http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56889
Bug #: 56889
Summary: =delete(ing) default copy and move operations for a
polymorphic type gives compilation error messages
Classification: Unclassified
Product: gcc
Version: 4.8.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
AssignedTo: unassig...@gcc.gnu.org
ReportedBy: amalispe...@yahoo.com
Created attachment 29834
--> http://gcc.gnu.org/bugzilla/attachment.cgi?id=29834
smalltestfile
when I add
Stack(const Stack&)=delete;
Stack& operator=(const Stack&)=delete;
//no move operations
Stack(Stack&&)=delete;
Stack& operator=(Stack&&)=delete;
to the stack polymorphic type in the attached file, the compiler gives error
messages. But if I don't add these methods, as Bjarne Stroutstrup's programming
language fourth edition-third chapter draft copy- says,
'In case you forgot to delete a copy or move operation, no harm is done. A move
operation is not implicitly generated for a class where the user has explicitly
declared a destructor. Furthermore, the generation of copy operations are
deprecated in this case
(§42.2.3). This can be a good reason to explicitly define a destructor even
where the compiler would have implicitly provided one (§17.2.3).
The C++ Programming Language, 4th edition ©2012 by Pearson Education, Inc.
Reproduced in draft form with the permission of the publisher.', my program
gives nomore compiler error messages, and it works as I expect it to.
However, I think the compiler should allow me to specify the copy and move
methods as =delete in the Stack polymorphic type.
-------------- Build: Debug in TestforError ---------------
x86_64-w64-mingw32-g++.exe -Wall -fexceptions -g -std=c++0x -Wextra -Wall -v
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#include "..." search starts here:
#include <...> search starts here:
c:\amali\x64-4.8.0-release-win32-seh-rev1\mingw64\bin\../lib/gcc/x86_64-w64-mingw32/4.8.0/include/c++
c:\amali\x64-4.8.0-release-win32-seh-rev1\mingw64\bin\../lib/gcc/x86_64-w64-mingw32/4.8.0/include/c++/x86_64-w64-mingw32
c:\amali\x64-4.8.0-release-win32-seh-rev1\mingw64\bin\../lib/gcc/x86_64-w64-mingw32/4.8.0/include/c++/backward
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c:\amali\x64-4.8.0-release-win32-seh-rev1\mingw64\bin\../lib/gcc/x86_64-w64-mingw32/4.8.0/include-fixed
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End of search list.
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Compiler executable checksum: 198a59f18ac22b34b3ce85756ec21810
C:\Users\Pugazhendhi Albert\Desktop\Amali\TestforError\main.cpp: In function
'void StackAbst::constanduse()':
C:\Users\Pugazhendhi Albert\Desktop\Amali\TestforError\main.cpp:92:46: error:
use of deleted function
'StackAbst::vector_stack<int>::vector_stack(std::initializer_list<int>)'
vector_stack<int> vst{1,2,3,4,5,6,7,8,9,10};
^
C:\Users\Pugazhendhi Albert\Desktop\Amali\TestforError\main.cpp:39:19: note:
'StackAbst::vector_stack<int>::vector_stack(std::initializer_list<int>)' is
implicitly deleted because the default definition would be ill-formed:
using Base::Base;
^
C:\Users\Pugazhendhi Albert\Desktop\Amali\TestforError\main.cpp:39:19: error:
no matching function for call to 'StackAbst::Stack<int>::Stack()'
C:\Users\Pugazhendhi Albert\Desktop\Amali\TestforError\main.cpp:39:19: note:
candidates are:
C:\Users\Pugazhendhi Albert\Desktop\Amali\TestforError\main.cpp:19:4: note:
StackAbst::Stack<T>::Stack(StackAbst::Stack<T>&&) [with T = int] <deleted>
Stack(Stack&&)=delete;
^
C:\Users\Pugazhendhi Albert\Desktop\Amali\TestforError\main.cpp:19:4: note:
candidate expects 1 argument, 0 provided
C:\Users\Pugazhendhi Albert\Desktop\Amali\TestforError\main.cpp:16:4: note:
StackAbst::Stack<T>::Stack(const StackAbst::Stack<T>&) [with T = int] <deleted>
Stack(const Stack&)=delete;
^
C:\Users\Pugazhendhi Albert\Desktop\Amali\TestforError\main.cpp:16:4: note:
candidate expects 1 argument, 0 provided
C:\Users\Pugazhendhi Albert\Desktop\Amali\TestforError\main.cpp: In
instantiation of 'StackAbst::vector_stack<T>*
StackAbst::vector_stack<T>::clone() const [with T = int]':
C:\Users\Pugazhendhi Albert\Desktop\Amali\TestforError\main.cpp:102:1:
required from here
C:\Users\Pugazhendhi Albert\Desktop\Amali\TestforError\main.cpp:43:39: error:
use of deleted function 'StackAbst::vector_stack<int>::vector_stack(const
StackAbst::vector_stack<int>&)'
return new vector_stack(*this); // using copy constructor
^
C:\Users\Pugazhendhi Albert\Desktop\Amali\TestforError\main.cpp:32:7: note:
'StackAbst::vector_stack<int>::vector_stack(const
StackAbst::vector_stack<int>&)' is implicitly deleted because the default
definition would be ill-formed:
class vector_stack : public Stack<T>, private std::vector<T>{
^
C:\Users\Pugazhendhi Albert\Desktop\Amali\TestforError\main.cpp:32:7: error:
use of deleted function 'StackAbst::Stack<T>::Stack(const StackAbst::Stack<T>&)
[with T = int]'
C:\Users\Pugazhendhi Albert\Desktop\Amali\TestforError\main.cpp:16:4: error:
declared here
Stack(const Stack&)=delete;
^
Process terminated with status 1 (0 minutes, 0 seconds)
13 errors, 0 warnings
