Set mock instance of interface into typed properties

[dkarlovi]

Is your feature request related to a problem? Please describe.

A user has a class like so

interface Interface {}

class InterfaceInstance implements Interface
{
    public int $foo;
}

class C
{
    private Interface $prop;
    
    function foo(): int
    {
        return $this->prop->foo;
    }
}

Describe the solution you'd like

The user is typing an interface, but actually expecting the specific implementation to be available. Static analysis notices this when used.

A new mutator might set this property to a mocked interface which does the absolute minimum to match the interface, it would mean any reliance on the specific implementation would fail.

Describe alternatives you've considered

Incorporate static analysis output in some way instead?

Additional context

User claims "code works, tests work" and is wondering what is static analysis on about here.

[theofidry]

I think this is related to #650

[dkarlovi]

@theofidry in what way? I imagine this as a new mutator.

[maks-rafalko]

It will be caught by https://github.com/Roave/infection-static-analysis-plugin, and actually related to #1323