Merge #10066

10066: internal: improve compile times a bit r=matklad a=matklad

I wanted to *quickly* remove `smol_str = {features = "serde"}`, and figured out that the simplest way to do that is to replace our straightforward proc macro serialization with something significantly more obscure. 

Co-authored-by: Aleksey Kladov <[email protected]>

Author: bors[bot]

Cargo.lock

@@ -9,4 +9,7 @@ edition = "2018"
 doctest = false
 
 [dependencies]
-serde = "1"
+# Adding this dep sadly puts a lot of rust-analyzer crates after the
+# serde-derive crate. Even though we don't activate the derive feature here,
+# someone else in the crate graph certainly does!
+# serde = "1"

crates/paths/Cargo.toml

@@ -66,27 +66,6 @@ impl PartialEq<AbsPath> for AbsPathBuf {
     }
 }
 
-impl serde::Serialize for AbsPathBuf {
-    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
-    where
-        S: serde::Serializer,
-    {
-        self.0.serialize(serializer)
-    }
-}
-
-impl<'de> serde::Deserialize<'de> for AbsPathBuf {
-    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
-    where
-        D: serde::Deserializer<'de>,
-    {
-        let path = PathBuf::deserialize(deserializer)?;
-        AbsPathBuf::try_from(path).map_err(|path| {
-            serde::de::Error::custom(format!("expected absolute path, got {}", path.display()))
-        })
-    }
-}
-
 impl AbsPathBuf {
     /// Wrap the given absolute path in `AbsPathBuf`
     ///

crates/paths/src/lib.rs

@@ -21,7 +21,9 @@ use tt::{SmolStr, Subtree};
 
 use crate::process::ProcMacroProcessSrv;
 
-pub use rpc::{ExpansionResult, ExpansionTask, ListMacrosResult, ListMacrosTask, ProcMacroKind};
+pub use rpc::{
+    flat::FlatTree, ExpansionResult, ExpansionTask, ListMacrosResult, ListMacrosTask, ProcMacroKind,
+};
 pub use version::{read_dylib_info, RustCInfo};
 
 #[derive(Debug, Clone)]
@@ -58,10 +60,10 @@ impl ProcMacroProcessExpander {
         env: Vec<(String, String)>,
     ) -> Result<Subtree, tt::ExpansionError> {
         let task = ExpansionTask {
-            macro_body: subtree.clone(),
+            macro_body: FlatTree::new(subtree),
             macro_name: self.name.to_string(),
-            attributes: attr.cloned(),
-            lib: self.dylib_path.to_path_buf(),
+            attributes: attr.map(FlatTree::new),
+            lib: self.dylib_path.to_path_buf().into(),
             env,
         };
 
@@ -70,7 +72,7 @@ impl ProcMacroProcessExpander {
             .lock()
             .unwrap_or_else(|e| e.into_inner())
             .send_task(msg::Request::ExpansionMacro(task))?;
-        Ok(result.expansion)
+        Ok(result.expansion.to_subtree())
     }
 }
 

crates/proc_macro_api/src/lib.rs

@@ -12,13 +12,13 @@ use crate::{
     ExpansionResult, ExpansionTask,
 };
 
-#[derive(Debug, Serialize, Deserialize, Clone)]
+#[derive(Debug, Serialize, Deserialize)]
 pub enum Request {
     ListMacro(ListMacrosTask),
     ExpansionMacro(ExpansionTask),
 }
 
-#[derive(Debug, Serialize, Deserialize, Clone)]
+#[derive(Debug, Serialize, Deserialize)]
 pub enum Response {
     Error(ResponseError),
     ListMacro(ListMacrosResult),

crates/proc_macro_api/src/msg.rs

@@ -39,7 +39,7 @@ impl ProcMacroProcessSrv {
         &mut self,
         dylib_path: &AbsPath,
     ) -> Result<Vec<(String, ProcMacroKind)>, tt::ExpansionError> {
-        let task = ListMacrosTask { lib: dylib_path.to_path_buf() };
+        let task = ListMacrosTask { lib: dylib_path.to_path_buf().into() };
 
         let result: ListMacrosResult = self.send_task(Request::ListMacro(task))?;
         Ok(result.macros)