nix: include rust-src so rust-analyzer works correctly.

helix-core/src/indent.rs

@@ -135,8 +135,8 @@ fn calculate_indentation(node: Option<Node>, newline: bool) -> usize {
         //     let len = 1;
         // })
 
-        if ((indent_scopes.contains(&parent_kind) && true) // not_first_or_last_sibling
+        if (indent_scopes.contains(&parent_kind) // && not_first_or_last_sibling
-            || (indent_except_first_scopes.contains(&parent_kind) && true))
+            || indent_except_first_scopes.contains(&parent_kind))
             && !starts_same_line
         {
             // println!("is_scope {}", parent_kind);

helix-core/src/position.rs

@@ -39,9 +39,9 @@ impl From<(usize, usize)> for Position {
     }
 }
 
-impl Into<tree_sitter::Point> for Position {
+impl From<Position> for tree_sitter::Point {
-    fn into(self) -> tree_sitter::Point {
+    fn from(pos: Position) -> Self {
-        tree_sitter::Point::new(self.row, self.col)
+        Self::new(pos.row, pos.col)
     }
 }
 

shell.nix

@@ -2,7 +2,7 @@
 
 pkgs.mkShell {
   nativeBuildInputs = with pkgs; [
-    rust-bin.nightly.latest.rust
+    (rust-bin.nightly.latest.rust.override { extensions = ["rust-src"]; })
     lld_10
     # pkgconfig
   ];