test: add a test case to demonstrate the #2107 issue

cli/src/tests/github_issue_test.rs

@@ -6,7 +6,9 @@
 // cargo test --target $(rustc -vV | sed -nr 's/^host: //p') -- --test-threads 1
 // ```
 
+use super::helpers::query_helpers::assert_query_matches;
 use crate::tests::helpers::fixtures::get_language;
+use indoc::indoc;
 use tree_sitter::Query;
 
 #[test]
@@ -14,3 +16,27 @@ fn issue_2162_out_of_bound() {
     let language = get_language("java");
     assert!(Query::new(language, "(package_declaration _ (_) @name _)").is_ok());
 }
+
+#[test]
+fn issue_2107_first_child_group_anchor_had_no_effect() {
+    let language = get_language("c");
+    let source_code = indoc! {r#"
+        void fun(int a, char b, int c) { };
+    "#};
+    let query = indoc! {r#"
+        (parameter_list
+            .
+            (
+                (parameter_declaration) @constant
+                (#match? @constant "^int")
+            )
+        )
+    "#};
+    let query = Query::new(language, query).unwrap();
+    assert_query_matches(
+        language,
+        &query,
+        source_code,
+        &[(0, vec![("constant", "int a")])],
+    );
+}