options-new.md

title	type	description	num	previous-page	next-page
New Compiler Options	section	This chapter lists all the new compiler options in Scala 3	25	options-lookup	scaladoc-settings-compatibility

The current page only contains the options that were added in Scala 3.0.x.

Standard settings

3.0.x	description
-color	Colored output Default: always.
-doc-snapshot	Generate a documentation snapshot for the current Dotty version
-explain	Explain errors in more detail.
-from-tasty	Compile classes from tasty files. The arguments are .tasty or .jar files.
-indent	Together with -rewrite, remove {...} syntax when possible due to significant indentation.
-new-syntax	Require then and do in control expressions.
-no-indent	Require classical {...} syntax, indentation is not significant.
-old-syntax	Require (...) around conditions.
-pagewidth	Set page width Default: 80.
-print-lines	Show source code line numbers.
-print-tasty	Prints the raw tasty.
-project	The name of the project.
-project-logo	The file that contains the project's logo (in /images).
-project-url	The source repository of your project.
-project-version	The current version of your project.
-rewrite	When used in conjunction with a ...-migration source version, rewrites sources to migrate to new version.
-siteroot	A directory containing static files from which to generate documentation. Default: ./docs.
-sourceroot	Specify workspace root directory. Default: ..

Verbose settings

3.2.x	description
-Vprofile	Show metrics about sources and internal representations to estimate compile-time complexity.
-Vprofile-sorted-by:<column-name>	Show metrics about sources and internal representations sorted by given column name.
-Vprofile-details N	Like -Vprofile, but also show metrics about sources and internal representations of the N most complex methods

Warning settings

3.3.x	description
-Wunused:all	Enable all warnings
-Wnonunit-statement	Warn when block statements are non-Unit expressions (added in 3.3.1)

Advanced settings

3.0.x	description
-Xignore-scala2-macros	Ignore errors when compiling code that calls Scala2 macros, these will fail at runtime.
-Ximport-suggestion-timeout	Timeout (in ms) for searching for import suggestions when errors are reported.
-Xmax-inlined-trees	Maximal number of inlined trees. Default: 2000000
-Xmax-inlines	Maximal number of successive inlines. Default: 32.
-Xprint-diff	Print changed parts of the tree since last print.
-Xprint-diff-del	Print changed parts of the tree since last print including deleted parts.
-Xprint-inline	Show where inlined code comes from.
-Xprint-suspension	Show when code is suspended until macros are compiled.
-Xrepl-disable-display	Do not display definitions in REPL.
-Xwiki-syntax	Retains the Scala2 behavior of using Wiki Syntax in Scaladoc.

Private settings

3.0.x	description
-Ycheck-all-patmat	Check exhaustivity and redundancy of all pattern matching (used for testing the algorithm).
-Ycheck-mods	Check that symbols and their defining trees have modifiers in sync.
-Ycheck-reentrant	Check that compiled program does not contain vars that can be accessed from a global root.
-Ycook-comments	Cook the comments (type check @usecase, etc.)
-Ydebug-error	Print the stack trace when any error is caught.
-Ydebug-flags	Print all flags of definitions.
-Ydebug-missing-refs	Print a stacktrace when a required symbol is missing.
-Ydebug-names	Show internal representation of names.
-Ydebug-pos	Show full source positions including spans.
-Ydebug-trace	Trace core operations.
-Ydebug-tree-with-id	Print the stack trace when the tree with the given id is created. Default: -2147483648.
-Ydebug-type-error	Print the stack trace when a TypeError is caught
-Ydetailed-stats	Show detailed internal compiler stats (needs Stats.enabled to be set to true).
-YdisableFlatCpCaching	Do not cache flat classpath representation of classpath elements from jars across compiler instances.
-Ydrop-comments	Drop comments when scanning source files.
-Ydump-sbt-inc	For every compiled foo.scala, output the API representation and dependencies used for sbt incremental compilation in foo.inc, implies -Yforce-sbt-phases.
-Yerased-terms	Allows the use of erased terms.
-Yexplain-lowlevel	When explaining type errors, show types at a lower level.
-Yexplicit-nulls	Make reference types non-nullable. Nullable types can be expressed with unions: e.g. String|Null.
-Yforce-sbt-phases	Run the phases used by sbt for incremental compilation (ExtractDependencies and ExtractAPI) even if the compiler is ran outside of sbt, for debugging.
-Yfrom-tasty-ignore-list	List of tasty files in jar files that will not be loaded when using -from-tasty
-Yindent-colons	Allow colons at ends-of-lines to start indentation blocks.
-Yinstrument	Add instrumentation code that counts allocations and closure creations.
-Yinstrument-defs	Add instrumentation code that counts method calls; needs -Yinstrument to be set, too.
-Yno-decode-stacktraces	how raw StackOverflow stacktraces, instead of decoding them into triggering operations.
-Yno-deep-subtypes	Throw an exception on deep subtyping call stacks.
-Yno-double-bindings	Assert no namedtype is bound twice (should be enabled only if program is error-free).
-Yno-kind-polymorphism	Disable kind polymorphism.
-Yno-patmat-opt	Disable all pattern matching optimizations.
-Yplain-printer	Pretty-print using a plain printer.
-Yprint-debug	When printing trees, print some extra information useful for debugging.
-Yprint-debug-owners	When printing trees, print owners of definitions.
-Yprint-pos	Show tree positions.
-Yprint-pos-syms	Show symbol definitions positions.
-Yprint-syms	When printing trees print info in symbols instead of corresponding info in trees.
-Yrequire-targetName	Warn if an operator is defined without a @targetName annotation
-Yretain-trees	Retain trees for top-level classes, accessible from ClassSymbol#tree
-Yscala2-unpickler	Control where we may get Scala 2 symbols from. This is either "always", "never", or a classpath. Default: always.
-Yshow-print-errors	Don't suppress exceptions thrown during tree printing.
-Yshow-suppressed-errors	Also show follow-on errors and warnings that are normally suppressed.
-Yshow-tree-ids	Uniquely tag all tree nodes in debugging output.
-Yshow-var-bounds	Print type variables with their bounds.
-Ytest-pickler	Self-test for pickling functionality; should be used with -Ystop-after:pickler.
-Yunsound-match-types	Use unsound match type reduction algorithm.