Invalid decorator parameter type

Current versions keep this code for compatibility but emit F_SYSTEM_CANNOT_INFER_VALUE_TYPE, F_SYSTEM_INVALID_METHOD_DECORATOR_TARGET, F_SYSTEM_INVALID_FIELD_DECORATOR_TARGET, or F_SYSTEM_EXPECTED_ARRAY_PARAM for the corresponding invariant.

Reproduction

A common case is a @Value() field whose runtime type cannot be inferred:

src/options.ts

import { Value } from 'func'

class Options {
  @Value()
  when: Date = new Date()
}

What this error means

func received a value of the wrong structural type. This code covers several definition failures, including an unsupported inferred @Value() type, a field or method decorator placed on a static member, and an option such as path, enum, or SubOptions that should be an array.

For type-inference failures, details.reason is cannot-infer-value-type and details.property identifies the field.

How to fix it

Provide a supported runtime parser explicitly when inference is unavailable:

src/options.ts

class Options {
  @Value({ type: String })
  when!: string
}

Keep @Handler() and @Catch() on instance methods, keep field decorators on instance properties, and pass arrays to APIs that require arrays. Supported value parsers are String, Number, Boolean, and [String].