``Statement has no effect`` warning should be emitted for ``view`` expressions.

[0xrisec]

// SPDX-License-Identifier: GPL-3.0
pragma solidity 0.8.17;

contract Lottery{
    address public owner;
    constructor(){
        owner == msg.sender;
    }
} 

Issue: In the given code, there is a mistake in the assignment of the owner variable in the constructor function. Instead of using the assignment operator =, the double equal == operator is used, which is a comparison operator and does not assign a value to the variable. This mistake can be hard to identify, as the Solidity compiler does not raise any warnings or errors for this issue.

Feature Expected: As a result, it is essential for the compiler should carefully check the code and make sure that the correct operators are used at the time of initialization of a variable at the function level.

[ekpyron]

We in fact do have a warning for cases like this: Statement has no effect. However, we reserved it to only pure statement for a somewhat odd reason: a view statement without effect can be used to silence the mutability can be restricted to pure warning and we don't have a better workaround.

The middle ground here would probably be to only allow very specific view statements without effect (like e.g. this), while extending the "has no effect" warning to all other more complex cases. An even better solution may be to extend the warning to all statements without effect and to come up with a new way to silence mutability warnings explicitly.

[mehtavishwa30]

Some other duplicate issues that point to this problem and potentially add more context are cited below:

• Missing "statement has no effect" diagnostic #13471
• Raise warning when reading from storage with no effect #6682
• msg.sender.call.value(address(this).balance); should produce a warning #7096
• pop without parentheses is accepted by the compiler as a valid storage array type member #1464