Solution-Wide Code Inspections
Most of ReSharper's code inspections only need the source code of a single file to detect code issues. In addition to these inspections, ReSharper provides solution-wide inspections for code issues which are only detectable in the scope of the entire solution — for example to detect an unused non-private member ReSharper needs to analyze the entire solution.
For the solution-wide inspection to work, you need either or both of the following:
The simplified global usage checking is enabled — Show unused non-private type members when solution-wide analysis is off on the page of ReSharper options (Alt+R, O).
The solution-wide analysis is enabled — Enable solution-wide analysis on the page of ReSharper options (Alt+R, O).
Note that even if a symbol has no direct usages in your solution and ReSharper warns you about it, there could be cases where symbols are used indirectly — for example, via reflection — or they could just be designed as public API. In all those cases you would want to suppress the usage-checking inspection for the symbol, and there are several ways to do so:
The recommended way is to decorate the implicitly used symbols with code annotation attributes. There are two attributes for this purpose: [UsedImplicitly] and [PublicAPI], which are functionally similar, but let you and your teammates understand how the symbol is actually used.
You can also suppress usage-checking inspections with any custom attribute. To do so, mark the definition of that attribute with the [MeansImplicitUse] attribute.
And finally, you can suppress a specific usage-checking inspection as any other code inspection with a suppression comment or a suppression attribute.
Similarly to any other inspection, you can also disable or change severity level of any solution-wide inspection. This can be done right from the Alt+Enter menu on a code issue that the inspection highlights. Alternatively, you can disable/enable or change severity levels of inspections on the page of ReSharper options (Alt+R, O)— solution-wide inspections are marked with the Non-private accessibility label. Note that you cannot set the 'Error' severity for solution-wide inspections.
When the solution-wide analysis is enabled, issues detected by the solution-wide inspections are highlighted in the opened files in the same way as other issues, and they also appear in the Inspection Results window when you run code inspection in specific scope. However, they do not appear in the Errors/Warnings in Solution window.
If necessary, you can disable solution-wide inspections or only enable solution-wide inspections on internal symbols for specific projects. To do so, use the Solution-Wide Inspections selector in the Project Item Properties popup, which you can invoke by selecting Edit project item properties from the context menu of the project in the Solution Explorer.
Note that independently of the value in this selector, solution-wide inspections would be disabled if the solution-wide analysis is disabled in ReSharper options.
ReSharper provides the following solution-wide inspections: