[Issue 13798] New: Suggestions for classes and methods that can be final

[via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=13798

          Issue ID: 13798
           Summary: Suggestions for classes and methods that can be final
           Product: D
           Version: D2
          Hardware: x86
                OS: Windows
            Status: NEW
          Severity: enhancement
          Priority: P1
         Component: DMD
          Assignee: nobody at puremagic.com
          Reporter: bearophile_hugs at eml.cc

I suggest to add a compiler tip (enabled with warnings) that suggests the
programmer to add a "final" to methods and to classes definitions like this
that don't need to be virtual, to avoid some virtual calls:

class Bar {}
class Foo : Bar {}
void main() {}


This is similar to the -Wsuggest-final-types and -Wsuggest-final-methods
warnings of G++ 5.0, that also tells how many virtual calls are avoided:

/aux/hubicka/firefox/docshell/base/nsDocShell.h:124:0: warning: Declaring type
‘struct nsDocShell’ final would enable devirtualization of 216 calls
[-Wsuggest-final-types]
 class nsDocShell : public nsDocLoader,
 ^

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