Intellij can't find java.net.http when compiling with Java 11

Question

I'm trying to get one of my projects ready for Java 11 but for some reason Intellij can't find java.net.http. It isn't underlining it as not found in module-info.java like it would if I typed it wrong but when I try build the project I get the error below. I've tried reinstalling Intellij 2018.2.3 and uninstalling all other versions of Java. Any advice on how to get this working would be appreciated.

Error:

Information:java: Errors occurred while compiling module 'crawler'
Information:javac 11 was used to compile java sources
Information:15/09/2018 11:16 - Compilation completed with 1 error and 0 warnings in 636 ms
C:\Users\Will\IdeaProjects\crawler\src\module-info.java
Error:(2, 22) java: module not found: java.net.http

module-info.java:

module crawler {
    requires java.net.http;
}

Request.java:

package Request;

import java.io.IOException;
import java.net.URI;
import java.net.http.HttpClient;
import java.net.http.HttpRequest;
import java.net.http.HttpResponse;

public class Request {
    public static void main(String[] args) throws IOException, InterruptedException {
        System.out.println("starting download");
        String body = HttpClient.newBuilder().build().send(HttpRequest.newBuilder().uri(URI.create("https://example.com")).build(), HttpResponse.BodyHandlers.ofString()).body();
        System.out.println("finished download:" + body);
    }
}

Structure:

crawler
    src
        Request
            Request.java
        module-info.java

Answer 1

In the case that the above proposed resolution (by @Will) does not solve your issue as was the case with me (i.e. setting the project language level), check to to see what the bytecode target version of your java compiler has been set to, in your project preferences: