Use platform specific default for finding Go binary

src/goInstallTools.ts

@@ -227,23 +227,20 @@ export function updateGoPathGoRootFromConfig(): Promise<void> {
 		}
 	}
 
-	if (process.env['GOPATH'] && process.env['GOROOT']) {
+	if (process.env['GOPATH']) {
 		return Promise.resolve();
 	}
 
-	// If GOPATH and GOROOT are still not set, then use the ones from `go env`
+	// If GOPATH is still not set, then use the one from `go env`
 	let goRuntimePath = getGoRuntimePath();
 	return new Promise<void>((resolve, reject) => {
-		cp.execFile(goRuntimePath, ['env', 'GOROOT', 'GOPATH'], (err, stdout, stderr) => {
+		cp.execFile(goRuntimePath, ['env', 'GOPATH'], (err, stdout, stderr) => {
 			if (err) {
 				return reject();
 			}
 			let envOutput = stdout.split('\n');
-			if (!process.env['GOROOT'] && envOutput[0].trim()) {
-				process.env['GOROOT'] = envOutput[0].trim();
-			}
-			if (!process.env['GOPATH'] && envOutput[1].trim()) {
-				process.env['GOPATH'] = envOutput[1].trim();
+			if (!process.env['GOPATH'] && envOutput[0].trim()) {
+				process.env['GOPATH'] = envOutput[0].trim();
 			}
 			return resolve();
 		});

src/goPath.ts

@@ -82,6 +82,12 @@ export function getGoRuntimePath(): string {
 		let pathparts = (<string>process.env.PATH).split(path.delimiter);
 		runtimePathCache = pathparts.map(dir => path.join(dir, correctBinNameGo)).filter(candidate => fileExists(candidate))[0];
 	}
+	if (!runtimePathCache) {
+		let defaultPathForGo = process.platform === 'win32' ? 'C:\\Go\\bin\\go.exe' : '/usr/local/go/bin/go';
+		if (fileExists(defaultPathForGo)) {
+			runtimePathCache = defaultPathForGo;
+		}
+	}
 	return runtimePathCache;
 }