启用迁移警告

Question

我正在将 2.7.7 scala 代码库移植到 2.8，并且想知道是否有编译器选项来显示迁移通知？我被可变序列的行为变化所困扰，该序列具有以下迁移通知[1]，但是当我构建项目时它不会显示任何内容（我已经启用了弃用和未经检查的警告）

1：@migration (2, 8, "从 2.8 开始，此操作创建一个新地图。将元素添加为\n"+ “对现有地图产生副作用并返回该地图本身，使用 +=。” ）

Answer 1

选项为：-Xmigration

输入scalac -help将显示Scala编译器的标准选项。

输入 scalac -X 将显示高级选项。

输入 scalac -Y 将会显示私有选项。

Answer 2

它是一个扩展选项，-Xmigration。

 ~: scala -X
Usage: scala <options> <source files>
Possible advanced options include:
  -Xassem-extdirs <dirs>         List of directories containing assemblies, defaults to `lib'
  -Xassem-name <file>            Name of the output assembly (only relevant with -target:msil)
  -Xassem-path <path>            List of assemblies referenced by the program (only relevant with -target:msil)
  -Xcheck-null                   Emit warning on selection of nullable reference
  -Xcheckinit                    Add runtime checks on field accessors. Uninitialized accesses result in an exception being thrown.
  -Xdisable-assertions           Generate no assertions and assumptions
  -Xelide-below                  Generate calls to @elidable-marked methods only if method priority is greater than argument.
  -Xexperimental                 Enable experimental extensions
  -Xfatal-warnings               Fail the compilation if there are any warnings.
  -Xfuture                       Turn on future language features
  -Xgenerate-phase-graph <file>  Generate the phase graphs (outputs .dot files) to fileX.dot
  -Xlog-implicits                Show more info on why some implicits are not applicable
  -Xmigration                    Warn about constructs whose behavior may have changed between 2.7 and 2.8
  -Xno-forwarders                Do not generate static forwarders in mirror classes
  -Xno-uescape                   Disables handling of \u unicode escapes
  -Xnojline                      Do not use JLine for editing
  -Xplugin-disable:<plugin>      Disable a plugin
  -Xplugin-list                  Print a synopsis of loaded plugins
  -Xplugin-require:<plugin>      Abort unless a plugin is available
  -Xplugin:<file>                Load a plugin from a file
  -Xpluginsdir <path>            Path to search compiler plugins
  -Xprint-icode                  Log internal icode to *.icode files
  -Xprint-pos                    Print tree positions (as offsets)
  -Xprint-types                  Print tree types (debugging option)
  -Xprint:<phase>                Print out program after <phase> or "all"
  -Xprompt                       Display a prompt after each error (debugging option)
  -Xresident                     Compiler stays resident, files to compile are read from standard input
  -Xscript <object>              Compile as a script, wrapping the code into object.main()
  -Xshow-class <class>           Show class info
  -Xshow-object <object>         Show object info
  -Xshow-phases                  Print a synopsis of compiler phases
  -Xsource-reader <classname>    Specify a custom method for reading source files
  -Xsourcedir <directory>        When -target:msil, the source folder structure is mirrored in output directory.
  -Xwarninit                     Warn about possible changes in initialization semantics
  -Y                             Print a synopsis of private options

Answer 3

% scala -X
Usage: scala <options> <source files>
Possible advanced options include:
  ...
  -Xmigration                    Warn about constructs whose behavior may have changed between 2.7 and 2.8
  ...