diff --git a/src/tools/msvc/vcregress.pl b/src/tools/msvc/vcregress.pl
index 155f8358326..4432c7cb73a 100644
--- a/src/tools/msvc/vcregress.pl
+++ b/src/tools/msvc/vcregress.pl
@@ -190,7 +190,7 @@ sub tap_check
 	  unless $config->{tap_tests};
 
 	my @flags;
-	foreach my $arg (0 .. scalar(@_))
+	foreach my $arg (0 .. scalar(@_) - 1)
 	{
 		next unless $_[$arg] =~ /^PROVE_FLAGS=(.*)/;
 		@flags = split(/\s+/, $1);