diff --git a/t/08-performance/03-corekeys.t b/t/08-performance/03-corekeys.t
new file mode 100644
index 00000000000..c4812f8f25d
--- /dev/null
+++ b/t/08-performance/03-corekeys.t
@@ -0,0 +1,766 @@
+use Test;
+plan 1;
+
+# output of "perl6 -e '.say for CORE::.keys.sort.map: { qq:!c/  Q{$_},/ }'"
+my %allowed = (
+  Q{!CORE_MARKER},
+  Q{!INIT_VALUES},
+  Q{$!},
+  Q{$/},
+  Q{$=pod},
+  Q{$?BITS},
+  Q{$?COMPILATION-ID},
+  Q{$?NL},
+  Q{$?TABSTOP},
+  Q{$CORE_METAOP_ASSIGN},
+  Q{$RAKUDO-VERBOSE-STACKFRAME},
+  Q{$_},
+  Q{%DEPRECATIONS},
+  Q{&CLONE-HASH-DECONTAINERIZED},
+  Q{&CLONE-LIST-DECONTAINERIZED},
+  Q{&CMP-SLOW},
+  Q{&COMP_EXCEPTION},
+  Q{&CREATE_RATIONAL_FROM_INTS},
+  Q{&DEPRECATED},
+  Q{&DIVIDE_NUMBERS},
+  Q{&DUMP},
+  Q{&DYNAMIC},
+  Q{&ENUM_VALUES},
+  Q{&EVAL},
+  Q{&EVALFILE},
+  Q{&EXCEPTION},
+  Q{&GATHER},
+  Q{&GENERATE-ROLE-FROM-VALUE},
+  Q{&HOW},
+  Q{&HYPER},
+  Q{&HYPERWHATEVER},
+  Q{&INDIRECT_NAME_LOOKUP},
+  Q{&INITIALIZE-A-DISTRO-NOW},
+  Q{&INITIALIZE-A-VM-NOW},
+  Q{&MD-ARRAY-SLICE},
+  Q{&MD-ARRAY-SLICE-ONE-POSITION},
+  Q{&MD-HASH-SLICE-ONE-POSITION},
+  Q{&METAOP_ASSIGN},
+  Q{&METAOP_CROSS},
+  Q{&METAOP_HYPER},
+  Q{&METAOP_HYPER_CALL},
+  Q{&METAOP_HYPER_POSTFIX},
+  Q{&METAOP_HYPER_POSTFIX_ARGS},
+  Q{&METAOP_HYPER_PREFIX},
+  Q{&METAOP_NEGATE},
+  Q{&METAOP_REDUCE_CHAIN},
+  Q{&METAOP_REDUCE_LEFT},
+  Q{&METAOP_REDUCE_LIST},
+  Q{&METAOP_REDUCE_LISTINFIX},
+  Q{&METAOP_REDUCE_RIGHT},
+  Q{&METAOP_REDUCE_XOR},
+  Q{&METAOP_REVERSE},
+  Q{&METAOP_TEST_ASSIGN:<&&>},
+  Q{&METAOP_TEST_ASSIGN:<//>},
+  Q{&METAOP_TEST_ASSIGN:<and>},
+  Q{&METAOP_TEST_ASSIGN:<andthen>},
+  Q{&METAOP_TEST_ASSIGN:<notandthen>},
+  Q{&METAOP_TEST_ASSIGN:<or>},
+  Q{&METAOP_TEST_ASSIGN:<orelse>},
+  Q{&METAOP_TEST_ASSIGN:<||>},
+  Q{&METAOP_ZIP},
+  Q{&ORDER},
+  Q{&POSITIONS},
+  Q{&QX},
+  Q{&REACT},
+  Q{&REACT-ONE-WHENEVER},
+  Q{&REQUIRE_IMPORT},
+  Q{&RETURN-LIST},
+  Q{&RUN-MAIN},
+  Q{&SEQUENCE},
+  Q{&SLICE_HUH},
+  Q{&SLICE_MORE_HASH},
+  Q{&SLICE_MORE_LIST},
+  Q{&SLICE_ONE_HASH},
+  Q{&SLICE_ONE_LIST},
+  Q{&SUPPLY},
+  Q{&SUPPLY-ONE-EMIT},
+  Q{&SUPPLY-ONE-WHENEVER},
+  Q{&THROW},
+  Q{&THROW-NIL},
+  Q{&UNBASE},
+  Q{&UNBASE_BRACKET},
+  Q{&VAR},
+  Q{&WHAT},
+  Q{&WHENEVER},
