Find unused code

Question

I have to refactor a large C  application  and I found a lot of functions that are never used  How can I check for unused code  so I can remove all the unused functions

User · Answer

FXCop is a code analyzer    It does much more than find unused code  I used FXCop for a while  and was so lost in its recommendations that I uninstalled it   I think NDepend looks like a more likely candidate

User · Answer

I have come across AXTools CODESMART  Try that once  Use code analyzer in reviews section It will list dead local and global functions along with other issues

User · Answer

ReSharper does a great job of finding unused code   In the VS IDE  you can right click on the definition and choose  Find All References   although this only works at the solution level

User · Answer

I would also mention that using IOC aka Unity may make these assessments misleading   I may have erred but several very important classes that are instantiated via Unity appear to have no instantiation as far as ReSharper can tell   If I followed the ReSharper recommendations I would get hosed

User · Answer

Yes  ReSharper does this  Right click on your solution and selection  Find Code Issues   One of the results is  Unused Symbols   This will show you classes  methods  etc   that aren t used

User · Answer

It s a great question  but be warned that you re treading in dangerous waters here  When you re deleting code you will have to make sure you re compiling and testing often   One great tool come to mind   NDepend - this tool is just amazing  It takes a little while to grok  and after the first 10 minutes I think most developers just say  Screw it   and delete the app  Once you get a good feel for NDepend  it gives you amazing insight to how your apps are coupled   Check it out  http   www ndepend com   Most importantly  this tool will allow you to view methods which do not have any direct callers   It will also show you the inverse  a complete call tree for any method in the assembly  or even between assemblies    Whatever tool you choose  it s not a task to take lightly   Especially if you re dealing with public methods on library type assemblies  as you may never know when an app is referencing them

User · Answer

As pointed Jeff the tool NDepend can help to find unused methods  fields and types    To elaborate a bit  NDepend proposes to write Code Rule over LINQ Query  CQLinq   Around 200 default code rules are proposed  3 of them being dedicated to unused dead code detection  Basically such a rule to detect unused method for example looks like       lt Name gt Dead Methods lt  Name gt  warnif count  gt  0  from m in Application Methods where  m MethodsCallingMe Any   select m     But this rule is naive and will return trivial false positives  There are many situations where a method is never called yet it is not unused  entry point  class constructor  finaliser     this is why the 3 default rules are more elaborated    Potentially dead Types  hence detect unused class  struct  interface  delegate     Potentially dead Methods Potentially dead Fields   NDepend integrates in Visual Studio 2017 2015  2013  2012  2010  thus these rules can be checked browsed edited right inside the IDE  The tool can also be integrated into your CI process and it can build reports that will show rules violated and culprit code elements  NDepend has also a VS Team Services extension   If you click these 3 links above toward the source code of these rules  you ll see that the ones concerning types and methods are a bit complex  This is because they detect not only unused types and methods  but also types and methods used only by unused dead types and methods  recursive    This is static analysis  hence the prefix Potentially in the rule names  If a code element is used only through reflection  these rules might consider it as unused which is not the case    In addition to using these 3 rules  I d advise measuring code coverage by tests and striving for having full coverage  Often  you ll see that code that cannot be covered by tests  is actually unused dead code that can be safely discarded  This is especially useful in complex algorithms where it is not clear if a branch of code is reachable or not   Disclaimer  I work for NDepend

User · Answer

ReSharper does a great job of finding unused code   In the VS IDE  you can right click on the definition and choose  Find All References   although this only works at the solution level

User · Answer

Resharper is good for this like others have stated  Be careful though  these tools don t find you code that is used by reflection  e g  cannot know if some code is NOT used by reflection

User · Answer

The truth is that the tool can never give you a 100  certain answer  but coverage tool can give you a pretty good run for the money   If you count with comprehensive unit test suite  than you can use test coverage tool to see exactly what lines of code were not executed during the test run  You will still need to analyze the code manually  either eliminate what you consider dead code or write test to improve test coverage   One such tool is NCover  with open source precursor on Sourceforge  Another alternative is PartCover   Check out this answer on stackoverflow

User · Answer

It s a great question  but be warned that you re treading in dangerous waters here  When you re deleting code you will have to make sure you re compiling and testing often   One great tool come to mind   NDepend - this tool is just amazing  It takes a little while to grok  and after the first 10 minutes I think most developers just say  Screw it   and delete the app  Once you get a good feel for NDepend  it gives you amazing insight to how your apps are coupled   Check it out  http   www ndepend com   Most importantly  this tool will allow you to view methods which do not have any direct callers   It will also show you the inverse  a complete call tree for any method in the assembly  or even between assemblies    Whatever tool you choose  it s not a task to take lightly   Especially if you re dealing with public methods on library type assemblies  as you may never know when an app is referencing them

