top_level_cycle

The type of '{0}' can't be inferred because it depends on itself through the cycle: {1}.

The analyzer produces this diagnostic when a top-level variable has no type annotation and the variable's initializer refers to the variable, either directly or indirectly.

The following code produces this diagnostic because the variables x and y are defined in terms of each other, and neither has an explicit type, so the type of the other can't be inferred:

var x = y;
var y = x;

If the two variables don't need to refer to each other, then break the cycle:

var x = 0;
var y = x;

If the two variables need to refer to each other, then give at least one of them an explicit type:

int x = y;
var y = x;

Note, however, that while this code doesn't produce any diagnostics, it will produce a stack overflow at runtime unless at least one of the variables is assigned a value that doesn't depend on the other variables before any of the variables in the cycle are referenced.

Unless stated otherwise, the documentation on this site reflects Dart 3.8.1. Page last updated on 2025-05-08. View source or report an issue.