Set the in-rust-tree` feature for all rust-analyzer{-proc-macro-srv} steps

crates/mbe/Cargo.toml

@@ -27,5 +27,8 @@ span.workspace = true
 [dev-dependencies]
 test-utils.workspace = true
 
+[features]
+in-rust-tree = ["parser/in-rust-tree", "syntax/in-rust-tree"]
+
 [lints]
-workspace = true
+workspace = true

crates/proc-macro-srv-cli/Cargo.toml

@@ -14,6 +14,8 @@ proc-macro-api.workspace = true
 
 [features]
 sysroot-abi = ["proc-macro-srv/sysroot-abi"]
+in-rust-tree = ["proc-macro-srv/in-rust-tree"]
+
 
 [[bin]]
 name = "rust-analyzer-proc-macro-srv"

crates/proc-macro-srv/Cargo.toml

@@ -37,7 +37,8 @@ expect-test = "1.4.0"
 proc-macro-test.path = "./proc-macro-test"
 
 [features]
-sysroot-abi = ["proc-macro-test/sysroot-abi"]
+sysroot-abi = []
+in-rust-tree = ["mbe/in-rust-tree"]
 
 [lints]
-workspace = true
+workspace = true

crates/proc-macro-srv/src/lib.rs

@@ -11,11 +11,12 @@
 //!   rustc rather than `unstable`. (Although in general ABI compatibility is still an issue)…
 
 #![cfg(any(feature = "sysroot-abi", rust_analyzer))]
-#![feature(proc_macro_internals, proc_macro_diagnostic, proc_macro_span)]
+#![feature(proc_macro_internals, proc_macro_diagnostic, proc_macro_span, rustc_private)]
 #![warn(rust_2018_idioms, unused_lifetimes)]
 #![allow(unreachable_pub, internal_features)]
 
 extern crate proc_macro;
+extern crate rustc_driver as _;
 
 mod dylib;
 mod server;