cleanup + docs + tests

crates/ide-db/src/helpers.rs

@@ -9,7 +9,10 @@ use syntax::{
     AstToken, SyntaxKind, SyntaxToken, TokenAtOffset,
 };
 
-use crate::{defs::Definition, generated, RootDatabase};
+use crate::{
+    defs::{Definition, IdentClass},
+    generated, RootDatabase,
+};
 
 pub fn item_name(db: &RootDatabase, item: ItemInNs) -> Option<Name> {
     match item {
@@ -109,3 +112,16 @@ pub fn is_editable_crate(krate: Crate, db: &RootDatabase) -> bool {
     let source_root_id = db.file_source_root(root_file);
     !db.source_root(source_root_id).is_library
 }
+
+pub fn get_definition(
+    sema: &Semantics<'_, RootDatabase>,
+    token: SyntaxToken,
+) -> Option<Definition> {
+    for token in sema.descend_into_macros(token) {
+        let def = IdentClass::classify_token(sema, &token).map(IdentClass::definitions_no_ops);
+        if let Some(&[x]) = def.as_deref() {
+            return Some(x);
+        }
+    }
+    None
+}