Unknown type on errorName and fieldName collision

[tabboud]

When the errorName collides with the fieldName (either safe or unsafe), the fieldName ends up masking the private struct type, and ultimately will fail to compile.

$ go build ./...
    # github.com/tdabboud/testing/pkg/testservice/errors
    pkg/testservice/errors/errors.conjure.go:657:94: unknownSortOrder is not a type

The following conjure-IR will repro the issue

{
  "version": 1,
  "errors": [
    {
      "errorName": {
        "name": "UnknownSortOrder",
        "package": "com.palantir.testservice.errors"
      },
      "docs": "Sort order was unknown.\n",
      "namespace": "TestService",
      "code": "INVALID_ARGUMENT",
      "safeArgs": [
        {
          "fieldName": "unknownSortOrder",
          "type": {
            "type": "primitive",
            "primitive": "STRING"
           }
        }
      ],
      "unsafeArgs": []
    }
  ]
}

The resulting code

// shortened for brevity...

type unknownSortOrder struct {
	UnknownSortOrder string `json:"unknownSortOrder" yaml:"unknownSortOrder,omitempty"`
}

// NewUnknownSortOrder returns new instance of UnknownSortOrder error.
func NewUnknownSortOrder(unknownSortOrder string) *UnknownSortOrder {
	return &UnknownSortOrder{errorInstanceID: uuid.NewUUID(), unknownSortOrder: unknownSortOrder{UnknownSortOrder: unknownSortOrder}}
}

// UnknownSortOrder is an error type.
//
// Sort order was unknown.
type UnknownSortOrder struct {
	errorInstanceID uuid.UUID
	unknownSortOrder
}

As you can see above the fieldName is unknownSortOrder which collides with the private struct unknownSortOrder