llvm-project/llvm/test/FileCheck/check-multiple-prefixes-substr.txt

// RUN: FileCheck -check-prefix=CHECKER -check-prefix=CHECK -input-file %s %s -allow-unused-prefixes
// RUN: FileCheck -check-prefix=CHECK -check-prefix=CHECKER -input-file %s %s -allow-unused-prefixes

foo
; CHECKER: fo{{o}}