+  Q{&abs},
+  Q{&acos},
+  Q{&acosec},
+  Q{&acosech},
+  Q{&acosh},
+  Q{&acotan},
+  Q{&acotanh},
+  Q{&all},
+  Q{&any},
+  Q{&append},
+  Q{&asec},
+  Q{&asech},
+  Q{&asin},
+  Q{&asinh},
+  Q{&atan},
+  Q{&atan2},
+  Q{&atanh},
+  Q{&atomic-add-fetch},
+  Q{&atomic-assign},
+  Q{&atomic-dec-fetch},
+  Q{&atomic-fetch},
+  Q{&atomic-fetch-add},
+  Q{&atomic-fetch-dec},
+  Q{&atomic-fetch-inc},
+  Q{&atomic-fetch-sub},
+  Q{&atomic-inc-fetch},
+  Q{&atomic-sub-fetch},
+  Q{&await},
+  Q{&bag},
+  Q{&cache},
+  Q{&callframe},
+  Q{&callsame},
+  Q{&callwith},
+  Q{&cas},
+  Q{&categorize},
+  Q{&ceiling},
+  Q{&chars},
+  Q{&chdir},
+  Q{&chmod},
+  Q{&chomp},
+  Q{&chop},
+  Q{&chr},
+  Q{&chrs},
+  Q{&circumfix:<:{ }>},
+  Q{&circumfix:<[ ]>},
+  Q{&circumfix:<{ }>},
+  Q{&cis},
+  Q{&classify},
+  Q{&close},
+  Q{&comb},
+  Q{&combinations},
+  Q{&copy},
+  Q{&cos},
+  Q{&cosec},
+  Q{&cosech},
+  Q{&cosh},
+  Q{&cotan},
+  Q{&cotanh},
+  Q{&cross},
+  Q{&dd},
+  Q{&deepmap},
+  Q{&defined},
+  Q{&die},
+  Q{&dir},
+  Q{&done},
+  Q{&duckmap},
+  Q{&elems},
+  Q{&emit},
+  Q{&end},
+  Q{&exit},
+  Q{&exp},
+  Q{&expmod},
+  Q{&fail},
+  Q{&fc},
+  Q{&first},
+  Q{&flat},
+  Q{&flip},
+  Q{&floor},
+  Q{&from-json},
+  Q{&full-barrier},
+  Q{&get},
+  Q{&getc},
+  Q{&gethostname},
+  Q{&gist},
+  Q{&goto},
+  Q{&grep},
+  Q{&hash},
+  Q{&index},
+  Q{&indices},
+  Q{&indir},
+  Q{&infix:<!=>},
+  Q{&infix:<!~~>},
+  Q{&infix:<%%>},
+  Q{&infix:<%>},
+  Q{&infix:<&&>},
+  Q{&infix:<&>},
+  Q{&infix:<(&)>},
+  Q{&infix:<(+)>},
+  Q{&infix:<(-)>},
+  Q{&infix:<(.)>},
+  Q{&infix:<(^)>},
+  Q{&infix:<(cont)>},
+  Q{&infix:<(elem)>},
+  Q{&infix:<(|)>},
+  Q{&infix:<**>},
+  Q{&infix:<*>},
+  Q{&infix:<+&>},
+  Q{&infix:<+>},
+  Q{&infix:<+^>},
+  Q{&infix:<+|>},
+  Q{&infix:<,>},
+  Q{&infix:<->},
+  Q{&infix:<...>},
+  Q{&infix:<...^>},
+  Q{&infix:<..>},
+  Q{&infix:<..^>},
+  Q{&infix:<//>},
+  Q{&infix:</>},
+  Q{&infix:<=:=>},
+  Q{&infix:<===>},
+  Q{&infix:<==>},
+  Q{&infix:<=>},
+  Q{&infix:<=~=>},
+  Q{&infix:<=~>},
+  Q{&infix:<?&>},
+  Q{&infix:<?^>},
+  Q{&infix:<?|>},
+  Q{&infix:<X>},
+  Q{&infix:<Z>},
+  Q{&infix:<^..>},
+  Q{&infix:<^..^>},
+  Q{&infix:<^>},
+  Q{&infix:<^^>},
