if !ok {
			return
		}

		for _, c := range f.Calls {
			if !c.Done && c.Call.Lparen == call.Lparen {
				cstr, nu := p.rewriteCall(f, c)
				if cstr != "" {
					// Smuggle the rewritten call through an ident.
					*px = ast.NewIdent(cstr)
					if nu {
						needsUnsafe = true
					}
					c.Done = true
				}
			}
		}
	})
	return *arg, needsUnsafe
}