constant-time slice affectation crashes the compiler

[dlesnoff]

const slice = 32..40

/home/lesnoff/nim3/nimony/src/nimony/nimsem.nim(211) nimsem
/home/lesnoff/nim3/nimony/src/nimony/nimsem.nim(192) handleCmdLine
/home/lesnoff/nim3/nimony/src/nimony/nimsem.nim(59) singleModule
/home/lesnoff/nim3/nimony/src/nimony/sem.nim(5410) semcheck
/home/lesnoff/nim3/nimony/src/nimony/sem.nim(5350) semcheckCore
/home/lesnoff/nim3/nimony/src/nimony/sem.nim(5162) phaseX
/home/lesnoff/nim3/nimony/src/nimony/sem.nim(655) semStmt
/home/lesnoff/nim3/nimony/src/nimony/sem.nim(4836) semExpr
/home/lesnoff/nim3/nimony/src/nimony/semdecls.nim(163) semLocal
/home/lesnoff/nim3/nimony/src/nimony/semdecls.nim(97) semLocal
/home/lesnoff/nim3/nimony/src/nimony/sem.nim(630) semConstExpr
/home/lesnoff/nim3/nimony/src/nimony/expreval.nim(574) evalExpr
/home/lesnoff/nim3/nimony/src/nimony/expreval.nim(546) eval
/home/lesnoff/nim3/nimony/src/nimony/expreval.nim(191) evalCall
/home/lesnoff/nim3/nimony/src/nimony/exprexec.nim(532) executeCall
/home/lesnoff/nim3/nimony/src/nimony/exprexec.nim(482) genMissingProcs
/home/lesnoff/nim3/nimony/src/nimony/exprexec.nim(470) genProcDecl
/home/lesnoff/.choosenim/toolchains/nim-#devel/lib/std/assertions.nim(45) failedAssertImpl
/home/lesnoff/.choosenim/toolchains/nim-#devel/lib/std/assertions.nim(38) raiseAssert
Error: unhandled exception: /home/lesnoff/nim3/nimony/src/nimony/exprexec.nim(470, 7) `false` empty hook created [AssertionDefect]
make: /home/lesnoff/nim3/nimony/bin/nimsem m --isMain nimcache/mwe8l1ngg.p.nif
FAILURE: /home/lesnoff/nim3/nimony/bin/nifmake --base:'' -j run nimcache/mwe8l1ngg.build.nif

No error with var.