I tried export NXF_SYNTAX_PARSER=v2, closing and openning a new terminal, before rerunning nextflow run ./core-hello -profile docker,test --outdir core-hello-results --validate_params false. Got the same error.
Note Getting started - training.nextflow.io does suggest running export NXF_SYNTAX_PARSER=v1, this avoids an error I ran into Part 1: Run a demo pipeline - training.nextflow.io yesterday, see Github codespace hello-nf-core import nf-schema error - Training - Seqera Community. I ran export NXF_SYNTAX_PARSER=v1 at the start of my codespace session today.
Maybe if I start a new codespace session without first running export NXF_SYNTAX_PARSER=v1 I wont run into this problem in Part 2: Rewrite Hello for nf-core - training.nextflow.io. Will try next week.
Not sure I have given the clearest of explanations here. Have a nice weekend.