[Wesley Wigham (weswigham)]

At least if the pattern/string passed as a filter is simple enough. This works because compiler test names are derived from the file names - so we can use the targeted test names filter to filter the files we load, reducing IO and setup work we're just going to discard anyway. On windows (where file IO can be... elongated), this improves the performance of starting a limited subset of tests from ~14s to ~1s on my lower performance machine.

...there is some regex pattern reparsing going on to achieve that, though, so you can still get that benefit when you filter for, eg, TestLocal/declarationEmit(With|Empty)StatementNoCrash, rather than just a single test.

[Copilot]

🟢 Approval recommended

The filtering is conservative, integrated before file reads, and adequately tested.

0 open findings

What changed in this PR

Adds a conservative pre-read filter to speed targeted compiler test runs.

Changes:

• Parses -test.run patterns to identify candidate files.
• Skips unrelated files before loading test contents.
• Adds coverage for regex, configuration, and fallback cases.

File	Description
compiler_test_filter.go	Implements conservative filename filtering.
compiler_test_filter_test.go	Tests matching and fallback behavior.
compiler_runner.go	Applies filtering before loading tests.

🧠 Review effort: Balanced

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[Jake Bailey (jakebailey)]

If it works it's good