Webpack warnings cannot be matched

[cjam]

• VSCode Version: 1.3.1
• OS Version: OS X 10.11.5

I am using webpack to build and pack up my application. Webpack produces warnings in the following format when you accidentally use an import with the wrong case in the file path: (i.e. ./Components/SomeComponent vs ./components/SomeComponent)

WARNING in ./src/Components/SomeComponent.tsx
There is another module with an equal name when case is ignored.
This can lead to unexpected behavior when compiling on a filesystem with other case-semantic.
Rename module if multiple modules are expected or use equal casing if one module is expected.

Now when I try to use the following problem matcher for this:

                {
                    "owner": "webpack",
                    "fileLocation": "relative",
                    "severity": "warning",
                    "pattern": [                        
                        {
                            "regexp": "WARNING in (.*)",
                            "file": 1
                        }
                        ,{
                            "regexp": "(.*)$",
                            "message": 1,
                            "loop": true
                        }
                    ]                   
                }

I get the following message when trying to build the project:

The problem pattern is invalid. It must have at least a file, message and line or location match group.

So it seems that the problem matcher validation logic requires that there is a location (line,col) for a rule to be valid. Couldn't the default just being the first line / column of a file so that the matcher could handle scenarios like this where its a file in general that produces the warning?

I admit, I feel like Webpack's warning should include a line/col as it is complaining about a specific import. But it would also be nice to be able to handle plugins that aren't necessarily being good citizens with respects to the output they surface.

[dbaeumer]

Dups #6538