diagnostic: fix MissingFields

Author: xuhuanzy

crates/emmylua_code_analysis/src/diagnostic/checker/check_field.rs

@@ -64,6 +64,11 @@ fn check_index_expr(
     let prefix_typ = semantic_model
         .infer_expr(index_expr.get_prefix_expr()?)
         .unwrap_or(LuaType::Unknown);
+
+    if !is_valid_prefix_type(&prefix_typ) {
+        return Some(());
+    }
+
     let index_name = index_key.get_path_part();
     match code {
         DiagnosticCode::InjectField => {

crates/emmylua_code_analysis/src/diagnostic/test/missing_fields_test.rs

@@ -149,4 +149,18 @@ foo({})
         "#
         ));
     }
+
+    #[test]
+    fn test_1() {
+        let mut ws = VirtualWorkspace::new();
+        assert!(ws.check_code_for(
+            DiagnosticCode::MissingFields,
+            r#"
+                ---@type table 
+                local a = {}
+
+                print(a[1])
+        "#
+        ));
+    }
 }