feat(tvix/eval): track source spans for paths

Change-Id: I42fbd0bb6c2a8feb520e262a25f59ff27dcd035c
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6381
Tested-by: BuildkiteCI
Reviewed-by: sterni <sternenseemann@systemli.org>

tvix/eval/src/compiler/mod.rs

@@ -217,7 +217,7 @@ impl Compiler<'_> {
         // TODO: Use https://github.com/rust-lang/rfcs/issues/2208
         // once it is available
         let value = Value::Path(path.clean());
-        self.emit_constant_old(value);
+        self.emit_constant(value, &node);
     }
 
     fn compile_str(&mut self, slot: Option<LocalIdx>, node: ast::Str) {