[A02-2] [LOW] Six unused errors declared in ErrFlow.sol

[thedavidmeister]

Description

The following errors are declared in src/error/ErrFlow.sol but never reverted or referenced anywhere in src/ or test/:

• L10 UnsupportedNativeFlow()
• L24 BurnerNotOwner() (also separately declared in src/interface/deprecated/v4/IFlowERC721V4.sol:40, see below)
• L26 UnsupportedHandleTransferInputs()
• L27 InsufficientHandleTransferOutputs()
• L28 UnsupportedTokenURIInputs()
• L29 InsufficientTokenURIOutputs()

grep -rn across src/ and test/ shows zero revert sites for any of these. They are declared but unreachable from any code path — dead surface that integrators may import expecting them to be thrown.

BurnerNotOwner is additionally redeclared in the deprecated v4 interface (IFlowERC721V4.sol:40). That redeclaration is itself unused, so both copies are dead.

Location

• src/error/ErrFlow.sol:10
• src/error/ErrFlow.sol:24
• src/error/ErrFlow.sol:26-29

Proposed fix

Delete the unused error declarations from ErrFlow.sol:

-/// Thrown for unsupported native transfers.
-error UnsupportedNativeFlow();
-
 /// Thrown for unsupported erc20 transfers.
 error UnsupportedERC20Flow();

-/// Thrown when burner of tokens is not the owner of tokens.
-error BurnerNotOwner();
-
-error UnsupportedHandleTransferInputs();
-error InsufficientHandleTransferOutputs();
-error UnsupportedTokenURIInputs();
-error InsufficientTokenURIOutputs();
 error UnsupportedFlowInputs();
 error InsufficientFlowOutputs();

If any of these are intended to be thrown by a current code path that is currently missing the revert, that path should be added in the same change. Otherwise drop them. Also remove the duplicate BurnerNotOwner in src/interface/deprecated/v4/IFlowERC721V4.sol:40 if BurnerNotOwner is dropped.