Eliminate dependency on serde's "derive" feature

CHANGELOG.md

@@ -35,6 +35,7 @@
   - [BREAKING] `SyntaxMapping::{empty,builtin}` are removed; use `SyntaxMapping::new` instead
   - [BREAKING] `SyntaxMapping::mappings` is replaced by `SyntaxMapping::{builtin,custom,all}_mappings`
 - Make `Controller::run_with_error_handler`'s error handler `FnMut`, see #2831 (@rhysd)
+- Improve compile time by 20%, see #2815 (@dtolnay)
 
 # v0.24.0
 

Cargo.toml

@@ -53,7 +53,8 @@ content_inspector = "0.2.4"
 shell-words = { version = "1.1.0", optional = true }
 unicode-width = "0.1.11"
 globset = "0.4"
-serde = { version = "1.0", features = ["derive"] }
+serde = "1.0"
+serde_derive = "1.0"
 serde_yaml = "0.9.28"
 semver = "1.0"
 path_abs = { version = "0.5", default-features = false }
@@ -74,7 +75,7 @@ optional = true
 default-features = false
 
 [dependencies.syntect]
-version = "5.1.0"
+version = "5.2.0"
 default-features = false
 features = ["parsing"]
 
@@ -94,6 +95,7 @@ serial_test = { version = "2.0.0", default-features = false }
 predicates = "3.0.4"
 wait-timeout = "0.2.0"
 tempfile = "3.8.1"
+serde = { version = "1.0", features = ["derive"] }
 
 [target.'cfg(unix)'.dev-dependencies]
 nix = { version = "0.26.4", default-features = false, features = ["term"] }
@@ -104,8 +106,9 @@ indexmap = { version = "2.2.2", features = ["serde"] }
 itertools = "0.11.0"
 once_cell = "1.18"
 regex = "1.10.2"
-serde = { version = "1.0", features = ["derive"] }
-serde_with = { version = "3.4.0", default-features = false, features = ["macros"] }
+serde = "1.0"
+serde_derive = "1.0"
+serde_with = { version = "3.6.1", default-features = false, features = ["macros"] }
 toml = { version = "0.8.9", features = ["preserve_order"] }
 walkdir = "2.4"
 

build/syntax_mapping.rs

@@ -10,7 +10,7 @@ use indexmap::IndexMap;
 use itertools::Itertools;
 use once_cell::sync::Lazy;
 use regex::Regex;
-use serde::Deserialize;
+use serde_derive::Deserialize;
 use serde_with::DeserializeFromStr;
 use walkdir::WalkDir;
 

src/assets/assets_metadata.rs

@@ -3,7 +3,7 @@ use std::path::Path;
 use std::time::SystemTime;
 
 use semver::Version;
-use serde::{Deserialize, Serialize};
+use serde_derive::{Deserialize, Serialize};
 
 use crate::error::*;
 

src/assets/lazy_theme_set.rs

@@ -3,8 +3,7 @@ use super::*;
 use std::collections::BTreeMap;
 use std::convert::TryFrom;
 
-use serde::Deserialize;
-use serde::Serialize;
+use serde_derive::{Deserialize, Serialize};
 
 use once_cell::unsync::OnceCell;