Internal Script Error - opcode #12 accessing enum

[jcsato]

Godot version:
Godot 3.2.3, Windows 64-bit

OS/device including version:
Windows 10 Pro, version 20H2

Issue description:
When attempting to run the project, I get an internal script error when I attempt to compare an int parameter to an enum:

Apologies if I'm just doing something wrong - the error message said to report, though, so I figured I'd do that.

Steps to reproduce:
Run the included project.
The debugger should break on TerrainData.gd:19

Minimal reproduction project:
InternalScriptErrorOpcode12.zip

Can also find the project here, it's very nascent and should hopefully be relatively straightforward to browse through. . .: https://github.com/jcsato/Bunker-Godot (Repo is now private, if anyone looks at this and finds the minimal project is insufficient let me know, but I'm guessing this issue will probably be closed since we're on Godot 3.4 now)

[jcsato]

For additional color, I was previously on Godot 3.2.1 and was getting the same error on the same line, but it said opcode #9. Did my due diligence upgrading to 3.2.3 and on that version I get opcode #12 instead.

[jcsato]

In debugging, the debugger didn't seem to know what the TERRAIN_TYPES enum was. I changed things up to put TERRAIN_TYPES into its own script (Const) and autloaded it. When I did that and changed the code to e.g.

if type == Const.TERRAIN_TYPES.LIGHT:

it compiled without issues.

Based on that, I think what happened here is that my enum/const wasn't accessible to the Terrain class for some reason, and the compiler broke trying to figure out that error.

. . .Maybe. Either way, hope that's at least somewhat helpful.