Fix recent regression with comments right before imports

amm/compiler/src/main/scala-2/ammonite/compiler/DefaultPreprocessor.scala

@@ -111,8 +111,13 @@ class DefaultPreprocessor(parse: => String => Either[String, Seq[G#Tree]],
 
   val Import = Processor{
     case (name, code, tree: G#Import) =>
-      val Array(keyword, body) = code.split(" ", 2)
-      val tq = "\"\"\""
+      val body = fastparse.parse(code, Parsers.ImportFinder(_)) match {
+        case s: fastparse.Parsed.Success[String] =>
+          s.value
+        case _ =>
+          val Array(keyword, body) = code.split(" ", 2)
+          body
+      }
       Expanded(code, Seq(
         s"""
         _root_.ammonite

amm/compiler/src/main/scala-2/ammonite/compiler/Parsers.scala

@@ -17,7 +17,7 @@ object Parsers extends IParser {
   private def `_`[_: P] = scalaparse.Scala.Underscore
 
 
-  private def ImportSplitter[_: P]: P[Seq[ammonite.util.ImportTree]] = {
+  private def ImportExpr[_: P]: P[ammonite.util.ImportTree] = {
     def IdParser = P( (Id | `_` ).! ).map(
       s => if (s(0) == '`') s.drop(1).dropRight(1) else s
     )
@@ -28,18 +28,22 @@ object Parsers extends IParser {
     )
     def Prefix = P( IdParser.rep(1, sep = ".") )
     def Suffix = P( "." ~/ (BulkImport | Selectors) )
-    def ImportExpr: P[ammonite.util.ImportTree] = {
-      // Manually use `WL0` parser here, instead of relying on WhitespaceApi, as
-      // we do not want the whitespace to be consumed even if the WL0 parser parses
-      // to the end of the input (which is the default behavior for WhitespaceApi)
-      P( Index ~~ Prefix ~~ (WL0 ~~ Suffix).? ~~ Index).map{
-        case (start, idSeq, selectors, end) =>
-          ammonite.util.ImportTree(idSeq, selectors, start, end)
-      }
+
+    // Manually use `WL0` parser here, instead of relying on WhitespaceApi, as
+    // we do not want the whitespace to be consumed even if the WL0 parser parses
+    // to the end of the input (which is the default behavior for WhitespaceApi)
+    P( Index ~~ Prefix ~~ (WL0 ~~ Suffix).? ~~ Index).map{
+      case (start, idSeq, selectors, end) =>
+        ammonite.util.ImportTree(idSeq, selectors, start, end)
     }
-    P( `import` ~/ ImportExpr.rep(1, sep = ","./) )
   }
 
+  def ImportSplitter[_: P]: P[Seq[ammonite.util.ImportTree]] =
+    P( `import` ~/ ImportExpr.rep(1, sep = ","./) )
+
+  def ImportFinder[_: P]: P[String] =
+    P(WL ~ `import` ~/ ImportExpr.! ~ End)
+
   private def PatVarSplitter[_: P] = {
     def Prefixes = P(Prelude ~ (`var` | `val`))
     def Lhs = P( Prefixes ~/ BindPattern.rep(1, "," ~/ Pass) ~ (`:` ~/ Type).? )

amm/repl/src/test/scala/ammonite/session/AdvancedTests.scala

@@ -695,5 +695,18 @@ object AdvancedTests extends TestSuite{
       val files = os.walk(dir).filter(os.isFile(_)).map(_.relativeTo(dir))
       assert(files.sorted == expectedFiles.sorted)
     }
+    test("comment and import") {
+      check.session(
+        """
+          @ import $ivy.`org.typelevel::cats-kernel:2.6.1`
+
+          @ {
+          @   // hello
+          @   import cats.kernel._
+          @ }
+          import cats.kernel._
+        """
+      )
+    }
   }
 }