Enable semanticdb by default

Author: tgodzik

compiler/src/dotty/tools/dotc/config/ScalaSettings.scala

@@ -153,7 +153,7 @@ private sealed trait XSettings:
   val XverifySignatures: Setting[Boolean] = BooleanSetting("-Xverify-signatures", "Verify generic signatures in generated bytecode.")
   val XignoreScala2Macros: Setting[Boolean] = BooleanSetting("-Xignore-scala2-macros", "Ignore errors when compiling code that calls Scala2 macros, these will fail at runtime.")
   val XimportSuggestionTimeout: Setting[Int] = IntSetting("-Ximport-suggestion-timeout", "Timeout (in ms) for searching for import suggestions when errors are reported.", 8000)
-  val Xsemanticdb: Setting[Boolean] = BooleanSetting("-Xsemanticdb", "Store information in SemanticDB.", aliases = List("-Ysemanticdb"))
+  val Xsemanticdb: Setting[Boolean] = BooleanSetting("-Xsemanticdb", "Store information in SemanticDB.", aliases = List("-Ysemanticdb"), initialValue = true)
   val Xtarget: Setting[String] = ChoiceSetting("-Xtarget", "target", "Emit bytecode for the specified version of the Java platform. This might produce bytecode that will break at runtime. When on JDK 9+, consider -release as a safer alternative.", ScalaSettings.supportedTargetVersions, "", aliases = List("--Xtarget"))
   val XcheckMacros: Setting[Boolean] = BooleanSetting("-Xcheck-macros", "Check some invariants of macro generated code while expanding macros", aliases = List("--Xcheck-macros"))