Show rust build errors in Visual Studio Code.

cargo-shell.js

var ChildProcess = require('child_process');

var task = process.argv[2];

var cargo = ChildProcess.exec('cargo ' + task);

cargo.stdout.on('data', function (data) {
    process.stdout.write(data);
});

cargo.stderr.on('data', function (data) {
    var lines = data
        .split(/\n\s*/)
        .map(function (line, index) {
            if (!line || (index && /^[^:]+\.rs:/.test(line))) {
                return '\n' + line;
            } else {
                return line;
            }
        });
        
    data = lines.join(' ');
    process.stderr.write(data);
});

cargo.on('error', function (error) {
    process.exit(1);
});

tasks.json

{
    "version": "0.1.0",
    "command": "node",
    "showOutput": "silent",
    "tasks": [
        {
            "taskName": "build",
            "isBuildCommand": true,
            "args": [
                ".settings/cargo-shell.js",
                "build"
            ],
            "problemMatcher": {
                "fileLocation": ["relative", "${cwd}"],
                "pattern": {
                    "regexp": "^([^:]*\\.rs):(\\d+):(\\d+): (\\d+):(\\d+) (error|warning|info): (.+?)(?:\\s*\\[([^\\]]+)\\]\\s*)?$",
                    "file": 1,
                    "line": 2,
                    "column": 3,
                    "endLine": 4,
                    "endColumn": 5,
                    "severity": 6,
                    "message": 7,
                    "code": 8
                }
            }
        },
        {
            "taskName": "test",
            "isTestCommand": true,
            "args": [
                ".settings/cargo-shell.js",
                "run"
            ],
            "problemMatcher": {
                "fileLocation": ["relative", "${cwd}"],
                "pattern": {
                    "regexp": "^([^:]*\\.rs):(\\d+):(\\d+): (\\d+):(\\d+) (error|warning|info): (.+?)(?:\\s*\\[([^\\]]+)\\]\\s*)?$",
                    "file": 1,
                    "line": 2,
                    "column": 3,
                    "endLine": 4,
                    "endColumn": 5,
                    "severity": 6,
                    "message": 7,
                    "code": 8
                }
            }
        }
    ]
}