Compilation enters compiler panic

[vbuterin]

Version Information

• vyper Version (output of vyper --version): 0.4.3
• OS: linux
• Python Version (output of python --version): 3.13.11

What's your issue about?

Here is a minimal testcase (this was taken by starting with AI-generated code, and then removing bits that did not contribute to the error):

# Constants for maximum allowed values in the demo
MAX_MESSAGES: constant(uint256) = 64  # for example, limit to 64 messages

# Main parsing function
@external
def parse_blob(blob: Bytes[4096]):
    # Read all start offsets
    starts: DynArray[uint16, MAX_MESSAGES] = empty(MAX_MESSAGES)

It returns this error:

    raise CompilerPanic(f"Not a type: {typ_}", node)
vyper.exceptions.CompilerPanic: Not a type: VarInfo(typ=uint256, location=<DataLocation.UNSET: 'unset'>, modifiability=<Modifiability.CONSTANT: 'constant'>, is_public=False, decl_node=vyper.ast.nodes.VariableDecl:
---> 1 MAX_MESSAGES: constant(uint256) = 64  # for example, limit to 64 messages
-------^
     2)

  function "parse_blob", line 7:51
       6     # Read all start offsets
  ---> 7     starts: DynArray[uint16, MAX_MESSAGES] = empty(MAX_MESSAGES)
  ----------------------------------------------------------^
       8


This is an unhandled internal compiler error. Please create an issue on Github to notify the developers!
https://github.com/vyperlang/vyper/issues/new?template=bug.md

It looks like the problem is that the AI generated the code wrong and empty(...) needs to contain something else, but the compiler is crashing on it.