added an error for duplicate labels

1 job for 1-check-labels-for-dupes in 4 seconds (queued for 2 seconds)
latest
Status Job ID Name Coverage
  Build
failed build #2622

00:00:04

 
Name Stage Failure
failed
build Build There is an unknown failure, please try again
      [cup]   Code written to "parser.java", and "sym.java".
[cup] ---------------------------------------------------- (v0.11a beta 20060608)

jflex:
[jflex] Generated: Lexer.java

compile:
[javac] /home/gitlab-runner/builds/ca62c1d8/0/parsergenerators/cup/build.xml:83: warning: 'includeantruntime' was not set, defaulting to build.sysclasspath=last; set to false for repeatable builds
[javac] Compiling 45 source files to /home/gitlab-runner/builds/ca62c1d8/0/parsergenerators/cup/target/classes
[javac] warning: [options] bootstrap class path not set in conjunction with -source 8