Function get_callee_span_generic_args_and_args 

fn get_callee_span_generic_args_and_args<'tcx>(
    cx: &LateContext<'tcx>,
    expr: &'tcx Expr<'tcx>,
) -> Option<(DefId, Span, GenericArgsRef<'tcx>, Option<&'tcx Expr<'tcx>>, &'tcx [Expr<'tcx>])>

Checks whether an expression is a function or method call and, if so, returns its DefId, Span, GenericArgs, and arguments. This is a slight augmentation of a similarly named Clippy function, get_callee_generic_args_and_args.