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# Description
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This PR fixes a corner case of goto definition in lsp server.
```nushell
let foo = 1
match $foo {
_ if $foo == 1 => 1
# |_______________ goto definition does not work here
_ => 2
}
```
Since `match_pattern.guard` is not handled in this function (which could
be another issue).
23dc1b600a/crates/nu-parser/src/flatten.rs (L604-L658)
In this PR, however, finding leaf expression at the cursor is done with
the new AST traversing helper functions.
Theoretically, this is faster as the flattening and filtering are
combined in a single scan; the difference could be negligible though.
# User-Facing Changes
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# Tests + Formatting
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3 new test cases added, will add more if new issues found.
# After Submitting
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e5337b50a9