Support capture checking language imports in REPL

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

@@ -137,12 +137,14 @@ object Feature:
   /** Is pureFunctions enabled for this compilation unit? */
   def pureFunsEnabled(using Context) =
     enabledBySetting(pureFunctions)
+    || enabledByImport(pureFunctions)
     || ctx.compilationUnit.knowsPureFuns
     || ccEnabled
 
   /** Is captureChecking enabled for this compilation unit? */
   def ccEnabled(using Context) =
     enabledBySetting(captureChecking)
+    || enabledByImport(captureChecking)
     || ctx.compilationUnit.needsCaptureChecking
 
   /** Is pureFunctions enabled for any of the currently compiled compilation units? */

compiler/src/dotty/tools/dotc/parsing/Parsers.scala

@@ -4684,12 +4684,12 @@ object Parsers {
      *                 | Expr1
      *                 |
      */
-    def blockStatSeq(): List[Tree] = checkNoEscapingPlaceholders {
+    def blockStatSeq(allowGlobalImport: Boolean = false): List[Tree] = checkNoEscapingPlaceholders {
       val stats = new ListBuffer[Tree]
       while
         var empty = false
         if (in.token == IMPORT)
-          stats ++= importClause()
+          stats ++= importClause(outermost = allowGlobalImport)
         else if (isExprIntro)
           stats += expr(Location.InBlock)
         else if in.token == IMPLICIT && !in.inModifierPosition() then

compiler/src/dotty/tools/repl/ParseResult.scala

@@ -122,7 +122,7 @@ object ParseResult {
 
   private def parseStats(using Context): List[untpd.Tree] = {
     val parser = new Parser(ctx.source)
-    val stats = parser.blockStatSeq()
+    val stats = parser.blockStatSeq(allowGlobalImport = true)
     parser.accept(Tokens.EOF)
     stats
   }