IncompleteArrayType spec fails due to LLVM 3.9 backwards incompatible changes

[mverzilli]

Env: macOS 10.12.2, LLVM 3.9.1

This test is failing with LLVM 3.9: https://github.com/crystal-lang/crystal_lib/blob/029bd721a0d5107ba9a2140fe9c9780988f2e454/spec/parser_spec.cr#L237

This is a reduced snippet to reproduce the issue:

require "../src/crystal_lib"
require "../src/clang"

include CrystalLib

nodes = Parser.parse("int some_var[];")
var = nodes.last.as(Var)
pp var

When linking against LLVM 3.7, the code above yields:

var # => #<CrystalLib::Var:0x10feca4e0
          @name="some_var",
          @type=
           #<CrystalLib::IncompleteArrayType:0x10feca500
            @type=#<CrystalLib::PrimitiveType:0x10ee4dfc0 @kind=Int>>>

Whereas linking against LLVM 3.9, it yields:

var # => #<CrystalLib::Var:0x10327a4a0
          @name="some_var",
          @type=
           #<CrystalLib::ConstantArrayType:0x10327a4c0
            @size=1,
            @type=#<CrystalLib::PrimitiveType:0x1029bbfc0 @kind=Int>>>

I'll be happy to send in a PR to fix the test, but I'm not sure what's the right way to go. If I fix it for 3.9, it'll fail on 3.7.

I could put the test behind an {% if %} that checks for the current LLVM version and tests conditionally, but would that make sense? Instead of doing that, I guess it'd make more sense simply to remove the test and trust whatever type the underlying clang version tells us to assign to that expression.

cc: @asterite @spalladino @ysbaddaden

[ysbaddaden]

Some changes were introduced in LLVM 3.8 or 3.9, where there are now opaque EnumType and RecordType, which break how crystal_lib is detecting an Enum type or a Struct definition. I understood the issue, but don't know how to start fixing that for crystal_lib —it seems to rely too much on type when it should rely more on cursors, then seek for types, but I must be mistaken.

[mverzilli]

We just removed that spec. It didn't make sense to maintain it because anyway we are delegating the responsibility to Clang. So this is fixed (as in, now the specs pass).