Rethrow stackless parse error

Author: som-snytt

Diff for: compiler/src/dotty/tools/dotc/ast/MainProxies.scala

@@ -96,8 +96,9 @@ object MainProxies {
         EmptyTree,
         Block(
           List(Apply(ref(defn.CLP_showError.termRef), errVar :: Nil)),
-          Apply(Select(Select(Select(Ident(termName("java")), termName("lang")), termName("System")), termName("exit")),
-            List(Literal(Constant(1))))
+          Throw(errVar)
+        //Apply(Select(Select(Select(Ident(termName("java")), termName("lang")), termName("System")), termName("exit")),
+        //  List(Literal(Constant(1))))
         )
       )
       val body = Try(call, handler :: Nil, EmptyTree)

Diff for: library/src/scala/util/CommandLineParser.scala

@@ -9,7 +9,7 @@ object CommandLineParser {
    *  @param idx  The index of the argument that's faulty (starting from 0)
    *  @param msg  The error message
    */
-  class ParseError(val idx: Int, val msg: String) extends Exception(msg)
+  class ParseError(val idx: Int, val msg: String) extends Exception(msg, null, false, false)
 
   /** Parse command line argument `s`, which has index `n`, as a value of type `T`
    *  @throws ParseError if argument cannot be converted to type `T`.

Diff for: tests/printing/infix-operations.check

@@ -31,6 +31,7 @@ package <empty> {
         {
           case error @ _:scala.util.CommandLineParser.ParseError =>
             scala.util.CommandLineParser.showError(error)
+            throw error
         }
   }
 }