fn handle_call(
builder: &mut SourceChangeBuilder,
ctx: &AssistContext<'_, '_>,
closure_ref: Expr,
captures_as_args: &[Expr],
) -> Option<()>fn handle_call(
builder: &mut SourceChangeBuilder,
ctx: &AssistContext<'_, '_>,
closure_ref: Expr,
captures_as_args: &[Expr],
) -> Option<()>