+  Q{&infix:<after>},
+  Q{&infix:<and>},
+  Q{&infix:<andthen>},
+  Q{&infix:<before>},
+  Q{&infix:<but>},
+  Q{&infix:<cmp>},
+  Q{&infix:<coll>},
+  Q{&infix:<div>},
+  Q{&infix:<does>},
+  Q{&infix:<eq>},
+  Q{&infix:<eqv>},
+  Q{&infix:<gcd>},
+  Q{&infix:<ge>},
+  Q{&infix:<gt>},
+  Q{&infix:<lcm>},
+  Q{&infix:<le>},
+  Q{&infix:<leg>},
+  Q{&infix:<lt>},
+  Q{&infix:<max>},
+  Q{&infix:<min>},
+  Q{&infix:<minmax>},
+  Q{&infix:<mod>},
+  Q{&infix:<ne>},
+  Q{&infix:<notandthen>},
+  Q{&infix:<o>},
+  Q{&infix:<or>},
+  Q{&infix:<orelse>},
+  Q{&infix:<unicmp>},
+  Q{&infix:<x>},
+  Q{&infix:<xor>},
+  Q{&infix:<xx>},
+  Q{&infix:<|>},
+  Q{&infix:<||>},
+  Q{&infix:<~&>},
+  Q{&infix:<~>},
+  Q{&infix:<~^>},
+  Q{&infix:<~|>},
+  Q{&infix:<~~>},
+  Q{&infix:<×>},
+  Q{&infix:<÷>},
+  Q{&infix:<…>},
+  Q{&infix:<…^>},
+  Q{&infix:<∈>},
+  Q{&infix:<∉>},
+  Q{&infix:<∋>},
+  Q{&infix:<∌>},
+  Q{&infix:<−>},
+  Q{&infix:<∖>},
+  Q{&infix:<∘>},
+  Q{&infix:<∩>},
+  Q{&infix:<∪>},
+  Q{&infix:<≅>},
+  Q{&infix:<≠>},
+  Q{&infix:<≤>},
+  Q{&infix:<≥>},
+  Q{&infix:<≼>},
+  Q{&infix:<≽>},
+  Q{&infix:<⊂>},
+  Q{&infix:<⊃>},
+  Q{&infix:<⊄>},
+  Q{&infix:<⊅>},
+  Q{&infix:<⊆>},
+  Q{&infix:<⊇>},
+  Q{&infix:<⊈>},
+  Q{&infix:<⊉>},
+  Q{&infix:<⊍>},
+  Q{&infix:<⊎>},
+  Q{&infix:<⊖>},
+  Q{&infix:<⚛+=>},
+  Q{&infix:<⚛-=>},
+  Q{&infix:<⚛=>},
+  Q{&infix:<⚛−=>},
+  Q{&infix:«(<)»},
+  Q{&infix:«(<+)»},
+  Q{&infix:«(<=)»},
+  Q{&infix:«(>)»},
+  Q{&infix:«(>+)»},
+  Q{&infix:«(>=)»},
+  Q{&infix:«+<»},
+  Q{&infix:«+>»},
+  Q{&infix:«<=>»},
+  Q{&infix:«<=»},
+  Q{&infix:«<»},
+  Q{&infix:«=>»},
+  Q{&infix:«>=»},
+  Q{&infix:«>»},
+  Q{&infix:«~<»},
+  Q{&infix:«~>»},
+  Q{&is-prime},
+  Q{&item},
+  Q{&join},
+  Q{&keys},
+  Q{&kv},
+  Q{&last},
+  Q{&lastcall},
+  Q{&lc},
+  Q{&leave},
+  Q{&lines},
+  Q{&link},
+  Q{&list},
+  Q{&log},
+  Q{&log10},
+  Q{&lsb},
+  Q{&make},
+  Q{&map},
+  Q{&max},
+  Q{&min},
+  Q{&minmax},
+  Q{&mix},
+  Q{&mkdir},
+  Q{&move},
+  Q{&msb},
+  Q{&next},
+  Q{&nextcallee},
+  Q{&nextsame},
+  Q{&nextwith},
+  Q{&nodemap},
+  Q{&none},
+  Q{&not},
+  Q{&note},
+  Q{&one},
+  Q{&open},
+  Q{&ord},
+  Q{&ords},
+  Q{&pair},
+  Q{&pairs},
+  Q{&parse-base},
+  Q{&parse-names},
