Implement arity check for function types

[jacob314]

From di/lib/src/injector.dart

library di.check_bind_args;

import "src/module.dart";
export "src/module.dart" show DEFAULT_VALUE, IDENTITY, isSet, isNotSet;

checkBindArgs(dynamic toValue, Function toFactory,
              Type toImplementation, List inject, toInstanceOf) {
  int count = 0;
  bool argCountMatch = true;
  if (isSet(toValue)) count++;
  if (isSet(toFactory)) {
    count++;
    var len = inject.length;
    switch (len) {
      case 0: argCountMatch =  /* severe: InvalidRuntimeCheckError */ toFactory is _0; break;
      case 1: argCountMatch =  /* severe: InvalidRuntimeCheckError */ toFactory is _1; break;
      case 2: argCountMatch =  /* severe: InvalidRuntimeCheckError */ toFactory is _2; break;
      case 3: argCountMatch =  /* severe: InvalidRuntimeCheckError */ toFactory is _3; break;
      case 4: argCountMatch =  /* severe: InvalidRuntimeCheckError */ toFactory is _4; break;
      case 5: argCountMatch =  /* severe: InvalidRuntimeCheckError */ toFactory is _5; break;
      case 6: argCountMatch =  /* severe: InvalidRuntimeCheckError */ toFactory is _6; break;
      case 7: argCountMatch =  /* severe: InvalidRuntimeCheckError */ toFactory is _7; break;
      case 8: argCountMatch =  /* severe: InvalidRuntimeCheckError */ toFactory is _8; break;
      case 9: argCountMatch =  /* severe: InvalidRuntimeCheckError */ toFactory is _9; break;
      case 10: argCountMatch =  /* severe: InvalidRuntimeCheckError */ toFactory is _10; break;
      case 11: argCountMatch =  /* severe: InvalidRuntimeCheckError */ toFactory is _11; break;
      case 12: argCountMatch =  /* severe: InvalidRuntimeCheckError */ toFactory is _12; break;
      case 13: argCountMatch =  /* severe: InvalidRuntimeCheckError */ toFactory is _13; break;
      case 14: argCountMatch =  /* severe: InvalidRuntimeCheckError */ toFactory is _14; break;
      case 15: argCountMatch =  /* severe: InvalidRuntimeCheckError */ toFactory is _15; break;
    }
    if (!argCountMatch) throw "toFactory's argument count does not match amount provided by inject";
  }

[sigmundch]

yeah, we should support arity checks. I assume _1 etc are defined like:

typedef dynamic _0();
typedef dynamic _1(arg);
typedef dynamic _2(arg, arg);
...

[vsmenon]

Here's the code: https://github.com/angular/di.dart/blob/master/lib/check_bind_args.dart

We disallow this as our subtype rule (i.e., is) is stricter than standard for this case. We could provide a helper function for arity instead.

[vsmenon]

This should be obsolete now.