(DO NOT MERGE) fix: proc_macro_srv: temporary abi fix (rust-lang/rust#84717)

crates/proc_macro_srv/src/proc_macro/bridge/mod.rs

@@ -112,6 +112,7 @@ macro_rules! with_api {
             Literal {
                 fn drop($self: $S::Literal);
                 fn clone($self: &$S::Literal) -> $S::Literal;
+                fn from_str(s: &str) -> Result<$S::Literal, ()>;
                 fn debug_kind($self: &$S::Literal) -> String;
                 fn symbol($self: &$S::Literal) -> String;
                 fn suffix($self: &$S::Literal) -> Option<String>;
@@ -318,6 +319,19 @@ impl<T: Unmark> Unmark for Option<T> {
     }
 }
 
+impl<T: Mark, E: Mark> Mark for Result<T, E> {
+    type Unmarked = Result<T::Unmarked, E::Unmarked>;
+    fn mark(unmarked: Self::Unmarked) -> Self {
+        unmarked.map(T::mark).map_err(E::mark)
+    }
+}
+impl<T: Unmark, E: Unmark> Unmark for Result<T, E> {
+    type Unmarked = Result<T::Unmarked, E::Unmarked>;
+    fn unmark(self) -> Self::Unmarked {
+        self.map(T::unmark).map_err(E::unmark)
+    }
+}
+
 macro_rules! mark_noop {
     ($($ty:ty),* $(,)?) => {
         $(

crates/proc_macro_srv/src/proc_macro/mod.rs

@@ -37,6 +37,12 @@ pub struct LexError {
     _inner: (),
 }
 
+impl LexError {
+    fn new() -> Self {
+        LexError { _inner: () }
+    }
+}
+
 impl TokenStream {
     /// Returns an empty `TokenStream` containing no token trees.
     pub fn new() -> TokenStream {
@@ -925,6 +931,17 @@ impl fmt::Debug for Literal {
     }
 }
 
+impl FromStr for Literal {
+    type Err = LexError;
+
+    fn from_str(src: &str) -> Result<Self, LexError> {
+        match bridge::client::Literal::from_str(src) {
+            Ok(literal) => Ok(Literal(literal)),
+            Err(()) => Err(LexError::new()),
+        }
+    }
+}
+
 pub mod tracked_env {
     use std::env::{self, VarError};
     use std::ffi::OsStr;

crates/proc_macro_srv/src/rustc_server.rs

@@ -521,6 +521,9 @@ impl server::Ident for Rustc {
 }
 
 impl server::Literal for Rustc {
+    fn from_str(&mut self, _s: &str) -> Result<Self::Literal, ()> {
+        unimplemented!()
+    }
     fn debug_kind(&mut self, _literal: &Self::Literal) -> String {
         // r-a: debug_kind and suffix are unsupported; corresponding client code has been changed to not call these.
         // They must still be present to be ABI-compatible and work with upstream proc_macro.