[Lint] Report unused results

[turbolent]

Feature Request

Add a new analyzer which detects unused value-typed results. For example, the following code is likely a bug:

let string = "hello"
string.concat("world")

Suggested Solution

• Report ExpressionStatements of:
  • Function call with value-typed result
  • Literals (strings, boolean, array, dictionary, etc.)
  • Variable (no side-effect)