Refine timeout config

Author: odersky

compiler/src/dotty/tools/dotc/Run.scala

@@ -31,6 +31,12 @@ import scala.util.control.NonFatal
 /** A compiler run. Exports various methods to compile source files */
 class Run(comp: Compiler, ictx: Context) extends ImplicitRunInfo with ConstraintRunInfo {
 
+  /** Default timeout to stop looking for further implicit suggestions, in ms.
+   *  This is usually for the first import suggestion; subsequent suggestions
+   *  may get smaller timeouts. @see ImportSuggestions.reduceTimeBudget
+   */
+  var importSuggestionBudget: Int = ictx.settings.XimportSuggestionTimeout.value
+
   /** If this variable is set to `true`, some core typer operations will
    *  return immediately. Currently these early abort operations are
    *  `Typer.typed` and `Implicits.typedImplicit`.

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

@@ -87,6 +87,7 @@ class ScalaSettings extends Settings.SettingGroup {
   val XfatalWarnings: Setting[Boolean] = BooleanSetting("-Xfatal-warnings", "Fail the compilation if there are any warnings.")
   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 XmixinForceForwarders = ChoiceSetting(
     name    = "-Xmixin-force-forwarders",

compiler/src/dotty/tools/dotc/typer/Implicits.scala

@@ -481,20 +481,6 @@ trait ImplicitRunInfo:
 
   private val EmptyTermRefSet = new TermRefSet(using NoContext)
 
-  /** Global timeout to stop looking for further implicit suggestions, in ms.
-   *  This is for the first import suggestion; subsequent suggestions
-   *  get smaller timeouts.
-   */
-  private inline val suggestFirstImplicitsTimeOut = 10000
-
-  /** Global default timeout to stop looking for further implicit suggestions, in ms.
-   *  This is usually for the first import suggestion; subsequent suggestions
-   *  may get smaller timeouts. Specifically, the importSuggestions method reduces
-   *  the budget available after it is run by the time it took, but never less
-   *  than to half of the previous budget.
-   */
-  var importSuggestionBudget: Long = 10000
-
   private def isExcluded(sym: Symbol) =
     if migrateTo3 then false else sym.is(Package) || sym.isPackageObject
 

compiler/src/dotty/tools/dotc/typer/ImportSuggestions.scala

@@ -252,11 +252,16 @@ trait ImportSuggestions:
         (Nil, Nil)
     finally
       timer.cancel()
-      ctx.run.importSuggestionBudget =
-        (ctx.run.importSuggestionBudget - (System.currentTimeMillis() - start))
-        `max` (ctx.run.importSuggestionBudget / 2)
+      reduceTimeBudget(((System.currentTimeMillis() - start) min Int.MaxValue).toInt)
   end importSuggestions
 
+  /** Reduce next timeout for import suggestions by the amount of time it took
+   *  for current search, but but never less than to half of the previous budget.
+   */
+  private def reduceTimeBudget(used: Int)(using Context) =
+    ctx.run.importSuggestionBudget =
+      (ctx.run.importSuggestionBudget - used) max (ctx.run.importSuggestionBudget / 2)
+
   /** The `ref` parts of this list of pairs, discarding subsequent elements that
    *  have the same String part. Elements are sorted by their String parts.
    */