Redesign the indexing compiler phase

crates/indexing/Cargo.toml

@@ -0,0 +1,18 @@
+[package]
+name = "indexing"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+la-arena = "0.3.1"
+paste = "1.0.15"
+rowan = "0.16.1"
+rustc-hash = "2.1.1"
+smol_str = "0.3.2"
+syntax = { version = "0.1.0", path = "../syntax" }
+
+[dev-dependencies]
+insta = "1.42.1"
+lexing = { path = "../lexing" }
+parsing = { path = "../parsing" }
+test_each_file = "0.3.4"

crates/indexing/build.rs

@@ -0,0 +1,3 @@
+fn main() {
+    println!("cargo:rerun-if-changed=tests/indexing")
+}

crates/indexing/src/algorithm.rs

@@ -0,0 +1,25 @@
+mod declaration;
+
+use declaration::index_declaration;
+use syntax::cst;
+
+use crate::{Index, IndexError, Source};
+
+#[derive(Debug, Default)]
+pub(super) struct State {
+    pub(super) index: Index,
+    pub(super) source: Source,
+    pub(super) error: Vec<IndexError>,
+}
+
+pub(super) fn index_module(module: &cst::Module) -> State {
+    let mut state = State::default();
+
+    if let Some(statements) = module.statements() {
+        for declaration in statements.children() {
+            index_declaration(&mut state, &declaration);
+        }
+    }
+
+    state
+}