Inappropriate functions visibility

Low  ML – 01 |  Unresolved

There are some functions that are never called in the contract itself with visibility ‘public’ so they can be marked as ‘external’.

Recommendation:

Consider changing visibility from public to external to safe gas usage on calling for functions release() and release(address).

Cached storage value

Low  ML – 02 |  Unresolved

In the function _vestingSchedule() there are 3 storage calls for the _start variable value and 2 for the _duration variable. Consider avoiding useless storage calls to decrease gas usage on the function call and on the deployment.

Recommendation:

Consider caching the result of start() and duration() and use a local variable for calculation:

uint256 start_ = start();
uint256 duration_ = duration();

Optimization by ternary operator

Low  TL – 01 |  Not relevant

The _vestingSchedule() function can be optimized to return result of ternary operator that will avoid using of if-else branching:

if (timestamp < start()) {
return 0;
} else if (timestamp > start() + duration()) {
return totalAllocation;
} else {
return (totalAllocation * (timestamp - start())) / duration();
}

to:

return
timestamp < start() ? 0 : timestamp > start() + duration()
? totalAllocation
: (totalAllocation * (timestamp - start())) / duration();

Recommendation:

Consider using ternary operators.

Useless import

Informational  MI – 01 |  Not relevant

VestingWaleet inherits the Context contract but its functionality is never used.

Recommendation:

Consider avoiding import and Inheritness of unused functionality to decrease contract bytecode.

Order of Layout

Informational  MI – 02 |  Unresolved

The layout contract elements in the VestingWallet contract are not logically grouped.

Use the following order:

• Library declarations (using statements);
• Constant variables;
• Type declarations;
• State variables;
• Events;
• Modifiers;
• Functions.

Recommendation:

Consider changing the layout order according to the solidity style guide documentation, that is switching events and state variables order.

Lack of NatSpec comments

Informational  MI – 03 |  Unresolved

The VestingWallet is partly covered by the NatSpec comments but there is some code without required comments. For example, events and state variables. Also, tag @param for explanation function parameters is missed for each function.

Recommendation:

Consider adding full NatSpec documentation.