Error

Numbers starting with TUKI (9)

Number	What it means	Description
TUKI0001	A form this language can’t write	Valid C#, but the runtime has no mechanism for it. The most common number. The boundaries list has an alternative way to write it.
TUKI0099	A form that doesn’t compile	Accepted as syntax, but there’s no way to turn it into Udon instructions. Often appears together with TUKI0001.
TUKI0101	A call not present in the runtime	The method being called doesn’t exist on the Udon side.
TUKI0102	A type not present in the runtime	The variable’s type doesn’t exist on the Udon side.
TUKI0103	A type that can’t be synced	The type of a variable marked [UdonSynced] isn’t eligible for sync (sync).
TUKI0106	A type that can’t interpolate	[UdonSynced(UdonSyncMode.Linear)] or similar is attached to a type that can’t produce intermediate values (sync).
TUKI0108	A form that holds a method as a value	Delegates and lambdas. Udon has no function values. Whether it appears in a type, a creation, or a call, it stops for the same reason.
TUKI0109	Two or more programs in one file	One file becomes one program (the shape of a program).
TUKI0201	A null-safety violation	Only appears in a range marked #nullable enable. What C# treats as a warning, this treats as an error (null and references).

Numbers with no example in this document (6)

Number	What it means	Description
TUKI0104	Not enough room for variables	There’s a cap on the number of variables one program can use.
TUKI0105	Too many type argument expansions	Too many combinations were put into the generic to expand.
TUKI0107	A conflict between the sync mode and the variable	The [UdonBehaviourSyncMode] setting and the way [UdonSynced] is attached don’t match up.
TUKI0202	A null comparison that always gives the same result	Comparing a value type to null. This compiles (it doesn’t stop).
TUKI0203	Taking a value type out of an object	Taking it out costs one conversion. This compiles (it doesn’t stop).
TUKI0204	The cost of a 2D array	Each element ends up boxed and unboxed one at a time. This compiles (it doesn’t stop).