Debug protocol: setVariable identifies variables by display name

[vadimcn]

• VSCode Version: 1.4
• OS Version: All

The new setVariable request identifies variables by display name.
This is fragile because the name may have been generated by the adapter (e.g. [N] for array indices).
There may also be more than one variable with the same name in the stack frame in languages that allow variable shadowing. For example, in C++ one can write

int a = 10; 
{ 
    int a = 20;
    ... // There are now two `a`'s here! 

The debugger can see both, even though in C++ there's no way to access the outer one.

To make this work robustly, I would suggest adding an optional "handle" field into Variable, which gets round-tripped back to the adapter in setVariable.

[weinand]

This issue was moved to Microsoft/vscode-debugadapter-node#54