False positive: ConstParameterNotModified.Pointer on a pointee modified in a lambda #188

ConstParameterNotModified.Pointer suggests const for a pointer parameter whose pointee is modified through a lambda that captures the parameter by reference.

Example

lambda-modifies-pointee.cpp:

struct Counter
{
    unsigned long count = 0;
};

int count_through_lambda(int x, Counter* counter)
{
    const auto add = [&](int value)
    {
        if (counter)
            ++counter->count;
        return value;
    };
    return add(x) + add(1);
}

With the analyzer built from main 112ffcf:

$ stack_usage_analyzer lambda-modifies-pointee.cpp
	at line 6, column 0
	[ !Info! ] ConstParameterNotModified.Pointer: parameter 'counter' in function 'count_through_lambda(int, Counter*)' is never used to modify the pointed object
		 ↳ current type: Counter *counter
		 ↳ suggested type: const Counter *counter

Why it is wrong

The lambda increments counter->count. With the suggested type, the file no longer compiles:

lambda-modifies-pointee.cpp:11:13: error: cannot assign to variable 'counter' with const-qualified type 'const Counter *'

Where it shows

The self-analysis reports it on computeSummary (src/analysis/ownership/OwnershipEngine.cpp), whose SummaryWork* work is incremented in the lambda solveCounted (#184).

Alert: https://github.com/CoreTrace/coretrace-stack-analyzer/security/code-scanning/256 (#187).