From fcd9c36f3bd88748d760b893cd0fd00c8a199f3a Mon Sep 17 00:00:00 2001
From: A4-Tacks <wdsjxhno1001@163.com>
Date: Wed, 1 Apr 2026 11:09:56 +0800
Subject: [PATCH] fix: Fix param inlayHints on empty expr and comma

Example
---
```rust
pub fn test(a: i32, b: i32, c: i32) {}
fn main() {
    test(, 2,);
    test(, , 3);
}
```

**Before this PR**

```rust
    test(, 2,);
         //^ a
    test(, , 3);
           //^ a
```

**After this PR**

```rust
    test(, 2,);
         //^ b
    test(, , 3);
           //^ c
```
---
 .../crates/ide/src/inlay_hints/param_name.rs     | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/src/tools/rust-analyzer/crates/ide/src/inlay_hints/param_name.rs b/src/tools/rust-analyzer/crates/ide/src/inlay_hints/param_name.rs
index 08588bbed090..8dddf9d37e4f 100644
--- a/src/tools/rust-analyzer/crates/ide/src/inlay_hints/param_name.rs
+++ b/src/tools/rust-analyzer/crates/ide/src/inlay_hints/param_name.rs
@@ -37,8 +37,9 @@ pub(super) fn hints(
     let hints = callable
         .params()
         .into_iter()
-        .zip(arg_list.args())
+        .zip(arg_list.args_maybe_empty())
         .filter_map(|(p, arg)| {
+            let arg = arg?;
             // Only annotate hints for expressions that exist in the original file
             let range = sema.original_range_opt(arg.syntax())?;
             if range.file_id != file_id {
@@ -561,6 +562,19 @@ fn main() {
         )
     }
 
+    #[test]
+    fn param_name_hints_show_after_empty_arg() {
+        check_params(
+            r#"pub fn test(a: i32, b: i32, c: i32) {}
+fn main() {
+    test(, 2,);
+         //^ b
+    test(, , 3);
+           //^ c
+}"#,
+        )
+    }
+
     #[test]
     fn function_call_parameter_hint() {
         check_params(