Scalafix Workshop

on YouTube ↗01h 29m

" summary

Scalafix performs automated, semantic-aware rewrites and linters by combining Scalameta trees with a semanticdb index, producing token-level patches that precisely edit source without reprinting whole files. Examples include automated migration of Cats 0.9→1.0 (co-product → EitherK and operator changes), a null-infer warning that spots inferred Any, and a simple literal rewrite demo. Rules compile on-the-fly from GitHub, tests use paired input/output projects, and the key helper is the replaceSymbol API that updates uses and imports.

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" chapters (26)

1. 0:00Start
2. 2:09AGENDA
3. 3:08WHAT IS SCALAFIX
4. 4:33NOPROCEDURESYNTAX
5. 5:16NOAUTOTUPLING
6. 6:20REMOVECARTESIANBUILDER
7. 7:16NOINFER
8. 10:33MEANWHILE IN SWIFT
9. 12:45LET'S START FROM THE ANSWER
10. 13:06TOKENS
11. 14:41SCALAC
12. 15:12MACROS
13. 15:46SCALAFMT
14. 18:05WHAT SCALAFIX DOES INSTEAD
15. 20:17META PROGRAMMING DEVTOOLS!
16. 21:19TREES
17. 22:24PARSER
18. 22:46TREE MANIPULATION PRIMITIVES
19. 23:15SEMANTIC API: DATABASE
20. 24:33SEMANTIC API: NAMES
21. 25:18SEMANTIC API: SYMBOLS
22. 26:23SEMANTIC API: MESSAGES
23. 27:04SEMANTIC API: SYNTHETICS (SUGARS)
24. 28:17RECAP
25. 29:37Patch
26. 31:19SemanticdbIndex

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