Create unstable `From` builtin macro and register it

3 files changed, 15 insertions, 0 deletions

diff --git a/compiler/rustc_builtin_macros/src/deriving/from.rs b/compiler/rustc_builtin_macros/src/deriving/from.rs
new file mode 100644
index 00000000000..79fd4caa440
--- /dev/null
+++ b/compiler/rustc_builtin_macros/src/deriving/from.rs
@@ -0,0 +1,13 @@
+use rustc_ast as ast;
+use rustc_expand::base::{Annotatable, ExtCtxt};
+use rustc_span::{Span, sym};
+
+pub(crate) fn expand_deriving_from(
+    cx: &ExtCtxt<'_>,
+    span: Span,
+    mitem: &ast::MetaItem,
+    item: &Annotatable,
+    push: &mut dyn FnMut(Annotatable),
+    is_const: bool,
+) {
+}
diff --git a/compiler/rustc_builtin_macros/src/deriving/mod.rs b/compiler/rustc_builtin_macros/src/deriving/mod.rs
index 1edc2965def..cee6952fa34 100644
--- a/compiler/rustc_builtin_macros/src/deriving/mod.rs
+++ b/compiler/rustc_builtin_macros/src/deriving/mod.rs
@@ -23,6 +23,7 @@ pub(crate) mod clone;
 pub(crate) mod coerce_pointee;
 pub(crate) mod debug;
 pub(crate) mod default;
+pub(crate) mod from;
 pub(crate) mod hash;
 
 #[path = "cmp/eq.rs"]
diff --git a/compiler/rustc_builtin_macros/src/lib.rs b/compiler/rustc_builtin_macros/src/lib.rs
index 7bc448a9acb..86a4927f390 100644
--- a/compiler/rustc_builtin_macros/src/lib.rs
+++ b/compiler/rustc_builtin_macros/src/lib.rs
@@ -139,6 +139,7 @@ pub fn register_builtin_macros(resolver: &mut dyn ResolverExpand) {
         PartialEq: partial_eq::expand_deriving_partial_eq,
         PartialOrd: partial_ord::expand_deriving_partial_ord,
         CoercePointee: coerce_pointee::expand_deriving_coerce_pointee,
+        From: from::expand_deriving_from,
     }
 
     let client = rustc_proc_macro::bridge::client::Client::expand1(rustc_proc_macro::quote);