+  Q{&permutations},
+  Q{&pick},
+  Q{&pop},
+  Q{&postcircumfix:<[ ]>},
+  Q{&postcircumfix:<[; ]>},
+  Q{&postcircumfix:<{ }>},
+  Q{&postcircumfix:<{; }>},
+  Q{&postfix:<++>},
+  Q{&postfix:<-->},
+  Q{&postfix:<i>},
+  Q{&postfix:<ⁿ>},
+  Q{&postfix:<⚛++>},
+  Q{&postfix:<⚛-->},
+  Q{&prefix:<!>},
+  Q{&prefix:<++>},
+  Q{&prefix:<++⚛>},
+  Q{&prefix:<+>},
+  Q{&prefix:<+^>},
+  Q{&prefix:<-->},
+  Q{&prefix:<--⚛>},
+  Q{&prefix:<->},
+  Q{&prefix:<?>},
+  Q{&prefix:<?^>},
+  Q{&prefix:<^>},
+  Q{&prefix:<let>},
+  Q{&prefix:<not>},
+  Q{&prefix:<so>},
+  Q{&prefix:<temp>},
+  Q{&prefix:<|>},
+  Q{&prefix:<~>},
+  Q{&prefix:<~^>},
+  Q{&prefix:<−>},
+  Q{&prefix:<⚛>},
+  Q{&prepend},
+  Q{&print},
+  Q{&printf},
+  Q{&proceed},
+  Q{&produce},
+  Q{&prompt},
+  Q{&push},
+  Q{&put},
+  Q{&rand},
+  Q{&redo},
+  Q{&reduce},
+  Q{&rename},
+  Q{&repeated},
+  Q{&return},
+  Q{&return-rw},
+  Q{&reverse},
+  Q{&rindex},
+  Q{&rmdir},
+  Q{&roll},
+  Q{&roots},
+  Q{&rotate},
+  Q{&round},
+  Q{&roundrobin},
+  Q{&run},
+  Q{&samecase},
+  Q{&samemark},
+  Q{&samewith},
+  Q{&say},
+  Q{&sec},
+  Q{&sech},
+  Q{&set},
+  Q{&shell},
+  Q{&shift},
+  Q{&sign},
+  Q{&signal},
+  Q{&sin},
+  Q{&sinh},
+  Q{&sleep},
+  Q{&sleep-timer},
+  Q{&sleep-until},
+  Q{&slip},
+  Q{&slurp},
+  Q{&so},
+  Q{&sort},
+  Q{&splice},
+  Q{&split},
+  Q{&sprintf},
+  Q{&spurt},
+  Q{&sqrt},
+  Q{&squish},
+  Q{&srand},
+  Q{&subbuf-rw},
+  Q{&substr},
+  Q{&substr-rw},
+  Q{&succeed},
+  Q{&sum},
+  Q{&symlink},
+  Q{&take},
+  Q{&take-rw},
+  Q{&tan},
+  Q{&tanh},
+  Q{&tc},
+  Q{&tclc},
+  Q{&term:<now>},
+  Q{&term:<time>},
+  Q{&to-json},
+  Q{&trait_mod:<does>},
+  Q{&trait_mod:<handles>},
+  Q{&trait_mod:<hides>},
+  Q{&trait_mod:<is>},
+  Q{&trait_mod:<of>},
+  Q{&trait_mod:<returns>},
+  Q{&trait_mod:<trusts>},
+  Q{&trait_mod:<will>},
+  Q{&trim},
+  Q{&trim-leading},
+  Q{&trim-trailing},
+  Q{&truncate},
+  Q{&uc},
+  Q{&undefine},
+  Q{&unimatch},
+  Q{&uniname},
+  Q{&uninames},
+  Q{&uniparse},
+  Q{&uniprop},
+  Q{&uniprop-bool},
+  Q{&uniprop-int},
+  Q{&uniprop-str},
+  Q{&uniprops},
+  Q{&unique},
+  Q{&unival},
+  Q{&univals},
+  Q{&unlink},
+  Q{&unpolar},
+  Q{&unshift},
+  Q{&val},
+  Q{&values},
