JetBrains Rider 2020.2 Help

Code Inspection and Quick-Fixes in C++

The key features of JetBrains Rider's code analysis are also supported in C++. You can find the detailed information on these features in the corresponding topics of the Code Analysis section. In the main topic of the section, you can also find the feature matrix and check what exactly is supported in C++.

In this topic, you can find some examples of using code analysis features in C++.

By default, code inspection, quick-fixes, and context actions are available in all solution files. If necessary, you can enable these features in external files referenced from solution with the Enable inspections, quick fixes and context actions in files external to the solution checkbox on the Languages and Frameworks | C++ | Inspections page of JetBrains Rider settings Ctrl+Alt+S.

Code Inspection

JetBrains Rider's static code analysis detects most of compiler errors and some compiler warnings in C++ files.

Besides, it finds other code issues, which otherwise would be found in runtime. For example, using a virtual method in constructor leads to unexpected behavior as mentioned in this StackOverflow question. JetBrains Rider points at this problem before you even compile:

JetBrains Rider warning. virtual method in constructor

The analysis is performed by applying Code Inspections to the current document or in any specified scope.

Code inspection results in an UE project

To find out what kind of code inspections JetBrains Rider provides, check out the full list of JetBrains Rider C++ code inspections.

To learn how to customize code inspection, see Configure Code Inspection Settings.

To quickly turn off a particular inspection or suppress all the inspections, use the inspection context menu:

Disable inspections in C++

Quick-fixes

Quick-fixes let you automatically resolve most of code issues found with code inspection. If one or more quick-fixes are available for a code issue, you will see the corresponding action indicator when your caret is on the highlighted code. Press Alt+Enter to see and apply the desired fix.

JetBrains Rider provides over 50 quick-fixes for C++. Here are some examples:

Add missing #include directive

If you use a symbol that is defined in the standard libraries or elsewhere in your solution, JetBrains Rider helps you add the missing #include directives automatically:

JetBrains Rider: helps adding missing C++ includes automatically

You can use the Show popups for import actions checkbox on the Languages and Frameworks | C++ | Inspections page of JetBrains Rider settings Ctrl+Alt+S to disable the popup. If the checkbox is not selected, the corresponding action will be available in the action list on Alt+Enter.

Add forward declaration

JetBrains Rider can also generate a forward declaration for an unresolved symbol:

JetBrains Rider: Add forward declaration quick-fix

Add [[maybe_unused]]

The [[maybe_unused]] attribute can be added to avoid warnings from the compiler about an unused name or entity. When the caret is on an unused entity, the following quick-fix will be available:

Add [[maybe_unused]]

And another context action will help you to replace usages of UNREFERENCED_PARAMETER and Q_UNUSED with a [[maybe_unused]] attribute:

add [[maybe_unused]]

Add to capture list

If a local variable is used inside a lambda body but not captured by this lambda, JetBrains Rider suggests quick-fixes to update the capture list. You can capture the variable or this by value, by reference, or implicitly capture all the used automatic variables:

JetBrains Rider C++: quick-fix to update the capture list

Change return type

If a function return type does not match the value it actually returns, JetBrains Rider lets you quickly fix the return type:

JetBrains Rider helps fixing types of variables and fields

Change variable type

If the specified type of a variable or a field does not match to the assigned value, JetBrains Rider provides a quick-fix to use the correct type in the declaration:

JetBrains Rider helps fixing types of variables and fields

Create declaration

If a member function in a C++ file does not have declaration in the header file, JetBrains Rider helps you create the missing declaration according to the signature of the implementation:

Generating declaration for C++ class member

Create from usage

If you use an undeclared symbol, JetBrains Rider suggests one or more quick-fixes for creating the symbol based on the usage:

Generating C++ field from usage

Initialize members

If JetBrains Rider detects uninitialized type members, it suggests initializing all members in one fix. You can also use the sub-menu of this fix to generate initializations for specific members.

JetBrains Rider C++: quick-fix to initialize members

Initialize variable

JetBrains Rider detects uninitialized variables and helps initializing them with the default value:

JetBrains Rider helps initialize variables in C++

Remove unused #include directives

All unused #include are highlighted and can be easily removed with a quick-fix:

Removing unused #include directives

Remove unused lambda capture

If a local variable is captured by a lambda but not used inside the lambda body, JetBrains Rider notifies you and suggests removing the unused capture:

Remove unused lambda capture

Replace the dot (.) with arrow (->) and vice versa

If the dot . operator is erroneously applied to a pointer, JetBrains Rider helps you replace it with the arrow -> operator:

JetBrains Rider helps replacing the dot operator with arrow

The reverse quick-fix is also available:

JetBrains Rider helps replacing the arrow operator with the dot

Use explicit template parameters in lambda

JetBrains Rider detects when lambda can be rewritten to use the new C++20 template syntax:

Use explicit template parameters in lambda

If the parameter’s type is an rvalue reference, you may want to pass that type directly to std::forward. In this case, you can use familiar perfect forwarding syntax:

perfect forwarding syntax

Use static_cast

JetBrains Rider detects cases when you should prefer static_cast and helps you update your code:

  • Functional-style cast used instead of a C++ cast:

    Functional-style cast used instead of a C++ cast

  • reinterpret_cast used instead of a static_cast when casting to void*:

    reinterpret_cast used instead of a static_cast when
                    casting to void*

Making JetBrains Rider ignore specific code

JetBrains Rider allows you to ignore specific files, folders and file masks in different ways. You can configure ignored files on the following options pages:

Last modified: 05 August 2020