Cross-module struct field access is broken

This one only appears when accessing an exported struct field from another module. To reproduce, you'll need two files. First, the library module, call it "lib.ic":

#{export}
foo ::= struct {
  #{export}
  length: u64
}

#{export}
make ::= (len: u64) -> foo {
  return foo.{ length = len }
}

And then the main file:

lib ::= import "lib.ic"
x := lib.make(10)
n := x.length

Running this results in a crash:

[139710557980488 compiler/verify/access.cc:327 operator()] data.context().AstLiteral(s) is unexpectedly null.
*** SIGABRT received at time=1641821701 on cpu 3 ***
PC: @     0x7f10e637f808  (unknown)  pthread_kill
    @          0x184e180         64  absl::WriteFailureInfo()
    @          0x184de64        224  absl::AbslFailureSignalHandler()
    @     0x7f10e632b520  (unknown)  (unknown)
Aborted (core dumped)

asoffer / Icarus

Cross-module struct field access is broken #105