User · Answer

It s a great question  but be warned that you re treading in dangerous waters here  When you re deleting code you will have to make sure you re compiling and testing often   One great tool come to mind   NDepend - this tool is just amazing  It takes a little while to grok  and after the first 10 minutes I think most developers just say  Screw it   and delete the app  Once you get a good feel for NDepend  it gives you amazing insight to how your apps are coupled   Check it out  http   www ndepend com   Most importantly  this tool will allow you to view methods which do not have any direct callers   It will also show you the inverse  a complete call tree for any method in the assembly  or even between assemblies    Whatever tool you choose  it s not a task to take lightly   Especially if you re dealing with public methods on library type assemblies  as you may never know when an app is referencing them

User · Answer

Resharper is good for this like others have stated  Be careful though  these tools don t find you code that is used by reflection  e g  cannot know if some code is NOT used by reflection

User · Answer

The truth is that the tool can never give you a 100  certain answer  but coverage tool can give you a pretty good run for the money   If you count with comprehensive unit test suite  than you can use test coverage tool to see exactly what lines of code were not executed during the test run  You will still need to analyze the code manually  either eliminate what you consider dead code or write test to improve test coverage   One such tool is NCover  with open source precursor on Sourceforge  Another alternative is PartCover   Check out this answer on stackoverflow

User · Answer

I have come across AXTools CODESMART  Try that once  Use code analyzer in reviews section It will list dead local and global functions along with other issues

User · Answer

I would also mention that using IOC aka Unity may make these assessments misleading   I may have erred but several very important classes that are instantiated via Unity appear to have no instantiation as far as ReSharper can tell   If I followed the ReSharper recommendations I would get hosed

User · Answer

FXCop is a code analyzer    It does much more than find unused code  I used FXCop for a while  and was so lost in its recommendations that I uninstalled it   I think NDepend looks like a more likely candidate

User · Answer

ReSharper does a great job of finding unused code   In the VS IDE  you can right click on the definition and choose  Find All References   although this only works at the solution level

User · Answer

Resharper is good for this like others have stated  Be careful though  these tools don t find you code that is used by reflection  e g  cannot know if some code is NOT used by reflection

User · Answer

Yes  ReSharper does this  Right click on your solution and selection  Find Code Issues   One of the results is  Unused Symbols   This will show you classes  methods  etc   that aren t used

User · Answer

FXCop is a code analyzer    It does much more than find unused code  I used FXCop for a while  and was so lost in its recommendations that I uninstalled it   I think NDepend looks like a more likely candidate

User · Answer

Resharper is good for this like others have stated  Be careful though  these tools don t find you code that is used by reflection  e g  cannot know if some code is NOT used by reflection

User · Answer

It s a great question  but be warned that you re treading in dangerous waters here  When you re deleting code you will have to make sure you re compiling and testing often   One great tool come to mind   NDepend - this tool is just amazing  It takes a little while to grok  and after the first 10 minutes I think most developers just say  Screw it   and delete the app  Once you get a good feel for NDepend  it gives you amazing insight to how your apps are coupled   Check it out  http   www ndepend com   Most importantly  this tool will allow you to view methods which do not have any direct callers   It will also show you the inverse  a complete call tree for any method in the assembly  or even between assemblies    Whatever tool you choose  it s not a task to take lightly   Especially if you re dealing with public methods on library type assemblies  as you may never know when an app is referencing them

User · Answer

FXCop is a code analyzer    It does much more than find unused code  I used FXCop for a while  and was so lost in its recommendations that I uninstalled it   I think NDepend looks like a more likely candidate

User · Answer

As pointed Jeff the tool NDepend can help to find unused methods  fields and types    To elaborate a bit  NDepend proposes to write Code Rule over LINQ Query  CQLinq   Around 200 default code rules are proposed  3 of them being dedicated to unused dead code detection  Basically such a rule to detect unused method for example looks like       lt Name gt Dead Methods lt  Name gt  warnif count  gt  0  from m in Application Methods where  m MethodsCallingMe Any   select m     But this rule is naive and will return trivial false positives  There are many situations where a method is never called yet it is not unused  entry point  class constructor  finaliser     this is why the 3 default rules are more elaborated    Potentially dead Types  hence detect unused class  struct  interface  delegate     Potentially dead Methods Potentially dead Fields   NDepend integrates in Visual Studio 2017 2015  2013  2012  2010  thus these rules can be checked browsed edited right inside the IDE  The tool can also be integrated into your CI process and it can build reports that will show rules violated and culprit code elements  NDepend has also a VS Team Services extension   If you click these 3 links above toward the source code of these rules  you ll see that the ones concerning types and methods are a bit complex  This is because they detect not only unused types and methods  but also types and methods used only by unused dead types and methods  recursive    This is static analysis  hence the prefix Potentially in the rule names  If a code element is used only through reflection  these rules might consider it as unused which is not the case    In addition to using these 3 rules  I d advise measuring code coverage by tests and striving for having full coverage  Often  you ll see that code that cannot be covered by tests  is actually unused dead code that can be safely discarded  This is especially useful in complex algorithms where it is not clear if a branch of code is reachable or not   Disclaimer  I work for NDepend

User · Answer

ReSharper does a great job of finding unused code   In the VS IDE  you can right click on the definition and choose  Find All References   although this only works at the solution level

[c#] Find unused code

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