Compiler doesn't realize that private function is top-level

[BrucePerens]

Compiling this:

private def test
  data = self
end
test

results in this:

Module validation failed: Stored value type does not match pointer operand type!
  store i32 1511, i1* %data, !dbg !9
 i1Function return type does not match operand type of return inst!
  ret i32 1511, !dbg !9
 i1 (Exception)
  from /crystal/src/string.cr:5017:14 in 'finish'
  from /crystal/src/compiler/crystal/codegen/codegen.cr:69:7 in 'codegen'
  from /crystal/src/compiler/crystal/compiler.cr:172:16 in 'compile'
  from /crystal/src/compiler/crystal/command.cr:210:5 in 'run_command'
  from /crystal/src/compiler/crystal/command.cr:117:7 in 'run'
  from /crystal/src/compiler/crystal.cr:11:1 in '__crystal_main'
  from /crystal/src/crystal/main.cr:110:5 in 'main'
  from src/env/__libc_start_main.c:94:2 in 'libc_start_main_stage2'
Error: you've found a bug in the Crystal compiler. Please open an issue, including source code that will allow us to reproduce the bug: https://github.com/crystal-lang/crystal/issues