+  Q{&warn},
+  Q{&wordcase},
+  Q{&words},
+  Q{&zip},
+  Q{AST},
+  Q{Any},
+  Q{Array},
+  Q{Associative},
+  Q{Attribute},
+  Q{Awaitable},
+  Q{Awaiter},
+  Q{Backtrace},
+  Q{Bag},
+  Q{BagHash},
+  Q{Baggy},
+  Q{BigEndian},
+  Q{Blob},
+  Q{Block},
+  Q{Bool},
+  Q{Broken},
+  Q{Buf},
+  Q{CX},
+  Q{CallFrame},
+  Q{Callable},
+  Q{Cancellation},
+  Q{Capture},
+  Q{Channel},
+  Q{Code},
+  Q{Collation},
+  Q{CompUnit},
+  Q{Compiler},
+  Q{Complex},
+  Q{ComplexStr},
+  Q{ContainerDescriptor},
+  Q{Cool},
+  Q{CurrentThreadScheduler},
+  Q{Cursor},
+  Q{Date},
+  Q{DateTime},
+  Q{Dateish},
+  Q{Deprecation},
+  Q{Distribution},
+  Q{Distro},
+  Q{Duration},
+  Q{EXPORTHOW},
+  Q{Empty},
+  Q{Encoding},
+  Q{Endian},
+  Q{Enumeration},
+  Q{Exception},
+  Q{Exceptions},
+  Q{Failure},
+  Q{False},
+  Q{FatRat},
+  Q{FileChangeEvent},
+  Q{FileChanged},
+  Q{FileRenamed},
+  Q{ForeignCode},
+  Q{Grammar},
+  Q{HardRoutine},
+  Q{Hash},
+  Q{Hyper},
+  Q{HyperConfiguration},
+  Q{HyperSeq},
+  Q{HyperWhatever},
+  Q{IO},
+  Q{Inf},
+  Q{Instant},
+  Q{Int},
+  Q{IntAttrRef},
+  Q{IntLexRef},
+  Q{IntPosRef},
+  Q{IntStr},
+  Q{Iterable},
+  Q{IterationBuffer},
+  Q{IterationEnd},
+  Q{Iterator},
+  Q{JSONException},
+  Q{Junction},
+  Q{Kept},
+  Q{Kernel},
+  Q{Label},
+  Q{Less},
+  Q{List},
+  Q{LittleEndian},
+  Q{Lock},
+  Q{Macro},
+  Q{Map},
+  Q{Match},
+  Q{Metamodel},
+  Q{Method},
+  Q{MethodDispatcher},
+  Q{Mix},
+  Q{MixHash},
+  Q{Mixy},
+  Q{More},
+  Q{Mu},
+  Q{MultiDispatcher},
+  Q{NFC},
+  Q{NFD},
+  Q{NFKC},
+  Q{NFKD},
+  Q{NQPMatchRole},
+  Q{NQPdidMATCH},
+  Q{NaN},
+  Q{NativeEndian},
+  Q{Nil},
+  Q{Num},
+  Q{NumAttrRef},
+  Q{NumLexRef},
+  Q{NumPosRef},
+  Q{NumStr},
+  Q{Numeric},
+  Q{NumericEnumeration},
+  Q{NumericStringyEnumeration},
+  Q{ObjAt},
+  Q{Order},
+  Q{PF_INET},
+  Q{PF_INET6},
+  Q{PF_LOCAL},
+  Q{PF_MAX},
+  Q{PF_UNIX},
+  Q{PROCESS},
+  Q{PROTO_TCP},
+  Q{PROTO_UDP},
+  Q{Pair},
+  Q{Parameter},
+  Q{Perl},
+  Q{PhasersList},
+  Q{Planned},
+  Q{Pod},
+  Q{Positional},
+  Q{PositionalBindFailover},
+  Q{PredictiveIterator},
+  Q{Proc},
+  Q{Promise},
+  Q{PromiseStatus},
+  Q{ProtocolFamily},
+  Q{ProtocolType},
+  Q{Proxy},
+  Q{PseudoStash},
