Shorthand function signature issues with IOPortManager

[axmmisaka]

Issue

In port.ts, if the following change is made according to ESLint suggestion:

interface IOPortManager<T> extends TriggerManager {
-  addReceiver(port: WritablePort<T>): void;
+  addReceiver: (port: WritablePort<T>) => void;
-  delReceiver(port: WritablePort<T>): void;
+  delReceiver: (port: WritablePort<T>) => void;
}

Then lingua-franca tests will fail, and __tests__/bank.ts will error.

Specifically, this.d.allWritable(this.d.port((member) => member.o)); will experience typing error. While tsc can correctly infer the lambda type to be function(member: MultiPeriodic): OutMultiPort<number>, it infers port to be Bank<MultiPeriodic, unknown>.port<Port<unknown> | MultiPort<unknown>>(selector: (reactor: MultiPeriodic) => Port<unknown> | MultiPort<unknown>): (Port<unknown> | MultiPort<unknown>)[]; the generic types are unknown instead of number`.

The issue specifically is

Type 'OutMultiPort<number>' is not assignable to type 'Port<unknown> | MultiPort<unknown>'.
      Type 'OutMultiPort<number>' is not assignable to type 'MultiPort<unknown>'.
        The types returned by 'channels()' are incompatible between these types.
          Type 'OutPort<number>[]' is not assignable to type 'IOPort<unknown>[]'.
            Type 'OutPort<number>' is not assignable to type 'IOPort<unknown>'.
              The types of 'asWritable(...).getPort().getManager(...).addReceiver' are incompatible between these types.
                Type '(port: WritablePort<number>) => void' is not assignable to type '(port: WritablePort<unknown>) => void'.
                  Types of parameters 'port' and 'port' are incompatible.
                    Type 'WritablePort<unknown>' is not assignable to type 'WritablePort<number>'.
                      The types returned by 'get()' are incompatible between these types.
                        Type 'unknown' is not assignable to type 'number | undefined'.

Failed LF tests include NestedMulti.ts where similar error message could be observed:

this._connectMulti([...this.b.port(it => it.y)], [this.x], false);

src/NestedBanks.ts(429,28): error TS2345: Argument of type '(Port<unknown> | MultiPort<unknown>)[]' is not assignable to parameter of type '(MultiPort<number> | IOPort<number>)[]'.
  Type 'Port<unknown> | MultiPort<unknown>' is not assignable to type 'MultiPort<number> | IOPort<number>'.
    Type 'Port<unknown>' is not assignable to type 'MultiPort<number> | IOPort<number>'.
      Type 'Port<unknown>' is missing the following properties from type 'IOPort<number>': get, asWritable, writer, manager
src/NestedBanks.ts(429,50): error TS2322: Type 'OutMultiPort<number>' is not assignable to type 'Port<unknown> | MultiPort<unknown>'.
  Type 'OutMultiPort<number>' is not assignable to type 'MultiPort<unknown>'.
    The types returned by 'channels()' are incompatible between these types.
      Type 'OutPort<number>[]' is not assignable to type 'IOPort<unknown>[]'.
        Type 'OutPort<number>' is not assignable to type 'IOPort<unknown>'.
          The types of 'asWritable(...).getPort().getManager(...).addReceiver' are incompatible between these types.
            Type '(port: WritablePort<number>) => void' is not assignable to type '(port: WritablePort<unknown>) => void'.
              Types of parameters 'port' and 'port' are incompatible.
                Type 'WritablePort<unknown>' is not assignable to type 'WritablePort<number>'.
                  The types returned by 'get()' are incompatible between these types.
                    Type 'unknown' is not assignable to type 'number | undefined'.

Based on my observation, a lot of Port-related places also requires type assertion to compile with error after this change. While I think these assertion are safe to make and it is okay to keep them, I think this is a situation that is worth attention.

See Also

#162
#175

microsoft/TypeScript#40855