fix: fix casts and use typed syntax tree API in convert_to_guarded_return

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

@@ -75,26 +75,17 @@ fn if_expr_to_guarded_return(
 
     let let_chains = flat_let_chain(cond);
 
-    let then_block = if_expr.then_branch()?;
-    let then_block = then_block.stmt_list()?;
+    let then_branch = if_expr.then_branch()?;
+    let then_block = then_branch.stmt_list()?;
 
     let parent_block = if_expr.syntax().parent()?.ancestors().find_map(ast::BlockExpr::cast)?;
 
     if parent_block.tail_expr()? != if_expr.clone().into() {
         return None;
     }
 
-    // FIXME: This relies on untyped syntax tree and casts to much. It should be
-    // rewritten to use strongly-typed APIs.
-
     // check for early return and continue
-    let first_in_then_block = then_block.syntax().first_child()?;
-    if ast::ReturnExpr::can_cast(first_in_then_block.kind())
-        || ast::ContinueExpr::can_cast(first_in_then_block.kind())
-        || first_in_then_block
-            .children()
-            .any(|x| ast::ReturnExpr::can_cast(x.kind()) || ast::ContinueExpr::can_cast(x.kind()))
-    {
+    if is_early_block(&then_block) || is_never_block(&ctx.sema, &then_branch) {
         return None;
     }
 
@@ -284,6 +275,17 @@ fn clean_stmt_block(block: &ast::BlockExpr) -> ast::BlockExpr {
     }
 }
 
+fn is_early_block(then_block: &ast::StmtList) -> bool {
+    let is_early_expr =
+        |expr| matches!(expr, ast::Expr::ReturnExpr(_) | ast::Expr::ContinueExpr(_));
+    let into_expr = |stmt| match stmt {
+        ast::Stmt::ExprStmt(expr_stmt) => expr_stmt.expr(),
+        _ => None,
+    };
+    then_block.tail_expr().is_some_and(is_early_expr)
+        || then_block.statements().filter_map(into_expr).any(is_early_expr)
+}
+
 #[cfg(test)]
 mod tests {
     use crate::tests::{check_assist, check_assist_not_applicable};