fix: extract function panics on more than one usage of variable in macro

Author: dfireBird

crates/ide-assists/src/handlers/extract_function.rs

@@ -2060,7 +2060,7 @@ fn fix_param_usages(
             .filter_map(|reference| path_element_of_reference(syntax, reference))
             .map(|expr| tm.make_mut(&expr));
 
-        usages_for_param.push((param, usages.collect()));
+        usages_for_param.push((param, usages.dedup().collect()));
     }
 
     let res = tm.make_syntax_mut(syntax);
@@ -6233,4 +6233,42 @@ fn $0fun_name(a: i32, b: i32) {
         cov_mark::check!(extract_function_in_braces_is_not_applicable);
         check_assist_not_applicable(extract_function, r"fn foo(arr: &mut $0[$0i32]) {}");
     }
+
+    #[test]
+    fn issue_20965_panic() {
+        check_assist(
+            extract_function,
+            r#"
+//- minicore: fmt
+#[derive(Debug)]
+struct Foo(&'static str);
+
+impl Foo {
+    fn text(&self) -> &str { self.0 }
+}
+
+fn main() {
+    let s = Foo("");
+    $0print!("{}{}", s, s);$0
+    let _ = s.text() == "";
+}"#,
+            r#"
+#[derive(Debug)]
+struct Foo(&'static str);
+
+impl Foo {
+    fn text(&self) -> &str { self.0 }
+}
+
+fn main() {
+    let s = Foo("");
+    fun_name(&s);
+    let _ = s.text() == "";
+}
+
+fn $0fun_name(s: &Foo) {
+    *print!("{}{}", s, s);
+}"#,
+        );
+    }
 }