Allow #[rustc_builtin_macro = "name"].

This makes it possible to have both std::panic and core::panic as a
builtin macro, by using different builtin macro names for each.

Also removes SyntaxExtension::is_derive_copy, as the macro name (e.g.
sym::Copy) is now tracked and provides that information directly.

2 files changed, 5 insertions, 5 deletions

diff --git a/compiler/rustc_resolve/src/lib.rs b/compiler/rustc_resolve/src/lib.rs
index a6d0240b6fd..fdeacafc4a8 100644
--- a/compiler/rustc_resolve/src/lib.rs
+++ b/compiler/rustc_resolve/src/lib.rs
@@ -1443,7 +1443,7 @@ impl<'a> Resolver<'a> {
     }
 
     fn is_builtin_macro(&mut self, res: Res) -> bool {
-        self.get_macro(res).map_or(false, |ext| ext.is_builtin)
+        self.get_macro(res).map_or(false, |ext| ext.builtin_name.is_some())
     }
 
     fn macro_def(&self, mut ctxt: SyntaxContext) -> DefId {
@@ -2010,7 +2010,7 @@ impl<'a> Resolver<'a> {
                 // The macro is a proc macro derive
                 if let Some(def_id) = module.expansion.expn_data().macro_def_id {
                     let ext = self.get_macro_by_def_id(def_id);
-                    if !ext.is_builtin
+                    if ext.builtin_name.is_none()
                         && ext.macro_kind() == MacroKind::Derive
                         && parent.expansion.outer_expn_is_descendant_of(span.ctxt())
                     {
diff --git a/compiler/rustc_resolve/src/macros.rs b/compiler/rustc_resolve/src/macros.rs
index e6360cccf3b..60a1fc88631 100644
--- a/compiler/rustc_resolve/src/macros.rs
+++ b/compiler/rustc_resolve/src/macros.rs
@@ -285,7 +285,7 @@ impl<'a> ResolverExpand for Resolver<'a> {
                                 helper_attrs.extend(
                                     ext.helper_attrs.iter().map(|name| Ident::new(*name, span)),
                                 );
-                                if ext.is_derive_copy {
+                                if ext.builtin_name == Some(sym::Copy) {
                                     self.containers_deriving_copy.insert(invoc_id);
                                 }
                                 ext
@@ -1089,9 +1089,9 @@ impl<'a> Resolver<'a> {
             edition,
         );
 
-        if result.is_builtin {
+        if let Some(builtin_name) = result.builtin_name {
             // The macro was marked with `#[rustc_builtin_macro]`.
-            if let Some(builtin_macro) = self.builtin_macros.get_mut(&item.ident.name) {
+            if let Some(builtin_macro) = self.builtin_macros.get_mut(&builtin_name) {
                 // The macro is a built-in, replace its expander function
                 // while still taking everything else from the source code.
                 // If we already loaded this builtin macro, give a better error message than 'no such builtin macro'.