Incorrect boxing highlight for string concatenation and modern compilers

[citizenmatt]

The code var x = "Hello " + longValue will show a highlight for boxing of the longValue variable. It appears previous compilers would box the value and call String.Concat(object, object). Modern compilers will call longValue.ToString() and then call String.Concat(string, string)

[neonb]

myPrimitive.ToString() will still allocate a string object, if it hasn't been interned, right? In any case, if modern compilers skip the boxing then the plugin's message at least is incorrect.

[controlflow]

Partially fixed, boxing is not reported now. Will report implicit .ToString() invocation

[controlflow]

Both allocations are now reported:

Boxing is eliminated, but implicit .ToString() call still allocates a new string (at least for BCL's numeric types)