+  Q{QuantHash},
+  Q{REPL},
+  Q{RaceSeq},
+  Q{Rakudo},
+  Q{Range},
+  Q{Rat},
+  Q{RatStr},
+  Q{Rational},
+  Q{Real},
+  Q{Regex},
+  Q{Routine},
+  Q{SIGABRT},
+  Q{SIGALRM},
+  Q{SIGBREAK},
+  Q{SIGBUS},
+  Q{SIGCHLD},
+  Q{SIGCONT},
+  Q{SIGEMT},
+  Q{SIGFPE},
+  Q{SIGHUP},
+  Q{SIGILL},
+  Q{SIGINFO},
+  Q{SIGINT},
+  Q{SIGIO},
+  Q{SIGKILL},
+  Q{SIGPIPE},
+  Q{SIGPROF},
+  Q{SIGPWR},
+  Q{SIGQUIT},
+  Q{SIGSEGV},
+  Q{SIGSTKFLT},
+  Q{SIGSTOP},
+  Q{SIGSYS},
+  Q{SIGTERM},
+  Q{SIGTHR},
+  Q{SIGTRAP},
+  Q{SIGTSTP},
+  Q{SIGTTIN},
+  Q{SIGTTOU},
+  Q{SIGURG},
+  Q{SIGUSR1},
+  Q{SIGUSR2},
+  Q{SIGVTALRM},
+  Q{SIGWINCH},
+  Q{SIGXCPU},
+  Q{SIGXFSZ},
+  Q{SOCK_DGRAM},
+  Q{SOCK_MAX},
+  Q{SOCK_PACKET},
+  Q{SOCK_RAW},
+  Q{SOCK_RDM},
+  Q{SOCK_SEQPACKET},
+  Q{SOCK_STREAM},
+  Q{Same},
+  Q{Scalar},
+  Q{Scheduler},
+  Q{SeekFromBeginning},
+  Q{SeekFromCurrent},
+  Q{SeekFromEnd},
+  Q{SeekType},
+  Q{Semaphore},
+  Q{Seq},
+  Q{Sequence},
+  Q{Set},
+  Q{SetHash},
+  Q{Setty},
+  Q{Signal},
+  Q{Signally},
+  Q{Signature},
+  Q{Slang},
+  Q{Slip},
+  Q{SlippyIterator},
+  Q{SocketType},
+  Q{SoftRoutine},
+  Q{Stash},
+  Q{Str},
+  Q{StrAttrRef},
+  Q{StrDistance},
+  Q{StrLexRef},
+  Q{StrPosRef},
+  Q{Stringy},
+  Q{StringyEnumeration},
+  Q{Sub},
+  Q{Submethod},
+  Q{Supplier},
+  Q{Supply},
+  Q{Systemic},
+  Q{Tap},
+  Q{Tappable},
+  Q{Thread},
+  Q{ThreadPoolScheduler},
+  Q{True},
+  Q{UINT64_UPPER},
+  Q{UInt},
+  Q{Uni},
+  Q{VM},
+  Q{ValueObjAt},
+  Q{Variable},
+  Q{Version},
+  Q{Whatever},
+  Q{WhateverCode},
+  Q{WrapDispatcher},
+  Q{X},
+  Q{array},
+  Q{atomicint},
+  Q{blob16},
+  Q{blob32},
+  Q{blob64},
+  Q{blob8},
+  Q{buf16},
+  Q{buf32},
+  Q{buf64},
+  Q{buf8},
+  Q{byte},
+  Q{e},
+  Q{i},
+  Q{int},
+  Q{int16},
+  Q{int32},
+  Q{int64},
+  Q{int8},
+  Q{num},
+  Q{num32},
+  Q{num64},
+  Q{pi},
+  Q{str},
+  Q{tau},
+  Q{uint},
+  Q{uint16},
+  Q{uint32},
+  Q{uint64},
+  Q{uint8},
+  Q{utf16},
+  Q{utf32},
+  Q{utf8},
+  Q{π},
+  Q{τ},
+  Q{𝑒},
+).map: { $_ => 1 };
+
+my @unknown;
+@unknown.push($_) unless %allowed{$_}:exists for CORE::.keys;
+diag "Found {+@unknown} unexpected entries: { @unknown.sort }" unless
+ok @unknown == 0, "No unexpected entries in CORE::";