Parser error: quantifiers after other expressions or in parentheses

[zhao-nan]

Description

When a quantifier is preceeded by another term, or when it is in parentheses, a parser error is thrown.

Steps to Reproduce

pragma solidity ^0.5.0;

contract ExistTest {
    bool[] arr;

    /// @notice postcondition exists (uint u) (0 <= u && u < arr.length && arr[u]) == result
    function test() public view returns (bool result) {
        bool res = false;
        /// @notice invariant exists (uint j) (0 <= j && j < i && arr[j]) == res
        for (uint i = 0; i < arr.length; i += 1) {
            if (arr[i]) {res = true;}
        }
        return res;
    }
}

When the equality in the postcondition is flipped ...

/// @notice postcondition result == exists (uint u) (0 <= u && u < arr.length && arr[u])

... or when the quantifier term is in parentheses ...

/// @notice postcondition (exists (uint u) (0 <= u && u < arr.length && arr[u])) == result

... a parser error happens:

Annotation:1:24: solc-verify error: Expected ',' but got identifier
result == exists (uint u) (0 <= u && u < arr.length && arr[u])

[dddejan]

Duplicate of #170