LTO error when verifying sketch, UNO

I get the following errors when I try to verify a sketch. I've tried verifying basic sketches from the Arduino Editor examples, but I always get the same error. I have a Genuino UNO and it worked a couple of days ago. I haven't changed anything since.

./opt/arduino-builder/arduino-builder -compile -core-api-version 10611 -hardware opt/arduino-builder/hardware -hardware ./opt/cores -tools opt/arduino-builder/tools -tools ./opt/tools -built-in-libraries opt/libraries/latest -logger humantags -fqbn arduino:avr:uno -build-cache /tmp -build-path /tmp/093139344/build -verbose -prefs -prefs -prefs -libraries /tmp/093139344/custom -libraries /tmp/093139344/pinned /tmp/093139344/BareMinimum

Linking everything together...

lto1: fatal error: bytecode stream generated with LTO version 3.0 instead of the expected 4.1

compilation terminated.

lto-wrapper: fatal error: ./opt/tools/avr-gcc/5.4.0-atmel3.6.1-arduino2/bin/avr-gcc returned 1 exit status

compilation terminated.

/home/ubuntu/opt/tools/avr-gcc/5.4.0-atmel3.6.1-arduino2/bin/../lib/gcc/avr/5.4.0/../../../../avr/bin/ld: error: lto-wrapper failed

collect2: error: ld returned 1 exit status

exit status 1

There are multiple other reports of this bug:

I recommend subscribing to those threads so that you'll be sure to get news of any progress in fixing it.

This is an Arduino Web Editor specific problem so the workaround is to use the regular Arduino IDE, which you can download for free from:

Hello, please follow topic Issue 2018-10-30: lto-wrapper error prevent compilations for further information and updates about this.

Thank you.