regex with / and \ causes compilation error on 1.5.1

C:\>groovy -v
Groovy Version: 1.5.1 JVM: 1.5.0_13-b05

C:\>groovy -e "'foo/bar' =~ /\/|
/"
org.codehaus.groovy.control.MultipleCompilationErrorsException: startup failed, script_from_command_line: 1: unexpected
char: '\' @ line 1, column 19.
1 error

C:\>programs\Java\Groovy1.0\bin\groovy -v
Groovy Version: 1.0 JVM: 1.5.0_13-b05

C:\>programs\Java\Groovy1.0\bin\groovy -e "'foo/bar' =~ /\/|
/"

C:\>