Fix missing parentheses for missing_unsafe

crates/ide-diagnostics/src/handlers/missing_unsafe.rs

@@ -50,7 +50,12 @@ fn fixes(ctx: &DiagnosticsContext<'_>, d: &hir::MissingUnsafe) -> Option<Vec<Ass
 
     let node_to_add_unsafe_block = pick_best_node_to_add_unsafe_block(&expr)?;
 
-    let replacement = format!("unsafe {{ {} }}", node_to_add_unsafe_block.text());
+    let mut replacement = format!("unsafe {{ {} }}", node_to_add_unsafe_block.text());
+    if let Some(expr) = ast::Expr::cast(node_to_add_unsafe_block.clone())
+        && needs_parentheses(&expr)
+    {
+        replacement = format!("({replacement})");
+    }
     let edit = TextEdit::replace(node_to_add_unsafe_block.text_range(), replacement);
     let source_change = SourceChange::from_text_edit(
         d.node.file_id.original_file(ctx.sema.db).file_id(ctx.sema.db),
@@ -112,6 +117,17 @@ fn pick_best_node_to_add_unsafe_block(unsafe_expr: &ast::Expr) -> Option<SyntaxN
     None
 }
 
+fn needs_parentheses(expr: &ast::Expr) -> bool {
+    let node = expr.syntax();
+    node.ancestors()
+        .skip(1)
+        .take_while(|it| it.text_range().start() == node.text_range().start())
+        .map_while(ast::Expr::cast)
+        .last()
+        .and_then(|it| Some(it.syntax().parent()?.kind()))
+        .is_some_and(|kind| ast::ExprStmt::can_cast(kind) || ast::StmtList::can_cast(kind))
+}
+
 #[cfg(test)]
 mod tests {
     use crate::tests::{check_diagnostics, check_fix, check_no_fix};
@@ -527,6 +543,27 @@ fn main() {
         )
     }
 
+    #[test]
+    fn needs_parentheses_for_unambiguous() {
+        check_fix(
+            r#"
+//- minicore: copy
+static mut STATIC_MUT: u8 = 0;
+
+fn foo() -> u8 {
+    STATIC_MUT$0 * 2
+}
+"#,
+            r#"
+static mut STATIC_MUT: u8 = 0;
+
+fn foo() -> u8 {
+    (unsafe { STATIC_MUT }) * 2
+}
+"#,
+        )
+    }
+
     #[test]
     fn ref_to_unsafe_expr() {
         check_fix(