How to exclude generated sources from Inspection?

We are using a code generator to create REST controllers from openapi yaml files.

Generated code is in build/generated-sources and added to the gradle build like this:

def generatedSrcDir = layout.buildDirectory.dir("generated-sources").get().asFile
def openApiGeneratedSrcDir = "$generatedSrcDir/openapi"

sourceSets {
   main {
       java {
           srcDir openApiGeneratedSrcDir
       }
   }
}

When I use “Inspect Code” to run inspections, I get a lot of errors in generated code.

I tried to create a custom Scope, but failed so far:
Started with pattern src:*..* which results in “Scope contains 164 of total 51,535 files”.

Now, how do I extend this pattern to exclude everything under build/generated-sources?

In the scope editor window (Settings → Appearance & Behavior → Scopes") I don't even see  any build directory.

Also, no variation of this pattern works: src:*..*&&!file:generated-sources//* (still finds all 164 source files).