How to store 100% with TrancheWithPercentage?

[smol-ninja]

TrancheWithPercentage struct is used to store percentage and tranche duration of a LT stream in case of MLLT.

struct TrancheWithPercentage {
    // slot 0
    UD2x18 unlockPercentage;
    uint40 duration;
}

However, UD2x18 can only have upto 2 digits that means it cannot store 100%. The maximum it can have is 99.9999999....(18 digits).

There could be a use case where there is a single tranche with 100% of the amount.

There are two possible solutions I can think of:

1. Change the datatype to UD60x18 but it will add a new storage slot.
2. We define a new fixed point number in prb-math such as 4 digits and 14 decimals.

cc @andreivladbrg @PaulRBerg

PS: I might be wrong with the claim that it cannot take 100%.

[andreivladbrg]

UD2x18 is a uint64 and the maximum number that uint64 can have is 2^64, which has this value - a 20-decimal number. This is not a problem because we store the percentage as 1e18 = 100%:

v2-periphery/src/types/DataTypes.sol

Lines 115 to 117 in 8683889

	/// @dev Each recipient may have a different amount allocated, this struct stores the percentage of the
	/// amount designated for each duration unlock. We use a 18 decimals format to represent percentages:
	/// 100% = 1e18.

Thus, if there is a single tranche, 100% can still be achieved.

[smol-ninja]

Yes you are right.