Guide to Scala 3 Compiler Contribution

Cheatsheets

This page is a quick-reference guide for common tasks while working with the compiler. For more in-depth explanations, see the rest of this chapter.

sbt Commands

The following commands can be run within sbt in the dotty directory:

Commands
`testCompilation` Run compilation tests on files that match the first argument.
`scala3/scalac` Run the compiler directly, with any current changes.
`scala3/scala` Run the main method of a given class name.
`repl` Start a REPL with the bootstrapped compiler.
`testOnly CompilationTests -- pos` Run test `pos` from the compilation test suite.
`scala3-compiler/Test/runMain dotty.tools.printTypes` Print types underlying representation
`scala3/scalac -print-tasty Foo.tasty` Print the TASTy of top-level class `Foo`
`scala3-bootstrapped/test` Run all tests for Scala 3. (Slow, recommended for CI only)
`scala3-bootstrapped/publishLocal` Build Scala 3 locally. (Use to debug a specific project)

Command	Description
`rm -rv .tasty .class out \|\| true`	clean all compiled artifacts, from root dotty directory

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