"step already defined" errors when I try to extend Behat FeatureContext with MinkContext

Question

I'm new to Behat and Mink, and I'm trying to extend FeatureContext with MinkContext, but when I do, every step throws an error stating that the first function defined in MinkContext is also defined in FeatureContext (it isn't). The error message is as follows:

Step "/^(?:|I )am on (?:|the )homepage$/" 
is already defined in FeatureContext::iAmOnHomepage()

If I remove the first function from the class, every step throws the same error, but now it refers to the second function in the MinkContext class:

Step "/^(?:|I )am on "(?P<page>[^"]+)"$/" 
is already defined in FeatureContext::visit()

Extending FeatureContext with RawMinkContext works fine.

What could be causing this?

---- EDIT (additional info) ------------

I'm using Behat 3.

This is my entire current FeatureContext.php, and I'm still getting the error. I searched the entire folder containing my Behat install, and I could only find one instance of the

<?php

use Behat\Behat\Context\Context;
use Behat\Behat\Context\SnippetAcceptingContext;
use Behat\Gherkin\Node\PyStringNode;
use Behat\Gherkin\Node\TableNode;
use Behat\MinkExtension\Context\MinkContext;

/**
 * Defines application features from the specific context.
 */
class FeatureContext extends MinkContext implements SnippetAcceptingContext
{
    /**
     * Initializes context.
     *
     * Every scenario gets its own context instance.
     * You can also pass arbitrary arguments to the
     * context constructor through behat.yml.
     */
    public function __construct()
    {
        date_default_timezone_set("US/Eastern");
    }



}

This is my behat.yml file:

# behat.yml
default:
    extensions:
        Behat\MinkExtension:
            goutte: ~
            selenium2: ~
            base_url: https://harvest.cals.ncsu.edu/
    suites:
        default:
            contexts:
            - FeatureContext
            - Behat\MinkExtension\Context\MinkContext

This is the top portion of MinkContext.php: namespace Behat\MinkExtension\Context;

use Behat\Behat\Context\TranslatableContext;
use Behat\Gherkin\Node\TableNode;

/**
 * Mink context for Behat BDD tool.
 * Provides Mink integration and base step definitions.
 *
 * @author Konstantin Kudryashov <ever.zet@gmail.com>
 */
class MinkContext extends RawMinkContext implements TranslatableContext
{
    /**
     * Opens homepage
     * Example: Given I am on "/"
     * Example: When I go to "/"
     * Example: And I go to "/"
     *
     * @Given /^(?:|I )am on (?:|the )homepage$/
     * @When /^(?:|I )go to (?:|the )homepage$/
     */
    public function iAmOnHomepage()
    {
        $this->visitPath('/');
    }
...

--- EDIT 2: Working versions ------------

FeatureContext.php:

    <?php

    use Behat\Behat\Context\Context;
    use Behat\Behat\Context\SnippetAcceptingContext;
    use Behat\Gherkin\Node\PyStringNode;
    use Behat\Gherkin\Node\TableNode;
    use Behat\MinkExtension\Context\MinkContext;
    use Behat\Mink\WebAssert;

    /**
     * Defines application features from the specific context.
     */
    class FeatureContext extends MinkContext implements Context, SnippetAcceptingContext
    {
    ...

behat.yml (now with Selenium tags to enable Chrome)

# behat.yml
default:
    extensions:
        Behat\MinkExtension:
            goutte: ~
            selenium2: 
                wd_host: "http://127.0.0.1:4444/wd/hub"
                # chrome
                capabilities: { "browserName": "chrome", "browser": "chrome", "version":  "25", 'chrome': {'switches':['--no-sandbox']}}
            base_url: https://harvest.cals.ncsu.edu/
            browser_name: chrome
    suites:
        default:
            contexts:
            - FeatureContext

Answer 1

Seems that MinkContext is loaded twice: in FeatureContext and in behat.yml If you remove MinkContex from behat.yml it should work.