How to fix GCC error ‘the lambda has no capture-default’

When encountering a GCC error like this:

error: the lambda has no capture-default

fixing it is usually quite easy. Look for a Lambda function that captures some variable like this

[&myVar] (/* ... */) {/* ... */}

&myVar means “capture myVar by reference”.

In most cases you can just capture all local variables by using a capture default:

[&] (/* ... */) {/* ... */}

In rare cases this will have unintended side-effects as you now are capturing all variables by reference where you might want to capture some by copy – so be sure to check your code.

Note that this error is GCC version-dependent. For me using GCC 7.2 fixed the error.