inference_failure_on_function_return_type

The return type of '{0}' can't be inferred.

The analyzer produces this diagnostic when:

• the language option strict-inference is enabled in the analysis options file,
• the declaration of a method or function has no return type, and
• the return type can't be inferred.

Given an analysis options file containing the following:

analyzer:
  language:
    strict-inference: true

The following code produces this diagnostic because the method m doesn't have a return type:

class C {
  m() => 7;
}

Add a return type to the method or function:

class C {
  int m() => 7;
}