Webpack invalid mapping

[leefernandes]

node_modules/source-map/lib/source-map-generator.js:277
Error: Invalid mapping: {"generated":{"line":13415,"column":2},"source":"node_modules/@material/theme/_mixins.scss","original":{"line":94,"column":-1},"name":null}

When each of the below component stylesheets are imported by "app.scss" the compiler fails. Remove one of the imports, or remove line #94 of theme/_mixins.scss (&--theme-dark,) and it successfully compiles.

What MDC-Web Version are you using?

"material/button": "0.3.6",
"material/icon-toggle": "0.1.11",
"material/radio": "0.2.4",
"material/switch": "0.1.7",
"material/textfield": "0.2.9",

What are the steps to reproduce the bug?

• Clone the provided repo (https://github.com/ItsLeeOwen/mcw-sanity-check.git)
• npm install
• npm run build

@import "@material/button/mdc-button";
@import "@material/icon-toggle/mdc-icon-toggle";
@import "@material/radio/mdc-radio";
@import "@material/switch/mdc-switch";
@import "@material/textfield/mdc-textfield";

var webpack = require("webpack"),
    path = require("path"),
    ExtractTextPlugin = require("extract-text-webpack-plugin")

module.exports = {
    devtool: "source-map",
    entry: {
        "app.css": "app.scss",
    },
    output: {
        filename: "[name]",
        path: path.resolve(__dirname, "dist")
    },
    resolve: {
        modules: [
            path.resolve(__dirname, './'),
            path.resolve(__dirname, './node_modules'),
        ]
    },
    plugins: [
        new ExtractTextPlugin({
            filename: '[name]',
            publicPath: '/',
            allChunks: true
        })
    ],
    module: {
        rules: [{
            test: /\.scss$/,
            use: ExtractTextPlugin.extract({
                fallback: "style-loader",
                use: [{
                        loader: "css-loader",
                        options: {
                            sourceMap: true
                        }
                    },
                    {
                        loader: "sass-loader",
                        options: {
                            sourceMap: true,
                            outputStyle: "nested",
                            includePaths: [
                                path.resolve(__dirname, './node_modules')
                            ]
                        }
                    }
                ]
            })
        }]
    },
};

What is the expected behavior?

The stylesheets should compile when any combination of components are imported.

What is the actual behavior?

The compiler fails when the above five are imported.

[leefernandes]

Potentially related: sass/libsass#2312

[leefernandes]

Closing due to the issue being external: webpack-contrib/sass-loader#351