fix: remove infinite loop on function A(A) {} (#6976)

Author: siketyan

.changeset/evil-mangos-type.md

@@ -0,0 +1,5 @@
+---
+"@biomejs/biome": patch
+---
+
+Fixed [#6692](https://github.com/biomejs/biome/issues/6692): The rules `noUnusedVariables` and `noUnusedFunctionParameters` no longer cause an infinite loop when the suggested name is not applicable (e.g. the suggested name is already declared in the scope).

crates/biome_js_analyze/src/lint/correctness/no_unused_function_parameters.rs

@@ -216,7 +216,9 @@ impl Rule for NoUnusedFunctionParameters {
                 let new_name = format!("_{name_trimmed}");
 
                 let model = ctx.model();
-                mutation.rename_node_declaration(model, binding, &new_name);
+                if !mutation.rename_node_declaration(model, binding, &new_name) {
+                    return None;
+                }
 
                 Some(JsRuleAction::new(
                     ctx.metadata().action_category(ctx.category(), ctx.group()),

crates/biome_js_analyze/src/lint/correctness/no_unused_variables.rs

@@ -373,7 +373,9 @@ impl Rule for NoUnusedVariables {
                 let new_name = format!("_{name_trimmed}");
 
                 let model = ctx.model();
-                mutation.rename_node_declaration(model, binding, &new_name);
+                if !mutation.rename_node_declaration(model, binding, &new_name) {
+                    return None;
+                }
 
                 Some(JsRuleAction::new(
                     ctx.metadata().action_category(ctx.category(), ctx.group()),

crates/biome_js_analyze/src/utils/rename.rs

@@ -156,6 +156,7 @@ impl TryFrom<JsSyntaxNode> for AnyJsRenamableDeclaration {
 
 pub trait RenameSymbolExtensions {
     /// Rename the binding and all its references to "new_name".
+    #[must_use = "Check the return value and ignore the mutation if false was returned"]
     fn rename_node_declaration(
         &mut self,
         model: &SemanticModel,

crates/biome_js_analyze/tests/spec_tests.rs

@@ -280,6 +280,8 @@ fn check_code_action(
     options: JsParserOptions,
     root: &AnyJsRoot,
 ) {
+    assert!(!action.mutation.is_empty(), "Mutation must not be empty");
+
     let (new_tree, text_edit) = match action
         .mutation
         .clone()

crates/biome_js_analyze/tests/specs/correctness/noUnusedFunctionParameters/issue6692.js

@@ -0,0 +1 @@
+function _A(A) {}

crates/biome_js_analyze/tests/specs/correctness/noUnusedFunctionParameters/issue6692.js.snap

@@ -0,0 +1,24 @@
+---
+source: crates/biome_js_analyze/tests/spec_tests.rs
+expression: issue6692.js
+---
+# Input
+```js
+function _A(A) {}
+
+```
+
+# Diagnostics
+```
+issue6692.js:1:13 lint/correctness/noUnusedFunctionParameters ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
+
+  ! This parameter is unused.
+  
+  > 1 │ function _A(A) {}
+      │             ^
+    2 │ 
+  
+  i Unused parameters might be the result of an incomplete refactoring.
+  
+
+```

crates/biome_js_analyze/tests/specs/correctness/noUnusedVariables/issue6692.js

@@ -0,0 +1,2 @@
+function _A() {}
+function A() {}

crates/biome_js_analyze/tests/specs/correctness/noUnusedVariables/issue6692.js.snap

@@ -0,0 +1,26 @@
+---
+source: crates/biome_js_analyze/tests/spec_tests.rs
+expression: issue6692.js
+---
+# Input
+```js
+function _A() {}
+function A() {}
+
+```
+
+# Diagnostics
+```
+issue6692.js:2:10 lint/correctness/noUnusedVariables ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
+
+  ! This function A is unused.
+  
+    1 │ function _A() {}
+  > 2 │ function A() {}
+      │          ^
+    3 │ 
+  
+  i Unused variables are often the result of an incomplete refactoring, typos, or other sources of bugs.
+  
+
+```

crates/biome_rowan/src/ast/batch.rs

@@ -555,6 +555,10 @@ where
     pub fn root(&self) -> &SyntaxNode<L> {
         &self.root
     }
+
+    pub fn is_empty(&self) -> bool {
+        self.changes.is_empty()
+    }
 }
 
 #[cfg(test)]