Calls dg(Dsymbol) for each Dsymbol, which should be a VarDeclaration inside VarExp (isexp == true).
Calls dg(Dsymbol) for each Dsymbol, which should be a VarDeclaration inside VarExp (isexp == true). If dg returns !=0, stops and returns that value else returns 0.
Issue an error if an attempt to call a disabled method is made
Check to see if declaration can be modified in this context (sc). Issue error if not.
Returns the linkage, resolving the target-specific System one.