invalid_inline_function_type

Inline function types can't be used for parameters in a generic function type.

The analyzer produces this diagnostic when a generic function type has a function-valued parameter that is written using the older inline function type syntax.

The following code produces this diagnostic because the parameter f, in the generic function type used to define F, uses the inline function type syntax:

typedef F = int Function(int f(String s));

Use the generic function syntax for the parameter's type:

typedef F = int Function(int Function(String));

Unless stated otherwise, the documentation on this site reflects Dart 3.8.0. Page last updated on 2025-05-08. View source or report an issue.