internal: Split serde derive feature into `serde_derive` usage

Ideally we'd not have any dependency pull in the derive feature for faster build times, once that is the case this change would have an actual effect.
See https://github.com/matklad/macro-dep-test/blob/master/README.md for context.

3 files changed, 5 insertions, 3 deletions

diff --git a/src/tools/rust-analyzer/crates/proc-macro-api/Cargo.toml b/src/tools/rust-analyzer/crates/proc-macro-api/Cargo.toml
index 911301e22b4..dac8e094357 100644
--- a/src/tools/rust-analyzer/crates/proc-macro-api/Cargo.toml
+++ b/src/tools/rust-analyzer/crates/proc-macro-api/Cargo.toml
@@ -14,6 +14,7 @@ doctest = false
 
 [dependencies]
 serde.workspace = true
+serde_derive.workspace = true
 serde_json = { workspace = true, features = ["unbounded_depth"] }
 tracing.workspace = true
 rustc-hash.workspace = true
diff --git a/src/tools/rust-analyzer/crates/proc-macro-api/src/msg.rs b/src/tools/rust-analyzer/crates/proc-macro-api/src/msg.rs
index 883528558d9..bbd9f582df9 100644
--- a/src/tools/rust-analyzer/crates/proc-macro-api/src/msg.rs
+++ b/src/tools/rust-analyzer/crates/proc-macro-api/src/msg.rs
@@ -4,7 +4,8 @@ pub(crate) mod flat;
 use std::io::{self, BufRead, Write};
 
 use paths::Utf8PathBuf;
-use serde::{de::DeserializeOwned, Deserialize, Serialize};
+use serde::de::DeserializeOwned;
+use serde_derive::{Deserialize, Serialize};
 
 use crate::ProcMacroKind;
 
@@ -123,7 +124,7 @@ impl ExpnGlobals {
     }
 }
 
-pub trait Message: Serialize + DeserializeOwned {
+pub trait Message: serde::Serialize + DeserializeOwned {
     fn read<R: BufRead>(
         from_proto: ProtocolRead<R>,
         inp: &mut R,
diff --git a/src/tools/rust-analyzer/crates/proc-macro-api/src/msg/flat.rs b/src/tools/rust-analyzer/crates/proc-macro-api/src/msg/flat.rs
index af3412e90e4..5de1e59f280 100644
--- a/src/tools/rust-analyzer/crates/proc-macro-api/src/msg/flat.rs
+++ b/src/tools/rust-analyzer/crates/proc-macro-api/src/msg/flat.rs
@@ -39,7 +39,7 @@ use std::collections::VecDeque;
 
 use intern::Symbol;
 use rustc_hash::FxHashMap;
-use serde::{Deserialize, Serialize};
+use serde_derive::{Deserialize, Serialize};
 use span::{EditionedFileId, ErasedFileAstId, Span, SpanAnchor, SyntaxContextId, TextRange};
 
 use crate::msg::EXTENDED_LEAF_DATA;