Truffle: Update Assert.sol to 0.4.21 and avoid compilation warnings

[luisfidelis]

Issue

The contract Assert.sol within truffle's test environment has deprecated things according to solidity 0.4.21. Maybe it happens in other contracts too.

Steps to Reproduce

Create a test in solidity, import "truffle/Assert.sol" and run the test.

Actual Results

• Warning: Use of the "var" keyword is deprecated.
• Warning: Invoking events without "emit" prefix is deprecated.

Environment

• Truffle version: 4.1.5

[snehasatya]

Updated Assert.sol to 0.4.21 but still getting these warnings
Warning: Use of the "var" keyword is deprecated.
Warning: Invoking events without "emit" prefix is deprecated.

[luisfidelis]

Hey.
To avoid the first warning, about the use of "var", you have to introduce the types on tuple assignments...
use
address a; uint256 b; address c; (a,b,c) = myFunction();
Instead of
var (a, b, c) = myFunction()

To avoid the second warning, about the keyword "emit", just type it when fire contract events. For example:
emit LogSomething(var1, var2, ..., varN)

[vzts]

Fixed in https://github.com/trufflesuite/truffle-core/pull/131.
The issue can be closed.

[gnidan]

Added this to the release bucket. Will close when it's released. Thanks!

[cgewecke]

@luisfidelis Still a few warning in there sorry, they're new to 0.4.23 - sorry. But lots are gone. Going to close this, but we'll continue to revisit.