Using it, produces output like this on stdout:
```
>> vlib/v/tests/typeof_type_test.v:4: keyword `typeof` token `(` token `[` keyword `fn` token `(` name `s` name `string`
>> vlib/v/tests/typeof_type_test.v:8: keyword `typeof` token `(` token `[` name `int` token `]` token `)` token `.`
>> vlib/v/tests/typeof_type_test.v:9: keyword `typeof` token `(` token `[` name `int` token `]` token `)` token `.`
>> vlib/v/tests/typeof_type_test.v:13: keyword `typeof` token `(` token `[` name `u32` token `]` token `)` token `.`
>> vlib/v/tests/typeof_type_test.v:14: keyword `typeof` token `(` token `[` name `u32` token `]` token `)` token `.`
>> vlib/v/tests/typeof_type_test.v:18: keyword `typeof` token `(` token `[` name `string` token `]` token `)` token `.`
```
Note: this tracing output is *deliberately on `stdout`*, instead of `stderr`,
so that you can filter it more easily, without saving it to a file first, i.e.
you can use it while developing/debugging parser issues like this:
`./v -o vnew cmd/v && ./vnew some_file.v | grep some_file.v`
-> this will show only the parsing context for the constructs you are debugging,
for that specific file *only*, instead of for all of `builtin` and the imported files etc.
vlib is the term for all modules included by default with V and
maintained as part of the V source code repository.
Some included modules depend on third party libraries, and these are kept
separate in the thirdparty directory at the root level of the source
repository.
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