Fix short/long name distinction

Author: nicolasstucki

library/src/scala/annotation/newMain.scala

@@ -65,7 +65,7 @@ final class newMain extends MainAnnotation[FromString, Any]:
   private inline val argMarker = "--"
   private inline val shortArgMarker = "-"
 
-  private val longArgRegex = "--[a-zA-Z][a-zA-Z0-9]*".r
+  private val longArgRegex = "--[a-zA-Z][a-zA-Z0-9]+".r
   private val shortArgRegex = "-[a-zA-Z]".r
 
   extension (param: Parameter)
@@ -148,6 +148,8 @@ final class newMain extends MainAnnotation[FromString, Any]:
                   case None =>
                     error(s"unknown argument name: $name")
                 i += 1 // consume `value`
+          case name if name.startsWith("-") =>
+            error(s"ill-formed argument name: $name")
           case value =>
             positionalArgs += value
         i += 1

tests/run/main-annotation-short-name.check

@@ -1,7 +1,5 @@
 2 + 3 = 5
 2 + 3 = 5
-Error: unknown argument name: --n
-Error: unknown argument name: --i
-Error: missing argument for n
-Error: missing argument for i
+Error: ill-formed argument name: --n
+Error: ill-formed argument name: --i
 Usage: add [-n] <Int> [-i] <Int>

tests/run/main-annotation-wrong-param-names.check

@@ -1,7 +1,5 @@
-Error: unknown argument name: --n
-Error: unknown argument name: --i
-Error: missing argument for num
-Error: missing argument for inc
+Error: ill-formed argument name: --n
+Error: ill-formed argument name: --i
 Usage: add [--num] <Int> [--inc] <Int>
 Error: unused argument: inc
 Error: unused argument: 10