1 files changed, 50 insertions, 0 deletions

diff --git a/xtask/src/codegen/gen_features.rs b/xtask/src/codegen/gen_features.rs
new file mode 100644
index 000000000..78268308b
--- /dev/null
+++ b/xtask/src/codegen/gen_features.rs
@@ -0,0 +1,50 @@
+//! Generates descriptors structure for unstable feature from Unstable Book
+use std::path::{Path, PathBuf};
+
+use quote::quote;
+use walkdir::WalkDir;
+
+use crate::{
+    codegen::{project_root, reformat, update, Mode, Result},
+    not_bash::{fs2, run},
+};
+
+pub fn generate_features(mode: Mode) -> Result<()> {
+    if !Path::new("./target/rust").exists() {
+        run!("git clone https://github.com/rust-lang/rust ./target/rust")?;
+    }
+
+    let contents = generate_descriptor("./target/rust/src/doc/unstable-book/src".into())?;
+
+    let destination = project_root().join("crates/ide/src/completion/generated_features.rs");
+    update(destination.as_path(), &contents, mode)?;
+
+    Ok(())
+}
+
+fn generate_descriptor(src_dir: PathBuf) -> Result<String> {
+    let definitions = ["language-features", "library-features"]
+        .iter()
+        .flat_map(|it| WalkDir::new(src_dir.join(it)))
+        .filter_map(|e| e.ok())
+        .filter(|entry| {
+            // Get all `.md ` files
+            entry.file_type().is_file() && entry.path().extension().unwrap_or_default() == "md"
+        })
+        .map(|entry| {
+            let path = entry.path();
+            let feature_ident = path.file_stem().unwrap().to_str().unwrap().replace("-", "_");
+            let doc = fs2::read_to_string(path).unwrap();
+
+            quote! { LintCompletion { label: #feature_ident, description: #doc } }
+        });
+
+    let ts = quote! {
+        use crate::completion::complete_attribute::LintCompletion;
+
+        pub(super) const FEATURES:  &[LintCompletion] = &[
+            #(#definitions),*
+        ];
+    };
+    reformat(ts)
+}