Internal compiler error from calling is_a? on union of metaclasses

[HertzDevil]

The code example in #11188 does not actually compile, up to the is_a? and name calls. Reduced:

class A; end

class B < A
  def self.foo; end
end

class C; end

(B || C).is_a?(A.class)
B.foo

This fails with:

Invalid memory access (signal 11) at address 0x0
[0x55d50d100f06] *Exception::CallStack::print_backtrace:Nil +118 in .build/crystal
[0x55d50d0ce76a] ~procProc(Int32, Pointer(LibC::SiginfoT), Pointer(Void), Nil) +330 in .build/crystal
[0x7f4e5513a200] ?? +139974411526656 in /lib/x86_64-linux-gnu/libpthread.so.0
[0x7f4e5648ba70] _ZN4llvm11PointerType3getEPNS_4TypeEj +32 in /usr/lib/x86_64-linux-gnu/libLLVM-13.so.1
[0x7f4e56364dfc] ?? +139974430576124 in /usr/lib/x86_64-linux-gnu/libLLVM-13.so.1
[0x7f4e56363967] _ZN4llvm25ConstantFoldGetElementPtrEPNS_4TypeEPNS_8ConstantEbNS_8OptionalIjEENS_8ArrayRefIPNS_5ValueEEE +87 in /usr/lib/x86_64-linux-gnu/libLLVM-13.so.1
[0x7f4e563858d9] _ZN4llvm12ConstantExpr16getGetElementPtrEPNS_4TypeEPNS_8ConstantENS_8ArrayRefIPNS_5ValueEEEbNS_8OptionalIjEES2_ +105 in /usr/lib/x86_64-linux-gnu/libLLVM-13.so.1
[0x7f4e56412ff3] ?? +139974431289331 in /usr/lib/x86_64-linux-gnu/libLLVM-13.so.1
[0x7f4e5639c26b] ?? +139974430802539 in /usr/lib/x86_64-linux-gnu/libLLVM-13.so.1
[0x7f4e5639c1cd] LLVMBuildInBoundsGEP +93 in /usr/lib/x86_64-linux-gnu/libLLVM-13.so.1
[0x55d50e0eb24a] *LLVM::Builder#inbounds_gep<LLVM::Value, LLVM::Value, LLVM::Value, String>:LLVM::Value +218 in .build/crystal
[0x55d50e130701] *Crystal::CrystalLLVMBuilder#inbounds_gep<LLVM::Value, LLVM::Value, LLVM::Value, String>:LLVM::Value +241 in .build/crystal
[0x55d50e06d49b] *Crystal::CodeGenVisitor +91 in .build/crystal
[0x55d50e06d42f] *Crystal::CodeGenVisitor +127 in .build/crystal
[0x55d50e06fe48] *Crystal::CodeGenVisitor +72 in .build/crystal
[0x55d50e06fdef] *Crystal::CodeGenVisitor#aggregate_index<LLVM::Value, Int32>:LLVM::Value +47 in .build/crystal
[0x55d50e06fda9] *Crystal::CodeGenVisitor#union_type_id<LLVM::Value>:LLVM::Value +41 in .build/crystal
[0x55d50e073d37] *Crystal::CodeGenVisitor#union_type_and_value_pointer<LLVM::Value, Crystal::MixedUnionType>:Tuple(LLVM::Value, LLVM::Value) +39 in .build/crystal
[0x55d50e073cf1] *Crystal::CodeGenVisitor#type_id_impl<LLVM::Value, Crystal::MixedUnionType>:LLVM::Value +49 in .build/crystal
[0x55d50e073c6e] *Crystal::CodeGenVisitor#type_id<LLVM::Value, Crystal::Type+>:LLVM::Value +974 in .build/crystal
[0x55d50e0c43e4] *Crystal::CodeGenVisitor#visit<Crystal::IsA>:Bool +84 in .build/crystal
[0x55d50d4db1e5] *Crystal::ASTNode+ +3989 in .build/crystal
[0x55d50e084461] *Crystal::CodeGenVisitor#accept<Crystal::ASTNode+>:Nil +17 in .build/crystal
[0x55d50e0b7e34] *Crystal::CodeGenVisitor#visit<Crystal::Expressions>:Bool +276 in .build/crystal
[0x55d50d4da824] *Crystal::ASTNode+ +1492 in .build/crystal
[0x55d50e084461] *Crystal::CodeGenVisitor#accept<Crystal::ASTNode+>:Nil +17 in .build/crystal
[0x55d50d31aa44] *Crystal::Program#codegen<Crystal::ASTNode+, Bool, Crystal::Debug>:Hash(String, Crystal::CodeGenVisitor::ModuleInfo) +68 in .build/crystal
[0x55d50d31a9f3] *Crystal::Program#codegen:debug:single_module<Crystal::ASTNode+, Crystal::Debug, Bool>:Hash(String, Crystal::CodeGenVisitor::ModuleInfo) +19 in .build/crystal
[0x55d50df71bd7] *Crystal::Compiler#codegen<Crystal::Program, Crystal::ASTNode+, Array(Crystal::Compiler::Source), String>:(Tuple(Array(Crystal::Compiler::CompilationUnit), Array(String)) | Nil) +471 in .build/crystal
[0x55d50df7617c] *Crystal::Compiler#compile<Array(Crystal::Compiler::Source), String>:Crystal::Compiler::Result +188 in .build/crystal
[0x55d50e2189d9] *Crystal::Command::CompilerConfig#compile<String>:Crystal::Compiler::Result +57 in .build/crystal
[0x55d50e20f0af] *Crystal::Command#run_command<Bool>:Nil +415 in .build/crystal
[0x55d50e208a17] *Crystal::Command#run:(Bool | Nil) +1367 in .build/crystal
[0x55d50e208389] *Crystal::Command::run<Array(String)>:(Bool | Nil) +25 in .build/crystal
[0x55d50e20834d] *Crystal::Command::run:(Bool | Nil) +29 in .build/crystal
[0x55d50d0ada9e] __crystal_main +2830 in .build/crystal
[0x55d50d2a1f46] *Crystal::main_user_code<Int32, Pointer(Pointer(UInt8))>:Nil +6 in .build/crystal
[0x55d50d2a1e99] *Crystal::main<Int32, Pointer(Pointer(UInt8))>:Int32 +41 in .build/crystal
[0x55d50d0bb076] main +6 in .build/crystal
[0x7f4e54ef17fd] __libc_start_main +205 in /lib/x86_64-linux-gnu/libc.so.6
[0x55d50d0ace7a] _start +42 in .build/crystal
[0x0] ???

This oddly goes away when the result of is_a? is assigned to a variable:

x = (B || C).is_a?(A.class) # => true
B.foo