                 ModuleDefId::BuiltinType(_) => return None,
             },
-            ItemInNs::Macros(id) => return id.krate,
+            ItemInNs::Macros(id) => return Some(id.krate),
         })
     }
 }
diff --git a/crates/hir_def/src/nameres/collector.rs b/crates/hir_def/src/nameres/collector.rs
index c2f741060..785895277 100644
--- a/crates/hir_def/src/nameres/collector.rs
+++ b/crates/hir_def/src/nameres/collector.rs
@@ -309,13 +309,13 @@ impl DefCollector<'_> {
         let macro_def = match self.proc_macros.iter().find(|(n, _)| n == name) {
             Some((_, expander)) => MacroDefId {
                 ast_id: None,
-                krate: Some(self.def_map.krate),
+                krate: self.def_map.krate,
                 kind: MacroDefKind::ProcMacro(*expander),
                 local_inner: false,
             },
             None => MacroDefId {
                 ast_id: None,
-                krate: Some(self.def_map.krate),
+                krate: self.def_map.krate,
                 kind: MacroDefKind::ProcMacro(ProcMacroExpander::dummy(self.def_map.krate)),
                 local_inner: false,
             },
@@ -784,14 +784,6 @@ impl DefCollector<'_> {
         directive: &DeriveDirective,
         path: &ModPath,
     ) -> Option<MacroDefId> {
-        if let Some(name) = path.as_ident() {
-            // FIXME this should actually be handled with the normal name
-            // resolution; the std lib defines built-in stubs for the derives,
-            // but these are new-style `macro`s, which we don't support yet
-            if let Some(def_id) = find_builtin_derive(name) {
-                return Some(def_id);
-            }
-        }
         let resolved_res = self.def_map.resolve_path_fp_with_macro(
             self.db,
             ResolveMode::Other,
@@ -984,7 +976,9 @@ impl ModCollector<'_, '_> {
                     // to define builtin macros, so we support at least that part.
                     if mac.is_builtin {
                         let krate = self.def_collector.def_map.krate;
-                        if let Some(macro_id) = find_builtin_macro(&mac.name, krate, ast_id) {
+                        let macro_id = find_builtin_macro(&mac.name, krate, ast_id)
+                            .or_else(|| find_builtin_derive(&mac.name, krate, ast_id));
+                        if let Some(macro_id) = macro_id {
                             let vis = self
                                 .def_collector
                                 .def_map
@@ -1326,7 +1320,7 @@ impl ModCollector<'_, '_> {
         // Case 2: normal `macro_rules!` macro
         let macro_id = MacroDefId {
             ast_id: Some(ast_id),
-            krate: Some(self.def_collector.def_map.krate),
+            krate: self.def_collector.def_map.krate,
             kind: MacroDefKind::Declarative,
             local_inner: mac.is_local_inner,
         };
diff --git a/crates/hir_def/src/nameres/tests/macros.rs b/crates/hir_def/src/nameres/tests/macros.rs
index 305fca0f9..6fe2ee78a 100644
--- a/crates/hir_def/src/nameres/tests/macros.rs
+++ b/crates/hir_def/src/nameres/tests/macros.rs
@@ -633,15 +633,44 @@ pub struct bar;
 fn expand_derive() {
     let map = compute_crate_def_map(
         "
-        //- /main.rs
+        //- /main.rs crate:main deps:core
+        use core::*;
+
         #[derive(Copy, Clone)]
         struct Foo;
+
+        //- /core.rs crate:core
+        #[rustc_builtin_macro]
+        pub macro Copy {}
+
+        #[rustc_builtin_macro]
+        pub macro Clone {}
         ",
     );
     assert_eq!(map.modules[map.root].scope.impls().len(), 2);
 }
 
 #[test]
+fn resolve_builtin_derive() {
+    check(
+        r#"
+//- /main.rs crate:main deps:core
+use core::*;
+
+//- /core.rs crate:core
+#[rustc_builtin_macro]
+pub macro Clone {}
+
+pub trait Clone {}
+"#,
+        expect![[r#"
+            crate
+            Clone: t m
+        "#]],
+    );
+}
+
+#[test]
 fn macro_expansion_overflow() {
     mark::check!(macro_expansion_overflow);
     check(