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I am curious that what causes us 'to to' typos, I had seen the same typos before.

I am curious that what causes us 'to to' typos, I had seen the same typos before.

I would say that "double word typos" are a common typing error. When I do such mistakes, I guess it happens like this:

1. Start writing a sentence
2. Think about the bigger picture
3. Finish writing the sentence

In step 3 I forgot where I stopped typing.

Automated checks

In this pull request @Hixie considered whether it actually might be a good idea to run tests for this kind of error: #81325

It could be done with scripts like this:

• https://opendev.org/openstack/searchlight/commit/5252235d9403fd8a57c2134d1cbd93ec40f7ad68
• https://unix.stackexchange.com/questions/256409/command-line-method-to-find-repeat-word-typos-with-line-numbers

Do you already have static code analysis scripts as part of the build process?

Prototype

I don't know whether it makes sense to introduce such a tool, but the "double word error" seems like being present a few times more.

laptop-jm:flutter (stable) janux$ time find . -name "*.dart" | xargs -n 1 pcregrep -Min --color=auto '\b([^[:space:]]+)[[:space:]]+\1\b' | grep "///" > /tmp/potential-double-word-typos.txt

real	0m3,129s
user	0m2,714s
sys	0m0,740s

Result (including false positives but also a dozen double word errors):

potential-double-word-typos.txt

test-exempt: only affects comments